Comments
INITIAL SYMPTOMS:
Fever, chills, nausea, myalgia, sore throat, prostration & headache followed by intensely painful buboes (regional lymphadenitis); Inguinal nodes are involved in cases of flea bites to the legs. Septicemia occurs with/without prior lymphadenopathy. [CCDM]
FINDINGS:
The three main types of plague are bubonic, septicemic, and pneumonic. In bubonic plague, some patients have a papule, pustule, or ulcer at the site of the flea bite. Some distinguishing features of bubonic plague versus other causes of acute lymphadenitis are rapid onset, severe systemic symptoms, exquisite tenderness of buboes, and absence of cellulitis or lymphangitis. Secondary pneumonic plague develops in some cases with a grave prognosis. [Guerrant, p. 279-80] Flea bite lesions (papules, vesicles, or pustules distal to the affected lymph nodes) are occasionally found. Some patients have prominent gastrointestinal symptoms including nausea, vomiting, diarrhea, and abdominal pain. [PPID, p. 2609, 2611] Febrile seizures are common in children. [PPID 7th Ed., p. 2946] Leukocytosis is expected, but leukopenia may occur. [Harrison ID, p. 607]
COMPLICATIONS:
Complications of septicemia include pneumonia, meningitis, shock, and disseminated intravascular coagulation (DIC). [CCDM, p. 456-65] Platelet counts are usually normal, but are low in the presence of DIC. [ID, p. 1457] Oculoglandular plague occurs after inoculation through the conjunctiva. [Cohen, Ch. 120] "Localized infection is unlikely to be observed in the lungs of patients with secondary pneumonic plague because the lung tissues are infected initially through circulatory spread, which results in a diffuse interstitial pneumonitis." [Cecil, p. 1898]
EPIDEMIOLOGY:
Mortality rate as high as 50% for untreated patients; [Gorbach, p. 317] Cats and dogs may carry rodent fleas into households. Plague bacilli can also be transmitted by handling the tissues of infected animals and, rarely, by inhaling droplets from infected patients or animals with plague pneumonia or pharyngitis. Natural reservoirs are wild rodents; also rabbits, hares, cats, and wild carnivores may become infected. [CCDM] Ingestion of meat from an infected animal can cause pharyngeal plague. [Harrison ID, p. 606]
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Diagnostic
Gram stain (bipolar staining like safety pin); Culture (Notify lab that Y. pestis is suspected.); DFA and serology EIA for F1 capsular antigen; [ABX Guide] Culture; Gram Stain; DFA (direct fluorescent antibody); PCR; [Harrison, Table 33-3]