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467 Cards in this Set
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Causative agent of nausea, vomiting (onset < 6 hr) after eating cold cuts, or potato salad, or mayonnaise, or custards?
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Staphylococcus aureus
|
|
Rapid-onset food poisoning is mediated by what component of staphylococcus?
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Enterotoxin
|
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Tx of staphylococcal food poisoning?
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Rehydration
|
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Microbial cause of nausea and vomiting, +/- diarrhea (onset < 6 hr) after eating reheated rice?
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Bacillus cereus
|
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Bacterial spores are resistant to heat due to what component?
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dipicolinic acid core
|
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Microbial cause of nausea, vomiting, watery diarrhea w/ rapid (onset >6 hr) after eating reheated meat or gravy?
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Clostridium perfringens
|
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Most likely cause of persistent dyspepsia in a pt not receiving NSAIDs is
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Helicobacter pylori
|
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Increased risk of gastric adenocarcinoma and MALT lymphoma
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H. pylori colonization
|
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Indications to treat H. pylori-associated PUD
|
Presence of organism
|
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Standard first-line abx for PUD due to H. pylori is
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PPI + clarith + amox
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Cause of acute onset of diarrhea with rice-water stools, vomiting, dehydration during travel to South America
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Vibrio cholerae
|
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Pathophysiology of cholera is due to what mechanism?
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A-B toxin causes ↑ cAMP
|
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Cholera pathogen is isolated from stool by culture on selective medium called
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thiosulfate-citrate-buffered sucrose (TCBS) agar
|
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The comma-shaped cholera organisms are microscopically similar to
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Campylobacter
|
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Tx of cholera involves
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Rehydration (tet in severity)
|
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Secretory diarrhea, fever and vomiting during travel are caused by
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Enterotoxic E. coli
|
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Secretory diarrhea w/ fatty, foul-smelling stools in campers, hikers; also day-care outbreaks is caused by
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Giardia lamblia
|
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Following ingestion of 15-25 cysts, excysted trophozoites adhere at brush border of enterocytes and contribute to malabsorption. TOW?
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Giardiasis
|
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Dx of giardiasis is confirmed by
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Stool antigen (+)
|
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Giardiasis is specifically treated with
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Metronidazole
|
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Protracted, secretory diarrhea w/ large fluid loss in AIDS is caused by (clue: acid-fast organisms)
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Cryptosporidium >> Cyclospora > Isospora
|
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Frank bloody diarrhea, after eating undercooked meats or drinking fruits drinks, is caused by prepared foods or water, contaminated w/
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E. coli O157:H7
|
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Pathogenesis of hemorrhagic enterocolitis caused by E. coli involves
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Shiga toxin (a cytotoxin)
|
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Complication of hemorrhagic enterocolitis in children
|
hemolytic uremic syndrome
|
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Profuse diarrhea, fever, vomiting, and dehydration in infants is caused by
|
Rotavirus
|
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Mechanism of rotaviral diarrhea involves
|
Villus destruction
|
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Infantile watery diarrhea and fever are caused by
|
Adenovirus 40,41
|
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Outbreak of nausea, vomiting, fever in adults is caused by
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Norovirus
|
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Cause of nausea/vomiting, abdominal cramps, diarrhea +/- bloody 12-48h after eating eggs or poultry or peanut butter?
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Non-typhoidal Salmonella
|
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Abx treatment in acute gastroenteritis due to Salmonella spp. is not warranted to avoid
|
carrier (in bile ducts) state
|
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Abx used only to treat septic phase of salmonella gastroenteritis is
|
ciprofloxacin
|
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Cause of fevers (>103°), headaches; macular rash on torso (“rose spots”) abdominal pain and little diarrhea later; PE: bradycardia; hepatosplenomegaly (+/-) in a pt with hx of travel (to tropics)?
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Salmonella typhi
|
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Cause of diarrhea w/ occult blood, abdominal cramping and fever, 2d after ingestion of poultry-contaminated salad
|
Campylobacter jejuni
|
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Abx to treat campylobacter enteritis with high fevers in
pregnancy, and HIV is |
Erythromycin
|
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Cause of dysentery-like illness with fever + abdominal cramps, tenesmus + blood & mucus in children?
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Shigella sonnei
|
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Dysentery due to invasive Shigella spp. in elderly is treated with
|
Ciprofloxacin
|
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Cause of dysentery-like illness (+/- pseudoappendicitis or pseudo-crohn syndrome) in the northern region after eating cheese
|
Yersinia enterocolitica
|
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Cause of dysentery-like illness in a patient w/ hx of broad-spectrum abx use
|
Clostridium difficile
|
|
Clostridium difficile-associated diarrhea (CDAD) is mediated by toxins
|
A (enterotoxin) + B (cytotoxin).
|
|
Lab confirmation of CDAD does not require stool Cx, but is based on
|
EIA for stool toxins A or B
|
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Besides rehydration and cessation of inciting meds, CDAD is treated with
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Metronidazole (mild) or oral vancomycin (severe/relapse)
|
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Health-care associated (nosocomial) spread of Clostridium difficile diarrhea and protracted outbreak is due to
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Fecal-oral and/or contact w/ environmental spores
|
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Hx of abdominal pain, tenesmus, stools with mucus + blood in a patient, who recently traveled to tropics; CBC: eosinophilia. TOW?
|
Amebic dysentery
|
|
Stool microscopy to confirm amebic dysentery should reveal characteristic trophozoites of Entamoeba histolytica w/
|
endocytosed RBCs
(distinction from luminal ameba) |
|
Rx of amebic dysentery involves
|
Metronidazole + iodoquinol
|
|
Abscesses in liver or peritonitis in travelers w/ or w/o hx of amebic dysentery is confirmed by
|
Serology for E. histolytica
|
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A boar hunter develops dysentery after eating meat at campsite; O & P test should reveal a ciliate parasite, known as
|
Balantidium coli
|
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Most likely cause of chronic abdominal pain, diarrhea; intestinal obstruction; cholangitis; liver abscess, in children
|
Ascaris lumbricides
|
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Ova & Parasite test using microscopy for oval eggs (with a thick coarse shell) in stool confirms
|
ascariasis
|
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A child has stomach ache, distended abdomen, poor appetite. “Pearl-colored earthworm”-like organisms in the stool. Major immune response against this infection?
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IgE
|
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DOC of ascariasis is
|
Mebendazole
|
|
Vomiting, cramping, diarrhea, epigastric pain, weight loss in an immigrant from developing country is caused by
|
Strongyloides stercoralis
|
|
DOC of strongyloidosis is
|
Ivermectin
|
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Pt w/ AIDS (low CD4+ counts) develops pulmonary infiltrates (+ eosinophilia) and/or gram negative sepsis. TOW?
|
Invasive strongyloidosis
|
|
Weakness, fatigue, lightheadedness, dyspnea, pruritis; pallor; iron-deficiency anemia; eosinophilia (hx of outdoor activity). TOW?
|
Hookworm (Necator americanas) infection
|
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Fever, periorbital edema, subconjunctival hemorrhages, muscle weakness, and rash, after eating undercooked pork (Lab: eosinophilia., .CPK, .LDH &). TOW?
|
Trichinellosis
|
|
Abdominal pain, bloating, altered appetite after ingestion of sushi. CBC: megaloblastic anemia; leukocytosis/eosinophilia. TOW?
|
Diphyllobothriasis (fish tapeworm)
|
|
Dx of tape worm infection is confirmed by
|
Proglottids in stool
|
|
Tape worm infections are treated with broad-spectrum agent
|
Praziquantel
|
|
Cause of fever, lymphadenopathy, hepatosplenomegaly in an immigrant from Africa or Orient; pt recalls wading in stagnant water. RUQ ultrasound (+); CBC: eosinophilia.
|
Schistosoma mansoni (Africa)
S. japonicum (Far East) |
|
Microscopy of stool in chronic stage of schistosomiasis reveals
|
Large eggs with lateral spine.
|
|
Chronic stage of schistosomiasis is treated with
|
Praziquantel
|
|
Patient with acute jaundice is HAV IgM (+); household contact should receive for prophylaxis
|
Inactivated HAV vaccine
|
|
Patient with jaundice for < 1 week has HBsAg (+), Anti-HBc IgM (+). TOW?
|
Acute HBV infection
|
|
Multiple sex partners, IDU, infants born to infected mothers are risk groups for which hepatitis virus
|
HBV
|
|
This is an enveloped, double stranded DNA virus w/ ss-break; transmitted by infective body fluids. TOW?
|
HBV
|
|
This asymptomatic man has hep serology profile of HBsAg (-), Anti-HBs (+), Anti-HBc IgG (+), Anti-HBc IgM (-). TOW?
|
Resolved hepatitis B
|
|
This man has jaundice and is HBsAg (+) > 6 months, Anti-HBs (-), HBeAg (+), Anti-HBc IgG (+), HBV DNA > 20,000 IU/ml. TOW?
