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71 Cards in this Set

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The patient has onychomycosis most likely caused by E. floccosum. Distinguishing characteristics include smooth-walled macroconidia in pairs or triads and no microconidia. It causes
tinea pedis and tinea cruris.
Potassium hydroxide (KOH)-treated scrapings of the lesions reveal both budding yeasts and hyphae.M. furfur causes
tinea versicolor—a superficial skin infection that presents with hypopigmented lesions with subtle scaling and itching.
In tissue and cultures incubated at 37°C (98.6°F), S. schenckii appears as budding yeast. When cultured at room temperature, the fungus develops slender branching hyphae with conidiophores ending with rosettes of conidia. S. schenckii causes
lymphocutaneous sporotrichosis characterized by ulcerating nodular lesions along the lymphatics.
No macroconidia and microconidia are seen in cultures. Diagnosis is made by demonstration of typical antler-like hyphae, commonly known as “favic chandeliers” in culture and tissue specimens. T. schoenleinii causes
favus—a form of tinea capitis that presents with crusted lesions on the scalp and permanent hair loss. It is common in Eurasia and Africa but rare in the United States.
caused by a hemoflagellate Trypanosoma brucei, which is transmitted by tsetse flies. The initial symptoms of fever, lymphadenopathy, and itching are followed by lethargy, changes in mental status, uncontrollable sleepiness, and coma.During this period, myocarditis can develop, resulting in heart failure.
African trypanosomiasis

Detection of trypanosomes in wet preparations or Giemsa-stained smears of clinical specimens confirms the diagnosis.
characterized by massive hemorrhage and destruction of visceral organs, causing death in up to 90% of patients. The disease is acquired through direct contact with infected animals.
Ebola hemorrhagic fever
characterized by periodic bouts of intense fever and chills, nausea, vomiting, and diarrhea. The lysis of red blood cells results in anemia and jaundice.
Malaria

The detection of intracellular plasmodia in peripheral blood smears confirms the diagnosis.
mosquito-borne viral hemorrhagic fever that occurs primarily in South America and sub-Saharan Africa. Symptoms include fever, headache, back pain, myalgias, photophobia, nausea, and vomiting. Hemorrhage into the gastrointestinal tract causes multiple organ system failure resulting in jaundice and shock.
Yellow fever
most likely immune-mediated. In this case, maternal IgGs against one of the four serotypes of the virus crossed the placenta and cross-reacted with the baby's strain of different genotype. Immune complexes formed, which damaged the blood vessels. Symptoms include fever and headache, followed by a cough, petechial rash, and ecchymoses. Gastrointestinal (GI) bleeding causes severe abdominal pain, vomiting, followed by shock
Dengue shock syndrome (DSS) affects young children and develops as a result of dengue hemorrhagic fever (DHF), a mosquito-borne disease endemic in Southeast Asia.
Dengue virus is an enveloped Flavivirus with a (+) sense, ssRNA genome.
he only method that effectively sterilizes surgical instruments is autoclaving. The autoclave uses
highly pressurized steam to inactivate endospores.
Traumatic gas gangrene is a fulminant disease, typically caused by Clostridium perfringens type A and characterized by extensive tissue destruction rapidly progressing to shock and death. Muscle biopsy in clostridial gas gangrene reveals
large Gram-positive rods with truncated ends and a striking paucity of leukocyte infiltration.
can cause necrotizing fasciitis with crepitation that clinically is indistinguishable from gas gangrene.
This is a feature of group A streptococcal (S. pyogenes) gangrene. Infection with pyrogenic exotoxin producing S. pyogenes strains of certain M serotypes can cause necrotizing fasciitis with crepitation that clinically is indistinguishable from gas gangrene.
Humans acquire the infection when their skin comes in contact with contaminated fresh water in rivers or lakes. Free-swimming cercariae penetrate the skin and reach the intrahepatic portal circulation where they develop into adult worms. These worms produce eggs, which can lodge in the brain.dx?
Schistosomiasis is caused by S. mansonii that is endemic in Africa.

S. mansoni eggs have a prominent lateral spine.
The hemoflagellate is transmitted by tsetse flies. Symptoms include fever, lymphadenopathy, and itching, followed by lethargy, personality changes, narcolepsy, and coma. Myocarditis and heart failure are not uncommon.
African trypanosomiasis or sleeping sickness

Detection of trypanosomes in wet preparations or Giemsa-stained smears of clinical specimens confirms the diagnosis.
infectioin that produces fever spikes every 48 hours
P. falciparum
chelates iron and makes it unavailable for use by pathogenic agents. It is operative in the pathogenesis of anemia of chronic inflammation.
Lactoferrin
adverse effect, which occurs in up to 80% of patients treated with amantadine, is benign and reversible.
amantadine-induced livedo reticularis.

