Plague

Plague: Excerpt from The 5-Minute Pediatric Consult

Bruce Tempest, MDJonathan Iralu, MD

Plague - BASICS

Plague - description

Plague is a flea transmitted enzootic disease affecting wild rodents. Humans and sometimes their pets can enter this cycle resulting in human plague.

Plague - general prevention

• Reduce rodent shelter and food sources in the immediate vacinity of the home by storing grain and animal food in rodent proof containers.
• Deinfestation of cats and dogs living in endemic areas
• Hospital isolation (negative pressure) of suspected plague patients:
  • Patients with bubonic plague with no evidence of pneumonia require contact isolation precautions after 24 hours of droplet isolation and a persistently clear chest radiograph.
  • Patients with pneumonic plague require strict droplet and contact isolation precautions.
• Exposed persons: All contacts of patients thought to suffer from plague should undergo:
  • Daily surveillance for fever or symptoms of disease for 7–10 days.
    • Persons who have had contact with a patient with pneumonic plague require antimicrobial prophylaxis with tetracycline (15 mg/kg/d).
    • For children <8 years of age, use trimethoprim-sulfamethoxazole (40 mg/kg/d) or IM streptomycin (20 mg/kg/d) for 7 days.
• State public health authorities should be notified in cases of suspected plague.
• Vaccination is no longer available and is not considered useful to prevent plague from an enzootic source.

Plague - epidemiology

• >50% of the contemporary cases of plague occur in persons <20 years of age, possibly because of an increased tendency for children to encounter small animals and rodents when living in rural areas.
• A large proportion of the cases in the US have occurred in the Southwest throughout the year but most commonly during the spring and summer.
• Bubonic plague:
  • 75% of plague cases worldwide
• An outbreak of the pneumonic plague has been reported recently in India; however, the identification of the specific causative organism has been called into question.
• 13 cases of plague occurred in the US in 2006 including 5 septicemic and 8 bubonic cases. 2 developed plague pneumonia.
• No cases of person-to-person transmissions of plague pneumonia have been reported in the US since 1925.

Plague - pathophysiology

• Dermatologic portal of entry:
  • Yersinia pestis is most commonly transmitted from fleas to humans via the regurgitation of the organism into the bite during the flea’s blood meal (into a foregut already obstructed with plague organisms). Rodents, dogs, cats, and rabbits can thereby act as reservoirs of infection (by harboring infected fleas). Alternatively, direct skin inoculation of organisms from infected animal tissue or blood can occur through breaks in the skin typically occuring when hunters are skinning quarry.
  • Lymphatic spread of infection to the regional lymph nodes creates a localized inflammatory response (bubo).
  • Subsequent hematogenous spread of the organism to other organs results in the production of greater levels of bacterial endotoxin (septicemic plague).
  • Both the bubonic and septicemic presentations of plague can progress to pneumonic plague if untreated.
• Respiratory portal of entry:
  • Pneumonic plague: Acquired via contact with the saliva or respiratory droplets (either from a human or more commonly in the US, from a cat with plague pneumonia)
• Incubation period:
  • Usually 2–6 days between exposure and 1st presentation of symptoms, but this period can be shorter for pneumonic plague.

Plague - etiology

The illness commonly known as the plague is caused by Y. pestis, a Gram-negative pleomorphic bacillus that is part of the Enterobacteriaceae family.

Plague - DIAGNOSIS

Pitfalls:

• Patients who present with fever, tachycardia, or tachypnea, rather than lymphadenitis, are at higher risk for delayed diagnosis and serious sequelae (i.e., septicemic plague).
• Failing to consider septicemic plague in the appropriate epidemiologic setting and withholding appropriate antibiotics or using an empiricโ-lactam
• Failing to treat suspect bubonic plague with antibiotics when needle aspiration of the bubo shows no organisms on direct stain and while awaiting culture results.

Plague - signs & symptoms

• Bubonic plague:
  • Initial symptom: Pain in the groin or axillae prior to lymph node swelling
  • Lymphadenitis (usually inguinal > axillary > cervical)
  • Systemic manifestations
• Septicemic plague:
  • Tachycardia
  • Hypotension
  • Other organ involvement
• Bubonic or septicemic plague may progress to pneumonic plague.
• Pneumonic plague:
  • Pneumonia
  • Systemic manifestations
  • Rapidly progressive
  • Often fatal

Plague - history

• A thorough travel history (especially to the southwestern US) is imperative to raise the index of suspicion for diagnosing plague.
• Environmental history should include deaths (die-offs) of rats, ground squirrels, or prairie dogs in the patient’s locale.
• In enzootic areas a household dog or cat is an additional risk factor

Plague - physical exam

• Patients may present initially with very tender lymphadenitis in the groin, axillae, or neck regions.
• Patients with rapidly progressive illness are tachycardiac, hypotensive, and toxic in appearance.
• Other common symptoms are:
  • GI: Abdominal pain, nausea, and diarrhea are usually owing to the presence of inflammatory mediators.
  • Neurologic: Weakness, delirium, and coma are owing to the effects of the endotoxin of Y. pestis.
• Patients with septicemia can experience hematologic (disseminated intravascular coagulation) and renal (glomerular and parenchymal damage) manifestations.