|
Chronic active hepatitis B
|
|
This man has jaundice and is HBsAg (+) > 6 months, HBeAg (+) and evidence of necroinflammation. He should receive
|
Peg-IFNa 2a + lamivudine
(or cidofovir) |
|
This man has no jaundice, but HBsAg (+) >6 months, Anti-HBs (-), Anti-HBc IgG (+), HBeAg (-), persistently normal ALT. TOW?
|
Inactive HBsAg carrier
|
|
This man, at the time of annual physical exam, reveals Anti-HBs (+) and other markers are (-). TOW?
|
HBV immunized
|
|
Virologic confirmation of chronic jaundice in a HBV-immunized pt w/ IDU or hemodialysis is based on
|
HCV RNA > HCV IgG
|
|
More chronicity of HCV (than HBV) is due to immune-evasive quasispecies generated during replication (in blood) of
|
error-prone HCV RNA virus
|
|
Fulminant hepatitis in a patient, who has multiple sexual partners and is HBsAg (+); HBcIgM (-), can be fatal due to what?
|
HDV superinfection
|
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Cause of acute onset of jaundice, nausea, right-upper quadrant pain, hepatomegaly in pregnant women in India
|
HEV
|
|
Fever, arthralgia, carditis, polyarthritis, chorea, erythema
marginatum; elevated WBCs or ESR/CRP. Clinical Dx is confirmed by |
Rising ASO titer
|
|
Type II hypersensitivity due to molecular mimicry in a
immunological sequel of streptococcal pharyngitis causes |
Acute rheumatic fever (ARF)
|
|
ARF is diagnosed and treated with
|
Anti-streptolysin O (ASO) titer and benzathine penG.
|
|
A man with IDU has flu-like symptoms; 1-3 minor peripheral signs: conjunctival hemorrhage, Janeway lesions, Osler nodes, Roth spots, plus vegetation in tricuspid valve. Blood Cx (BCx) should yield
|
S. aureus
|
|
A pt w/ hx of extraction of impacted tooth 3 weeks ago now has subacute (native, mitral-valve) endocardits. BCx should yield
|
Viridans streptococci.
|
|
A pt w/ hx of St. Jude bypass 2 months ago has now subacute bacterial endocarditis. BCx should yield
|
Staphylococcus epidermidis
|
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A pt with AIDS and recent hx of UTI has now subacute, native mitral-valve endocarditis. BCx should yield
|
Enterococcus faecalis (or faecium)
|
|
DOC of acute endocarditis in patient with IDU due to sensitive S. aureus (MSSA).
|
Nafcillin +gentamicin
|
|
DOC of acute endocarditis in patient with IDU due to resistant S. aureus (MRSA).
|
Vancomycin + rifampin
|
|
DOC of subacute, native mitral-valve endocarditits due to viridans streptococci.
|
PenG +/- gentamicin
|
|
DOC of subacute, prosthetic-valve endocarditis due to
Staphylococcus epidermidis |
Vancomycin + gentamicin
|
|
DOC of subacute, native mitral-valve endocardits due to
Enterococcus faecalis (or faecium) |
High-dose ampicillin + gentamicin
|
|
Patient with enterococcal bacteremia fails to respond to
vancomycin. MOR of the organism |
D-Ala-D-Ala is changed to D-Ala-D-lac
|
|
Hx of catheter-related endocarditis, involving prosthetic or native valves. BCx (+) for budding yeast. Pt does not respond to AmphoB or fluconazole; should receive
|
Caspofungin
|
|
Patient with colon cancer has bacteremia due to
|
Streptococcus bovis
|
|
Cause of febrile, malaise, arthralgia, dyspnea, edema, palpitations. ST/T wave change, heart block, dysrhythmias; CXR: cardiomegaly
|
Coxsackievirus > echovirus > Trypanosoma cruzi (Chagas)
|
|
Cause of runny nose, red throat, and nasal pus
|
Rhinoviruses
|
|
Rhinoviruses and enteroviruses belong to picornavirus family, but the rhinoviruses differ from enteroviruses on
|
Growth at 22oC/noninvasive
|
|
Rhinovirus receptor in the nasal passages and upper
tracheobronchial tree is |
ICAM-1
|
|
Rhinovirus, influenza, parainfluenza, coronavirus, RSV,
metapneumovirus, and adenovirus all cause |
Upper-respiratory infections
(URIs) |
|
Sinusitis, otitis, laryngitis, exacerbations of bronchitis and asthma are mostly secondary to
|
Viral URIs
|
|
In HEENT, Streptococcus pneumoniae, non-typable Haemophilus influenzae, Moraxella catarrhalis all cause
|
Acute otitis media (AOM) & sinusitis
|
|
AOM and sinusitis are empirically treated with amoxicillin + clavulanate. Why use clavulanate?
|
Haemophilus and Moraxella are ß-lactamase producers
|
|
Cause of pharyngeal pain, dysphagia, fever; red throat + purulent exudate that responds to penicillin
|
Streptococcus pyogenes (aka: Group-A ß-hemolytic
Streptococcus = GABHS) |
|
GABHS is differentiated from GBBHS by what?
|
Bacitracin sensitivity
|
|
Common mode of acquisition of URI due to Streptococcus pyogenes?
|
Infective droplets
|
|
Major virulence factor with anti-phagocytic function of
Streptococcus pyogenes |
M-protein fibrils
|
|
Damage in posterior pharynx and tonsils due to
Streptococcus pyogenes is associated with what host response? |
Pyogenic inflammation
|
|
DOC of acute bacterial pharyngitis in a pt w/ Pen allergy
|
Erythromycin > clindamycin
|
|
Pyogenic complication of streptococcal pharyngitis
|
Tonsillar abscess
|
|
Toxigenic complication of streptococcal pharyngitis
|
Scarlet fever >> TSS (rare)
|
|
Immunologic complication of streptococcal pharyngitis
|
Acute rheumatic fever (ARF)
|
|
Cause of fever, red throat + purulent exudate -
pseudomembrane with lymphadenopathy, in a pt w/ questionable immunization |
Corynebacterium diphtheriae
|
|
Gram/special stain of Corynebacterium diphtheriae should reveal
|
Gram(+) rods in palisade arrangements/metachromatic
granules |
|
Virulence genotype of Corynebacterium diphtheriae is
acquired by |
Transduction (phage mediated transfer of exotoxin gene)
|
|
Isolate on tellurite agar culture of throat swab for a cause of diphtheria is confirmed by
|
Immunodiffusion (ELEK) assay for toxin
|
|
Mechanism of action of exotoxin of Corynebacterium
diphtheriae |
ADP ribosylation of EF-2
(inhibits protein synthesis) |
|
Damage to pharynx and cardiac myosites due to
Corynebacterium diphtheriae is mediated by |
Cytotoxicity of A-B toxin
|
|
Virologic Dx of URI symptoms, fever; red throat + purulent exudate; hepato-splenomegaly, lymphadenopathy, in a teenager, is confirmed by
|
heterophile antibody (+)
|
|
Host cells preferentially infected by EBV are
|
B cells
|
|
EBV is biologically similar to what class of viruses?
|
herpes viruses
|
|
Host immune system controls the EBV infection, mediated by
|
CD8+ T lymphocytes
|
|
Rash occurs following which antibiotic(s) to treat infectious mononucleosis?
|
amoxicillin
|
|
Burkitt's lymphoma in some African population is a B-cell
tumor due to oncogenesis by |
EBV
|
|
Nasopharyngeal carcinoma, a B-cell tumor that is common in the Oriental population that consumes preserved fish, is due to oncogenesis by
|
EBV
|
|
Heterophile-negative infectious mononucleosis syndrome is due to ?
|
CMV
|
|
Gram-positive bacteria that cause acute otitis media (AOM)
|
Streptococcus pneumoniae
|
|
Gram-negative diplococci bacteria that cause AOM
|
Moraxellar catarrhalis
|
|
Gram-negative coccobacilli bacteria that cause AOM
|
Haemophilus influenzae
|
|
> 7 days of nasal obstruction, rhinorrhea; purulent nasal
drainage + frontal pain/tenderness is treated with |
Amoxicillin & Clavulanate
|
|
DOC for acute mastoiditis in a young child is amoxicillin & clavulanate; why?
|
Same etiology as AOM
|
|
Cause of “seal-like barking” cough + episodic aphonia w/
symptoms of URI in a child |
parainfluenza virus
|
|
Gram-stain-nonreactive organism that causes redness;
purulent discharge at lid margin/eye corners, in a newborn |
Chlamydia trachomatis
|
|
Most common cause of redness; tenderess; hyperpurulent d/c; eye stuck shut in AM, lid edema. Gram stain (+)
|
Staphylococcus aureus
|
|
Cause of pharyngitis, conjunctivitis, fever with rhinitis, and cervical adenitis in a child.
|
Adenovirus
|
|
Cause of burning, gritty feeling in eyes; diffuse conjunctival injection & profuse tearing + preauricular LN.
|
Adenovirus
|
|
Cause of foreign body sensation, lacrimation, photophobia, conjunctival hyperemia, and ulceration
|
HSV-2>>1
|
|
Cause of severe pain and skin lesions in dermatomal pattern involving the ophthalmic division of the trigeminal nerve.