It is thought to be due to amantadine-stimulated local release of norepinephrine, which causes vasoconstriction and changes in the permeability of cutaneous blood vessels.
mutation in this co-receptor grants hiv resistance
CCR5
fungus that grows outside the hair shafts, causing an ectothrix infection called white piedra
A. Malassezia furfur
B. Microsporum audouinii
C. Piedraia hortae
D. Trichophyton mentagrophytes
E. Trichosporon beigelii
A. Malassezia furfur
B. Microsporum audouinii
C. Piedraia hortae
D. Trichophyton mentagrophytes
E. Trichosporon beigelii
Trichosporon beigelii
the agent of tinea versicolor, a disease characterized by patches of hyperpigmented or hypopigmented skin.

A. Malassezia furfur
B. Microsporum audouinii
C. Piedraia hortae
D. Trichophyton mentagrophytes
E. Trichosporon beigelii
Malassezia furfur)
infects the skin and hair but not the nails. It covers the outside of hair shafts with a black growth.
A. Malassezia furfur
B. Microsporum audouinii
C. Piedraia hortae
D. Trichophyton mentagrophytes
E. Trichosporon beigelii
Microsporum audouinii)
the agent of black piedra, which is characterized by black nodules on the outside of hair shafts.
A. Malassezia furfur
B. Microsporum audouinii
C. Piedraia hortae
D. Trichophyton mentagrophytes
E. Trichosporon beigelii
P. hortae
infects the scalp and invades the hair shaft, causing endothrix growth.
A. Malassezia furfur
B. Microsporum audouinii
C. Piedraia hortae
D. Trichophyton mentagrophytes
E. Trichosporon beigelii
Trichophyton mentagrophytes
at 10-year intervals Every adult should be immunized with
the combined tetanus and diphtheria toxoid (Td) at 10-year intervals.
Drugs such as atropine and scopolamine block acetylcholine actions at
muscarinic receptors
Alpha-bungarotoxin and d-tubocurarine inhibit what
nicotinic acetylcholine receptors by preventing opening of the receptor channel.
The channel is blocked by autoantibodies in Eaton-Lambert syndrome.
voltage-gated calcium channel (VGCC)

