Francisella tularensis

Snapshot

A 34-year-old man presents to the emergency room for acute-onset fever, pain in the eyes, and ulcer. He has not been to the physician in years, so his past medical history is unknown. He currently works at an angora rabbit farm and interacts with the animals daily. He reports being bit recently on his forearm, where there is now a lesion. On physical exam, he is febrile. He has severe conjunctival injection bilaterally and has multiple 1-2-cm tender cervical lymph nodes. On his left forearm, there is a 1-cm ulcer with elevated edges.

Introduction

Classification
- Francisella tularensis
  - an aerobic gram – coccobacilli
- transmission
  - hosts include ticks, rabbits, and deer flies
  - bites from exposed animals
  - inhalation of organism
Epidemiology
- incidence
  - rare
- demographics
  - south-central United States
- risk factors
  - exposure to small mammals (rabbits, voles, muskrats, etc.)
Pathogenesis
- inoculation of the skin or mucous membranes leads to spread of organism to the lymph nodes and other organs
- inhalation may result in pulmonary disease
Associated conditions
- ulceroglandular tularemia (most common)
- typhoidal tularemia
- pulmonary tularemia
  - may accompany both ulceroglandular (< 50% of cases) or typhoidal (80% of cases) tularemia
Prognosis
- symptoms arise acutely < 1 week after exposure
patients with pneumonia have the highest mortality

Presentation

Imaging

Studies

Differential

Cat-scratch disease
- distinguishing factor
  - lymphadenopathy with papular, pustular, or vesicular lesions without ulceration at the site of inoculation
Brucellosis
- distinguishing factor
often presents with osteoarticular disease, such as osteomyelitis or arthritis

Treatment

Complications