|
VZV
|
|
Cause of painful, swollen, red eyes, with conjunctival
hemorrhaging and excessive tearing in an outbreak |
Enterovirus
|
|
Cause of chorioretinitis in AIDS, but CMV antigen (-)
|
Toxoplasma gondii
|
|
Cause of painful keratitis, chronic corneal ulcers in contact lens users, unresponsive to abx.
|
Acanthamoeba spp.
|
|
In an infant w/ ?immunization, 2 wks of paroxysmal
coughs, inspiratory "whoop" + post-tussive emesis. TOW? |
Bordetella pertussis
|
|
Pertussis toxin inhibits chemotaxis via downregulation of
C3a/C5a receptor, resulting in? |
lymphocytic leukocytosis in CBC
|
|
Three major virulence factors of “whooping cough”
pathogen? |
ADP-ribosylating toxin; tracheal cytotoxin; hemolysin
|
|
Cause of fever + drooling, stridor, dyspnea in a child w/
?immunization (pt appears septic) |
Haemophilus influenzae b
|
|
Major virulence factor of Haemophilus influenzae
associated with pneumonia and meningitis |
Capsular polysaccharide (antiphagocytic and anti-C3b)
|
|
Since, absent spleen places host at increased risk for
invasive H. influenzae infection, pre-exposure prophylaxis prior to elective splenectomy is ? |
Hib immunization
|
|
Cause of acute exacerbation (cough, purulent sputum) in pt with chronic bronchitis (COPD); CXR: R/O pneumonia; Lab: sputum reveals Gram-negative coccobacilli.
|
Haemophilus influenzae (non capsular types)
|
|
Tx of AECB, caused by an organism that needs NAD +
hematin for growth; ß-lactamase (+), is |
Ceftriaxone (severe) > Amoxicillin-clavulanate (mild)
|
|
Most common cause of lower-respiratory infections in
neonates (babies < 4 wk)? |
Streptococcus agalactiae
(aka: group B streptococcus) |
|
Complicated illness in a newborn of a GBS-colonized
mother is |
Sepsis or meningitis
|
|
A mother colonized (recto-vaginally) w/ GBS is at risk for
preterm baby or premature membrane rupture. She should receive |
Ampicillin
|
|
An elderly comes up with an abrupt-onset fever, myalgia,
headache, malaise, dry cough, sore throat and rhinitis, in winter. Illness could have been prevented w/ ? |
annual influenza vaccine
|
|
Annual influenza vaccine protects at-risk subpopulation w/ 60% immune protection, and is composed of what 3 viruses?
|
A:H1N1 + A:H3N2 + B
|
|
Secondary spread of influenza occurs in a crowded setting (within 6 feet of infected person) via
|
respiratory droplets
|
|
Annual vaccine to prevent influenza is needed due to
antigenic drift. This occurs due to what genetic mechanism? |
Mutation
|
|
Occasionally serious pandemic of influenza occurs due to antigenic shift. This occurs due to what genetic mechanism?
|
Reassortment of 8 genomic
segments |
|
DOC of pts with influenza <48 hours is
|
Oseltamivir
|
|
Bacterial superinfection, causing pneumonia, after influenza occurs in elderly (in LTCF) due to what?
|
S. pneumoniae > S. aureus
|
|
A seriously ill young adult w/ necrotizing pneumonia,
poorly responding to vancomycin, should get |
Linezolid
|
|
Cause of febrile illness + bronchiolitis in an infant; BAL
viral culture (+). |
Respiratory syncytial virus
(RSV) |
|
RSV causes seasonal, nosocomial pneumonia outbreaks in the pediatric units via
|
Contact spread
|
|
Pathophysiology of asthmatic Sx + Sn in bronchioles in
high-risk infants due to RSV involves |
type III hypersensitivity
|
|
Inhaled anti-viral drug used in the sickest infants with
bronchiolitis is |
Ribavirin
|
|
Insidious onset of fever, dry cough, malaise and sore throat in young adults. CBC: anemia; CXR: diffuse infiltrates. TOW?
|
Mycoplasma pneumoniae
|
|
Dx of “walking pneumonia” in older children and young
adults, while waiting for serology, is supported by |
cold agglutinin (IgM Ab against RBCs) titer =1:32
|
|
ß-lactam abx is ineffective for Tx of mycoplasma
pneumonia because |
Wall-less bacteria
|
|
A male child with mycoplasma pneumonia now has
systemic rash, covering 10% of his body. TOW? |
erythema multiforme (SJS)
|
|
Cause of upper respiratory Sx, slow onset of cough
(laryngitis) >2wks + CXR: patchy infiltrate, viral serology (+) |
Chlamydophila pneumoniae
|
|
The most common cause of community-acquired
pneumonia (CAP) is |
Streptococcus pneumoniae
|
|
Cause of rapid onset of high fever, cough, & sputum,
dyspnea; tachypnea in an elderly; CXR: lobar infiltrate; CBC: pronounced neutrophilic leukocytosis with left shift, is |
Streptococcus pneumoniae
|
|
Gram-positive diplococci from sputum from a patient with lobar pneumonia yield a-hemolytic colonies and are confirmed by
|
Capsular swelling (Quelling rxn)
|
|
a-hemolytic colonies of Streptococcus pneumoniae is
differentiated from viridans streptococci definitively confirmed by |
Optochin sensitivity
|
|
Population w/ .incidence of pneumococcal pneumonia is
|
AIDS
|
|
incidence of colonization of what organism is seen in very young and elderly, crowding, following viral URI (.PAF
receptors), fall/winter season? |
Streptococcus pneumoniae
|
|
Streptococcus pneumoniae is transmitted P2P by
|
Respiratory droplets
|
|
Nasopharyngeal mucosal colonization is facilitated by
|
IgA protease
|
|
Streptococcus pneumoniae reaches lungs after
nasopharyngeal colonization via |
aspiration
|
|
Major virulence factor, facilitating invasion and
dissemination of Streptococcus pneumoniae is |
Polysaccharide capsule
|
|
Pneumococcal cell wall peptidoglycans, teichoic acid elicit
|
Inflammation
|
|
Lung cell injury in pneumococcal pneumonia is caused by
virulence factor? |
Pneumolysin (a-hemolysin)
|
|
Multiple myeloma, C3 deficiency, asplenia - Hg SS, COPD,
diabetes, alcoholism, smokers are risk factors for mortality due to |
pneumococcal pneumonia
|
|
Hematologic marker for poor prognosis of pneumococcal
pneumonia is |
Leukopenia
|
|
Emipiric DOC of CAP in pts at risk or w/ comorbidity is
|
Azithromycin (or
levofloxacin) + ceftriaxone |
|
Pneumonia due to highly penicillin-resistant Streptococcus
pneumoniae (Pen MIC >8) should receive |
moxifloxacin or vancomycin
|
|
Mechanism of penicillin resistance in Streptococcus
pneumoniae is |
PBP alteration by mutation
|
|
Pt w/ agammaglobulinemia or asplenia or sick-cell anemia
or decreased C3 should be vaccinated with |
Pneumococcal polysaccharide
vaccine (PPSV: 23-valent) |
|
Hx: a patient w/ serious CAD now on a ventilator, acquires
bronchopneumonia >72 hrs after hospitalization. TOW? |
Pseudomonas aeruginosa
(VAP) |
|
Cause of necrotizing pneumonia >72 hrs after
hospitalization of complicated viral illness |
Staphylococcus aureus
(assume MRSA) |
|
Patients that are aspiration prone have hx of
|
dysphagia, decreased
consciousness |
|
Hx of a patient w/ seizure illness has fever, cough evolving
over 2-4 wks; CXR infiltrate (+).TOW? |
Aspiration pneumonia
|
|
Community-acquired respiratory pathogens that cause
aspiration pneumonia |
Streptococcus pneumoniae >
Anaerobes |
|
Hospital-acquired respiratory pathogens that cause
aspiration pneumonia |
Gram-negative bacilli > S.