When an action potential reaches the terminal button of cholinergic neuron, a voltage-gated calcium channel (VGCC) opens. The influx of Ca2+ through the VGCC facilitates the exocytosis of acetylcholine-containing presynaptic vesicles into the synaptic cleft.
Many nerve gases and insecticides such as organophosphates inhibit
acetylcholinesterase
tetanus toxin cleaves synaptobrevins found in presynaptic vesicles of neurons, but does it in the CNS where it blocks the release of
inhibitory mediators (glycine and GABA), causing spastic paralysis.
the mechanism of action of exotoxin A produced by P. aeruginosa. This results in the inhibition of protein synthesis, followed by cell death. The toxin is a key mediator of tissue damage associated with dermatonecrosis.
A. Adenosine 5’-diphosphate (ADP)-ribosylates elongation factor 2
B. Cleaves mitogen-activated protein kinase kinase (MAPKK)
C. Cleaves terminal adenine from 28s ribosomal RNA (rRNA)
D. Glycosylation of Rho(G) protein
E. Has an adenylate cyclase activity
Option A (Adenosine 5’-diphosphate [ADP]-ribosylates elongation factor 2) is correct. ADP-ribosylation of elongation factor is the mechanism of action of exotoxin A produced by P. aeruginosa. This results in the inhibition of protein synthesis, followed by cell death. The toxin is a key mediator of tissue damage associated with dermatonecrosis.
the mechanism of action of lethal factor (LF) that is a part of the compound anthrax toxin.This results in the disruption of signal transduction, causing cell death.
A. Adenosine 5’-diphosphate (ADP)-ribosylates elongation factor 2
B. Cleaves mitogen-activated protein kinase kinase (MAPKK)
C. Cleaves terminal adenine from 28s ribosomal RNA (rRNA)
D. Glycosylation of Rho(G) protein
E. Has an adenylate cyclase activity
Option B (Cleaves mitogen-activated protein kinase kinase [MAPKK]) is incorrect. This is the mechanism of action of lethal factor (LF) that is a part of the compound anthrax toxin. LF is a zinc (Zn)-metalloprotease that cleaves MAPKK and irreversibly inactivates it. This results in the disruption of signal transduction, causing cell death.
the mechanism of action of Shiga toxin produced by Shigella dysenteriae and Escherichia coli O157:H7, resulting in the inhibition of protein synthesis.
A. Adenosine 5’-diphosphate (ADP)-ribosylates elongation factor 2
B. Cleaves mitogen-activated protein kinase kinase (MAPKK)
C. Cleaves terminal adenine from 28s ribosomal RNA (rRNA)
D. Glycosylation of Rho(G) protein
E. Has an adenylate cyclase activity
Option C (Cleaves terminal adenine from 28s ribosomal RNA [rRNA]) is incorrect. This is the mechanism of action of Shiga toxin produced by Shigella dysenteriae and Escherichia coli O157:H7. The toxin has an N-glycosidase activity, resulting in the inhibition of protein synthesis.
the mechanism of action of Clostridium difficile toxin. results in actin depolymerization, followed by cell death.
A. Adenosine 5’-diphosphate (ADP)-ribosylates elongation factor 2
B. Cleaves mitogen-activated protein kinase kinase (MAPKK)
C. Cleaves terminal adenine from 28s ribosomal RNA (rRNA)
D. Glycosylation of Rho(G) protein
E. Has an adenylate cyclase activity
Option D (Glycosylation of Rho[G] protein) is incorrect. This is the mechanism of action of Clostridium difficile toxin. ADP-ribosylation of Rho protein from the family of ubiquitous G proteins results in actin depolymerization, followed by cell death.
Edema factor, one of the three constituents of anthrax toxin, Its action results in fluid efflux, causing massive edema characteristic of anthrax.
A. Adenosine 5’-diphosphate (ADP)-ribosylates elongation factor 2
B. Cleaves mitogen-activated protein kinase kinase (MAPKK)
C. Cleaves terminal adenine from 28s ribosomal RNA (rRNA)
D. Glycosylation of Rho(G) protein
E. Has an adenylate cyclase activity
Option E (Has an adenylate cyclase activity) is incorrect. Edema factor, one of the three constituents of anthrax toxin, has an adenylate cyclase activity. Its action results in fluid efflux, causing massive edema characteristic of anthrax.
Gram-negative encapsulated bacteria that ferment lactose and produce urease are most likely
Klebsiella
parasitizes the venous plexus of the bladder. The eggs are steadily moved toward the lumen of the bladder and ureters and are eliminated with urine.
A. Human papilloma virus [HPV] 18
B. HPV 6
C. Schistosoma japonicum
D. Schistosoma hematobium
E. Schistosoma mansonii
Option D (Schistosoma hematobium) is correct. S. hematobium parasitizes the venous plexus of the bladder. The eggs are steadily moved toward the lumen of the bladder and ureters and are eliminated with urine. In endemic areas such Nigeria, cervical schistosomiasis is very common. The distinguishing characteristic of the S. hematobium egg is the terminal spine.
sets up its shop in the mesenteric veins draining the intestines. The eggs are steadily moved toward the lumen of the intestines and are eliminated with feces. Patients present with fever, abdominal pain, cough, diarrhea, hepatosplenomegaly, portal hypertension, and eosinophilia.
A. Human papilloma virus [HPV] 18
B. HPV 6
C. Schistosoma japonicum
D. Schistosoma hematobium
E. Schistosoma mansonii
c and e

Option C (Schistosoma japonicum) is incorrect. S. japonicum infection is associated with the gastrointestinal (GI) manifestations similar to the ones associated with Schistosoma mansoni. S. japonicum eggs have a nondistinctive vestigial spine.

