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262 Cards in this Set

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most common cause of pneumonia and bronchiolitis in infants
Respiratory syncytial virus
antigen shift requires a new egg based vaccine
influenza
most common cause of viral meningitis, myocarditis, and pericarditis
Coxsackievirus
most common viral cause of gastroenteritis in adults
Norwalk virus
acid labile virus transported by fingers to the eyes and nose
Rhinovirus
virus destroying anterior horn cells leading to paralysis in an elderly man who recently visited his young great grandchild
poliovirus
virus causing acute hemorrhagic conjuctivitis
enterovirus
virus causing inspiratory stridor in 5 month old infant with an anterior x-ray of the neck showing a steeple sign.
Parainfluenza
Virus associated with acute appendicitis, giant cell pneumonia, and slow virus disease causing demyelination
Rubeola
Virus transmitted by animal bite and aerosolization that causes hydrophobia and encephalitis
Rabies virus
Virus transmitted by mouse urine or feces to man who has ARDS and renal failure. He lives on Navajo reservation in Northern Arizona.
Hantavirus
Virus transmitted by mouse urine or feces that produces severe meningitis and encephalitis
lymphocytic choriomeningitis virus
virus that produces severe encephalitis that is transmitted by mosquitos. The reservoir of the virus is wild birds. Humans and horses are dead end host.
Eastern equine encephalitis virus
Virus transmitted by mosquitos that produces encephalitis. Reservoir is crows and other birds. Disease began in New York and has now spread to the west
West Nile Virus
Most common cause of gastroenteritis in children, particularly during the winter months. Virus produces a secretory diarrhea often requiring glucose-containing hypotonic salt solution replacement
Rotavirus
Most common acquired immunodeficiency syndrome.
Virus is cytolytic to CD4 T-cells
HIV
Teratogenic virus that produces sensorineural hearing loss in neonates and rash with painful postauricular lymphadenopathy in children and adults
Rubella virus
Retrovirus that produces T-cell leukemia and lymphoma
HTLV
Virus transmitted from infected patient secretions that produces a hemorrhagic fever in Africa.
Ebola virus
DNA virus associated with heterophile antibodies against horse RBCs. Produces atypical lymphocytosis, nasopharyngeal carcinoma, and malignant lymphoma involving the CNS and lymph nodes
EBV
Virus associated with parotitis, pancreatitis, orchitis, and a self-limited meningoencephalitis
Mumps virus
Virus associated with recurrent infections on the lips, conjunctivitis, and hemorrhagic necrosis of the temporal lobes
HSV-1
Virus transmitted by a mosquito bite that was a common cause of hemorrhagic fever in Vietnam
Dengue virus
Virus transmitted by the bite of a tick that produces biphasic fever, rash, and encephalitis.
Colorado tick fever virus
Virus transmitted by a mosquito that produces midzonal liver cell necrosis often leading to fulminant hepatic failure
yellow fever virus
Virus associated with recurrent vesicular lesions in the anogenital region, meningitis, and congenital infections in neonates
HSV-2
What is the primary reservoir cell for HIV in the CNS?
microglial cell: these cells are the macrophages of the CNS and used to a circulating monocyte, which carry the virus into the CNS
an HIV positive patient with fever, night sweats, cough, dyspnea with exertion, a CD4 T-helper cell count of 350 cells/mm, and a cavitary apical lung disease most likely has an infection due to:
Mycobacterium tuberculosis
The most common fungal infection and cause of odynophagia in an HIV positive patient is:
candidiasis
- Candidia is the MC fungal infection in HIV
The most common systemic fungus infecting the CNS in patients with AIDS is:
Cryptococus
A patient with AIDS has protracted watery diarrhea. A stool sample reveals oocysts that are acid-fast. The most-likely diagnosis is:
Cryptosporidosis
- sprozoan: Isospora belli is also a sporozoan that produces AIDS diarrhea and also has partially acid fast oocysts
A white plaque like lesion on the lateral aspect of the tongue that doesn't scrape off in an HIV + patient with a CD4 T cell count of 350 cells/mm is most likely caused by....
EBV: it is not premalignant and is not AIDS-defining
A patient with AIDS has cotton wool exudates in the retina, watery diarrhea, biliary tract disease, and odynophagia. The most likely pathogen is:
CMV
- ganciclovir is the Rx of choice.
- use Foscarnet if this doesn't work
A beefy red, exquisitely painful perirectal ulcer with vesicles involving hte gluteal folds in an HIV + patient is most likely due to
Herpes simplex
in these locations it is not AIDS-defining
what opportunistic infections are most likely to appear in the early manifestation of AIDS?
Shingles due to Herpes zoster
Hairy leukoplakia due to EBV
Oral candidiasis
A patient with AIDS has raised, painful erythematous lesions that blanch with pressure. A biopsy reveals an inflammatory type of vasculitis. A silver stain reveals organisms in the endothelial cells. The patient most likely has:
bacillary angiomatosis: due to Bartonella hensalae.
It simulates Kaposi's sarcoma
the rapidly increasing incidence of primary central nervous system malignant lymphoma in the US parallels the rapidly increasing incidence of:
HIV
- HIV in concert with EBV cause primary CNS lymphoma
An anorectal biopsy in a 35 year old homosexual revelas infiltrating squamous cell carcinoma. This is most likely secondary to:
HPV proctitis: due to unprotected anal intercourse
What body fluids have the greatest risk factor for transmitting HIV?
