Warren Alpert Medical School of Brown University Providence, RI
Introduction: Human granulocytic anaplasmosis (HGA) is a tick-borne illness caused by Anaplasma phagocytophilum, and is transmitted by Ixodes scapularis tick. Hyperbilirubinemia is an unusual feature of HGA, and if present, is usually indirect. We present a case of HGA who presented with jaundice and a non-obstructive direct hyperbilirubinemia.
Case Description/Methods: A 60-year-old male with a history of hypogonadism and no known history of chronic liver disease presented with a two-day history of yellowish eye discoloration and dark urine. These symptoms were associated with fever, chills, and arthralgias in bilateral hips and elbows. The patient resides in the New England area and spends significant time outdoors. He denied abdominal pain, nausea, vomiting, diarrhea, dizziness, joint swelling, skin rashes, tick bites, or antibiotic use. Vital signs were normal, and he was afebrile. Physical examination was remarkable for jaundice and mild tenderness at the elbows with no redness or swelling. The abdominal exam was normal. Laboratory tests revealed an AST of 93 IU/L, ALT of 151 IU/L, ALP of 310 IU/L, Total bilirubin of 7.5 mg/dl (direct bilirubin 4.8 mg/dl), Hgb 16.1 g/dl, platelets 41 x10exp9/L, reticulocyte index 0.82, LDH 256 IU/L, haptoglobin 197 mg/dl (Table 1), and INR of 1.6. CT scan of the abdomen demonstrated normal liver and biliary tree morphology without evidence of biliary dilation. Given the relatively high prevalence of tick-borne illnesses, the patient was empirically placed on doxycycline. The anaplasma Phagocytophilium IgG ab titer was strongly positive (1:320), and acute infection was confirmed with PCR. Ehrlichia PCR and Lyme serology were negative; babesiosis was also ruled out. 48 hours after starting therapy, the patient's jaundice and all other symptoms resolved.
Discussion: We present an unusual case of HGA presenting with direct hyperbilirubinemia and mild transaminitis in the absence of biliary obstruction. The pathophysiology of direct hyperbilirubinemia in HGA in not known. HGA is prevalent in the Northeast and Upper Midwest of the United States, and it is a common cause of undifferentiated fever in these regions. Infection, in most cases is mild, but rarely lead to life-threatening complications including demyelinating disorders, secondary infections, renal failure, and seizures. Hence, recognition and early therapy are essential. Although rare, direct hyperbilirubinemia can be a manifestation of HGA.