Option E (Schistosoma mansonii) is incorrect. S. mansoni sets up its shop in the mesenteric veins draining the intestines. The eggs are steadily moved toward the lumen of the intestines and are eliminated with feces. Patients present with fever, abdominal pain, cough, diarrhea, hepatosplenomegaly, portal hypertension, and eosinophilia. S. mansonii eggs have a characteristic lateral spine.
patient has a nosocomial (hospital acquired) right lower lobe pneumonia. Since she is currently on a respirator, the most likely pathogen is
Pseudomonas aeruginosa

gram-negative, water-loving bacterium that commonly contaminates respirators. It produces pyocyanin, which is a green-colored pigment.
the most common cause of acute bronchitis superimposed on chronic bronchitis in smokers.
Haemophilus influenzae, a gram-negative rod
When inhaled, it produces a nodular pulmonary disease. Infection may spread to meninges and cause meningitis, especially in immunocompromised individuals.
A. Candida albicans
B. Cryptococcus neoformans
C. Histoplasma capsulatum
D. Sporothrix schenckii
E. Trichophyton rubrum
Option B (Cryptococcus neoformans) is incorrect. C. neoformans is a budding yeast surrounded by a thick mucopolysaccharide. When inhaled, it produces a nodular pulmonary disease. Infection may spread to meninges and cause meningitis, especially in immunocompromised individuals.
characterized by ulcerating nodular lesions along the lymphatics.
A. Candida albicans
B. Cryptococcus neoformans
C. Histoplasma capsulatum
D. Sporothrix schenckii
E. Trichophyton rubrum
Option D (Sporothrix schenckii) is incorrect. S. schenckii causes lymphocutaneous sporotrichosis characterized by ulcerating nodular lesions along the lymphatics. In tissue and cultures incubated at 37°C, S. schenckii appears as budding yeast.
It is a known cause of Majocchi’s granuloma, an inflammatory disease of the hair follicle.
A. Candida albicans
B. Cryptococcus neoformans
C. Histoplasma capsulatum
D. Sporothrix schenckii
E. Trichophyton rubrum
Trichophyton rubrum
Clostridium difficile—a causative agent of pseudomembranous colitis.
A. Adenosine diphosphate ribosylation of Gi protein leading to out-of-control synthesis of adenosine 3’,5’-cyclic monophosphate
B. Adenosine diphosphate ribosylation of Gs protein leading to up-regulation of adenylate cyclase
C. Glycosylation of G proteins leading to impaired actin (de)polymerization
D. Inhibition of protein synthesis via adenosine diphosphate ribosylation of elongation factor 2
E. Inhibition of protein synthesis via N-glycosidase activity
Option C (Glycosylation of G proteins leading to impaired actin (de)polymerization) is correct. The disease has developed as a result of suppression of normal intestinal microbiota by this broad-spectrum beta-lactam antibiotic and subsequent proliferation of Clostridium difficile—a causative agent of pseudomembranous colitis.
This is the mechanism of action of pertussis toxin.
A. Adenosine diphosphate ribosylation of Gi protein leading to out-of-control synthesis of adenosine 3’,5’-cyclic monophosphate
B. Adenosine diphosphate ribosylation of Gs protein leading to up-regulation of adenylate cyclase
C. Glycosylation of G proteins leading to impaired actin (de)polymerization
D. Inhibition of protein synthesis via adenosine diphosphate ribosylation of elongation factor 2
E. Inhibition of protein synthesis via N-glycosidase activity
Option A (Adenosine diphosphate ribosylation of Gi protein leading to out-of-control synthesis of adenosine 3’,5’-cyclic monophosphate) is incorrect. This is the mechanism of action of pertussis toxin.
This is the mechanism of action of cholera toxin produced by Vibrio cholerae.
A. Adenosine diphosphate ribosylation of Gi protein leading to out-of-control synthesis of adenosine 3’,5’-cyclic monophosphate
B. Adenosine diphosphate ribosylation of Gs protein leading to up-regulation of adenylate cyclase
C. Glycosylation of G proteins leading to impaired actin (de)polymerization
D. Inhibition of protein synthesis via adenosine diphosphate ribosylation of elongation factor 2
E. Inhibition of protein synthesis via N-glycosidase activity