Colostrum
next to blood breast milk has the greatest viral burden. Breast feeding is contraindicated
- urine, tears, saliva all carry the virus
the major mode of transmission of HIV in developing countries is
heterosexual vaginal intercourse: greatest risk is male to female.
Receptive intercourse between man is the MC mechanism in the US
During the asymptomatic latent clinical phase of HIV infections, the virus is primarily trapped in:
lymph nodes by follicular dendritic cells
reservoirs of the virus during the stage
In HIV + patients, autoimmune disease is most commonly manifested by:
thrombocytopenia
it is the MC hematological manifestation of AIDS
type II HSR
IgG antibodies directed against GpIIb:IIIa fibrinogen receptor
Hypergammaglobulinemia in AIDS patient is most often secondary to:
polyclonal stimulation of B cells by EBV
Which of the following test is used to initially screen blood for HIV?
ELISA test for gp-120 antibody
- the p24 capture assay to detect p24 antigen is positive when the patient initially contracts HIV and when they develop an AIDS defining lesion
Which of the following test is used to confirm a positive or indefinite ELISA for HIV?
Western blot assay
- it requires the presence of antibodies against p24, gp41 and either gp120 or gp160 hence it has greater specificity
what test is usually positive when the patient first contracts HIV and when the patient develops an AIDS defining lesion?
p24 capture assay
- it detects the p24 antigen and is positive when the patient is initially contracts HIV and when they develop an AIDS defining lesion. It is negative during the early symptomatic phase
What test provide the best overall information concerning the viral burden in a patient with AIDS?
HIV RNA by PCR
List some AIDS defining lesions
Pneumocystis jiroveci pneumonia
Systemic candidiasis
Kaposi's sarcoma
what is the most common mode of transmission of HIV in a medical personnel?
needle stick exposure from an HIV + patient
1/300 chance of becoming HIV +
Must go on triple therapy for 6 months
What is the most common mode of transmission of HIV in the USA at the present time?
receptive anal intercourse between males
what is the most common method of transmitting HIV to a fetus?
Transplacental vertical transmission with vertical transmission by breast feeding a close second
a 23 year old pregnant woman is found to be positive for HIV antibody. What would you do for treatment of her and prevention of transmission to the baby?
Newborn will have a positive ELISA test: anti-gp120 is an IgG antibody
Mother should be treated with zidovudine (AZT) which reduces the risk of the baby becoming HIV + to < 10%
What would you expect in lab findings in a patient that has AIDS?
anergy to cutaneous skin testing with Candida
Decreased CD4 T- helper cells count
Mitogen blastogenesis of T-cells should be abnormal
Immunoglobulin G levels are increased due to EBV polyclonal stimulation
Lymph nodes will not show caseating granulomas because helper T-cells are required for granuloma formation
The median time for primary HIV Infection to development of AIDS is approximately
10 years
this is why the prevalence of HIV has increased in the US. the longer the duration of a disease the greater the prevalence
the most common cause of space occupying lesion in the CNS in AIDS that presents with focal seizure activity is:
Toxoplasmosis
The treatment for the most common initial AIDS-defining illness is:
TMP/SMX: pneumocystis is the MC initial AIDS defining illness
the most common cause of recurrent pneumonia in patient with AIDS is
Streptococcus pneumonia
The most common cause of fever, night sweats, and weight loss in patients with AIDS, who has helper T-cell count < 50 cells/mm is?
disseminated Mycobacterium avium intracellulare
note the decreased helper T-cell count
What complications in AIDS is directly due to the HIV virus?
Dementia
Wasting syndrome
Provide an accurate description of HIV.
gp120 antigen attaches to CD4 on the helper T-cell
p24 antigen peaks at two separate times during the infection
reverse transciptase converts genome RNA into double stranded DNA
what does the env gene code for in AIDS?
encodes gp120/gp41
what does the pol gene encode in AIDS?
reverse transcriptase and integrase
what does the gag gene encode?
p24 antigen
what group of immunizations can be given to a patient with AIDS?
killed polio vaccine
hepatitis B vaccine
MMR
Hemophilus influenzae type b
Pneumovax/influenza
DPT
Virus that produces congenital infection, atypical lymphocytosis, infections transmitted by blood transfusions, and disseminated disease in AIDS. It produces hypertrophied cells with basophilic intranuclear inclusions
CMV
Pathogen that is transmitted sexually and produces PID and non-specific urethritis
Ureaplasma urealyticum
Childhood viral infection associated with high fevers often precipitating febrile convulsions.
When fever breaks, a rash occurs
HHV-6: Roseola
Most common viral cause of hemorrhagic cystitis
adenovirus
intraleukocytic pathogen that is transmitted by a tick that produces a disease resembling Rocky Mountain Spotted fever except for absence of rash
Ehrlichia chaffeenisis
Viral gene products inactivate TP53 and RB Suppressor genes. Associated with lesions in the anogenital region that are either benigh or malignant
HPV
Virus that produces a slow virus type of encephalitis that is commonly seen in AIDS patients
JC virus
- progressive multifocal leukoencephalopathy
Virus that is latent in sensory ganglia that produces painful vesicular rashes that follow a sensory dermatome. Like HSV-1 and -2, the Tzank prep is positive.
