Part X: Clinical Case Questions

Clinical Case Questions

CASE 1. Your patient is a 20-year-old woman with the sudden onset of fever to 104°F and a severe headache. Physical examination reveals nuchal rigidity. You suspect meningitis and do a spinal tap. Gram stain of the spinal fluid reveals many neutrophils and many gram-negative diplococci.

Of the following bacteria, which one is MOST likely to be the cause?

(A) Haemophilus influenzae

(B) Neisseria meningitidis

(C) Streptococcus pneumoniae

(D) Pseudomonas aeruginosa

CASE 1. Your patient is a 20-year-old woman with the sudden onset of fever to 104°F and a severe headache. Physical examination reveals nuchal rigidity. You suspect meningitis and do a spinal tap. Gram stain of the spinal fluid reveals many neutrophils and many gram-negative diplococci.

Additional history reveals that she has had several serious infections with this organism previously. On the basis of this, which one of the following is the MOST likely predisposing factor?

(A) She is HIV antibody positive.

(B) She is deficient in CD8-positive T cells.

(C) She is deficient in one of the late-acting complement components.

(D) She is deficient in antigen presentation by her macrophages.

CASE 2. Your patient is a 70-year-old man with a long history of smoking who now has a fever and a cough productive of greenish sputum. You suspect pneumonia, and a chest X-ray confirms your suspicion.

If a Gram stain of the sputum reveals very small gram-negative rods and there is no growth on a blood agar but colonies do grow on chocolate agar supplemented with NAD and heme, which one of the following bacteria is the MOST likely cause?

(A) Chlamydia pneumoniae

(B) Legionella pneumophila

(C) Mycoplasma pneumoniae

(D) Haemophilus influenzae

CASE 3. Your patient is a 50-year-old woman who returned yesterday from a vacation in Peru, where there is an epidemic of cholera. She now has multiple episodes of diarrhea.

Of the following, which one is MOST compatible with cholera?

(A) Watery diarrhea without blood, no polys in the stool, and growth of curved gram-negative rods in the blood culture

(B) Watery diarrhea without blood, no polys in the stool, and no organisms in the ...