Case Presentation: 29 year old female presented with 3 days of low grade fever, chills, dyspnea, cough, nausea, headaches, night sweats and myalgias. She also had intermittent fatigue and dyspnea with exertion for the past 3 years. No sick contacts, recent travel, antibiotic use, or weight loss. Medical history included type 1 diabetes, depression, and anterior uveitis. She denied tobacco, alcohol, substance use and was taking no medications aside from insulin and ibuprofen. She lives with several dogs, cats, one pig and 2 parakeets and had no recent bites or scratches. Labs revealed leukocyte count (WBC) of 65000/microliter (µL) with the differential showing absolute eosinophil count (AEC) at 46000/µL (normal is under 420/µL), anemia and thrombocytosis, and elevated alkaline phosphatase of 314 units/L. Chest angiography showed diffuse bilateral ground glass changes, with peripheral nodularity concerning for an atypical pneumonia. Her records revealed consistent peripheral eosinophilia for 3 years, which had not been previously evaluated. Differential included primary hematological malignancy, eosinophilic pneumonia, hypereosinophilic syndrome (HES) and a parasitic infection. Blood and sputum cultures, rheumatological markers and testing for fungi, viruses and parasites were obtained.She underwent bronchoscopy (BAL) and bone marrow biopsy (BMB) and was started on prednisone (1mg/kg) and Ivermectin. Ivermectin was discontinued when Strongyloides serology returned negative. BAL showed 82% neutrophils and 5% eosinophils. BMB and molecular testing was negative for malignancy. IgG for Toxocara canis and Echinococcus was positive. Her mother then revealed that patient had been eating soil both as a child and as an adult. She had traveled to El Salvador and Jamaica in the past. They also reported a history of her dogs being wormed. No cysts were noted in liver or lungs to suggest Echinococcus infection. Patient’s travel history, soil consumption and exposure to animals associated with Toxocara (dogs, cats, pigs), in addition to reactive serology made her clinical picture consistent with Toxocariasis. She was started on treatment with Albendazole 400mg twice a day for 5 days. Her HES was determined to be secondary to chronic parasitic infection. On day of discharge, both her WBC and AEC had normalized. She was also discharged with a prednisone taper.
Discussion: Toxocara is a roundworm found in dogs, cats and pigs amongst other hosts. Forms of infection include visceral larva migrans (VLM) and ocular toxocariasis. Seroprevalence of Toxocara in USA is about 5%. Infection occurs using fecal oral transmission or consumption of undercooked meat. The eggs can remain infective for years. Clinical manifestations range from asymptomatic to severe organ injury resulting from migration of larvae and host immune response including eosinophilia. VLM can present with cough, fever, malaise, hepatomegaly and cutaneous symptoms. Lab findings can include leukocytosis, eosinophilia and hypergammaglobulinemia. Coinfection with other parasites and Borrelia is common. Diagnosis is made using a constellation of clinical symptoms, serum antibodies, and comprehensive history. Cross-reactivity with other parasite antigens is common, and the test may remain positive for several years following treatment. Follow up includes monitoring of AEC.
Conclusions: This case emphasizes the importance of comprehensive travel, behavioral and social history. A high index of suspicion is required to make a diagnosis of Toxocariasis.