Varicella zoster virus
-shingles
Pathogen associated with an atypical pneumonia and coronary artery disease
Chlamydia pneumonia
Pathogen transmitted by a tick that produces vasculitis producing lesions that begin on the palm and extend to the trunk
Rickettsia rickettsiae
Virus that produces multiple, raised umbilicated lesions with a central crater containing granular material that can produce other skin lesions.
Molluscum contagiosum virus
Virus associated with macules, papules, vesicles, and pustules that are at different stages of development. Associated with Reye's syndrome. Influenza virus can also be associated with Reye syndrome.
Varicella virus
Virus now eradicated by immunization that produces pustular lesions that are at the same stage of development. May be used for biological warfare.
Smallpox
Spongiform encephalopathy leading to dementia
Creutzfeldt-Jakob disease
caused by infectious particles lacking DNA and RNA (called prions)
Pathogen that produces atypical pneumonia in areas with crowded conditions and is associated with cold agglutinins and bullous myringitis
Mycoplasma pneumoniae
pathogen not transmitted by a vector that produces atypical pneumonia and granulomatous hepatitis
It commonly occurs in veterinarians, those in contact with farm yard manure, and those working in slaughterhouses
Coxiella burnetii (Q fever)
Pathogen with elementary bodies within metaplastic squamous cells. Associated with STD and blindnes
Chlamydia trachomatis
Virus associated with a "slapped face" appearance, aplastic anemia, anemia, arthritis, and spontaneous abortions.
Parvovirus
Pathogen that produces zoonosis in those who own pet stores that sale parrots and parakeets
Chlamydia psittaci
Serology of a patient with HBV who is non-infective and in the serologic gap.
Positive Anti-HBc-IgM
Serology of patient who has recovered from Hepatitis B
Positive Anti-HBc-IgG
Positive Anti-HBs
Serology of patient who has been vaccinated against HBV
Positive Anti-HBs
Serology of patient who is symptomatic acute HBV
positive HBsAg
positive HBeAg/HBV DNA
positive Anti-HBc-IgM
Serology of patient with infective chronic HBV
+ HBsAg
+ HBeAg/HBV DNA
+ Anti-HBc-IgG
Serology of patient who is a "healthy carrier" for hepatitis B
+ HBsAg
+ Anti-HBc-IgG
Type of hepatitis with no protective antibodies
HCV
HDV
presence of IgG antibodies indicates that they have an active infection
Types of hepatitis with no chronic state
HAV
HEV
Most common type of hepatitis found in daycares
HAV
reason why all day care children are vaccinated against HAV
Most common types of hepatitis leading the hepatocellular carinoma
HBV
HCV
Most common type of hepatitis associated with polyarteritis nodosa
HBV
produces vasculitis
most common hepatitis in travelers to places outside the US
HAV
Most common hepatitis in jails and corrective institutes
HAV
Most common sexually transmitted types of hepatitis
HAV
HBV
HCV
Most common cause of posttransfusion hepatitis and chronic hepatitis
HCV
also MC hepatitis without jaundice
MC type of hepatitis prevented by immunization with hepatitis B vaccine
HBV
HDV
also prevents HCC from HBV postnecrotic cirrhosis
MC type of hepatitis transmitted parenterally
Hepatitis B, C, D
Most common type(s) of hepatitis with protective antibodies
HAV
HBV
HEV
Most common hepatitis producing fulminant hepatitis in patients with pre-existing hepatitis
HDV
Most common type(s) of hepatitis transmitted by the fecal-oral route
Hepatitis A and E
Most common type of hepatitis in homosexuals
HAV
unprotected anal intercourse
virus in feces
Most common type(s) of hepatitis with chronic hepatitis
HBV
HCV (most common)
HDV
Most common type of hepatitis associated with cryoglubulins, type I membranoproliferative glomerulonephritis, and porphyria cutanea tarda.
hepatitis C
Hepatitis associated with glomerulonephritis and polyarteritis nodosa
HBV
Most common type of hepatitis transmitted by accidental needle stick
HBV
also underscores why HBV is the MC systemic disease in IVDA.
HBV is also the most common viral hepatitis
most common cause of nonsocomial septiciemia, UTIs, spontaneous perotinitis in ascites in adults, traverlers diarrhea, and hemolytic uremic syndrome
E.coli
MCC of toxic shock syndrome in menstruating women, wound abscesses, osteomyolitis, impetigo, and acute bacterial endocarditis in IVDA
Staphylococcus aureus
Pathogen that produces a rash in fish handlers
Erysipelothrix rhusiopathiae
Pathogen responsible for poisoning producing paralysis of young children who eat honey
Clostridium botulinum
- infant botulism: toxin develops after colonization of bowel
Farmer and his wife are brought to the ER with paralysis and mydriasis
Clostridium botulinus
- adult botulism, preformed toxin that blocks release of Ach, improperly sterilized bottled goods
MCC of spontaneous peritonitis in ascites in children with nephrotic syndrome, otitis media, sinusitis, community acquired typical pneumonia, sepsis in sickle cell disease, and meningitis in patients over 18 years old.