Option B (Adenosine diphosphate ribosylation of Gs protein leading to up-regulation of adenylate cyclase) is incorrect. This is the mechanism of action of cholera toxin produced by Vibrio cholerae. “Rice-water” stool is characteristic of secretory diarrhea caused by V. cholerae. It is extremely rare in the developed world.
This is the mechanism of action of diphtheria toxin.
A. Adenosine diphosphate ribosylation of Gi protein leading to out-of-control synthesis of adenosine 3’,5’-cyclic monophosphate
B. Adenosine diphosphate ribosylation of Gs protein leading to up-regulation of adenylate cyclase
C. Glycosylation of G proteins leading to impaired actin (de)polymerization
D. Inhibition of protein synthesis via adenosine diphosphate ribosylation of elongation factor 2
E. Inhibition of protein synthesis via N-glycosidase activity
Option D (Inhibition of protein synthesis via adenosine diphosphate ribosylation of elongation factor 2) is incorrect. This is the mechanism of action of diphtheria toxin.
his is the mechanism of action of Shiga toxin produced by either Shigella dysenteriae or enterohemorrhagic Escherichia coli (e.g., O157:H7).
A. Adenosine diphosphate ribosylation of Gi protein leading to out-of-control synthesis of adenosine 3’,5’-cyclic monophosphate
B. Adenosine diphosphate ribosylation of Gs protein leading to up-regulation of adenylate cyclase
C. Glycosylation of G proteins leading to impaired actin (de)polymerization
D. Inhibition of protein synthesis via adenosine diphosphate ribosylation of elongation factor 2
E. Inhibition of protein synthesis via N-glycosidase activity
Option E (Inhibition of protein synthesis via N-glycosidase activity) is incorrect. This is the mechanism of action of Shiga toxin produced by either Shigella dysenteriae or enterohemorrhagic Escherichia coli (e.g., O157:H7). There is no evidence that the patient has been infected with these pathogens, which typically produce bloody diarrhea.
pleurodynia, myocarditis, pericarditis, and aseptic meningitis. It is also linked to pustular stomatitis associated with erythema multiforme.
A. Coxsackievirus B5
B. Measles virus
C. Parvovirus B19
D. Rubivirus
E. Varicella zoster virus
A. Coxsackievirus B5
B. Measles virus
C. Parvovirus B19
D. Rubivirus
E. Varicella zoster virus
The virus infects erythroid progenitor cells, causing inhibition of erythropoiesis. Because of limited target cell range, it does not cause disseminated infection.
A. Coxsackievirus B5
B. Measles virus
C. Parvovirus B19
D. Rubivirus
E. Varicella zoster virus
Option C (Parvovirus B19) is correct. The outbreak described in this scenario involved fifth disease or erythema infectiosum caused by parvovirus B19. The virus infects erythroid progenitor cells, causing inhibition of erythropoiesis. Because of limited target cell range, it does not cause disseminated infection. Rash associated with fifth disease usually develops soon after seroconversion and is thought to be immune-mediated. Other manifestations include arthritis, particularly in women, and aplastic crisis in persons with underlying hematologic disorders. Rarely, in utero infection can result in miscarriage and Coombs-negative hydrops fetalis. Parvovirus B19 is a small virus with a ssDNA genome.
Rarely, in utero infection can result in miscarriage and Coombs-negative hydrops fetalis.
A. Coxsackievirus B5
B. Measles virus
C. Parvovirus B19
D. Rubivirus
E. Varicella zoster virus
Option C (Parvovirus B19) is correct. The outbreak described in this scenario involved fifth disease or erythema infectiosum caused by parvovirus B19. The virus infects erythroid progenitor cells, causing inhibition of erythropoiesis. Because of limited target cell range, it does not cause disseminated infection. Rash associated with fifth disease usually develops soon after seroconversion and is thought to be immune-mediated. Other manifestations include arthritis, particularly in women, and aplastic crisis in persons with underlying hematologic disorders. Rarely, in utero infection can result in miscarriage and Coombs-negative hydrops fetalis. Parvovirus B19 is a small virus with a ssDNA genome.
presents initially as a severe upper respiratory infection with fever, malaise, anorexia, coryza, and cough. The rash begins on the face and spreads downward.

