Micro 3050 {Clemson University}
Test Bank Actual Exam Questions
Reviewed 100% With Correct
Detailed Answers & Rationales
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1. A debilitated 72-year-old woman develops dry cough, fever, headache, and
muscular pains. She treats herself with aspirin and ampicillin without any
improvement. Her children take her to a local hospital, where chest x-ray
films reveal scattered opacities, suggestive of interstitial infiltration.
Laboratory investigations demonstrate the presence of cold agglutinins. She
is treated with erythromycin, and her symptoms rapidly improve. Which of
the following is the most likely etiologic agent of this patient's condition?
A. Influenza virus
B. Mycoplasma pneumoniae
C. Pneumocystis carinii
D. Respiratory syncytial virus
E. Streptococcus pneumoniae - The correct answer is B. The patient's clinical
presentation is typical of primary atypical pneumonia. In contrast to bacterial
pneumonia, primary atypical pneumonia presents with the following features:
- Caused by M. pneumoniae; less frequently by viruses (influenza, respiratory
syncytial virus, adenovirus,
,rhinoviruses, rubeola and varicella virus), Chlamydia, or Coxiella burnetii
- Characterized pathologically by interstitial, rather than intra-alveolar,
inflammation
- Characterized clinically by nonspecific symptomatology and few "localizing"
symptoms
Why is M. pneumoniae, and not influenza virus (choice A) or respiratory syncytial
virus (choice D), the cause of this patient's pneumonia? First, M. pneumoniae
infections are often associated with the appearance of cold agglutinins in the
serum, detection of which is diagnostically important. Second, the patient
responded quickly to treatment with erythromycin, an antibiotic effective against
M. pneumoniae, but obviously not effective in treating viral infections.
Pneumocystis carinii(choice C) is a fungal organism causing pneumonia in severely
immunocompromised hosts, especially AIDS patients. P. carinii pneumonia (PCP) is
characterized by accumulation of a frothy exudate containing numerous
organisms within alveolar spaces. Also, P. carinii is not sensitive to erythromycin.
The drug of choice for treatment of PCP is trimethoprim-sulfamethoxazole.
Streptococcus pneumoniae(choice E) is the usual causative agent of lobar
pneumonia, characterized by consolidation of a single lobe due to intra-alveolar
acute inflammatory exudation. Lobar pneumonia is more prevalent in young,
healthy individuals, whereas primary atypical pneumonia favors old, debilitated
patients. S. pneumoniae is highly sensitive to penicillin.
2. A 43-year-old executive presents to a physician with chronic, symmetric
polyarthritis involving the knees. The man gives a history of having
developed an extensive rash after a deer hunting trip in Connecticut several
years earlier. He recalls that he felt "sick" at the time, and developed knee
pain that prevented him from climbing stairs for several months, but then
, partially resolved. Which of the following organisms is most likely
etiologically related to the patient's arthritis?
A. Fungus
B. Gram-negative cocci
C. Gram-negative rod
D. Gram-positive cocci
E. Spirochete - The correct answer is E. The history is characteristic for Lyme
disease, caused by the spirochete Borrelia burgdorferi. The clues are deer,
Connecticut, rash, knees, and acute arthritis followed by chronic arthritis.
Fungal arthritis (choice A) can be caused by coccidioidomycosis, blastomycosis,
sporotrichosis, and
candidiasis.
N. gonorrhoeae are gram-negative cocci (choice B) that can cause septic arthritis.
Haemophilus (young children) and Salmonella (sickle cell patients) are gram-
negative rods (choice C) that can cause septic arthritis.
Staphylococcus are gram-positive cocci (choice E) that can cause septic arthritis.
3. A 39-year-old HIV-positive man is brought into the emergency room after
experiencing a seizure witnessed by several friends. The observers relate
that the patient suddenly lost consciousness and experienced both leg and
arm jerking. The man's tongue has been severely bitten, and loss of bowel
and bladder function is evident upon admission. On physical examination,
the patient is lethargic, unable to answer simple questions, and has an
obvious left-sided hemiparesis. An MRI of the head shows multiple ring-
enhancing lesions. Infection with which of the following agents is most
likely responsible for this presentation?
, A. Cryptococcus neoformans
B. Herpes simplex
C. Mycobacteria tuberculosis
D. JC virus
E. Toxoplasma gondii - The correct answer is E. While all five pathogens can
cause central nervous system (CNS) manifestations, toxoplasmosis (caused by
Toxoplasma gondii) presents with seizures in 15-25% of cases. The disease is
spread by ingestion of cysts from undercooked meat or from cat feces. Tachyzoites
develop from cysts phagocytized by macrophages, then spread to the brain,
muscle, and other tissues, where they encyst and multiply. Primary CNS
lymphoma in AIDS patients can present clinically in nearly the same manner as
toxoplasmosis, but the course is usually much more indolent.
Cryptococcal meningitis (choice A) usually presents as a subacute meningitis with
headache, nausea, vomiting, and confusion. Cranial nerve abnormalities are
common with cryptococcal infections.
Herpes simplex encephalitis (choice B) typically has a subacute onset with
headache, meningismus, and personality changes.
Mycobacterium tuberculosis (choice C) is a cause of a basilar meningitis, which
can present insidiously with headache and mental changes over a week or two, or
can present acutely as confusion, lethargy, altered sensorium, and a stiff neck.
Cranial nerve palsies, focal cerebral ischemia, and hydrocephalus are
characteristic.