aureus +/- anaerobes |
|
Clinical Dx of sudden dyspnea +/- cyanosis, fever,
wheezing, often ARDS-like picture is |
acid-related pneumonia
|
|
Bacterial etiology and Tx of aspiration pneumonia are
determined by |
Gram stain (polymicrobic)
and culture of sputum |
|
Empiric DOC of necrotizing pneumonia in a patient with
seizure illness |
clindamycin + levofloxacin
|
|
Targeted Abx for anaerobic aspiration pneumonia is
|
clindamycin
|
|
Pneumonia in homeless/alcoholics; Gram-positive
diplococci in sputum Gram smear. TOW? |
Streptococcus pneumoniae
|
|
Pneumonia in homeless/alcoholics; Gram-negative rods in
sputum smear. TOW? |
Klebsiella pneumoniae
|
|
Cause of pulmonary embolism in a pt with IVDU
|
Staphylococcus aureus
|
|
Common cause of pneumonia in pts with CF
|
Pseudomonas aeruginosa
|
|
Sputum of a patient with hospital-acquired pneumonia
yields a Gram-negative rod that is oxidase (+). TOW? |
Pseudomonas aeruginosa
|
|
Common cause of external otitis due to hot tub use is
|
Pseudomonas aeruginosa
|
|
A patient with diabetes has osteomyelitis after penetrating
foot injury. TOW? |
Pseudomonas aeruginosa
|
|
The most widely used anti-pseudomonal penicillin
|
The most widely used anti-pseudomonal penicillin
|
|
The most widely used anti-pseudomonal aminoglycoside
|
Tobramicin > gentamicin
|
|
This pt >50 years, smoking hx, CMI. has pneumonia;
diarrhea, renal failure. Urine antigen (+) for pathogen. Pt responds to azithromycin. TOW? |
Legionella penumophila
|
|
Penicillin is ineffective against Legionnaire’s dz because
|
Intracellular organism
|
|
Individuals with defective CMI response has poor prognosis
of Legionnaire’s dz because |
Intracellular organism
|
|
Asymptomatic patient with PPD (+)
|
Latent tuberculosis infection
(LTBI) |
|
Cough > 2 wks, fever, night sweats, weight loss,
hemoptysis, SOB; CXR: upper lobe infiltrate. TOW? |
Active Mycobacterium
tuberculosis infection |
|
Oral drug regimen of choice for treatment of active TB
(aka: 1st line drugs) is |
INH+RIF+PZA+EMB (oral)
+ Vit B6 |
|
Pyridoxine is added to 4-drug therapy for TB to prevent
|
neuropathy (due to INH)
|
|
Pt w/ TB fails to respond to 4-drug regimen w/ INH+RIF
resistance because |
Multiply drug-resistant
(MDR) TB |
|
Pt w/ MDR-TB fails to respond to INH +RIF+FQ+an
injectable drug (amikacin, capreomycin, or kanamycin) because |
Extremely-drug resistant
(XDR) TB |
|
Cause of TB-like Dz that does not respond to 1o TB Tx
regimen, in a pt. w/ AIDS |
Mycobacterium avium –
intracellulare (aka: MAC) |
|
Cause of chronic pneumonia in a patient with cancer,
receiving cytotoxic chemotherapy; lung-CT: halo/crescent sign (+)? |
Aspergillus fumigatus
|
|
Hx of chronic pneumonia w/ lung bpsy histopathology (+)
for hyphae 2-4µm wide, septate, acute- angle branching. TOW? |
Aspergillus fumigatus
|
|
Cause of TB-like LRI in a pt with outdoor activity (Giemsa
stain of bronchoscopy specimen: (+) for 2-5 µm yeasts) is |
Histoplasma capsulatum
|
|
Pt with AIDS has blood culture (+) for histoplasmosis.
DOC has effects on |
Ergosterol in fungal cell
membrane |
|
TB-like Dz w/ ulcerative skin lesions. lung bpsy
histopathology (+) for large yeast w/ broad-based bud. DOC? |
Intraconazole
|
|
Hx of acute onset of cough, fever, infiltrate in a black male
with CMI.; histopathology of lung (+) for a large sac of endospores. DOC? |
Fluconazole (indefinite)
|
|
Pt w/ aspiration pneumonia with cervico-facial lesion
should respond to |
Penicillin G
|
|
Granular specimen from draining fistulae from a pt with
LRI on anaerobic culture should yield |
Actinomyces israelii
|
|
Pt with AIDS or organ transplant has indolent pneumonia,
w/ or w/o CNS abscess or granuloma. TOW? |
Nocardiosis
|
|
Organism w/ characterization of Gram-positive branching,
beaded, filamentous rod, weakly acid fast is |
Nocardia asteroids
|
|
Hx of non-productive cough, fever and dyspnea evolving
over 2-4 wks. CXR (+): bilateral interstitial infiltrates, hypoxemia; .LDH, CD4 count <200/mm3 in a MSM. TOW? |
Pneumocystis pneumonia
|
|
DOC of pneumocystis pneumonia (PCP)
|
TMP-SMX
|
|
Pt has urinary urgency, frequency, dysuria; lab: pyuria (+)
or nitrite (+). TOW? |
Cystitis due to E. coli
|
|
Significant UTI is confirmed by semiquantitative MSU
culture based on the threshold of |
> 1,000 cfu/mL
|
|
Mode of acquisition of uropathogen is
|
Endogenous
|
|
Microbial (structure) factor favoring bacterial persistence
/colonization and UTI is |
bacterial binding via fimbriae
|
|
Factor favoring bacterial persistence/colonization and UTI
despite high osmolarity and urea concentrations and low pH is |
high bacterial growth rates
|
|
Host factor favoring bacterial persistence/colonization and
UTI is |
Urinary stasis
|
|
Host factor favoring bacterial persistence/colonization and
UTI despite frequent voiding and high urinary flow is |
Absence of bactericidal
effects of secreted proteins |
|
Pyogenic inflammation in complicated UTI due to Gram-
negative bacteria is due to |
Lipopolysaccharide (LPS)
|
|
Empiric DOC to treat community-acquired UTI in adults is
|
ciprofloxacin
|
|
The abx class that inhibits DNA gyrase or topoisomerase IV
and blocks with bacterial DNA replication is |
Fluoroquinolones
|
|
DOC to treat UTI in pregnant women is
|
Nitrofurantoin
|
|
Gram-positive bacteria that cause uncomplicated UTI in
sexually active, young women are |
Staphylococcus saprophyticus
|
|
Differentiation of Staphylococcus saprophyticus from S.
epidermidis (both coagulase negative) is based on |
novobiocin resistance
|
|
In elderly or pt with risks of urinary stasis, fever, chills,
flank pain, and CVA tenderness; Lab: pyuria, casts, nitrite+. TOW? |
Pyelonephritis due to E. coli
|
|
Pt hospitalized > 72 h for comorbidity has urinary
frequency, dysuria and foul-smelling urine; w/ flank pain, fever and chills, in the presence of a urinary catheter: Clue: GNR; fermenter; encapsulated; intrinsic ampicillin resistance) Clue: GNR; slow fermenter; red pigment; intrinsic drug resistance) Clue: GNR; swarming growth [very motile]; slow fermenter; intrinsic drug resistance) Clue: GNR; non fermenter; oxidase+, blue pigment; intrinsic drug resistance) Clue: GPC in chains; catalase-neg; grows in high salt; penicillin resistance) |
Klebsiella pneumoniae
Serretia marcescens Proteus mirabilis Pseudomonas aeruginosa Enterococcus faecalis |
|
If a patient with complicated UTI is severely ill or not
improving with therapy, do what rapid test next? |
renal ultrasound (to rule out
urinary tract obstruction) |
|
For a patient with complicated UTI, once culture and
sensitivity available, switch to what? |
Narrow-spectrum abx
|
|
2 or more of the following: fever (T>38°C) or hypothermia
(T< 36°C), tachycardia (HR>90), tachypnea (RR>20), leukocytosis (WBC>12,000 or differential w/ >10% bands). TOW? |
SIRS
|
|
SIRS + infection (e.g., positive blood culture) is
|
sepsis
|
|
Sepsis + organ failure, decreased perfusion (lactic acidosis,
oliguria, altered mental status) or low BP. TOW? |
Severe sepsis
|
|
Severe sepsis + hypotension despite fluids + lactic acidosis,
oliguria, altered mental status. |
Septic shock
|
|
Septic shock due to Gram-negative bacteria (e.g., E. coli,
Klebsiella spp., or Pseudomonas aeruginosa) is |
Endotoxic shock
|
|
Endotoxin that mounts pro-inflammatory cytokines,
responsible for endotoxic shock, is |
Lipid A of LPS
|
|
Genital chancre begins as a papule, ulcerates to form a
single, painless, clean-based ulcer. TOW? |
1o syphilis
|
|
Cause of genital chancre, begining as a papule, ulcerating to
form a single, painless, clean-based ulcer. |
Treponema pallidum
|
|
A pen-allergy, non-pregnant, female pt w/ fever, "copper
penny" macular lesions on the palms or soles; RPR(+) should be treated with |
Doxycycline
|
|
Management choice of tabes dorsalis (10-20yrs), iritis,
uveitis, or Argyll-Robertson pupils of pen-allergy in a pregnant woman w/ pen allergy; RPR(+) is |
Desensitization
|
|
Hx of painful clustered vesicles with an erythematous base;
urinary retention in a promiscuous woman. TOW? |
HSV-2 >> 1
|
|
Giemsa stain of fluid from a herpetic lesion should reveal
|
Multinucleated giant cells
|
|
Patient with genital herpes does not respond to acyclovir
because pt is infected with |
thymidine kinase deficient
HSV |
|
A pregnant woman with 1o symptomatic HSV-2 infection is
at risk of her baby developing |
neonatal (congenital) herpes
|
|
Cause of painful genital ulcers; purulent, grey base; painful
inguinal adenitis, in a man with multiple sexual partners is |
Haemophilus ducreyi
|
|
Fastidious organism in the infiltrate of the penile ulcer, co-
localized with neutrophils and fibrin, in a pt w/ chancroid is |
Haemophilus ducreyi
|
|
All sex partners of pt with chancroid, regardless of
symptoms, should be examined and treated with |
Azythromycin > ceftriaxone
|
|
Most common cause of mucopurulent endocervical exudate
(Gram stain non revealing) in a sexually promiscuous woman |
Chlamydia trachomatis D-K
|
|
Dx of mucopurulent urethral discharge, dysuria, penile
pruritis is based on |
NAAT of urethral specimen
or urine (+) |
|
DOC of most frequent cause of nongonococcal urethritis
|
Azythromycin > doxycycline
|
|
Cause of rare genital ulcers, inguinal lymphadenopathy
[cytology(-) for multi-nucleated giant cells; RPR (-)] in men is |
Chlamydia trachomatis L1-L3
|
|
Hx of systemic Sx/Sn w/ cervical motion tenderness in a
woman with turbo-ovarian abscess. TOW? |
PID
|
|
Cause of mucopurulent urethritis, dysuria, penile pruritis
[Smear (+):Gram-negative diplococci co-populated w/ PMNs] is |
Neisseria gonorrhoeae
|
|
Deficiency in serum factors in a female pt w/ frequent
gonorrhea and DGIs is |
C6-C9
|
|
Immune evasion of Neisseria gonorrhoeae in frequent mucosal infection is due to
|
Antigenic variation of pili.