A. Coxsackievirus B5
B. Measles virus
C. Parvovirus B19
D. Rubivirus
E. Varicella zoster virus
Option B (Measles virus) is incorrect. Measles virus causes a potentially serious childhood disease known as morbilli (measles). The disease presents initially as a severe upper respiratory infection with fever, malaise, anorexia, coryza, and cough. Mucous membranes display characteristic Koplik spots. The rash begins on the face and spreads downward. Complications of measles include pneumonia and encephalitis. The causative agent of measles is paramyxovirus—an enveloped, round-shaped virus with a (-) sense ssRNA.
Symptoms include rash, fever, and lymphadenopathy. First, the rash appears on the face and then spreads to the body.
A. Coxsackievirus B5
B. Measles virus
C. Parvovirus B19
D. Rubivirus
E. Varicella zoster virus
Option D (Rubivirus) is incorrect. Rubivirus causes rubella—a self-limited, febrile rash illness. Symptoms include rash, fever, and lymphadenopathy. First, the rash appears on the face and then spreads to the body. In contrast with measles, rubella rarely causes complications. Rubivirus, belonging to the Togavirus family, is an enveloped virus with a (+) sense ssRNA genome.
s (VZV) is a DNA virus that causes chicken pox (varicella). Symptoms include rash, low-grade fever, and malaise. An itchy rash appears first on the face and trunk and spreads to the rest of the body.
A. Coxsackievirus B5
B. Measles virus
C. Parvovirus B19
D. Rubivirus
E. Varicella zoster virus
Option E (Varicella zoster virus) is incorrect. Varicella zoster virus (VZV) is a DNA virus that causes chicken pox (varicella). Symptoms include rash, low-grade fever, and malaise. An itchy rash appears first on the face and trunk and spreads to the rest of the body. The lesions rapidly evolve into vesicles, followed by crusty pustules. VZV is an enveloped herpesvirus containing a double-stranded DNA (dsDNA). The diagnosis is made clinically.
infects young erythrocytes. The parasites may remain dormant in the liver for many months and even years, periodically entering the bloodstream and triggering relatively mild malaria episodes.
A. Babesiosis
B. Benign tertian or ovale malaria
C. Benign tertian or vivax malaria
D. Malignant tertian or falciparum malaria
E. Quartan or malarial malaria
b and c

