Myocarditis, Lyme; Cardiac, Vascular Tumors
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A 35-year-old female from Argentina complained for 3 months of shortness of breath, ankle swelling and palpitations. An X-ray showed cardiomegaly and a serological test showed antibodies to Trypanosoma cruzi. Before the serological result was available, the doctor suspected Chagas’ disease because of which clue?
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Pancytopenia due to splenomegaly
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Common reports of sandfly bites in his community
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Earlier presence of skin ulcer and eye swelling
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Blood smear showing amastigotes of T. cruzi
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.JPG "Myocarditis, Lyme; Cardiac, Vascular Tumors - Quiz")
Hello everyone and welcome back to another quiz in our long line of medical examinations. Today we’ll be taking a close look at some terrible illnesses and conditions including myocarditis, Lyme disease, as well as cardiac and vascular tumours. What do you know about them?
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- 2.
A 37-year-old female from Columbia complained for a month of palpitations, intermittent chest pain, dyspnea on exertion, and swollen ankles. The x-ray showed cardiomegaly and the EKG showed ST-wave abnormalities. What was a preceding event in his disease?
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Blood smear that showed amastigotes of Trypanosoma cruzi
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Transmission by infected feces of reduvid bug after its bite
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Cardiac muscle cells contained trypomastigotes of Trypanosoma cruzi
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Severe anemia causing high-output heart failure
Correct Answer
A. Transmission by infected feces of reduvid bug after its biteExplanation
The correct answer is "Transmission by infected feces of reduvid bug after its bite." This is the preceding event in the disease because it suggests that the patient has contracted Chagas disease, which is caused by the parasite Trypanosoma cruzi. The symptoms described, such as palpitations, chest pain, dyspnea on exertion, and swollen ankles, are consistent with the cardiac manifestations of Chagas disease. The presence of cardiomegaly on the x-ray and ST-wave abnormalities on the EKG further support this diagnosis.Rate this question:
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- 3.
An eleven year old boy presents with a two-days of severe headache, fever, and malaise followed yesterday by a macular rash on his extremities that appeared to be spreading inward. In taking his history, you find he had been tent camping with the family in South Carolina and had several "large" ticks removed first 14 days ago and for the next 4 days. Your thorough exam shows some edema of the extremities and a petechial rash largely on his extremities. You realize this might be serious and start him immediately on doxycycline. What is the pathophysiology of this disease?
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Multiplication of the causative agent in the skin with subsequent damage
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Immune-mediated rash
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Endothelial cell invasion and cellular destruction
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Adhesion of an organism to endothelial cells with damage from the outside
Correct Answer
A. Endothelial cell invasion and cellular destructionExplanation
The presentation of severe headache, fever, malaise, macular rash, and tick exposure suggests a possible tick-borne illness. The presence of edema, petechial rash, and the spreading nature of the rash indicate endothelial cell invasion and cellular destruction. Tick-borne illnesses such as Rocky Mountain spotted fever or Lyme disease can cause damage to endothelial cells, leading to symptoms like rash, edema, and petechiae. Prompt treatment with doxycycline is necessary to prevent further complications.Rate this question:
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- 4.
A 24-year-old man from New Jersey with fever and myalgias for a week develops shortness of breath and palpitations. In the clinic his pulse is irregular, there is no heart murmur, and the x-ray shows an enlarged heart. The doctor suspects myocarditis. What microbial etiology is the likely cause of his illness?
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Lyme disease
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Diphtheria
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Coxsackievirus
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Streptococcus pyogenes evoking acute rheumatic fever
Correct Answer
A. CoxsackievirusExplanation
The most likely microbial etiology for this patient's myocarditis is Coxsackievirus. Coxsackievirus is a common cause of viral myocarditis, which is inflammation of the heart muscle. The patient's symptoms of fever, myalgias, shortness of breath, and palpitations are consistent with myocarditis. The irregular pulse and enlarged heart on x-ray further support this diagnosis. Lyme disease, diphtheria, and Streptococcus pyogenes evoking acute rheumatic fever are not typically associated with myocarditis.Rate this question:
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- 5.
