Anaplasmosis

Abstract

Sir, A 59-year-old female patient who presented with the complaints of altered mental status and headache which was associated with nausea, photophobia, phonophobia and dizziness. There was no other significant complaint. There was no reported history of ill-contacts, pets in house and tick bites. On examination, she was febrile, oral temperature of 38.4°C (101.1°F), blood pressure 103/61 mmHg, heart rate 99/min and respiratory rate 18/min. A complete physical examination was benign otherwise. On admission, her labs revealed white blood cells (WBCs) 6300/mm3, red blood cells (RBCs) 3.92 million/mm3, hemoglobin 11.7 mg/dL, platelets 123,000/mm3, glucose 110 mg/dL, sodium 133 mmol/L, potassium 3.8 mmol/L, creatinine 0.8mg/dL, calcium 8.2 mg/dL. Computed tomography (CT) scan of the brain was unremarkable. Lumbar puncture was normal except elevated RBC from traumatic tap (2 WBCs/mm3, 790 RBCs/mm3, glucose 59 mg/dL, protein 29 mg/dL). Next day she had episode of high spiking fever reaching (39.4°C) 103°F with WBC dropping to 3500/mm3, RBCs to 3.17 million/mm3 and platelets to 52,000/mm3. C-reactive protein was 16.5 mg/dL and erythrocyte sedimentation rate 33 mm/h. Work-up for disseminated intravascular coagulation was negative. Her MRI scan of brain, CT scan of abdomen and pelvis were unremarkable. Her blood and urine cultures came back negative. Her liver function test, work-up for hepatitis A, hepatitis B, hepatitis C, human immunodeficiency virus, infectious mononucleosis, syphilis and Lyme disease was negative. Her peripheral blood smear image is shown in [Figure 1]. Figure 1 Morulae inside monocyte The image shows morulae inside monocytes characteristic of Anaplasmosis (formerly known as Human Granulocytic Ehrlichiosis). She was started on doxycycline 100 mg twice a day and she reported improvement in symptoms. Her altered mental status, headaches, dizziness, photophobia, phonophobia improved considerably after starting doxycycline. Her blood count also started improving. IgG and IgM for Anaplamsa phagocytophilum were positive. Polymerase chain reaction was sent for Anaplasma phagocytophilum which came back positive. A phagocytophilum, the rickettsial-like organisms, is an obligate intracellular parasite.[1] The principal vector is ixodes scapularis, which is also the vector of Lyme disease and Babesiosis. Anaplasmosis can present from subclinical and self-limited to subacute or chronic infection. Most of the patients are febrile with non-specific symptoms such as malaise, myalgia, headache, chills, arthralgia and cough. Neurologic symptoms, including mental status changes, stiff neck, and clonus, are less common. The most common laboratory findings include leucopenia and thrombocytopenia. Elevated plasma levels of aminotransferases, lactate dehydrogenase and alkaline phosphatases are also seen. Clinical diagnosis based upon the history, clinical and epidemiologic features of an individual case is crucial early in the course of disease and clinicians should have high index of suspicion even in the presence of a normal white blood cell and platelet count. Examination of peripheral blood can reveal intraleukocytic intracytoplasmic inclusions (morulae), which are highly specific for ehrlichiosis. Serologic testing for antibodies using the indirect fluorescent antibody test is the preferred and most widely available confirmatory test.[2] The drug of choice in all patients is doxycycline. Patients who have intolerance or allergy to tetracyclines can be treated with rifampin (300 mg twice a day) for 7-10 days.