COMSAE 107:- QUESTIONS AND ANSWERS (GRADED A+)
## Section 1: Infectious Disease
### Question 1
A 24-year-old woman presents with dysuria, frequency, and urgency for 2 days. She is otherwise healthy
with no significant medical history. Urinalysis shows positive leukocyte esterase and nitrites. What is the
most appropriate initial treatment?
A. Ciprofloxacin
B. Nitrofurantoin
C. Trimethoprim-sulfamethoxazole
D. Ceftriaxone
**Answer: B. Nitrofurantoin**
**Rationale:** This patient has uncomplicated acute cystitis. Nitrofurantoin is first-line therapy
due to low resistance rates and minimal systemic side effects . Fluoroquinolones (ciprofloxacin) are
avoided as first-line agents due to resistance concerns and side effect profile. TMP-SMX is an alternative
but resistance is increasing. Ceftriaxone is typically reserved for pyelonephritis.
---
### Question 2
A 19-year-old college student presents with fever, sore throat, posterior cervical lymphadenopathy, and
splenomegaly. Heterophile antibody test (Monospot) is positive. What is the causative agent?
A. Cytomegalovirus
B. Epstein-Barr virus
C. Adenovirus
D. HIV
,**Answer: B. Epstein-Barr virus**
**Rationale:** The classic triad of fever, pharyngitis, and lymphadenopathy along with
splenomegaly in a young adult is characteristic of infectious mononucleosis caused by EBV . The
Monospot test detects heterophile antibodies, which are positive in 90% of cases by the second week.
CMV can cause a similar syndrome but is Monospot-negative. Important clinical pearl: Avoid
amoxicillin/ampicillin in suspected EBV as it causes a characteristic maculopapular rash.
---
### Question 3
A 45-year-old man with a history of COPD presents with fever, productive cough with green sputum, and
right lower lobe consolidation on chest x-ray. Which organism is the most likely cause?
A. Mycoplasma pneumoniae
B. Streptococcus pneumoniae
C. Haemophilus influenzae
D. Moraxella catarrhalis
**Answer: B. Streptococcus pneumoniae**
**Rationale:** S. pneumoniae remains the most common cause of community-acquired
pneumonia (CAP) regardless of underlying lung disease . Typical presentation includes acute onset fever,
productive cough, and lobar consolidation. While H. influenzae and M. catarrhalis are common in COPD
exacerbations, they typically cause bronchitis rather than lobar pneumonia. M. pneumoniae presents
more subacutely with extrapulmonary symptoms.
---
### Question 4
, A 19-year-old woman presents with fever, hypotension, diffuse erythematous rash, and desquamation of
the palms. She reports using super-absorbent tampons during her last menstrual period. Which
organism is responsible?
A. Streptococcus pyogenes
B. Staphylococcus aureus
C. Pseudomonas aeruginosa
D. Neisseria meningitidis
**Answer: B. Staphylococcus aureus**
**Rationale:** This is toxic shock syndrome (TSS) caused by S. aureus producing TSST-1
superantigen . The superantigen bypasses normal antigen presentation, causing massive T-cell activation
and cytokine storm. Tampon use is a classic risk factor. Desquamation, especially of palms and soles,
occurs 1-2 weeks after onset. Group A Strep can cause streptococcal TSS but is less associated with
tampon use.
---
### Question 5
A 35-year-old woman presents with hemoptysis, hematuria, and rapidly progressive glomerulonephritis.
Labs show anti-glomerular basement membrane (anti-GBM) antibodies. What is the most likely
diagnosis?
A. Granulomatosis with polyangiitis
B. Microscopic polyangiitis
C. Goodpasture syndrome
D. Lupus nephritis
**Answer: C. Goodpasture syndrome**
## Section 1: Infectious Disease
### Question 1
A 24-year-old woman presents with dysuria, frequency, and urgency for 2 days. She is otherwise healthy
with no significant medical history. Urinalysis shows positive leukocyte esterase and nitrites. What is the
most appropriate initial treatment?
A. Ciprofloxacin
B. Nitrofurantoin
C. Trimethoprim-sulfamethoxazole
D. Ceftriaxone
**Answer: B. Nitrofurantoin**
**Rationale:** This patient has uncomplicated acute cystitis. Nitrofurantoin is first-line therapy
due to low resistance rates and minimal systemic side effects . Fluoroquinolones (ciprofloxacin) are
avoided as first-line agents due to resistance concerns and side effect profile. TMP-SMX is an alternative
but resistance is increasing. Ceftriaxone is typically reserved for pyelonephritis.
---
### Question 2
A 19-year-old college student presents with fever, sore throat, posterior cervical lymphadenopathy, and
splenomegaly. Heterophile antibody test (Monospot) is positive. What is the causative agent?
A. Cytomegalovirus
B. Epstein-Barr virus
C. Adenovirus
D. HIV
,**Answer: B. Epstein-Barr virus**
**Rationale:** The classic triad of fever, pharyngitis, and lymphadenopathy along with
splenomegaly in a young adult is characteristic of infectious mononucleosis caused by EBV . The
Monospot test detects heterophile antibodies, which are positive in 90% of cases by the second week.
CMV can cause a similar syndrome but is Monospot-negative. Important clinical pearl: Avoid
amoxicillin/ampicillin in suspected EBV as it causes a characteristic maculopapular rash.
---
### Question 3
A 45-year-old man with a history of COPD presents with fever, productive cough with green sputum, and
right lower lobe consolidation on chest x-ray. Which organism is the most likely cause?
A. Mycoplasma pneumoniae
B. Streptococcus pneumoniae
C. Haemophilus influenzae
D. Moraxella catarrhalis
**Answer: B. Streptococcus pneumoniae**
**Rationale:** S. pneumoniae remains the most common cause of community-acquired
pneumonia (CAP) regardless of underlying lung disease . Typical presentation includes acute onset fever,
productive cough, and lobar consolidation. While H. influenzae and M. catarrhalis are common in COPD
exacerbations, they typically cause bronchitis rather than lobar pneumonia. M. pneumoniae presents
more subacutely with extrapulmonary symptoms.
---
### Question 4
, A 19-year-old woman presents with fever, hypotension, diffuse erythematous rash, and desquamation of
the palms. She reports using super-absorbent tampons during her last menstrual period. Which
organism is responsible?
A. Streptococcus pyogenes
B. Staphylococcus aureus
C. Pseudomonas aeruginosa
D. Neisseria meningitidis
**Answer: B. Staphylococcus aureus**
**Rationale:** This is toxic shock syndrome (TSS) caused by S. aureus producing TSST-1
superantigen . The superantigen bypasses normal antigen presentation, causing massive T-cell activation
and cytokine storm. Tampon use is a classic risk factor. Desquamation, especially of palms and soles,
occurs 1-2 weeks after onset. Group A Strep can cause streptococcal TSS but is less associated with
tampon use.
---
### Question 5
A 35-year-old woman presents with hemoptysis, hematuria, and rapidly progressive glomerulonephritis.
Labs show anti-glomerular basement membrane (anti-GBM) antibodies. What is the most likely
diagnosis?
A. Granulomatosis with polyangiitis
B. Microscopic polyangiitis
C. Goodpasture syndrome
D. Lupus nephritis
**Answer: C. Goodpasture syndrome**
