He had an abrupt onset of fever, chills, headache, and malaise a few days after noticing this lesion. Exam showed regional tender lymphadenopathy. Routine lab tests were nonspecific. Routine cultures of blood, skin lesions, and lymph nodes did not show any organisms. But, you ask the lab to supplement the growth conditions with cysteine and CO2. The result is a pale-staining, small, aerobic, Gram negative coccobacillus.
Challenge: What is the organism? What's the clinical diagnosis?
Image is in the public domain.
Posts
1 comment:
Tricks are for Kids
This is Tularemia, a zoonosis caused by Francisella tularensis. Humans are accidental hosts following contact with infected animals or vectors. The organisms are fastidious and tough to grow without the supplementation mentioned in the case. It is a highly virulent organism (and a potential biological weapon). In the U.S., it has been reported in all continental states, but the majority of cases occur in the southeast. Sources of infection include vectors (ticks, biting flies, mosquitoes), handling of infected animals, ingestion of contaminated meat or water, cat scratches or bites, and contaminated aerosols. The clinical manifestations as in this case are generally nonspecific. There are six distinct syndromes: ulceroglandular (shown here), glandular, typhoidal, pneumonic, oropharyngeal, and oculoglandular. Diagnosis is usually confirmed serologically. Tularemia is also called rabbit fever; hence the title (“Silly rabbit…”).
Sources: terrorisminfo.ucsf.edu (image originally from the CDC Public Health image library); UpToDate.
Post a Comment