Test Bank Actual Exam Questions
Reviewed 100% With Correct
Detailed Answers & Rationales
Guaranteed Pass!!
1. A debilitated 72-year-old woman develops dry cough, fever, headache, and
muscular pains. She treats herself with aspirin and ampicillin without any
improvement. Her children take her to a local hospital, where chest x-ray
films reveal scattered opacities, suggestive of interstitial infiltration.
Laboratory investigations demonstrate the presence of cold agglutinins. She
is treated with erythromycin, and her symptoms rapidly improve. Which of
the following is the most likely etiologic agent of this patient's condition?
A. Influenza virus
B. Mycoplasma pneumoniae
C. Pneumocystis carinii
D. Respiratory syncytial virus
E. Streptococcus pneumoniae - The correct answer is B. The patient's clinical
presentation is typical of primary atypical pneumonia. In contrast to bacterial
pneumonia, primary atypical pneumonia presents with the following features:
- Caused by M. pneumoniae; less frequently by viruses (influenza, respiratory
syncytial virus, adenovirus,
,rhinoviruses, rubeola and varicella virus), Chlamydia, or Coxiella burnetii
- Characterized pathologically by interstitial, rather than intra-alveolar,
inflammation
- Characterized clinically by nonspecific symptomatology and few "localizing"
symptoms
Why is M. pneumoniae, and not influenza virus (choice A) or respiratory syncytial
virus (choice D), the cause of this patient's pneumonia? First, M. pneumoniae
infections are often associated with the appearance of cold agglutinins in the
serum, detection of which is diagnostically important. Second, the patient
responded quickly to treatment with erythromycin, an antibiotic effective against
M. pneumoniae, but obviously not effective in treating viral infections.
Pneumocystis carinii(choice C) is a fungal organism causing pneumonia in severely
immunocompromised hosts, especially AIDS patients. P. carinii pneumonia (PCP) is
characterized by accumulation of a frothy exudate containing numerous
organisms within alveolar spaces. Also, P. carinii is not sensitive to erythromycin.
The drug of choice for treatment of PCP is trimethoprim-sulfamethoxazole.
Streptococcus pneumoniae(choice E) is the usual causative agent of lobar
pneumonia, characterized by consolidation of a single lobe due to intra-alveolar
acute inflammatory exudation. Lobar pneumonia is more prevalent in young,
healthy individuals, whereas primary atypical pneumonia favors old, debilitated
patients. S. pneumoniae is highly sensitive to penicillin.
2. A 43-year-old executive presents to a physician with chronic, symmetric
polyarthritis involving the knees. The man gives a history of having
developed an extensive rash after a deer hunting trip in Connecticut several
years earlier. He recalls that he felt "sick" at the time, and developed knee
pain that prevented him from climbing stairs for several months, but then
, partially resolved. Which of the following organisms is most likely
etiologically related to the patient's arthritis?
A. Fungus
B. Gram-negative cocci
C. Gram-negative rod
D. Gram-positive cocci
E. Spirochete - The correct answer is E. The history is characteristic for Lyme
disease, caused by the spirochete Borrelia burgdorferi. The clues are deer,
Connecticut, rash, knees, and acute arthritis followed by chronic arthritis.
Fungal arthritis (choice A) can be caused by coccidioidomycosis, blastomycosis,
sporotrichosis, and
candidiasis.
N. gonorrhoeae are gram-negative cocci (choice B) that can cause septic arthritis.
Haemophilus (young children) and Salmonella (sickle cell patients) are gram-
negative rods (choice C) that can cause septic arthritis.
Staphylococcus are gram-positive cocci (choice E) that can cause septic arthritis.
3. A 39-year-old HIV-positive man is brought into the emergency room after
experiencing a seizure witnessed by several friends. The observers relate
that the patient suddenly lost consciousness and experienced both leg and
arm jerking. The man's tongue has been severely bitten, and loss of bowel
and bladder function is evident upon admission. On physical examination,
the patient is lethargic, unable to answer simple questions, and has an
obvious left-sided hemiparesis. An MRI of the head shows multiple ring-
enhancing lesions. Infection with which of the following agents is most
likely responsible for this presentation?
, A. Cryptococcus neoformans
B. Herpes simplex
C. Mycobacteria tuberculosis
D. JC virus
E. Toxoplasma gondii - The correct answer is E. While all five pathogens can
cause central nervous system (CNS) manifestations, toxoplasmosis (caused by
Toxoplasma gondii) presents with seizures in 15-25% of cases. The disease is
spread by ingestion of cysts from undercooked meat or from cat feces. Tachyzoites
develop from cysts phagocytized by macrophages, then spread to the brain,
muscle, and other tissues, where they encyst and multiply. Primary CNS
lymphoma in AIDS patients can present clinically in nearly the same manner as
toxoplasmosis, but the course is usually much more indolent.
Cryptococcal meningitis (choice A) usually presents as a subacute meningitis with
headache, nausea, vomiting, and confusion. Cranial nerve abnormalities are
common with cryptococcal infections.
Herpes simplex encephalitis (choice B) typically has a subacute onset with
headache, meningismus, and personality changes.
Mycobacterium tuberculosis (choice C) is a cause of a basilar meningitis, which
can present insidiously with headache and mental changes over a week or two, or
can present acutely as confusion, lethargy, altered sensorium, and a stiff neck.
Cranial nerve palsies, focal cerebral ischemia, and hydrocephalus are
characteristic.