Streptococcus pneumonia
MCC of rheumatic fever and glomerulonephritis
Streptoccous pyogenes: rheumatic fever is a type II and IV HSR and post-streptococcal glomerulonephritis is a type III HSR
Patient with colon cancer due to UC develops acute endocarditis
Streptococcus bovis
Infant whose umbilical cord has not yet fallen off develops opisthotonus
Clostridium tetani
sexually active 23 year old woman develops dysuria. Urine culture grows out a coagulase negative organism
Staphylococcus saprophyticus
65 year old woman with a recent total hip replacement develops acute endocarditis
Staphylococcus epidermidis
24 year old man develops gastroenteritis after eating refried beans. Gram positive rods are present in stool
Bacillus cereus
35 year old woman with a history of congenital heart disease develops fever and pansystolic murmur at apex that does not increase in intensity with deep help inspiration shortly after a root canal
Streptococcus viridans
24 yr old woman with a history of PID complains of RUQ pain when she twists her torso doing aerobics. A laprascope reveals adhesions between the liver capsule and peritoneum
Neisseria gonorrhoeae
- Fitz-Hughs-Curtis syndrome
65 year old type 2 diabetic with sever peripheral vascular disease develops an infection of the big toe. The toe is gangrenous and has a foul smelling exudate and crepitance in teh underlying SQ tissue
Clostridium perfringens
a 32 year old heroin addict is unable to open his jaw and has painful muscle contractions.
Clostridium tetani
- neurotoxin inhibits glycine
62 year old woman with scurvy had numerous dental caries
Streptococcus mutans
a 14 year old boy develops fever, petechia, and nuchal rigidity. He later develops septic shock and bleeding from all orifices. Autopsy reveals bilateral hemorrhage of adrenal glands.
Neisseria meningitidis
- Waterhouse-Friderichsen syndrome with DIC
A pregnant woman, who eats goat cheese for lunch, delivers a baby with sepsis and meningitis
Listeria monocytogenes
A pregnant woman with premature rupture of membranes has a newborn who develops sepsis and meningitis
Streptococcus agalactiae
a 70 year old woman develops diarrhea while in the hospital with pneumonia. A proctoscope reveals a yellow pseudomembrane in the rectum
Clostridium difficile
An unimmunized child develops dysphonia and painful cervical lymphadenopathy
Oral exam reveals a shaggy gray membrane in the posterior pharynx
Corynebacterium diptheriae
a 62 year old man with COPD develops fever and a cough productive of greenish yellow sputum. A gram stain reveals gram negative diplococci
Moraxella catarrhalis
a 22 year old man has severe cystic acne
Propionibacterium acnes
a 45 year old woman develops a draining sinus tract in the jaw 6 weeks following removal of an abscessed tooth on the same side. Yellow granules are present in the draining exudate
Actinomyces israeli
also commonly infects IUDs
a 45 year old man who works in the post office, opens a letter that has a white powder in it. He develops a lung condition and dies
Bacillus antrhacis
A 2 year old child in a day care center develops fever and bloody diarrhea. The fecal smear for leukocytes is positive. The organism is gram negative and dose not ferment lactose
Shigella sonnei
A 49 year old man who is post heart transplant, develops severe pneumonia. A gram stain of the sputum reveals a gram positive filamentous bacteria that is partially acid fast
Nocardia asteroides
a 23 year old woman complains of foul smelling vaginal discharge after sexual intercourse
Vaginal pH is 5.5
A cervical pap smear reveals organisms adhering to superficial squamous cells
Gardnerella vaginalis
-bacterial vaginosis
- clue cells
a 30 year old man with a pet iguana develops severe enterocolitis with a positive fecal smear for leukocytes
Salmonella enteritidis
- Iguanas are reservoirs for Salmonella
a 48 year old woman has an alkaline urine that smells like ammonia
an ultrasound reveals a large calculus in the renal pelvis of the right kidney
Proteus mirabilis
- magnesium ammonia phosphate or struvite stone, urease producers
a febrile 22 year old man with sickle cell disease develops lytic lesions in the right femur
Salmonella paratyphi
- osteomyelitis
an 82 year old man in a nursing home develops fever and a cough productive of thick, bloody, mucoid sputum. A chest x-ray reveals right lower lobe lobar pneumonia.
Klebsiella pneumonia
- MC typical pneumonia in nursing home residents
-common in alcoholics, but S. pneumonia is still the MC typical pneumonia
a 28 year old man develops a severe, secretory type of diarrhea shortly after eating oysters in New Orleans. Physical exam reveals gram negative comma shaped organisms in his stool.
Vibrio cholera
or Vibrio parahaemolyticus
a veterinarian develops a cellulitis of the right index finger after being bitten by a cat
Pasteurella multocida
a 30 year old woman develops a high fever, abdominal pain, and bloody diarrhea after eating improperly cooked chicken. the fecal smear for leukocytes is positive and s-shaped negative bacteria are noted in the stool.