|
|
Auxotrophic strains of N. gonorrhoeae with serum
(complements) resistance are likely to cause |
Septic arthritis (aka: DGI)
|
|
Most frequent complication of gonococcal (GC) infection in
men |
Epididymitis
|
|
Cause of "bull headed clap", urethral stricture, prostatitis is
|
Neisseria gonorrhoeae
|
|
Urethritis is treated with ceftriaxone + azythromycin
because |
Urethritis is treated with ceftriaxone + azythromycin
because |
|
An older woman with PID and tubo-ovarian abscess
receives ceftriaxone, azythromycin, and metronidazole because |
Polymicrobic (endogenous)
infection |
|
Cause of anogenital warts w/ histology (+): koilocytes is
|
HPV 6 and 11
|
|
Cause of atypical squamous cells of undetermined
significance (ASCUS) on pap smear w/ no clinical signs of infection is |
HPV 16 and 18
|
|
Cause of koilocytotic cells and possible progression to
squamous cell carcinoma |
HPV 16 and 18
|
|
Next step to identify viral cause of ASCUS on pap smear w/
and further management in a woman of age > 29 years is |
Colposcopy > HPV DNA in
bpsy |
|
Wet prep of vaginal discharge from a pt w/ vaginal pruritis;
ectocervical erythema ("strawberry cervix") should reveal |
motile tissue flagellate
|
|
Gram stain of vaginal discharge w/ fishy odor from a pt w/
vaginal pruritis but no erythema and normal cervix should reveal |
SECs stippled with Gram-
variable organisms. |
|
Pathology of bacterial vagisnosis is overgrowth (in vagina)
of anaerobic Mobiluncus species and |
Gardnerella vaginalis
|
|
DOC of bacterial vaginosis is
|
metronidazole
|
|
Wet prep of curdy discharge (no odor), adhering to vaginal
walls, from a pregnant woman w/ recent UTI, who now has severe vaginal pruritis; vulvovaginal area - erythematous should reveal |
budding yeasts with
pseudohyphae |
|
Normal commensal of skin, GI & GU tracts; endogenous
overgrowth of budding yeast, capable of >10 diseases. TOW? |
Candida albicans
|
|
Mechanism of action of a po DOC of vulvovaginal
candidiasis is |
blocks C14a-lanosterol
demethylase |
|
Hx of flu-like illness, lymphadenopathy, maculopapular
rash in a bisexual man. Lab: lymphopenia and transaminase elevations; monospot/all serology (-). TOW? |
Acute retroviral syndrome
|
|
Time from infection (acquisition) to acute seroconversion detected by HIV serology (ELISA/ WBlot) is
|
6-12 weeks.
|
|
Hx of mononucleosis-like illness and lymphadenopathy in a
man who has sex man. Serology (-). What is HIV viral load? |
>10,000 copies/ml
|
|
Host-cell receptor for HIV-1 infection
|
CD4
|
|
Homozygous for deletions in what gene renders resistance
to infection and some protection against progression. |
CCR5
|
|
Host cells that trap HIV and mediate the efficient
transinfection of CD4+ T cells are |
Dendritic cells
|
|
A man, who practices “sex with another man”, has
antibodies to HIV (ELISA and WB) but asymptomatic. TOW? |
Clinical latency
|
|
What happens to HIV-1 virus when acute retroviral
syndrome progresses to clinical latency? |
Virus continues to replicate
low level. |
|
A man who practices “sex with another man”, is now HIV-1
serology (+) and has dual symptomatic infections/cancer (any two from below). Expected CD4+ count is i. Candidiasis, esophageal, bronchi, trachea, or lungs ii. Cervical cancer, invasive iii. Coccidioidomycosis, extrapulmonary iv. Cryptococcosis, extrapulmonary v. Cryptosporidiosis, chronic intestinal vi. Cytomegalovirus retinitis (with vision loss) vii. Encephalopathy, HIV-related viii. Herpes simplex - Chronic ulcers ix. Histoplasmosis, disseminated or extrapulmonary x. Isosporiasis, chronic intestinal (duration >1 mo) xi. Kaposi sarcoma xii. Lymphoma, Burkitt xiii. Lymphoma, primary, of the brain xiv. Mycobacterium avium complex or Mycobacterium kansasii infection, extrapulmonary xv. Mycobacterium tuberculosis infection, any site (pulmonary or extrapulmonary) xvi. Pneumocystis pneumonia xvii. Progressive multifocal leukoencephalopathy xviii. Wasting syndrome due to HIV infection |
CD4+ < 200/µL
|
|
A man with HIV infection has chronic diarrhea, oral thrush
+ toxoplasma encephalitis. Most likely CD4+ count is |
< 50 cells/µL.
|
|
Most common cause of HIV- associated peripheral skin or
mucosal ulcers |
HSV-1 (>> Histo > CMV >
VZV > Syphilis) |
|
Most common cause of HIV- associated nodules (neoplasia)?
|
HHV-8 (aka KSHV)
|
|
Hx of fatigue, nausea, abdominal pain, diarrhea, fever,
chills, night sweats, dry persistent cough w/ SOB and weight loss in a man with AIDS. Lab: PPD (-); blood culture (+) for AFB. TOW? |
Mycobacterium avium-
intracellulare (MAI) complex (aka: MAC) |
|
Common cause of retinitis, viral pneumonitis or esophagitis
in AIDS |
CMV
|
|
Cases of CMV disease occur with immunosuppression level
|
CD4< 50
|
|
cytopathology of CMV infected tissue is characterized by
large cells with |
nuclear (Cowdry owl’s eye)
and cytoplasmic inclusions |
|
Hx of progressive CNS dz in a pt w/ AIDS: hemiparesis,
visual, ataxia, aphasia, cranial nerves, sensory. Head MRI: ring- enhancing lesions. Toxo antibody (-). TOW? |
JC virus
|
|
Definitive indication for initial HAART is CD4+ count?
|
350/mm3.
|
|
Objective of ARV Tx is to reduce viremia to what level of
genomic RNA/mL |
< 50 copies RNA/mL.
|
|
Initial regimen of anti-retroviral therapy is
|
Emtricitabine + Tenofovir +
Efavirenz |
|
Abacavir, emtricitabine, lamivudine, zidovudine, tenofovir
belong to what class of antiretrovirals? |
NRTIs
|
|
Efavirenz, nevirapine belong to what class of
antiretrovirals? |
NNRTIs
|
|
Atazanavir, Lopinavir, Saquinavir belong to what class of
antiretrovirals? |
Protease inhibitors
|
|
This drug binds to gp41 and prevents conformational
change required for viral fusion and entry into cells. |
enfuvirtide
|
|
This drug inhibits integrase, responsible for insertion of
HIV proviral DNA into the host genome. |
raltegravir
|
|
A man has AIDS and CD4 <200cells/µL or thrush.
Antibacterial prophylaxis needed besides HAART is |
TMP-SMX (for PCP)
|
|
A man has AIDS and CD4 <100 + pos toxo IgG.
Chemoprophylaxis needed besides HAART is |
TMP-SMX (for Toxoplasma
encephalitis) |
|
A man has AIDS and CD4 <100 + PPD >5mm induration.
