Tick Bite Tachycardia
“Delayed treatment can increase the risk of complications including organ damage, coagulation issues, cardiac complications and neurologic issues such as encephalitis or seizures.”
CASE
The patient is a 61 year old male with a past medical history notable for hypertension, who presented for evaluation after a syncopal episode. The patient reported ongoing headaches for the past two days that persisted despite over the counter medications. The headache was not sudden onset or thunderclap. He denied numbness, weakness or visual changes. He also had a poor appetite. The patient denied trauma or head injury and was not on anticoagulation medication.
Upon arrival to the emergency department, his vitals were notable for a fever to 101F and tachycardia at 121 beats per minute. Initial blood pressure was 124/77 but repeat blood pressure was in the 90s systolic.
His workup included labs which were notable for a normal white blood cell count but with a 5% bandemia, normal electrolytes, thrombocytopenia with platelets at 137x10^9/L, an elevated troponin at 45 ng/L (Neutral Sex Reference Range: 3-27 ng/L), an elevated d-dimer to 1840 ng/mL (Ref: < 230 ng/mL cut off for VTE exclusion), elevated AST 141 IU/L (Ref: >20Y: 12-52 IU/L), elevated AST 106 IU/L (Ref Adult: 7-49 IU/L), and elevate total and direct bilirubin 1.5 mg/dL (Ref: >19Y: 0.1-1.2 mg/dL) and 0.6 mg/dL (Ref: 0.0-0.4 mg/dL) respectively. His workup also included a CT brain without contrast given persistent headache which was normal. Given his positive dimer, he was also ordered for a CTA chest which did not show a pulmonary embolism.
While in the emergency department, the patient had multiple episodes of non-sustained ventricular tachycardia. Cardiology was consulted and recommended administration of magnesium and amiodarone. The patient was admitted to the hospital for a syncope workup.
DISCUSSION
Human granulocytotropic anaplasmosis is a tick-borne disease caused by the bacteria Anaplasma phagocytophilum. The disease is transmitted by Ixodes scapularis in the Northeastern United States [1]. This is the same tick that transmits Lyme disease and babesiosis, and coinfection is not uncommon [2,3]. The disease usually presents with fever, headache, and myalgias. Rash is uncommon. Labs are notable for leukopenia, thrombocytopenia, and elevated transaminases.
Diagnosis of anaplasmosis can be complex but often relies on clinical suspicion [1,3]. The recommended diagnostic test is polymerase chain reaction (PCR) amplification, which has a high sensitivity and specificity in the acute phase of infection. However, treatment should be started prior to obtaining results of the PCR as early treatment is highly effective [1]. The treatment of choice for all patients, including pediatric patients, is doxycycline.
Delayed treatment can increase the risk of complications including organ damage, coagulation issues, cardiac complications and neurologic issues such as encephalitis or seizures. Although less common, anaplasmosis can have life threatening complications including hemodynamic collapse, acute renal failure, and acute respiratory distress syndrome [4]. Studies have demonstrated that ICU admission rates, pulmonary complications, need for mechanical ventilation and need for vasopressors were significantly more common among patients with a delay in the administration of doxycycline [5].
CASE RESOLUTION
While inpatient, the patient had a lumbar puncture performed which showed an elevated glucose with a normal protein and a negative gram stain. Infectious disease was consulted inpatient for his symptoms of fever and headache with thrombocytopenia and transaminitis. It was presumed that he had an Anaplasma infection and he was treated with doxycycline prior to definitive diagnosis. While inpatient, he had one episode of a ventricular tachycardia causing cardiac arrest requiring defibrillation to achieve ROSC. He had a negative catheterization. He had an Implantable Cardioverter-Defibrillator (ICD) placed prior to discharge.
KEY TAKE-AWAYS
Diagnosis of anaplasmosis can be complex but often relies on clinical suspicion.
Treatment should be started prior to obtaining results of the PCR as early treatment is highly effective and prevents downstream complications.
The treatment of choice for all patients, including pediatric patients, is doxycycline.
REFERENCES
Ismail N, McBride JW. Tick-Borne Emerging Infections: Ehrlichiosis and Anaplasmosis. Clin Lab Med. 2017 Jun;37(2):317-340. doi: 10.1016/j.cll.2017.01.006. Epub 2017 Mar 25. PMID: 28457353.
Schudel S, Gygax L, Kositz C, Kuenzli E, Neumayr A. Human granulocytotropic anaplasmosis-A systematic review and analysis of the literature. PLoS Negl Trop Dis. 2024 Aug 5;18(8):e0012313. doi: 10.1371/journal.pntd.0012313. PMID: 39102427; PMCID: PMC11326711.
Ismail, Nahed, et al. “Human Ehrlichiosis and Anaplasmosis.” Clinics in Laboratory Medicine, vol. 30, no. 1, Mar. 2010, pp. 261–292, https://doi.org/10.1016/j.cll.2009.10.004.
MacQueen D, Centellas F. Human Granulocytic Anaplasmosis. Infect Dis Clin North Am. 2022 Sep;36(3):639-654. doi: 10.1016/j.idc.2022.02.008. PMID: 36116840.
Hamburg, Brian J. MD; Storch, Gregory A. MD; Micek, Scott T. PharmD, BCPS; Kollef, Marin H. MD. The Importance of Early Treatment With Doxycycline in Human Ehrlichiosis. Medicine 87(2):p 53-60, March 2008. | DOI: 10.1097/MD.0b013e318168da1d