Diagnosis Synopsis
Septicemic plague is a an infection caused by the gram-negative bacillus Yersinia pestis, which is found in rodents (e.g., prairie dogs, squirrels, rats) and their fleas and sometimes in cats. This form occurs when the bacteria multiply in the blood. There are primary and secondary forms of septicemic plague; the former lacks the typical bubo. Secondary septicemic plague occurs when there is the progression of bubonic to septicemic plague. Both Septicemic and bubonic plague can progress to pneumonic plague (approximately 12%).

Septicemic plague is rarely transmissible human to human, but will become transmissible if it reaches the pneumonic stage. Plague is classified as a Category A bioterrorism agent because of its ease of dissemination, contagiousness and high mortality rate, however, the most likely method of dispersal would be as an aerosol resulting in the primary pneumonic form (discussed separately).

Septicemic plague causes fever, chills, weakness, abdominal pain, shock, and bleeding underneath the skin or other organs and may result in disseminated intravascular coagulation, necrosis of small vessels, and purpura. Acral regions such as the fingers, toes, and nose may become gangrenous, hence the term “black death,” the moniker for the second plague pandemic.

Plague is endemic to the southwestern United States (Colorado, New Mexico, Arizona, California) as well as Vietnam, India, the former Soviet Union, and parts of Africa. Hikers, campers, veterinarians and owners of infected cats, especially those living or visiting endemic areas, are more at risk for contracting plague.

Currently, a plague vaccine is not available in the United States. Plague must be reported to local and state health departments immediately.
Precautions: Strict isolation, droplet precautions and antibiotics for people with direct, close contact with infected patients.

Look For
Look for purpura and signs of skin necrosis. Acral regions such as the fingers, toes, and nose may become gangrenous. In later stages there may be hematuria and abnormal bleeding from the mouth, nose and rectum. Look for bite sites which may appear as small ulcers.

Diagnostic Pearls
Buboes do not develop in primary septicemic plague.

Differential Diagnosis & Pitfalls
Disseminated intravascular coagulation
Septic shock
Necrotizing fasciitis
Ecthyma gangrenosum
Acute meningococcemia
Cryoglobulinemia

Best Tests
Sputum gram stain shows gram-negative bacilli. Use Wright’s, Giemsa or Wayson tests to look for "closed safety pin" appearing bipolar staining. Culture blood, sputum and CSF if evidence of meningitis. There may be evidence of multiorgan failure such as leukocytosis with toxic granulations, coagulation abnormalities, aminotransferase elevations, and azotemia.
Note: Warn the laboratory that you suspect plague.

Management Pearls
Begin treatment within 24 hours of initial symptoms. Identify and evaluate people who have close contact with the patient and begin preventive antibiotic therapy. Respiratory and droplet isolation is needed as well as supportive care in the ICU.

Therapy
Adult First Line:
Streptomycin 1 gm IM twice daily for 10 days (not in pregnant women).
Or
Gentamicin 5 mg/kg IM or IV once daily or 2 mg/kg loading dose followed by 1.7 mg/kg IM or IV tid for 10 days.
Or
Doxycycline 100 mg IV twice daily or 200 mg IV once daily for 10 days (if gentamicin not available or oral antibiotics must be used).
Or
Ciprofloxacin 400 mg IV bid for 10 days (or other fluoroquinolones at appropriate dosing).
Chloramphenicol (add for plague meningitis), 25 mg/kg IV 4 times daily for 10 days. Concentrations should be maintained between 5 and 20 ug/ml, concentrations greater than 25 ug/ml can cause irreversible bone marrow suppression.

Child First Line:
Streptomycin 15 mg/kg IM twice daily for 10 days (maximum daily dose 2 gm).
Or
Gentamicin 2.5 mg/kg IM or IV tid for 10 days (adjust for renal function).
Or
Doxycycline:
>45 kg, give adult dosage.
<45 kg, 2.2 mg/kg IV twice daily for 10 days (maximum 200 mg/day).
Or
Ciprofloxacin 15 mg/kg IV bid for 10 days (maximum daily dose 1 gm).
Chloramphenicol (add for plague meningitis), 25 mg/kg IV 4 times daily for 10 days. Concentrations should be maintained between 5 and 20 ug/ml, concentrations greater than 25 ug/ml can cause irreversible bone marrow suppression. CONSULT SPECIALIST FOR DOSING.

*The information contained above is partially derived from the CDC and the Center for Infectious Disease Research and Policy of the University of Minnesota. For detailed treatment and laboratory specimen collection information please refer to:
http://www.cidrap.umn.edu/

Medical Disclaimer:
The information contained in this web page is intended to be an adjunct to traditional medical information sources. It is not intended to be a substitute for professional medical judgment.

Authors and Editors:
Tener Goodwin Veenema PhD, MPH, MS, CPNP