Your patient has been hiking along the Appalachian Trail for three weeks. While hiking he wore shorts and did not use insect repellant. He admitted that he appeared to get bitten quite frequently. Upon his return he noticed that he developed a fever along with severe headaches. Upon examination you notice a distinct macular rash upon his wrists, with obvious signs of myalgia. The patient asks why he feels so sick and you reply that this is partly due to his immune response. Which aspect of the patient’s immune response is considered to be crucial to his immune defense against the pathogen that is most likely causing his infection?
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CD8+ T cells
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Neutrophils
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MAC of complement
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CD4+ T cells
Correct Answer
A. CD8+ T cellsExplanation
Rickettsia:
Immune Response:
Antibodies form but are not protective
Antibodies can be used for diagnosis; cross-reacting antibodies to Proteus vulgaris was basis for older Weil-Felix reaction
CD8+ T cells important in clearance of organisms by destroying infected endothelial cells
Interferon-γ and TNF-α activate infected endothelial cells to kill organismsRate this question:
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- 6.
Four days after a camping trip in Oklahoma, a 24-year-old man presents with fever, headache, myalgia, and red, macular rash on his palms, soles, and arms. The causative organism infected primarily which cells and cell compartment?
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Granulocytes and vacuole
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Endothelial cells and cytoplasm
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Monocytes and cytoplasm
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Endothelial cells and vacuole
Correct Answer
A. Endothelial cells and cytoplasmExplanation
Biology of Rickettsia and Orientia
Obligate intracellular bacteria
Small : 0.3-1µm
Gram-negative - contain lipopolysaccharide and peptidoglycan
Serotyping by surface proteins called OmpA and OmpB
Invade vascular endothelial cells by phagocytosis
Escape from phagosome to cytoplasm where they obtain ATP, amino acids, and phosphorylated sugarsRate this question:
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- 7.
A 17-year old "street kid" is brought in from a free clinic because he had been sick with a fever and malaise for several days and when he presented to the free clinic, he was febrile and complaining of exertional fatigue. On exam had a heart murmur which he doesn't think he had when he ran away from his upper middle class home. He uses intravenous drugs. Imaging revealed a tricuspid vegetation. What is the most likely causative agent?
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Bartonella spp
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Candida albicans
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Enterococcus faecalis
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Staphylococcus aureus
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Streptococcus pyogenes
Correct Answer
A. Staphylococcus aureusExplanation
The most likely causative agent for the tricuspid vegetation in this case is Staphylococcus aureus. This is because the patient is a young "street kid" who uses intravenous drugs, which puts him at high risk for developing infective endocarditis. Staphylococcus aureus is a common cause of infective endocarditis in this population, and the presence of a heart murmur suggests an infection of the heart valves. Imaging revealing a tricuspid vegetation further supports the diagnosis of infective endocarditis caused by Staphylococcus aureus.Rate this question:
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- 8.
A 37-year-old unemployed man without health insurance had not been to a dentist for a long time. He came to the ER with a 2-week history of fever and fatigue. He had several carious teeth, an aortic diastolic murmur, and sore red nodules on the tips of his fingers. Bacteria grown in blood cultures would have which characteristics?
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Catalase-positive, coagulase-positive, beta hemolytic
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Catalase-positive, coagulase-negative, nonhemolytic
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Catalase-negative, alpha hemolytic, optochin resistant
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Catalase-negative, resistant to bile, resistant to high salt
Correct Answer
A. Catalase-negative, alpha hemolytic, optochin resistantExplanation
The patient's symptoms and physical examination findings suggest that he may have infective endocarditis, which is an infection of the heart valves. The presence of aortic diastolic murmur and sore red nodules on the tips of his fingers (known as Osler's nodes) are consistent with this diagnosis. In cases of infective endocarditis, the most common causative organism is Streptococcus viridans, which is catalase-negative, alpha hemolytic, and optochin resistant. Therefore, the correct answer is Catalase-negative, alpha hemolytic, optochin resistant.Rate this question:
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- 9.
