What is the appropriate treatment for a patient with relapsing fever?

Clinical Vignette: Relapsing Fever

Patient Presentation

A 32-year-old male presents to the emergency department with a 3-day history of high-grade fever (39.5°C), severe headache, myalgias, and rigors that began 7 days after returning from a camping trip in rural Tanzania. 1

Initial Clinical Features

• The patient reports sleeping in a cave during his trip and noticed what appeared to be tick bites on his lower extremities 2
• He describes the fever as coming in waves, with periods of intense chills followed by profuse sweating 1
• Associated symptoms include dry cough, nausea, and generalized body weakness 3
• On examination, vital signs reveal: temperature 39.2°C, heart rate 118 bpm, blood pressure 95/60 mmHg, and respiratory rate 22/min 2

Physical Examination Findings

• The patient appears acutely ill with flushed skin and diaphoresis 3
• Small erythematous papules consistent with tick bite scars are visible on both lower legs 2
• Mild cervical lymphadenopathy is palpable bilaterally 2
• A faint macular rash is present on the trunk 2
• Mild hepatosplenomegaly is detected on abdominal examination 1
• No focal neurological deficits are identified, though the patient complains of severe headache 1

Laboratory Investigations

• Complete blood count reveals thrombocytopenia (platelet count 85,000/μL) and mild leukopenia 1, 3
• Elevated inflammatory markers: C-reactive protein 145 mg/L, erythrocyte sedimentation rate 68 mm/hr 3
• Liver function tests show mild transaminitis (ALT 89 U/L, AST 102 U/L) 1
• Thick blood smear examination during the febrile episode reveals spirochetes consistent with Borrelia species 3
• Blood cultures are obtained but remain pending 4

Clinical Course and Diagnosis

• The diagnosis of tick-borne relapsing fever is established based on the visualization of spirochetes on thick blood smear during fever 3
• The patient's travel history to Tanzania, cave exposure, tick bites, and characteristic relapsing fever pattern support the diagnosis of Borrelia duttoni infection 5, 1
• Treatment is initiated with doxycycline 100 mg orally as a single dose, per FDA-approved indication for relapsing fever due to Borrelia recurrentis 6, 7

Post-Treatment Monitoring

• The patient is closely monitored for the first 4-6 hours after antibiotic administration for signs of Jarisch-Herxheimer reaction (JHR), which occurs in approximately 19.3% of TBRF cases 1
• Potential JHR manifestations include rigors, hypotension, tachycardia, and worsening fever 5, 1
• The patient develops mild tachycardia and transient hypotension 2 hours post-treatment, managed with intravenous fluids 5
• Fever resolves within 24 hours of treatment 3
• Follow-up at 2 weeks shows complete clinical recovery with normalization of platelet count and liver enzymes 3

Key Clinical Pearls from This Case

• Relapsing fever presents with the pathognomonic feature of recurrent fever episodes in 100% of cases, making it the most suggestive clinical symptom 1
• Thrombocytopenia is the most suggestive laboratory finding and should prompt consideration of this diagnosis in returning travelers 1
• Thick blood smear during febrile episodes remains the diagnostic gold standard in most clinical settings, despite availability of molecular methods 1
• Cave or bunker exposure in endemic areas represents a significant risk factor for soft tick exposure and TBRF acquisition 2
• Single-dose antibiotic therapy with tetracyclines (doxycycline 100 mg or tetracycline 500 mg) is equally effective for treatment 7
• Close monitoring for JHR is essential in the first hours after antibiotic initiation, particularly in critically ill patients 5