37 year-old male presents to the ED with four days of fevers, chills, abdominal pain, myalgias. Denies nausea, vomiting, and diarrhea. No known sick contacts. Works as a landscaper. Sexually active with one partner who is asymptomatic. Vitals on arrival: Tempt 100.9F, RR 16, BPM 115, BP 120/74, Sp02 100% RA. On exam, patient has diffuse lower abdominal tenderness. Labs demonstrate Na 131, AST 140, ALT 147, Hgb 14, Platelets 142, Lactate 1.4. CT Abd/pelvis negative for acute surgical pathology. What is the most appropriate treatment at this time?

A. Vancomycin and Cefepime

B. Doxycycline

C. Zosyn

D. Azithromycin and Ceftriaxone

Answer: B- Doxycycline

This patient is presenting with symptoms and laboratory studies concerning for tick-borne illness. Patients that are frequently outside are at higher risk of infection. These patients present with vague symptoms including fevers, chills, myalgias, headaches, abdominal pain. Laboratory studies often demonstrate transaminitis, thrombocytopenia, hyponatremia, leukopenia. Diagnosis is made by PCR, blood smear, or immunofluorescence. Treatment is as follows:

Lyme Disease: 

• Prophylaxis: Doxycycline 200mg once

• Treatment: 14-21 days of one of the following 

• Doxycycline 100mg BID

• Amoxicillin 500mg TID

• Cefuroxime 500mg BID 

Babesiosis: 

• Azithromycin (500mg day 1 followed by 250mg daily) plus Atovaquone (750mg BID) for 7-10 days 

Ehrlichiosis: 

• Doxycycline 100mg BID for 10 days 

Anaplasmosis:

• Doxycycline 100mg BID 10-14 days 

Rocky Mountain Spotted Fever:

• Doxycycline 100mg BID for 5-7 days 

Resources: 

Bridewell, R. (2019). Lyme Disease. In <http://www.emdocs.net/em3am-lyme-disease>.

Kitch, B. B., & Meredith, J. T. (2016). In Tintinalli's emergency medicine: a comprehensive study guide (pp. 1085–1090). essay, Mc Graw-Hill Education.