Campylobacter jejuni
a febrile 5 year old child complains of severe abdominal pain. Laparotomy reveals a normal vermiform appendix but enlarged mesenteric lymph nodes. Frozen sections reveals granulomatous microabscessses without caseation
Yersinia entercolitica
- mesenteric adenitis stimulating acute appendicitis
a patient with AIDS develops pneumonia with a cough productive of a red-pigmented sputum
Serratia marcescens
produces red pigment
A 48 year old smoker who works in the grocery produce section, develops a high fever, cough with bloody sputum, and muscle aches and pains. A silver stain of sputum reveals organisms
Legionella pneumophila
- mist can transmit organism
a 28 year old man with AIDS develops red, non-pruritic lesions. A biopsy reveals vessel inflammation and small organisms that are visible with a silver stain
Bartonella henselae
a 42 year old alcoholic with cirrhosis develops a skin and soft tissue infection. He normally shucks oysters for a living in a restaurant in New Orleans.
Vibrio vulnificus
a 2 year old child who has not been immunized properly, has had rhinorrhea and a conjunctivitis for the last week ad now has developed a cough at the end of expiration followed by an inspiratory whoop.. His WBC is 40,000 cells/mm with predominately mature lymphocytes
Bordetella pertussis
- whooping cough with absolute lymphocytosis
a physician in Iraq has a patient with fever, diarrhea, splenomegaly, sinus bradycardia, and absolute neutropenia
Salmonella typhi
pathogens that cause pneumonia in ICUS, death in burn patients, malignant external otitis in diabetics, death in CF patients, and osteomyolytis in puncture wounds through rubber foot wear.
Pseudomonas aeruginosa
pathogen that causes peptic ulcer disease, gastric adenocarcinoma, and malignant lymphoma
Helicobacter pylori
A rabbit hunter develops ulceration of papular lesions on the forearm and painful axillary lymphadenopathy. He recalls picking off a tick in the area of the skin lesion
Francisella tularensis
a mammalogist studying prairie dogs in Arizona develops painful, enlarged draining inguinal lymph nodes. He recalls being bitten by fleas when examining dead prairie dogs.
Yersinia pestis
a 4 year old child develops pink eye. A gram stain of watery exudate reveals a small gram negative coccobacillary organism
Haemophilus aegyptius
a 3 year old child who has not be properly immunized develops fever and nuchal rigidity. A spinal tap reveals increased protein, neutrophils, and decreased glucose. A gram stain reveals small gram negative coccobacillary organisms.
Haemophilus influenzae
a 48 year old man who works in the Grand Canyon as a mule handler for trips into the canyon develops ulcerative lesions on the skin of his forearm along with painful regional lymphadenopathy. A biopsy of the lesion reveals granulomatous inflammation
Burkholderia mallei
a 24 year old man develops painful ulcer on his penis and painful inguinal lymph nodes. A gram stain of the ulcer reveals gram negative rods oriented to the same direction like a "school of fish"
Haemophilus ducreyi
a sheepherder develops high fever, generalized lymphadenopathy, and hepatosplenomegaly. He later develops osteomyolitis
Brucella melitensis
a man from New Guinea develops genital ulceration without lymphadenopathy. A Giemsa stain of a biopsy of the lesion shows a granulomatous reaction with macrophages containing phagocytosed organisms.
Calymmatobacterium granulomatis
- granuloma inguinale, note the absence of lymphadenopathy, macrophage with organisms called Donovan bodies
a 48 year old smoker who works in a grocery produce section develops a high fever, cough with bloody sputum, and muscle aches and pains. A silver stain of sputum reveals organisms.
Legionella pneumophila
- mist can transmit the organism
a 28 year old man with AIDS develops red, non-pruritic lesions. A biopsy reveals vessel inflammation and small organisms that are visible with a silver stain.
Bartonella henselae
- also causes cat scratch fever
A 42 year old alcoholic with cirrhosis develops a skin and soft tissue infection. He normally shucks oysters for a living in New Orleans.
Vibrio vulnificus
A 2 year old child who has not been immunized properly, has had rhinorrhea and a conjuctivitis for the last week and now has developed a cough at the end of expiration followed by an inspiratory whoop. His WBC count shows 40,000 cells/mm with predominately mature lymphocytes
Bordetella pertussis
- whooping cough with absolute lymphocytosis
A physician in Iraq has a patient with fever, diarrhea, splenomegaly, sinus bradycardia, and absolute neutropenia
Salmonella typhi
Pathogen that causes pneumonia in ICUs, death in burn patients, malignant external otitis in diabetics, death in CF, osteomyelytis in puncture wounds through rubber footwear.
Pseudomonas aeruginosa
Pathogen that causes peptic ulcer disease, gastric adenocarcinoma, and malignant lymphoma
H. pylori
A rabbit hunter develops ulceration of papular lesion on the forearm and painful axillary lymphadenopathy
He recalls picking a tick off in the area of the lesion
Francisella tularensis
a mammalogist studying prairie dogs in Arizona develops painful, enlarged draining inguinal lymph nodes. He recalls being bitten by fleas when examining dead prairie dogs.