Option B (Benign tertian or ovale malaria) is incorrect. P. ovale is the cause of ovale malaria. Similarly to P. vivax, P. ovale infects young, flexible erythrocytes, which causes their distortion and oval transformation; Schüffner dots can be seen in peripheral blood smears. The parasite remains dormant in the liver for months and sometimes years, periodically entering the bloodstream and triggering mild malaria episodes.

Option C (Benign tertian or vivax malaria) is incorrect. P. vivax, the cause of benign tertian malaria, is characterized by febrile paroxysms every 48 hours. The parasite has the propensity to invade young pliable erythrocytes, which are large and contain pink granules known as Schüffner dots. The schizont of P. vivax contains twice as many merozoites as P. ovale. The parasites may remain dormant in the liver for many months and even years, periodically entering the bloodstream and triggering relatively mild malaria episodes.
infects only mature erythrocytes, where it produces characteristic rosettes; it does not have a hepatic phase.
A. Babesiosis
B. Benign tertian or ovale malaria
C. Benign tertian or vivax malaria
D. Malignant tertian or falciparum malaria
E. Quartan or malarial malaria
Option E (Quartan or malarial malaria) is incorrect. P. malariae infection causes fever every 72 hours (quartan malaria). In contrast with P. vivax and P. ovale, P. malariae infects only mature erythrocytes, where it produces characteristic rosettes; it does not have a hepatic phase. The disease is milder than other forms of malaria but relapses may occur.
both young and old erythrocytes may be infected, which become sticky and clog the cerebral blood vessels, causing micro-infarctions. Manifestations include severe headache, seizures, delirium, and coma.
A. Babesiosis
B. Benign tertian or ovale malaria
C. Benign tertian or vivax malaria
D. Malignant tertian or falciparum malaria
E. Quartan or malarial malaria
Option D (Malignant tertian or falciparum malaria) is correct. The patient has classical symptoms of cerebral malaria caused by P. falciparum. In falciparum malaria, both young and old erythrocytes may be infected with P. falciparum, which become sticky and clog the cerebral blood vessels, causing micro-infarctions. Manifestations include severe headache, seizures, delirium, and coma.
The eggs hatch in the small intestine into larvae, which invade the bloodstream and migrate to the lungs where they are coughed up and swallowed. This causes pneumonia-like symptoms with eosinophilia. In extreme cases, when large numbers of the nematode are present, patients can present with bowel obstruction, acute pancreatitis, and other complications.
A. Ancylostoma duodenale
B. Ascaris lumbricoides
C. Enterobius vermicularis
D. Strongyloides stercoralis
E. Taenia solium
Option B (Ascaris lumbricoides) is correct. Ascaris lumbricoides are the largest (25 to 30 cm [10 to 12 inches]) nematodes known to infect humans. Infection is acquired through ingestion of vegetables contaminated with Ascaris eggs. The eggs hatch in the small intestine into larvae, which invade the bloodstream and migrate to the lungs where they are coughed up and swallowed. This causes pneumonia-like symptoms with eosinophilia. In extreme cases, when large numbers of the nematode are present, patients can present with bowel obstruction, acute pancreatitis, and other complications.
The larvae penetrate the skin and migrate to the lungs where they cross the alveolar walls. Once in the airways, they are coughed up and swallowed. In the small intestine, they mature into blood-sucking adult worms.
A. Ancylostoma duodenale
B. Ascaris lumbricoides
C. Enterobius vermicularis
D. Strongyloides stercoralis
E. Taenia solium
Option A (Ancylostoma duodenale) is incorrect. A. duodenale is the Old World hookworm that causes a disease similar to that caused by the New World hookworm, Necator americanus. It is found in Southern Europe, Africa, South America, and Asia. The larvae of A. duodenale penetrate the skin and migrate to the lungs where they cross the alveolar walls. Once in the airways, they are coughed up and swallowed. In the small intestine, they mature into blood-sucking adult worms. Acute infection presents with “ground itch,” midepigastric pain, nausea, vomiting, diarrhea, increased flatulence, and eosinophilia. Heavy and chronic infestation with A. duodenale results in anemia, cardiac manifestations, and mental retardation.
infection is acquired through ingestion of eggs. The eggs hatch into larvae in the small intestine where they mature into adult worms. The adult male and female worms migrate to the colon to mate. The female worm then migrates further down and lays eggs in the perianal skin folds, causing perianal itching.
A. Ancylostoma duodenale
B. Ascaris lumbricoides
C. Enterobius vermicularis
D. Strongyloides stercoralis
E. Taenia solium
Option C (Enterobius vermicularis) is incorrect. E. vermicularis infection is acquired through ingestion of Enterobius eggs. The eggs hatch into larvae in the small intestine where they mature into adult worms. The adult male and female worms migrate to the colon to mate. The female worm then migrates further down and lays eggs in the perianal skin folds, causing perianal itching.
filariform larvae that penetrate the skin and migrate through the lungs to the upper airway where they are swallowed. In the small intestine, the larvae mature into adult parasitic females, which are capable of causing autoinfection. In immunocompromised persons such as this patient, the autoinfection can lead to a hyperinfection syndrome
A. Ancylostoma duodenale
B. Ascaris lumbricoides
C. Enterobius vermicularis
D. Strongyloides stercoralis
E. Taenia solium
Option D (Strongyloides stercoralis) is incorrect. Strongyloides stercoralis is a tiny (2-mm [.08 inch-] long) nematode. Humans become infected with filariform larvae that penetrate the skin and migrate through the lungs to the upper airway where they are swallowed. In the small intestine, the larvae mature into adult parasitic females, which are capable of causing autoinfection. In immunocompromised persons such as this patient, the autoinfection can lead to a hyperinfection syndrome and disseminated strongyloidiasis associated with a significant mortality rate.
nfection is limited to the intestine and is often asymptomatic. If symptoms occur, they consist of anorexia, nausea, weight loss, and diarrhea.
A. Ancylostoma duodenale
B. Ascaris lumbricoides
C. Enterobius vermicularis
D. Strongyloides stercoralis
E. Taenia solium
Option E (Taenia solium) is incorrect. Taenia solium is a pork tapeworm that causes taeniasis. It is very unlikely in this Turkish man because he probably would not eat pork because of his religious beliefs. The infection is limited to the intestine and is often asymptomatic. If symptoms occur, they consist of anorexia, nausea, weight loss, and diarrhea. The scolex of T. solium contains a crown of hooklets and sucking grooves. Adult worms are flat and measure 2 to 8 m (6.5 to 26 feet) in length.
poststreptococcal glomerulonephritis
A. Dense subendothelial deposits
B. IgA deposits
C. Ribbon-like dense intramembranous deposits
D. Subepithelial hump
E. “Tram track”-like glomerular capillary wall
Option D (Subepithelial hump) is correct. The patient has developed poststreptococcal glomerulonephritis. Immunofluorescent staining of the biopsied tissue would show IgG, IgM and C3 deposits in the mesangium and on the basement membrane. Electron microscopy shows electron dense subepithelial humps, which are most likely immune complex deposits.
Type I MPGN

A. Dense subendothelial deposits
B. IgA deposits
C. Ribbon-like dense intramembranous deposits
D. Subepithelial hump
E. “Tram track”-like glomerular capillary wall
Option A (Dense subendothelial deposits) is incorrect. Dense subendothelial deposits are characteristic of Type I MPGN. Immunofluorescent staining shows deposition of C3, IgG, C1q and C4.
Berger disease and Henoch-Schönlein purpura as well as secondary nephropathy in patients with underlying liver and intestinal diseases.
A. Dense subendothelial deposits
B. IgA deposits
C. Ribbon-like dense intramembranous deposits
D. Subepithelial hump
E. “Tram track”-like glomerular capillary wall
Option B (IgA deposits) is incorrect. IgA deposits are present in IgA nephropathy (Berger disease) – the most common type of glomerulonephritis worldwide. IgA deposits are also present in Henoch-Schönlein purpura as well as secondary IgA nephropathy in patients with underlying liver and intestinal diseases.
characteristic of MPGN type II.

