Case Presentation: A 24 year old male with a history of childhood asthma and COVID in 2021 presented to ED with worsening sore throat, fevers, tenderness of his mouth and gums, and mild lightheadedness. He was recently diagnosed with streptococcal pharyngitis and started on oral penicillin three days prior to presentation. He was on no medications or supplements except penicillin. He recently traveled to Massachusetts and had occasional vaping and alcohol use. In the ED, he was tachycardic and febrile to 39.1. Exam was notable for mild cervical lymphadenopathy and mild posterior oropharynx erythema. Labs revealed white blood cell count of 1.8 with absolute neutrophil count of 0 and normal hemoglobin, platelet count, chemistry panel, and liver function tests. Cultures were obtained and he was started on broad spectrum intravenous antibiotics for febrile neutropenia. Hematology was consulted. Neutropenia was felt to be related to acute streptococcal pharyngitis or viral infection; less likely related to penicillin given short duration of exposure. Absolute neutrophil count remained 0 and peripheral smear demonstrated leukopenia and marked neutropenia with no blasts. His blood cultures and viral studies remained negative. On hospital day 3, hematology performed bone marrow biopsy and elected to start filgrastim. White blood cell count and neutrophil count improved. Oral symptoms gradually improved and he developed filgrastim-associated bone pain. Bone marrow biopsy demonstrated hypocellular bone marrow with trilineage hematopoiesis and 6% blasts with no evidence of malignancy or other marrow infiltrative process. The myeloid lineage was left shifted which suggested a recovering marrow after a transient insult. Additional history was obtained from patient and he used cocaine while on vacation prior to the development of symptoms. Therefore, his presentation felt to be most consistent with agranulocytosis associated with levamisole.

Discussion: Levamisole is a common adulterant of cocaine in the United States. In one literature review of cases, roughly half of the patients with levamisole-induced agranulocytosis presented with oropharyngeal complaints (pharyngitis, mouth ulcers or odynophagia). This case illustrates the importance anchoring bias and premature closure with too much weight placed on infectious causes of neutropenia and delay in eliciting a critical piece of history.

Conclusions: In hospital medicine, admissions are frequently performed by an “admitter” or nocturnist rather than daily rounding providers. Hospitalists should be familiar with cognitive biases that may impact the diagnostic process including anchoring bias and premature closure. Health care system operations and time pressures on hospitalists can make it difficult for rounding providers to have sufficient time to obtain additional history necessary for accurate and timely diagnosis.