WITH CORRECT DETAILED ANSWERS |PRE-
EVALUATED A+
A 25-year-old man presents for evaluation of fever and cough. He
reports last week that he was diagnosed with influenza. In the last 2
days he developed a worsening cough productive of large amounts of
sputum. Vital signs are T 101°F, HR 98, BP 120/60, RR 18, and 95%
oxygen saturation on room air. His chest X-ray demonstrates a lobar
infiltrate in the left lower lobe. Which of the following would you most
likely expect to see on the patient's Gram stain?
Gram negative bacilli
Gram negative diplococci
Gram positive bacilli
Gram positive cocci in clusters
,Correct Answer ( D )
Explanation:
The patient had a recent influenza infection and now presents with a
lobar infiltrate. Staphylococcus aureus pneumonia is classically
associated with causing post-influenza bacterial pneumonia. On Gram
stain this is seen as Gram positive cocci in clusters
Question: In which population is Klebsiella pneumonia most commonly
seen in?
COPD, Alcoholics and the elderly.
Bacterial Pneumonia Overview
Bacterial Pneumonia
S. pneumonia: most common, rusty colored sputum, rigors, gram+
paired lancets
Klebsiella: alcoholics, currant jelly sputum, bulging fissures,
S. aureus: IVDA, postinfluenza, elderly, gram+ cocci in clusters
H. influenzae: COPD, gram negative pleomorphic rods
Pseudomonas: cystic fibrosis, nursing home resident and cyanosis
Health care associated pneumonia: pseudomonas, MRSA
Outpatient, healthy: macrolide or doxycycline
Outpatient, comorbidity: respiratory tract fluoroquinolone (RTF)
Inpatient: RTF
,ICU: antipneumococcal ß-lactam (ceftriaxone or cefotaxime) + either
azithromycin or an RTF
You evaluate a 65-year-old patient for shortness of breath and note on
exam decreased breath sounds at the left lung base. You are suspicious
of a small pleural effusion. In which of the following views on the chest
radiograph is the small pleural effusion most likely to be detected?
Lateral
Lateral decubitus left side down
Lateral decubitus right side down
Posterior-anterior (PA)
Correct Answer ( B )
Explanation:
Classic physical signs of a pleural effusion include diminished breath
sounds, dullness to percussion, decreased tactile fremitus, and
occasionally a localized pleural friction rub. Chest radiograph confirms
the suspicion of pleural effusion. The classic radiographic appearance of
a pleural effusion is blunting of the costophrenic angle on the upright
chest radiograph
Pleural Effusion
Transudate: CHF (most common)
Exudate: infection > malignancy, PE
↓ Breath sounds + dull percussion + ↓ tactile fremitus
CXR: blunting of the costophrenic angle
Question: A pleural effusion is most difficult to detect in which
radiographic position?
Supine.
, Which of the following complications can be prevented by
simultaneously administering pyridoxine and isoniazid in a patient with
tuberculosis exposure?
Color blindness
Hepatitis
Peripheral neuropathy
Renal failure
Correct Answer ( C )
Explanation:
Isoniazid (INH) inhibits the enzyme responsible for the conversion of
pyridoxine (vitamin B6) to one of its active metabolites, pyridoxal
phosphate (PLP). This depletion of vitamin B6 may lead to
complications such as peripheral neuropathy and seizures. Therefore,
vitamin B6 should be administered concomitantly to patients taking
isoniazid. PLP is also a coenzyme required for the synthesis of gamma-
aminobutyric acid (GABA), an inhibitory neurotransmitter. Decreased
GABA formation in the setting of vitamin B6 deficiency may also
contribute to seizures.
Color blindness (A) is not a complication of INH. However, another
commonly used drug in TB, ethambutol, is associated with retrobulbar
neuritis and red-green color blindness. INH is metabolized by the liver
and gets converted to an ammonium molecule that can lead to
hepatotoxicity (B). However, this is not affected by vitamin B6
supplementation. Renal failure (D) is a complication of pyridoxine
overdose.
Question: What is the most common location of extrapulmonary TB?