Plague - tests

Plague - lab

• Total WBC count:
  • Usually 10,000–20,000, but may be as high as 100,000
• Y. pestis culture:
  • Suspect bubonic plague: Needle aspiration of the bubo is critical to obtain fluid for stain and culture. The bubo is punctured with a 22 gauge needle and 1 mL of nonbacterostatic saline is repeatedly injected into and reaspirated from the bubo.
  • Suspect pneumonic plague: Sputum for stain and culture on blood agar plates
• Gram stain, Wayson stain, Giemsa stain, or fluorescent antibody staining of the specimen looking forbipolar organisms
  • Blood cultures are usually positive even with bubonic plague and should always be done prior to therapy.
• Comparison of acute and convalescent sera:
  • Taken 3–4 weeks apart, show at least a 4-fold increase in antibody titers by passive hemagglutination

Plague - differencial diagnosis

Diagnosis of plague follows a high index of suspicion and a thorough review of the patient’s lifestyle, travel history, and recent activities. The appearance of septicemia and endotoxin-mediated shock includes a large differential diagnosis that includes sepsis owing to other bacteria or viruses, as well as distributive shock resulting from toxic ingestion or anaphylaxis.

• Infection:
  • Streptococcal and staphylococcal infections, especially between the toes, can result in tender inguinal lymph nodes.
  • Hantavirus in humans has a clinical presentation similar to septicemic plague and occurs in many of the plague enzootic areas.
  • Recent reports of plaguelike illnesses have been associated with infections by other organisms such as Pseudomonas pseudomallei (melioidosis) and Francisella tularensis (tularemia).
  • Rocky Mountain spotted fever and relapsing fever due to Borellia sp. may mimic septicemic plague.

Plague - TREATMENT

Plague - initial stabilization

For septicemic patients, initial attention should be given to airway management and fluid resuscitation.

Plague - general measures

• Antibiotics (see “Medication”)
• Drainage of affected lymph nodes or abscesses, should wait until there is persisting fever and a fluctuant node (a rare event).

Plague - medication

• Continue antibiotic therapy for at least 10 days. Severely ill patients may require a substantially longer course of therapy. Patients treated with streptomycin is the drug of choice but usually not available so to avoid delay use gentamicin. This drug was recently shown to be equally efficacious as streptomycin in a series of 75 cases in New Mexico. Treatment can be switched to other medications a few days after improvement is noted.
• In the acutely ill patient suspected of Y. pestis infection, gentamicin in full doses: 1 mg/kg q8h, up to 5 mg/kg/d in life-threatening infections
• Tetracycline (20–30 mg/kg/d IV) or chloramphenicol (75–100 mg/kg/d IV) should be added in severe cases or if meningitis is present.
• For the patient who does not require hospitalization, IV gentamicin 5mg/kg/d, or tetracycline (20–30 mg/kg/d), or chloramphenicol (75–100 mg/kg/d) may be administered orally after cultures are obtained.
• Note: To avoid permanent dental staining, patients younger than 8 years should not receive tetracycline unless necessary.

Plague - FOLLOW UP

Resolution of symptoms should begin in the 1st 3 days after initiation of therapy; however, the rate of clinical improvement depends on the initial severity of illness.

Plague - prognosis

Good unless definitive treatment is delayed

Plague - complications

• Systemic:
  • Hematologic (disseminated intravascular coagulation)
• Renal (glomerular and parenchymal damage)

Plague - bibliography

American Academy of Pediatrics. Plague. In: 2006 Red Book: Report of the Committee on Infectious Diseases. 27th ed. Elk Grove IL: American Academy of Pediatrics; 2006.Boulanger LL, Ettestad P, et al. Gentamicin and tetracyclines for the treatment of human plague: Review of 75 cases in New Mexico. 1985–1999. CID. 2004;38:663–669.CDC Plague Home Page http://www.cdc.gov/ ncidod/dvbid/plague/index.htmCenters for Disease Control and Prevention, Human plague–four states, 2006. MMWR Dispatch, 2006;55:1–3.Centers for Disease Control and Prevention. Update: Human plague: India, 1994. MMWR 1994;43:722–723.Crook LD, Tempest B. Plague: A clinical review of 27 cases. Arch Intern Med. 1992;152:1253.Gage KL, Dennis DT, Orloski KA, et al. Cases of cat-associated human plague in the western US, 1977–1998. Clin Infect Dis. 2000;30:893–900.

Plague - CODES

Plague - icd9

020.9 Plague

Plague - FAQ

• Q: Can one determine the risks of being exposed to plague during international travel?
• A: Yes. The CDC provides a service that contains updated information for international travel at www.cdc.gov/travel.
• Q: Does persistent fever during treatment for plague warrant altering the antibiotic regimen?
• A: No, fever can persist for up to 2 weeks after appropriate antibiotic therapy for plague, but suggests a focus of infection that needs to be drained.

Book Source Details

• Book Title: The 5-Minute Pediatric Consult
• Author(s): M. William Schwartz MD; et al.
• Year of Publication: 2008
• Copyright Details: The 5-Minute Pediatric Consult, Copyright © 2008 Lippincott Williams & Wilkins.

More About Plague

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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.

More About This Book: Title: The 5-Minute Pediatric Consult Authors: M. William Schwartz MD; et al. Publisher: Lippincott Williams & Wilkins Copyright: 2008 ISBN: 0-7817-7577-9

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