Antibacterial prophylaxis needed besides HAART is |
INH + pyridoxine
|
|
A man has AIDS and CD4 <50. Antibacterial prophylaxis
needed besides HAART is |
azithromycin (for MAC)
|
|
Hx of fever, a pustule at a cat scratch site, adenopathy,
hepatosplenomegaly in a pt w/ AIDS. Warthin-Starry stain tissue (+). TOW (clue: bacillary angiomatosis)? |
Bartonella henselae
|
|
Leading causes of congenital infections are
|
ToRCH3eS-List
To = Toxoplasma gondii R = Rubella C = CMV H = HSV-2 H = HIV H = HBV S = Syphilis List = Listeria monocytogenes |
|
Cause of severe CNS sequelae, chorioretinitis, systemic
disease in a neonate (mom at pregnancy had mono-like illness after eating undercooked beef or pork or exposure to oöcysts in cat feces) is |
Toxoplasma gondii
|
|
Drug for pregnant woman in first trimester to prevent
transmission if mother seroconverts is |
Spiramycin
|
|
Hx of deafness, cataracts, heart defects, or microcephaly in
a child (of a seronegative, caregiver mom, exposed to “Blueberry muffin baby” in 1st trimester). TOW? |
congenital rubella syndrome
(CRS) |
|
Dx of CRS usually with positive anti-rubella antibody type?
|
IgM
|
|
Microcephaly, seizures, sensorineural hearing loss, feeding
difficulties, petechial rash, hepatosplenomegaly, or jaundice in a neonate. PCR of any body fluid should yield |
CMV
|
|
After primary infection, CMV, characterized as enveloped
dsDNA betaherpesvirus; establishes |
lifelong latency
|
|
Hepatosplenomegaly, neurologic abnormalities, frequent
infections in a neonate w/ low CD4+ counts. Woman before birthing should have received |
Nevirapine
|
|
Cause of vesicular skin lesions + conjunctivitis in a child
(asymptomatic at birth) |
HSV-2
|
|
Hx of cutaneous lesions, hepatosplenomegaly, jaundice,
saddle nose, and saber shins. Hutchinson teeth, + CN VIII deafness in a neonate (mom is a prostitute). TOW? |
3o syphilis
|
|
Neonatal septicemia or meningitis (mom had flu-like Sx and
ate imported cheese during pregnancy). TOW? |
Listeria monocytogenes
|
|
What are the SIX red rashes of childhood (acute, febrile
exanthema illnesses)? (Clue1: maculopapular rash; off-white lesions on buccal mucosa, MMRV vaccine prevents) (Clue2: maculopapular rash starting on face moving to foot; MMRV prevents) (Clue3: scarlatina rash post pharyngitis) (Clue4: vesicular rash, moderate pain) (Clue5: maculopapular “slapped face” appearance in a young child) (Clue6: maculopapular rash and systemic Dz in immunocompromised pt) |
Measles
Rubella Scarlet fever (GAS) Chicken pox (VZV) Parvovirus B19 HHV-6 |
|
Worldwide rubella infection, with only human reservoirs
known this infectious agent is a |
RNA togavirus
|
|
>95% seropositive after MMRV if >12mos age and lifelong
protection against rubella is conferred with? |
Single dose
|
|
Cause of single or multiple scaly and/or crusted patches
and/or plaques, affecting the scalp or beard area +/- inflammation. |
Dermatophytes
|
|
KOH prep of scales from the scalp and plucked hairs from
cutaneous mycoses may reveal? |
hyphae and spores
|
|
Most common cause of cutaneous mycoses
|
Trichophyton spp.
|
|
Common cause of cutaneous mycosis with animal contact
|
Microsporum spp.
|
|
Oral DOC of cutaneous mycoses
|
itraconazole
|
|
Topical DOC of cutaneous mycoses
|
terbinafine
|
|
Dz w/ subcutaenous lesions w/ slow spread by lymphatic
system producing nodules in a gardener, or from rose-thorn injury. |
Sporotrichosis
|
|
Cause of subcutaenous lesions w/ slow spread by lymphatic
system producing nodules in a gardener, or from rose-thorn injury. |
Sporothrix schenckii
|
|
Dimorphic fungus that grows at 37°C as cigar-shaped yeast,
and produces septate hyphae and conidia (in daisy arrangement) at 25°C is |
Sporothrix schenckii
|
|
DOC of sporotrchosis
|
itraconazole.
|
|
Cause of deeper and wider lesions with interconnecting
subcutaneous abscesses arising from infection of several neighboring hair follicles, in young children. |
Staphylococcus aureus
(Curbuncle) |
|
Cause of superficial pustules progressing to erosions
covered by honey-colored crusts, surrounded by erythematous halo, in young children. |
Staphylococcus aureus >>
Streptococcus pyogenes (non- bullous impetigo) |
|
Dz characterized by bullae and denuded areas after the
blisters rupture, covered by thin, varnish-like light brown crusts; regional lymphadenopathy, in children. DOC if lab: gram stain and culture of pus or base of the lesions yields GPC in chains. DOC if lab: gram stain and culture of pus or base of the lesions yields GPC in clusters. |
Bullous impetigo
Penicillin G Nafcillin |
|
mecA (SCC) genes which encode PBP2a, w/ low affinity for
ß-lactams; confers resistance in Staphylococcus aureus against what? |
Nafcillin
|
|
Cause of spreading (butterfly-wing) erythema on the face
that responds to empirical penicillin. |
Streptococcus pyogenes
(Erysipelas) |
|
Cause of severe pain on his knee w/ site of injury is tender
and erythematous. Blood culture may yield? |
Streptococcus pyogenes.
(Cellulitis) |
|
What is the microbial factor that promotes degradation of
C3b by binding to factor H, the serum ß globulin factor |
M protein
|
|
Other epidemiologically linked or risk-associated causes of
cellulitis are: Clue1: cat/dog bite. What? Clue2: Salt water exposure. What? Clue3: Fresh water exposure. What? Clue4: Neutropenia. What? Clue5: Human bite. What? |
Pasteurella multocida /
Capnocytophaga canimorous Vibrio vulnificus Aeromonas hydrophila Pseudomonas aeruginosa Eikenella corrodens |
|
Most likely cause of fever/chills/ night sweats, localizing
pain/tenderness or swelling/erythema (lab: .ESR, .CRP; .WBC w/ left shift. Radiology: periosteal elevation.) is |
Staphylococcus aureus
(Osteomyelitis) |
|
Major antiphagocytic virulence factor of drug-resistant
organism that causes osteomyelitis is |
protein A
|
|
Major neutrophil-damaging virulence factor of drug-
resistant organism that causes osteomyelitis is |
Penton-Valentine leukocydin
|
|
Cause of vertebral, sternoclavicular or pelvic bone
infections (in pt w/ IVDU) or osteochondritis of foot (following penetrating injuries through tennis shoes)? |
Pseudomonas aeruginosa
|
|
Cause of osteomyelitis in pt w/ underlying sickle cell Dz;
blood culture +)? |
Salmonella typhimurium
|
|
Cause of chronic, vertebral osteomyelitis (blood culture
negative)? |
Mycobacterium tuberculosis
|
|
Cause of osteomyelitis in pt. w/ hx of cat bites; GNSR;
fastidious growth of wound culture? |
Pasteurella multocida
|
|
Cause of fever, chills, malaise, joint pain, swelling. PE:
tenderness, erythema, heat, swelling, decreased ROM. CBC: leukocytosis w/ neutrophils predominating; joint aspirate: no crystals. Clue1: sexually active; BLCx (-); responds to ceftriaxone Think of other pathogens (BLCx negative): Clue2: Rheumatoid arthritis? Clue3: IVDU? Clue4: Unpasteurized dairy products Clue5: Diabetes |
Septic arthritis
Neisseria gonorrhoeae S. aureus S. aureus, P. aeruginosa Brucella spp. S. agalactiae (GBS) |
|
Dz is characterized by arthritis in up to 6 joints (especially
knees, feet), low back pain/stiffness, irritable eyes w/ or w/o redness, conjunctivitis, iritis, malaise. TOW? Caused by: Clue1: sexually acquired Clue2: non-sexually acquired Reactive arthritis |
C. trachomatis, N.
gonorrhoeae Campylobacter, Salmonella |
|
Cause of bacteremia in neutopenic pts with central line or
pts with prosthetic devices and catheters; blood culture (+) |
Staphylococcus epidermidis
|
|
Cause of intraabdominal abscess w/ putrid pus; anaerobic
bacteremia in pt with trauma or solid GI tumor? |
Bacteroides fragilis.
