A 45-year-old poultry farm worker presents with 8 days of fever, dry cough, headache and myalgia. Chest X-ray shows patchy lower zone consolidation. Examination reveals hepatosplenomegaly. Sputum culture is negative for bacteria. The most likely causative agent is:

• A Legionella pneumophila
• B Chlamydia trachomatis
• C Coxiella burnetii
• D Chlamydia psittaci ✓

Explanation

Psittacosis due to Chlamydia psittaci follows exposure to infected parrots, pigeons or poultry and produces an atypical pneumonia classically accompanied by splenomegaly and sometimes hepatomegaly. Doxycycline is the drug of choice. Legionella also causes atypical pneumonia but is linked to water aerosols rather than birds and does not typically cause prominent splenomegaly, which is the discriminating clue here.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.