A 58-year-old male complains of a 2-week history of fever and fatigue. A month ago he had 3 carious teeth extracted. You notice tender red nodules on his finger tips, splinter hemorrhages in fingernail beds, a Roth spot in a fundus, and a grade II/VI diastolic decrescendo murmur over the aortic and pulmonic areas. Two blood cultures grow Streptococcus mutans. What was the likely order of events in his illness?
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Bacteria in the blood attached to the endothelium of his aortic valve, a bacterial vegetation formed, emboli caused infarcts in his finger and eye
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Endothelial injury on his aortic valve led to nonbacterial thrombi, pieces of nonbacterial thrombi broke off and caused infarcts in his fingers and eye, bacteria in the blood attached to nonbacterial thrombi
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Nonbacterial thrombi formed on his aortic valve, bacteria in blood attached to the nonbacterial thrombi, antibodies formed antigen-antibody complexes that caused vascular damage in his fingers and eye
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Nonbacterial thrombi formed on his aortic valve, bacteria in blood attached to the nonbacterial thrombi, emboli caused infarcts in his fingers and eye
Correct Answer
A. Nonbacterial thrombi formed on his aortic valve, bacteria in blood attached to the nonbacterial thrombi, emboli caused infarcts in his fingers and eyeExplanation
The patient's symptoms and physical examination findings are consistent with infective endocarditis. The presence of tender red nodules on his fingertips, splinter hemorrhages in fingernail beds, a Roth spot in the fundus, and a diastolic decrescendo murmur over the aortic and pulmonic areas suggest embolic phenomena. The blood cultures growing Streptococcus mutans indicate a bacterial infection. The likely order of events in his illness is that nonbacterial thrombi formed on his aortic valve, bacteria in the blood attached to the nonbacterial thrombi, and emboli caused infarcts in his fingers and eye.Rate this question:
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- 10.
Which of these agents of endocarditis would not show up in two days on routine cultures?
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Bartonella spp
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Candida albicans
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Enterococcus faecalis
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Staphylococcus aureus
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Streptococcus pyogenes
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Viridans Streptococci
Correct Answer
A. Bartonella sppExplanation
Bartonella (formerly known as Rochalimaea) is a genus of Gram-negative bacteria. Facultative intracellular parasites, Bartonella species can infect healthy people but are considered especially important as opportunistic pathogens. Bartonella are transmitted by insect vectors such as ticks, fleas, sand flies, and mosquitoes. At least eight Bartonella species or subspecies are known to infect humans.
Bartonella henselae is the organism responsible for cat scratch disease, a self-limited disease except in immunocompromised hosts.Rate this question:
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- 11.
Which of the following test would be most helpful in confirming the diagnosis of the gross and microscopic lesion shown in images 1A & 1B?
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HHV 8 antibody test
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ANCA
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P-ANCA
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HIV antibody test
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CD 31 markers
Correct Answer
A. HHV 8 antibody testExplanation
The HHV 8 antibody test would be most helpful in confirming the diagnosis of the gross and microscopic lesion shown in images 1A & 1B. HHV 8, also known as human herpesvirus 8 or Kaposi's sarcoma-associated herpesvirus (KSHV), is strongly associated with Kaposi's sarcoma, a cancer that can present with the type of lesions shown in the images. Therefore, testing for HHV 8 antibodies can help confirm the diagnosis of Kaposi's sarcoma in this case.Rate this question:
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- 12.
A 44-year-old Hispanic female is brought to the emergency room with syncope, dizziness, and left-sided hemiplegia. After admission she developed intense chest pain and died. Postmortem examination reveals a cerebral infarction in the area of the middle cerebral artery and the left atrial lesion presented in the picture below. Which of the following is the most likely histologic findings in this case?