Yersinia pestis
a 4 year old child develops pink eye. A gram stain of the watery exudate reveals small gram negative coccobacillary organisms
Haemophilus aegyptius
a 3 year old child who has not been properly immunized develops fever and nuchal rigidity. A spinal tap reveals increased protein, neutrophils, and decreased glucose. A gram stain reveals small gram negative coccobacillary organisms
Haemophilus influenzae
a 48 year old man who works in the grand canyon as a mule handler for trips into the canyon develop ulcerative lesions on the skin of his forearm along the painful regional lymphadenopathy. A biopsy of the lesion reveals granulomatous inflammation
Burkholderia mallei
- patient has glanders
a 24 year old man develops painful ulcer on his penis and painful inguinal lymph nodes. A gram stain of the ulcer reveals gram negative rods oriented in the same direction like a school of fish.
Haemophilus ducreyi
-chancroid
A sheepherder develops high fever, generalized lymphadenopathy, and hepatosplenomegaly. He later develops osteomyolitis
Brucella melitensis
A man from New Guinea develops genital ulceration without lymphadenopathy. A Giemsa stain of a biopsy of the lesion shows a granulomatous reaction with macrophages containing phagocytosed organisms.
Calymmatobacterium granulomatis
Street person with punched out erosions of interdental papillae covered by gray necrotic pseudomembrane
Fusobacterium
- trench mouth
Anaerobe involved in subdiaphragmatic abscess
Bacteroides fragilies
Anaerobes involved in lung abscesses due to aspiration of oropharyngeal material
Prevotella melanogenicus
S. Fusobacterium
Pathogen involved in hand infection in patient recovering from a fist fight
Eikenella corrodens
a 25 year old woman with a maculopapular, erythematous rash on the palms and soles develops fever and intensification of the rash after being treated with penicilin
Treponema pallidum
- secondary syphilis
- Jarisch Herxheimer reaction
non-spirochetal pathogen responsible for rat bite fever in slum areas
Streptobacillus moniliformis
a 52 year old man with decreased vibratory sensation, ataxic gait, absent DTRs in the lower extremities, pupils that accomodate but does not react to direct light, and a positive VDRL in the CSF
Treponema pallidum
- tabes dorsalis with Argyll-Robertson pupil
Teenager with blindness, peg teeth, mulberry molars, saddle nose deformity, rhagades
Treponema pallidum
- congenital syphilis
- blindness due to interstitial keratitis
Farm boy with fever, jaundice, conjunctivitis, and dark field positive tightly coiled spirochetes in the urine. The boy commonly swims in ponds
Leptospira interrogans
- Weil's disease
a Patient with reactivation TB develops small bowel obstruction. A barium study reveals narrowing of the lumen in the terminal ilium
Mycobacterium tuberculosis
- intestinal TB from swallowing organisms
Atypical Mycobacteria that requires light for growing in culture. It produces lung disease similar to M. tubercuolosis
M. kansasii
surgical removal of enlarged lymph nodes in a child reveals granulomatous inflammation of acid fast bacilli
Mycobacterium scofulaceum
a patient with a prosthetic hip joint develops acid fast disease
M. fortitum-chelonei
patient in long island with a h/o tick bite develops erythematous concentric appearing rash in the area of the tick bite. The patient also has a hemolytic anemia with intraerythrocytic organisms noted in the peripheral smear
Borrelia burgdorferi
- Lyme disease with erythema chronicum migrans and hemolytic anemia due to BAbesia
Patient in Colorado with a h/o tick bite develops high fever with periods of relapse, an erythematous rash, and hepatosplenomegaly. Spirochetal organism are present in the peripheral blood smear
Borrelia recurrentis
- relapsing fever develops new antigens
patient in Texas has multiple hypopigmented macular skin lesions. He has a positive lepromin skin test.
Mycobacterium leprae: tuberculoid
- intact cellular immunity
- granulomas present
- no organisms
- autoamputation of digits
patient from India has nodular lesions on the face. Lepromin skin test is negative. Skin biopsy reveals a Grenz zone underlying which are foamy macrophages with acid fast organisms. During treatment she develops erythmea nodosum and is placed on thalidomide
Mycobacterium leprae: lepromatous
- deficient cellular immunity
- no granulomas
- numerous organisms
- erythema nodosum leprosum during dapsone Rx
patient with AIDS develops malabsorption
Small bowel biopsy reveals foamy macrophages in lamina propria that has acid fast bacilli
Mycobacterium avium intracellulare
- MAI produces Whipple's like syndrome
- CD4 count < 100
Farmer who drinks unpasteurized milk develops small bowel obstruction. A barium study reveals a string sign in the terminal ilium
Mycobacterium bovis
A man who works in a pet store in the fish department develops rash on his hands. Culture reveals acid fast organisms that grow best in light.
