Title : Ulceroglandular tularemia following arthropod bite - a case report
Abstract:
Introduction: Tularemia is an uncommon disease. An average of 173 cases per year were reported in the US for the past 20 years. A low minimal-infective-dose, high rate of dissemination and the possible mortality make tularemia a potential weapon for bioterrorism.This report summarizes the presentation of the ulceroglandular form - the most common among the six major classified forms of Tularemia.
Case: A 68-year-old male with a past medical history of deep vein thrombosis presented to the local hospital with concerns of left ankle pain, swelling and redness, two days after what he suspected was a spider bite over his left ankle. He was prescribed oral clindamycin for suspected cellulitis. However, he returned five days later, for worsening of his leg symptoms. He was afebrile but hypotensive with systolic blood pressure in the 80s. He was fluid resuscitated, treated with vancomycin and transferred to our institution for worsening cellulitis and suspected septic ankle joint.
On arrival, he rated the lower limb pain as 9/10. Upon further questioning, he recalled having two tick bites - one on the chest, another on the left leg. He also reported having subjective fevers, chills and anorexia for the past few days. On examination, he was hemodynamically stable, his left lower limb was warm to touch and had an ulcer. Edema and erythema could be demarcated from the surrounding skin. He had palpable pedal pulses and intact sensations. There was left groin lymphadenopathy. Rest of the examination was unremarkable. Labs were significant for elevated CRP (41.9mg/L), ESR (72mm/hr) with normal WBC (6.9k/uL). He was started on cefepime and vancomycin empirically.
Over the course of hospitalization, the ulcer progressed and turned into an eschar. Blood cultures and joint fluid aspirate were negative. Meanwhile, wound cultures grew Francisella tularensis. He was diagnosed with ulceroglandular tularemia. The antibiotics were switched to Ciprofloxacin 750 mg twice daily for 10 days and the patient made a good recovery.
Discussion: This case report re-emphasises the importance of detailed history-taking. All patients presenting with dermatologic lesions should be questioned about any recent history of outdoor exposure or exposure to animals or insects. Tularemia is a rare zoonotic disease and could be transmitted by various modes, the most common being through insect bites, particularly tick bites.
It should be included in the differential diagnosis involving refractory/worsening dermatologic lesions with lymphadenitis especially following an insect bite and/or when accompanied by fever. The best way to confirm is through blood and wound cultures along with serological assays. Effective antibiotic treatment options include Streptomycin, Gentamicin, Doxycycline or Ciprofloxacin depending on the severity of the disease.
