Snapshot A 53-year-old man presents to occupational health for suspected exposure to the plague. He works in a research laboratory that conducts research on infectious diseases and accidentally poked himself with a needle he used on an infected animal. He has had headaches, fatigue, and enlarged and painful "bug bite-like lesion" on his right groin. On physical exam, he has inguinal lymphadenopathy and a large and tender buboe in the right inguinal area. He is started on the appropriate antibiotics, and the incident is reported to the Centers for Disease Control and Prevention. Introduction Classification Yersinia pestis a nonmotile, gram-negative, facultative intracellular bacillus non-lactose fermenting, oxidase negative, and does not produce H2S reservoirs are rats and prairie dogs transmitted via fleas causes the bubonic plague (most common) and pneumonic plague Epidemiology incidence rare but outbreaks occur in the Southwest in the US demographics occurs in young people risk factors exposure with infected patients or small rodents, alive or dead flea bites occupational exposure Pathogenesis produces endotoxin, coagulase, and fibrinolysin bacteria migrate to regional lymph nodes and survive intracellularly within macrophages F1 capsular antigen is antiphagocytic Prevention plague vaccine field workers in endemic areas laboratory personnel who work with Yersinia pestis Prognosis if untreated, the disease will lead to death if untreated, mortality rates range from 10-50% pneumonic plague has the highest mortality Presentation Symptoms sudden onset high fever and chills headache myalgias fatigue Physical exam bubonic plague unilateral swollen and tender lymph nodes (buboes) often in the groin (Greek bubon = groin) and axilla can grow up to 10 cm in size may have eschar and vesicles buboes may rupture and have malodorous pus discharge pneumonic plague cough chest pain hemoptysis dyspnea Imaging Chest radiography indication suspected lung involvement findings diffuse patchy infiltrates or consolidations Studies Peripheral blood smear toxic granulations and Dohle bodies Wright-Giemsa stain with rods Wayson stain reveals “safety pin” appearance of bacteria with bipolar staining Labs positive blood cultures are diagnostic but can be hazardous rapid F1 antigen detection via immunofluorescence Lymph node aspirate Yersinia pestis on microscopy or culture Making the diagnosis based on clinical presentation and laboratory studies Differential Anthrax distinguishing factor presents with a necrotic ulcer rather than buboes Treatment Management approach mainstay of treatment is supportive care and antibiotics Conservative supportive care indication all patients modalities aggressive hydration respiratory support hemodynamic support Medical aminoglycosides indication all patients doxycycline indication treatment fluoroquinolones indication treatment post-exposure prophylaxis Operative incision and drainage indication enlarging buboes Complications Acute respiratory distress syndrome Disseminated intravascular coagulopathy Septic shock Lymphatic scarring and chronic lymphedema Superinfection of buboes with other bacteria