Mycobacterium marinum
A sexually active woman has flat, raised lesions in the anogenital region. A few weeks ago, she had a PAINLESS ulcer on the labia majora. An RPR test is initially reported as negative but becomes positive after multiple dilutions of the serum
Treponema pallidum
- secondary syphilis with condyloma lata
- prozone phenomenon-antibody excess
Spelunker in Ohio develops a solitary coin lesion in the right upper lobe
Histoplasma capsulatum
-bat/chicken excreta, macrophages phagocytose yeast forms
Chicken farmer in Arkansas has multiple calcifications in the lungs and spleen
Histoplasma capsulatum
- chicken excreta
- marked dystrophic calcification
Anthropologist studying Native American artifacts in Sonoran desert develops a painful nodule on the shins
Coccidioides immititis
- erythema nodosum association
- arthropsores in dust
Pulmonary infections after earthquake in Southern California
Coccidioides immitis
-arthrospores in the dust
Bridge painter in New York city develops a lung infection
Cryptococcus neoformans
- pigeon excreta
Patient with AIDS develops meningitis
Positive India ink prep in CSF
Cryptococcus neoformans
Wildlife manager in Great Lakes area who occasionally traps beavers develops a verrucoid appearing skin lesion and lung disease
Blastomyces dermatitidis
beavers are reservoirs for Giardia too
Bronchial asthma, fungus ball, hemorrhagic infarctions in lungs
Aspirgillus fumigatus
Diabetic recovering from ketoacidosis develops frontal lobe abscess
Mucor species
- rhinocerebral mucormycosis
Wood's light positive circular erythematous lesion with clear center on the skin
Trichophyton rubrum
- tinea corporis
Skin hypopigmentation
scaly dermatitis of the scalp
Malassezia furfur
- tinea versicolor, seborrheic dermatitis, spaghetti and meatballs KOH prep
Woods light positive area of alopecia with block dots
Microsporum canis
- tinea capitis infection of the outer hair shaft
Woods light negative area of alopecia with black dots
Trichophyton tonsurans
- tinea capitis
- infection of inner hair shaft
Lobster fisherman, forester planting pine seedlings, elderly woman who is a rose gardener develops an area of ulceration on the hands and lymphocutaneous nodules
Sporothrix schenckii
- sporotrichosis
- the fist 2 due to sphagnum moss
Alopecia with crusting of the scalp
Trichophyton schoeneleinii
- tinea captiis, favus
patient living in swamps in southern Georgia develops a lesion in the foot characterized by subcutaneous swelling and multiple draining sinuses with granules. the patient walks barefoot most of the time.
Pseudallescheria/Nocardia asteroides (mycetoma)
Carpenter develops a raised, verrucoid lesion. Biopsy reveals a granulomatous reaction and brown staining organisms.
Phialophora
Cladosporium (chromomycosis, splinters, dematiaceous fungi)
Infant with fiery red rash and white exudate in gluteal folds
Candida albicans
- yeast and pseudohyphae
HIV positive patient with oral thrush and hairy leukoplakia develops fever, dyspnea, tachypnea, and lung consolidation in both lungs. CD4 T-cell count is 200
Pneumocystis jiroveci
patient from south America develops lung disease. Biopsy reveals yeast in multiple buds resembling a ships wheel.
Paracoccidioides braziliensis
- south american blastomycosis
AIDS diarrhea with acid-fast occysts.
Cryptosporidium parvum, Cayetanensis
Isospora belli
AIDS diarrhea with spores in stool
Microsporidia species
Newborn infection with calcification of basal ganglia and blindness in woman who breeds cats.
Space occupying lesion in the brain in a patient with AIDS
Toxoplasma gondii
patient returning from Mexico develops blood diarrhea
Trophozoites with erythrophagocytosis noted in stools
Entamoeba histolytica
- flask shaped ulcers in cecum, liver abscesses
Soft lens wearer who does a lot of fresh water skiing develops meningoencephalitis and severe keratitis
Acanthamoeba castellanii
- Nagleria fowleri also causes meningoencephalitis
hemolytic anemia associated with tick bite
Babesia mcroti
carried by Ioxides tick
Malaria associated with fever every 72 hours and diffuse membranous glomerulopathy
Plasmodium malarieae
Malaria not contracted by blacks who are Duffy antigen negative
Plasmodium vivax
- tertian fever patter: every 48 hours
Malaria associated with multiple ring form infestation and banana shaped gametocytes
plasmodium falciporum
- quotidian fever pattern
severe disease often involving CNS
Blood sporozoans transmitted by bite of female Anopheles mosquito
Plasmodium vivax
Plasmodium malarieae
Plasmodium falciparum
Ciliate producing colonic ulcer and blood diarrhea
Balantidium coli
- largest cysts and trophozoites in stool
Hemoflagellate with only trypanosomes that produce an encephalitis leading to sleeping and eventual starvation. Transmitted by the tstse fly.
Trypanosoma gambiense
African sleeping sickness, increased IgM, antigen variation, winterbottom's sign
Pathogen associated with chronic heart failure, acquired achalasi and Hirschsprung's disease. Trypanosomes in blood and amastigotes in tissue. Xenodiagnosis is frequently used.
Trypansomoa cruzi
American trypanosomiasis, reduviid bug used to make Dx, Romana's sign in area of bite on face
called chagoma
Woman with severe cervicitis and vaginitis
frothy green exudate
male partner with urethritis
Trichomonas vaginalis
Chronic diarrhea with malabsorption in a patient with IgA deficiency
Positive string test and urine antigen test
Giardia lamblia
contaminates water supply and mountain streams
beaver is a reservoir
Transmitted by sandfly and produces massive hepatosplenomegaly
macrophages phagocytose leishmanial forms
Leishmania donovani
- visceral leishmaniasis
Kala azar
only leishmanial forms in tissue
transmitted by sandfly and produces cutaneous and mucocutaneous disease that offers immunity with recovery
Leishmania tropical/braziliensis
Invasive helminth that has larval phase in the lungs and is often disseminated in AIDS patients and a common cause of autoinfection and superinfection. Filariform larae in soil. No eggs in stool.