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Myxoid matrix with sparse stellate cells
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Hemorrhagic apipose tissue
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Bundles of spindle-shaped cells and vascular channels
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Pleomorphic rhabdomyocytes
Correct Answer
A. Myxoid matrix with sparse stellate cellsExplanation
Although a myxoma is not cancer, complications are common. Untreated, a myxoma can lead to an embolism (tumor cells breaking off and traveling with the bloodstream), which can block blood flow. Myxoma fragments can move to the brain, eye, or limbs.
If the tumor grows inside the heart, it can block blood flow through the mitral valve and cause symptoms of mitral stenosis. This may require emergency surgery to prevent sudden death.
Myxomas are the most common type of primary heart tumor.
The tumor is derived from multipotential mesenchymal cells and may cause a ball valve-type obstruction.
About 75% of myxomas occur in the left atrium of the heart, usually beginning in the wall that divides the two upper chambers of the heart. The rest are in the right atrium. Right atrial myxomas are sometimes associated with tricuspid stenosis and atrial fibrillation.
Myxomas are more common in women. About 10% of myxomas are passed down through families (inherited). Such tumors are called familial myxomas. They tend to occur in more than one part of the heart at a time, and often cause symptoms at a younger age than other myxomasRate this question:
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- 13.
A 36-year-old man in Texas with fever, headache, myalgia, and tick exposure had a serological test that showed antibodies against Ehrlichia chafeeensis. What is a feature of Ehrlichia that differs from other Rickettsia?
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Invasion of mononuclear leukocytes
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Invasion of vascular endothelium
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Cell wall that contains peptidoglycan
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Cell wall that contains lipopolysaccharide
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Invasion of polymorphonuclear leukocytes
Correct Answer
A. Invasion of mononuclear leukocytesExplanation
Ehrlichia differs from other Rickettsia in that it invades mononuclear leukocytes, while other Rickettsia typically invade polymorphonuclear leukocytes.Rate this question:
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- 14.
An outbreak of murine (endemic) typhus occurred in the US in 2008. Affected patients experienced fever, headache, chills, vomiting, nausea, myalgia, and rash. Of the 53 cases, 62% had a four-fold rise in antibody titer to Rickettsia typhi antigens. What is the vector associated with transmission of this organism?
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Mosquito
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Body louse
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Tick
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Flea
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Sand fly
Correct Answer
A. FleaExplanation
The correct answer is flea. Murine typhus is caused by Rickettsia typhi, which is transmitted to humans through the bite of infected fleas. Fleas become infected when they feed on small mammals, such as rats, that carry the bacteria. When an infected flea bites a human, it can transmit the bacteria, leading to the development of murine typhus. This explains why an outbreak of murine typhus occurred and why affected patients experienced symptoms such as fever, headache, chills, and rash.Rate this question:
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- 15.
How are the obligate intracellular pathogens of the genera Rickettsia, Ehrlichia, and Anaplasma transmitted by vectors?
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All are transmitted by ticks except for Rickettsia typhi, which is transmitted by lice
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Rocky Mountain spotted fever is transmitted mainly by Amblyoma ticks found in Texas
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Anaplasma is transmitted mainly by Ixodes ticks, which can be co-infected with Babesia or agent of Lyme disease
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Epidemic typhus is transmitted mainly by rodent fleas
Correct Answer
A. Anaplasma is transmitted mainly by Ixodes ticks, which can be co-infected with Babesia or agent of Lyme diseaseExplanation
The obligate intracellular pathogens of the genera Rickettsia, Ehrlichia, and Anaplasma are transmitted by vectors, with Anaplasma being mainly transmitted by Ixodes ticks. These ticks can also be co-infected with Babesia or the agent of Lyme disease.Rate this question:
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.JPG "A 44-year-old Hispanic female is brought to the emergency room with syncope, dizziness, and left-sided hemiplegia. After admission she developed intense chest pain and died. Postmortem examination reveals a cerebral infarction in the area of the middle cerebral artery and the left atrial lesion presented in the picture below. Which of the following is the most likely histologic findings in this case?")
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Mar 22, 2023Quiz Edited by
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Jul 14, 2012Quiz Created by
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