Introduction: Bubonic plague classically manifests as a painful, swollen superficial lymph node (bubo) that is readily apparent on physical examination. However, patients occasionally present with buboes formed in deep lymph nodes, which are difficult to detect and can lead to delays in diagnosis and treatment. To better characterize this phenomenon, we conducted a review of the published literature to identify reports of occult buboes among patients with plague. Methods: Articles were identified from two sources: a systematic review on plague treatment, and a search of the PubMed Central database. Articles were eligible if they described a patient with plague who had (1) no evidence of lymphadenopathy on examination; and (2) at least one bubo discovered during surgery or autopsy. Results: Six patients with occult buboes were identified among 5120 articles screened. The majority were male (n = 4/6) and three were <15 years of age. Fever (n = 6/6), leukocytosis (n = 5/6), and abdominal pain or distention (n = 4/6) were the most common signs and symptoms. Initial diagnoses included other bacterial infections, appendicitis, or acute abdomen. Four patients received at least one antimicrobial effective against Yersinia pestis; however, some experienced delayed treatment due to late diagnosis of plague. Occult buboes were discovered in retroperitoneal (n = 2), inguinal/femoral (n = 2), mesenteric (n = 2), axillary (n = 1), and mediastinal (n = 1) regions. Four of the six patients died. Conclusions: Patients with occult buboes experienced delays in the diagnosis of plague and a high fatality rate. Clinicians in plague-endemic areas should consider the presence of occult buboes among patients with compatible symptoms and exposure history.
Keywords: antimicrobial treatment; buboes; bubonic plague.