A. Dense subendothelial deposits
B. IgA deposits
C. Ribbon-like dense intramembranous deposits
D. Subepithelial hump
E. “Tram track”-like glomerular capillary wall
Option C (Ribbon-like dense intramembranous deposits) is incorrect. Ribbon-like, extremely dense deposits in the glomerular basement membrane of unknown origin are characteristic of MPGN type II. Immunofluorescent staining shows C3 outside the dense deposits.
characteristic of both type I and type II membranoproliferative glomerulonephritis (MPGN)

A. Dense subendothelial deposits
B. IgA deposits
C. Ribbon-like dense intramembranous deposits
D. Subepithelial hump
E. “Tram track”-like glomerular capillary wall
Option E (“Tram track”-like glomerular capillary wall ) is incorrect. “Tram track”-like appearance of the glomerular capillary wall is due to duplication of the basement membrane characteristic of both type I and type II membranoproliferative glomerulonephritis (MPGN).
Manifestations include dermatitis, subcutaneous nodules, keratitis, and chorioretinitis.
A. African trypanosomiasis
B. Katayama fever
C. Malaria
D. Onchocerciasis
E. Serum sickness
Option D (Onchocerciasis) is incorrect. Onchocerciasis is a major cause of blindness in Africa and Central America. The disease is caused by Onchocerca volvulus, which is transmitted to humans by a blackfly called Simulium damnosum. Manifestations include dermatitis, subcutaneous nodules, keratitis, and chorioretinitis. Onchocerciasis often is referred to as river blindness because it affects primarily indigenous people who reside along the rivers where blackflies breed.
High lactate dehydrogenase (LDH) and indirect bilirubin occurs in hemolytic uremic syndrome (HUS). Why?
RBCs are injured while passing through partially occluded capillaries. Some cells lyse, leaking LDH and hemoglobin. The liver becomes overloaded with bilirubin and cannot conjugate all of it, hence the rise in unconjugated or indirect bilirubin.

The hallmark of hemolytic uremic syndrome (HUS) is the appearance of schistocytes in the peripheral blood smear, representing damaged red blood cells (RBCs).
Patients with HUS from E. coli O157:H7typically have thrombocytopenia. Why?
Shiga toxin that damages the endothelium. As a consequence, platelet aggregation occurs in microvasculature with microthrombi occluding arterioles and glomerular capillaries. This leads to renal failure and thrombocytopenia.
abdominal pain and dysuria. A urinalysis showed microhematuria.
A. Clonorchis sinensis
B. Schistosoma hematobium
C. Schistosoma japonicum
D. Schistosoma mansonii
E. Wuchereria bancrofti
Option B (Schistosoma hematobium) is correct. S. haematobium parasitizes the venous plexus of the bladder. The eggs are steadily moved toward the lumen of the bladder and ureters and are eliminated with urine. In endemic areas of Africa, granulomatous disease of the bladder with resulting obstructive uropathy is quite common. The distinguishing characteristic of S. haematobium egg is the terminal spine.
After being injected into the skin, the larvae of the parasite spread to the lymph nodes where they mature into adult nematodes. The presence of these worms causes inflammation and obstruction of the lymphatics, resulting in lymphedema.

A. Clonorchis sinensis
B. Schistosoma hematobium
C. Schistosoma japonicum
D. Schistosoma mansonii
E. Wuchereria bancrofti
Option E (Wuchereria bancrofti) is incorrect. W. bancrofti causes a mosquito-borne disease known as filariasis. After being injected into the skin, the larvae of the parasite spread to the lymph nodes where they mature into adult nematodes. The presence of these worms causes inflammation and obstruction of the lymphatics, resulting in lymphedema. Recurrent infections can lead to massive edema of the legs and genitalia, causing elephantiasis. The demonstration of microfilariae in thick blood smears confirms the diagnosis.