Click image to enlarge (Photo courtesy of Dr Arthur CW Lau and Dr HP Shum)
A 70-year old lady was admitted because of fever. CXR showed bilateral basal pneumonia with pleural effusion which did not respond to treatment with antibiotics for community-acquired pneumonia in the general ward. Her condition worsened and developed mild septic shock. Sputum culture was negative. A more detailed physical examination showed conjunctival congestion and the above scalp lesion. Which of the following is incorrrect about this condition?
A. It is is transmitted by trombiculid mites, particularly Leptotrombidium deliense.
B. Chemosis is an uncommon finding.
C. Weil-Felix test is notoriously unreliable.
D. Rifampin and azithromycin are alternatives for those doxycycline-resistent cases.
Answer: B
The scalp lesion is an eschar, which looks something like a cigarette burn. She was later confirmed to be suffering from scrub typhus due to Orientia (formerly Rickettsia) tsutsugamushi, an obligate intracellular gram-negative bacterium. It was first described by the Chinese about 2000 years ago, and was first isolated in 1930. Chemosis and conjunctival congestion are common findings in patients suffering from scrub typhus. This patient eventually responded to doxycycline.
Reference
1. eMedicine
2. A similar case in our website here