|
|
A woman with obstetric infection has fever > 102oF, SBP <
90; diffuse sunburn-like rash or desquamation of palms and soles; multisystem Sx/Sns; vomiting, and diarrhea; BLCx (-). TOW? |
Staphylococcal Toxic shock
Syndrome |
|
What is the toxin associated with staphylococcal toxic
shock syndrome? |
TSST-1 (a superantigen)
|
|
Cause of severe, watery diarrhea in a woman with toxic
shock syndrome? |
Enterotoxin (coregulated with
TSST-1) |
|
Cause of toxic shock syndrome, which responds to
vancomycin and clindamycin? |
MRSA
|
|
Hx of fever > 38.9oC, SBP < 90 ; diffuse sunburn-like rash
or desquamation of palms and soles, in a man w/ necrotizing fasciitis or myositis; multisystem involvement; BLCx (+). TOW? |
Streptococcal toxic shock
syndrome |
|
What is the toxin associated with streptococcal toxic shock
syndrome? |
SpeA (superantigen)
|
|
DOC for streptococcal toxic shock syndrome
|
PenG + clindamycin
|
|
Hx of fever, chills, and hypotension. Blood culture yields a
GNR, oxidase (-), lactose fermenting organism on MacConkey agar. Immunological mediators of sepsis. |
IL-1 and TNF
|
|
DOC for a neutropenic pt w/ line-associated infection w/
immune suppression (hematologic malignancy, organ or hematopoietic stem cell transplantation, chemotherapy); w/ positive blood cultures and ß-D-glucan antigenemia? |
Caspofungin
|
|
DOC for a line-associated infection in a pt w/ GI tumor; lab:
positive blood cultures and ß-D-glucan antigenemia? |
Fluconazole
|
|
Without prophylaxis with valganciclovir, D+/R- solid organ txp pts will develop
|
CMV disease
|
|
Cause of mononucleosis-like dz with fever, myalgia/
arthralgia w/ lab: leukopenia, LFT abnls, in a pt w/ solid organ transplant? |
CMV
|
|
Lung biopsy reveals large cells with nuclear inclusions
(Cowdry owl's eyes inclusion bodies) in a pt with AIDS and interstitial pneumonia. TOW? |
CMV
|
|
DOC for CMV antigenemia in a febrile pt with solid organ
tansplant? |
valganciclovir
|
|
Cause of hematuria, hemorrhagic cystitis, or ureteric
stenosis, or interstitial nephritis in a severly immunocompromised pt? |
BK virus
|
|
What is the most common cause of bacteremia associated
w/ foreign device (prostheses, intravenous cathether, or central lines) in co-morbid, hospitalized pts? |
Staphylococcus epidermidis
|
|
What is the cause of infections associated w/ ventilator
support of respiration in co-morbid pts in the ICU? |
Pseudomonas aeruginosa
|
|
DOC for a pt w/ travel hx (back from the tropics), who has
flu-like symptoms; splenomegaly; lab: CBC: anemia, thrombocytopenia, hypoglycemia. Blood smear: enlarged RBCs and Schuffner dots. |
mefloquine + primaquine
|
|
Which drug is contraindicated in specific Tx of liver form
of malaria in pts w/ G6PD deficiency? |
Primaquine
|
|
DOC for a pt w/ travel hx (back from the tropics), who has
flu-like symptoms (fever > 103oF), seizure, hyperparasitemia (>2.5% of RBC), pulmonary edema, or renal failure, or severe anemia? |
Quinidine and doxycycline.
|
|
Cause of malaria-like illness in an immunosuppressed pt
w/o travel hx; lab: blood smear has cross-over rings in the RBCs? |
Babesia spp.
|
|
A pt from S. America has a week-long fever, anorexia,
lymphadenopathy, mild hepatosplenomegaly, and myocarditis; a nodular lesion on the arm. Blood smear should reveal motile species of what? |
Trypanosoma cruzi
|
|
Cause of a chronic-stage systemic dz w/ cardiomyopathy, megaesophagus, megacolon, and weight loss in a pt from S.
America, who does not respond to nifurtimox. |
Trypanosoma cruzi
|
|
Cause of protracted fever and Crohn’s, celiac dz, ocular
problems, and lymphadenopathy; duodenal biopsy demonstrating foamy macrophages in lamina propria? |
Tropheryma whipplei
|
|
Clinical Dx of painless papule (on arms, face, or chest),
then vesicles/bullae, then black eschar + edema evolving over 3-5d associated with animal exposure is |
Cutaeneous anthrax
|
|
Cutaneous anthrax can be treated in 7-10 days with
|
Ciprofloxacin
|
|
Animal exposure or biowarfare-associated fever, chills,
sweats, GI sx, cough, malaise, chest pain, but no coryza (first 3-4d); then sepsis; CXR: wide mediastinum and bloody pleural effusion. Blood culture should yield |
Bacillus anthracis
|
|
Inhalation anthrax is treated with
|
Fluoroquinolone >
doxycycline |
|
Need to treat inhalation anthrax 60-100 days because
|
Spores persist in vivo 30 days
|
|
PxPr to prevent inhalation anthrax via aerosolized spores
from powder particle size < 10 microns requires |
Cipro for 60 days
|
|
Species of Clostridium that causes afebrile, systemic toxic
diseases in infants (honey), and in adults foodborne (meat, canned vegetables), wound (injected), iatrogenic (cosmetic) is |
C. botulinum
|
|
Many pts w/ flaccid paralysis; unusual Clostrium botulium
types (not A, B or E), common geography without common food source are clues to |
bioterrorism
|
|
Aerobic small slender gram-negative rod, erroneously
identified as Pseudomonas sp., which causes glanders in horses and rarely humans; may be used in bioterrorism is |
Burkholderia mallei
|
|
Small, pleomorphic, aerobic Gram-neg rod that causes
pathophysiology: 1) bite/abrasion (acquired from tick exposure or contact with rabbits) . nodule/ulcer . node . sepsis, or 2) inhalation (bioterrorism) . acute fever, dry cough. CXR: infiltrates + hilar adenopathy, is |
Francisella turlarensis
|
|
Hx of acute fever, myalgias, remorrhagic rash,
conjunctivitis, pharyngitis, headache, diarrhea, and thrombocytopenia in bioterrorism indicates |
Viral hemorrhagic fever (e.g.,
Marburg, Ebola) |
|
Aerobic, Gram-neg bipolar rod, which causes
pathophysiology of (a) painful lymphadenitis, fever, chills, headache (after exposure to rodents, rabbits or fleas) (b) sepsis; (c) pneumonic (post bubo or epidemic): severe, often with hemoptysis and dyspnea, is |
Yersinia pestis
|
|
Hx of sudden fever = 39°C , homogeneous vesiculo-
pustular rash (unlike common viral exanthems) in multiple pts is caused by |
Variolla major virus (small
pox) |
|
Hx: fever, headache, neck stiffness, and altered mental
status; Kernig's/Brudzinski's sign other focal neurologic findings, rash, headache, seizures + myalgia; CSF: WBC > 2000 or PMNs > 1200; glucose < 34, protein > 220 CSF gram stain of the most likely pathogen of ABM in a 6 mos-6yr old (or adults > 50 years) should reveal CSF gram stain of the most likely pathogen of ABM in an older child or young adult should reveal |
Acute bacterial meningitis
(ABM) Gram-positive diplococci Gram-negative diplococci |
|
Most common cause of sepsis/meningitis in
newborns/neonates? |
Streptococcus agalactiae
|
|
Cause of fever, headache, photophobia, nausea/vomiting,
rash, diarrhea, meningeal signs, in older children in the summer months; CSF with 10-<1,000 WBC typical, mostly monos, moderately elevated protein? |
Aseptic meningitis caused by
enteroviruses |
|
Cause of aseptic meningitis in men with exposure to
rodents? |
Leptospira interrogans
|
|
Cause of aseptic meningitis with hx of tick bite and
erythema migrans? |
Borrelia burgdorferi
|
|
Cause of aseptic meningitis with hx of sex with multiple
partners; CSF PCR(+)? |
HSV-2 > 1
|
|
Cause of fever, headache, photophobia, meningismus, in pts
w/ solid organ transplant, malignancy, corticosteroid use. CSF glucose < 2/3 serum glucose, elevated protein, WBC > 5 with PMNs? |
Listeria monocyotgenes
|
|
How does Listeria monocytogenes differ from other ß-
hemolytic bacteria? |
Gram-positive rods; tumbling
motility |
|
Cause of chronic meningoencephalitis in a pt, who uses
infliximab or native from endemic region; PE: papilledema. CXR (+). Lab: elevated monocytes on differential, low CSF glucose? |
Mycobacterium tuberculosis
|
|
Test to confirm subacute mengoencephalitis in a,
immunocompromised pt (CD4 <100); vesicular skin lesions [CSF profile: protein 30-150mg/dl, monos 10-100]? |
CSF India ink
|
|
Cause of meningoencephalitis after a hx of respiratory
illness after travel to SW USA? |
Coccidioides immitis
|
|
Test to confirm CNS pathology with fever, cognitive
deficits, focal neurologic signs, seizures; temporal lobe involvement on MRI. Lab: no papilledema, CT (no brain lesion)? |
CSF PCR (+)
|
|
Cause of fever, cognitive deficits, focal neurologic signs,
seizures, abnormal mental status with ataxia, hemi-paresis, in a pt w/ AIDS? |
JC virus > HHV-6
|
|
Cause of fever, cognitive deficits, focal neurologic signs,
seizures or abnormal mental status with ataxia in an adult during outdoor activity? |
West-Nile virus > SLE
|
|
Hx of fever, cognitive deficits, focal neurologic signs,
seizures, in a pt w/ AIDS (CD4 < 50). MRI: multifocal (ring- enhancing) lesions in basal ganglia. Rule out? |
Toxoplasma encephalitis (TE)
|
|
HIV-infected Pt with TE should receive (for life)
|
pyrimethamine + leucovorin +
sulfadiazine |
|
Folinic acid (leucovorin) prevents bone marrow suppressive
effect of |
pyrimethamine.
|
|
Cause of confusion, stiff neck, irritability over wks to
months, in immunocompromised pts; CT/MRI = multifocal lesions in midbrain, brain stem, & cerebellum; wet mount CSF = motile macrophage-like organisms |
Acanthamoeba spp. (GAE)
|
|
Cause of severe headache and other meningeal signs, fever,
vomiting, and focal neurologic deficits, frequently progressing to coma, in a healthy boy (summer diving activity)? |
Naegleria fowleri (PAM)
|
|
Cause of seizures, chronic headache, symptomatic
hydrocephalus, in immigrants; pt. successfully responds to praziquantel + anti-convulsant drug? |
Taenia solium
(neurocysticercosis) |
|
Pt from Africa had fever, lymphadenopathy, chancre, and
pruritus weeks ago; now has headaches, somnolence, neuro Sns; slowly responds to pentamidine isothionate or suramin. TOW? |
Sleeping sickness caused by
Trypanosoma brucei |
|
Hx of rigidity, muscle spasm, and autonomic dysfunction.