Strongyloides stercoralis
- intestinal nematode
Produces eosinophilia in its transmigration through the lungs and bowel obstruction in its adult form.
Ascaris lumbricoides
intestinal nematode
Invasive helminth that is associated with rectal prolapse in children
Trichuris trichiura
intestinal nematode
Invasive helminth with larval phase in the lung that is associated with iron deficiency
Necator americanus
intestinal nematode
Associated with eating sushi and sashimi
Anisakis simplex
intestinal nematode
rx is surgical excision
Invasive helminth where the adult can be the definitive host in one manifestation of the disease and intermediate host in another manisfestation of the disease associated with focal epileptic seizures
Taenia solium
-cestode
- human who eats infected pork with larvae develops adults in the intestine (definitive host)
- human who ingests eggs develops cysticeri (larvae) that produce retinitis and CNS cysts (man is intermediate host)
Invasive helminth associated with vitamin B12 deficiency that cannot be corrected with intrinsic factor, pancreatic enzymes, or antibiotics
Diphyllobothrium latum
-cestode
-fish tape worm
Non-invasive helminth associated with pruritus ani, appendicitis, urethrititis in little girls
Enterobius vermicularis
- intestinal nematode
- MC helminth in US
- scotch tape test for embryonated eggs
Basque sheepherder has cystic lesion in the liver
Echinococcus granulosis
- cestode, hydatid cysts
- dog is definitive host
- man is intermediate host
Pig farmer develops muscle pain
Exam reveals splinter hemorrhage in nails and pain in deltoid muscle.
Radiograph reveals numerous areas of dystrophic calcification in muscle
Trichinella spiralis
- trichinosis
- intestinal nematode
- eating improperly cooked pork
- larvae encysts in striated muscle
Adult with 3 dogs and 20 cats has pronounced eosinophilia
PE reveals hepatosplenomegaly
Toxocara canis/cati
- intestinal nematode, visceral larva migrans
- man is dead end host for larvae
Child who commonly plays in an uncovered sandbox, develops pruritic skin lesions with tunnels in subcutaneous tissue
Ancyclostoma species
- intestinal nematode
- cutaneous larva migrans
- man dead end host
A cattle farmer has proglottidis in his stool
Taenia saginata
-cestode
- beef tapeworm
pathogen transmitted by a mosquito that produces lymphedema
Microfilaria are present in the blood at night
Wucheria bancrofti
tissue nematode
elephantiasis
Most common tapeworn infection in the US
Hymenolepsis nana
Spider with painful bite that causes severe thigh and abdominal muscle cramps and hypertensive crisis
Latrodectus mactans
- black widow
- neurotoxin of black widow
- red hour glass on ventral surface
spider that commonly bites at night and produces necrotic skin ulcers
Loxosceles recluses
- necrotoxin of brown recluse spider
pathogen produces pipe stem cirrhosis leading to portal HTN, ascites, and esophageal varices. Eggs have prominent lateral spines
Schistosoma mansoni
- trematode
- adults lay eggs in portal vein
Pathogen causes squamous cell carcinoma of bladder. Egg has nipple at the end.
Schistosoma hematobium
- adults lay eggs in urinary venous plexus
Clonorhcis sinensis
Chinese liver fluke
the only other parasite that produces cancer
cholangiocarcinoma
second intermediate host is transmitted by eating fish paste
Hiker in the Sonoran desert feels sharp pain in his foot when he puts his hiking boots on. His big toe initially hurts and then becomes numb as well as the rest of hist leg. Another hiker calls in for help. In the ER the patient develops HTN, and is beginning to exhibit signs of paralysis. Later he develops pancreatitis
Centruroides gertschi
scorpion presence with HTN is very characteristic
pancreatitis is another characteristic finding
A patient develops pruritic erythematous rash while at a picnic
patient notices red organisms on his skin
chiggers (mite)
a patient develops a pruritic erythematous rash in the web spaces of his right hand. A burrow is noted in the spaces
Sarcoptes scabies
human itch mite
spares the palms and soles of adults
children do not develop intertriginous lesions but lesions on the palms and soles
a second year medical student recognizes a moving organism in the pubic hair in a man he is checking for hernia
Phthirus pubis (crabs)
a second year medical student notices white eggs attached to hairs in a child he is examining
Pedicularis humanis capitis
- head lice
- eggs called nits
A second year medical student notices moving organisms in the underwear of a patient he is examining
Pedicularis humanis corporis
- body lice
0 adults live in clothes and do not attach to skin
Rx not for patient but for clothes with malathion or DDT
a plumber crawling under the house develops numerous painful bites that quickly develop a wheal and flare followed by vesiculations and skin necorisis
fire ants
a patient from China who sells herbs and other produce develops a severe lower respiratory tract infection that spreads systemically. Other members of the family develop the same infection
palm civet
the patient has SARS which is first transmitted to humans via handling of palm civets. The disease then spreads to other family members through human to human contact. The diagnosis is made by viral detection by PCR or detection of antibodies