Trismus due to masseter spasm in an infant w/ umbilical stump infection. Neurotoxin interferes w/ |
GABA and glycine
|
|
Hx of afebrile illness w/ diplopia, dysarthria, dysphoria,
dysphagia, in a pt w/ IDU skin poppers with black tar heroin. Neurotoxin blocks the release of |
Acetylcholine
|
|
Immediate treatment of a male infant w/ constipation, a
weak cry, and drooling, hypotonea and cranial neuropathy, after ingestion of home-processed honey. |
Equine immune globulin
(infant botulism) |
|
Ingestion of a raw potato delivers a new vaccine protein to
elicit an immune response. The immune structure to interact with the vaccine protein? |
Lamina propria mucosae
|
|
Inflammation and the resulting increase in vascular
permeability permit leakage into damaged or infected sites are effected by |
Phagocytic cells and acute
phase proteins |
|
The serum of a pt, who has IgG and IgM deficiency,
appears to fix complement in an assay for tetanus antibodies. What is the explanation? |
Activation of the alternate
pathway |
|
A 3-year-old boy with genetic C3 deficiency has recurrent
ear and lung infections due to pyogenic bacteria. Deficiency of what? |
B lymphocytes
|
|
A very young child, w/ recurrent infections due to
Staphylococcus aureus, now has numerous granulomas. TOW? |
Chronic granulomatous dz
|
|
Treatment with which protease enzyme causes decrease in
avidity of IgG w/o changing the specificity of the antibody? |
Papain
|
|
Cells activated by both .-IFN and CD40 are
|
Macrophages
|
|
High-dose chemo has caused severe bone marrow
suppression in a pt with hematologic malignancy. Reversal is plausible with what? |
GCSF
|
|
Function of the T-lymphocyte receptor (CD3) complex of
transmembrane proteins? |
Signal transduction
|
|
The MHC class I pathway presents an antigen directly to
what? |
CD8+ T lymphocytes
|
|
HSV infection can block the transfer of antigenic peptides
from the cytoplasm to the ER of the infected cells. As a result of this, action of what cell type is compromised? |
CD8+ T cells
|
|
Infection of the thyroid gland can induce the expression of
MHC II molecules. Which cell types would initiate an autoimmune response, leading to Hashimoto’s thyroiditis? |
CD4+ T cells.
|
|
PPD skin test (+) in a pt , who was vaccinated against
turberculosis in his native country, reflects response of what cell type? |
CD4+ T lymphocytes (Th1
response . .-IFN) |
|
A man with hx of MI is given a morphine injection for a
new episode of chest pain; 10 mins later, he has itching and urticaria. Mechanism of this reaction? |
mediators from sensitized
mast cells |
|
Loss of skin pigments, sense of touch, inability to feel
objects and pain in a pt from Africa, whose skin scraping contains AFBs, is caused by |
Th1-mediated DTH reactions
|
|
A man with polycystic kidney dz, who receives a renal
transplant and cyclosporine, develops a high temp and swelling and tenderness in the grafted kidney. TOW? |
Immunity to the donor MHC
antigens. |
|
A man who now has progressive stupor and laryngeal
spasms for 3 days after pt was being attacked by a wild bat in a cave a month ago should have received |
Inactivated rabies virus
vaccine |
|
Alternative and lectin pathways of complements activated
|
bacterial surfaces
|
|
Classic complement pathway is activated by antibody-
antigen complexes involving antibody class type |
IgM >> IgG
|
|
Chemotactic and anaphylotoxic complements are
|
C3a, C5a
|
|
successful opsonization of all non-encapsulated bacteria are
by complement |
C3b
|
|
Defect or deficiency of which complements predisposes
individuals to infections caused by Neisseria spp., the causative agents of gonorrhea and meningitis |
C6-C9
|
|
Antimicrobial (immune) response important for intracellular
bacterial infections involves cell type |
Th1 CD4 T cells
|
|
Immune response important for viral infections involves
cell type |
CD8 cytolytic T cells
|
|
Major antibody in secretions and plays a significant role in
first-line defense at the mucosal level is |
IgA
|
|
Main antibody in the initial “primary” immune response and
allows good complement activation is |
IgM
|
|
Fc region of this immunoglobulin binds to eosinophils,
basophils and mast cells and is significant mediator of allergic (hypersensitivity) reactions |
IgE
|
|
What on macrophages enables them to sense that the
material is microbial in origin, and must therefore be eliminated quickly? |
Toll-like receptor
|
|
These oxygen-dependent enzymes: NADPH oxidase,
superoxide dismutase, and myeloperoxidase are involved in killing of what? |
Gram-positive bacteria
|
|
These oxygen-independent enzymes/proteins: lysosome,
lactoferrin, defensins and other cationic proteins are involved in killing of what? |
Gram-negative bacteria
|
|
Infections persist, because m. activation is defective,
leading to chronic stimulation of CD4+ T cells in what dz? |
Chronic granulomatous Dz
|
|
Defective respiratory burst, predisposing chronic bacterial
infection is associated with deficiency of what? |
Glucose-6-phosphate
dehydrogenase (G6PD) |
|
All nucleated cells express MHC I antigens
|
HLA-A, B, C
|
|
Antigen-presenting cells express MHC II antigens
|
HLA-DP, DQ, DR
|
|
Lymphocyte proliferation (T, B) and NK . cytotoxicity are
undertaken by what cytokine? |
IL-2
|
|
B-cell activation, IgE and IgG4 switch, . TH1 cells/ Mf, .
IFN-., TH0 . TH2 are all undertaken by what cytokine? |
IL-4
|
|
Mf activation; elevated expression of MHC and FcRs
molecules on B cells, IgG2 class switching, increased IL-4 and TH2 are all undertaken by what cytokine? |
IFN.
|
|
The Th1 response, driven primarily by IFN-. leads to the
activation of |
macrophages
|
|
The Th2 response, driven primarily by IL-4 and IL-5, leads
to the production of IgE and IgG4 and to the activation of |
mast cells and eosinophils.
|
|
Variable T and B cells in DiGeroge’s syndrome is
associated with |
Thymic aplasia
|
|
No B cells and immunoglobulins in X-linked
agammaglobulinemia (Bruton’s) is associated with |
Loss of Btk tyrosine kinase
|
|
Lack of anti-polysaccharide antibody and impaired T-cell
activation causing Wiskott-Aldrich syndrome is associated with |
X-linked-defective WASP
gene |
|
Inability to control B cell growth in X-linked lympho-
proliferative syndrome is associated with |
SH2D1A mutant
|
|
Glomerulonephritis, pulmonary hemorrhage in
Goodpasture’s syndrome is caused by what autoantigen? |
basement membrane collagen
type IV |
|
Hyperthyroidism in Grave’s Dz is caused by what
autoantigen? |
Thyroid-stimulating hormone
|
|
Progressive muscle weakness in Myasthenia gravis is
caused by what autoantigen? |
Acetyl choline receptor
|
|
Brain degeneration, paralysis in Multiple sclerosis (MS) is
caused by what autoantigen? |
Myelin basic protein,
proteolipid protein |
|
Localized allergies (e.g., drug allergy, asthma, hay fever)
and anaphylaxis (food, drug) w/ systemic inflammation throughout circulation are associated with reaction? |
Type I hypersensitivity
|
|
Autoimmune hemolytic anemia: Ab’s produced vs RBC
membrane Ag’s, mismatched blood (transfusion rxn), and allergies to antibiotics (e.g., penicillins, sulfa drugs) are associated with reaction? |
Type II hypersensitivity
|
|
Grave’s Disease, Myasthenia Gravis, Goodpasture’s
syndrome are all associated with reaction? |
Type II hypersensitivity
|
|
Post-streptococcal glomerulonephritis, serum sickness to
horse diphtheria anti-toxin, systemic lupus erythematosis (SLE), and rheumatoid arthritis are all associated with reaction? |
Type III hypersensitivity
|
|
Poison ivy, erythematous induration in tuberculin skin test,
and transplantation/graft rejection are all associated with reaction? |
Type IV hypersensitivity
|