CBRNE - Plague Clinical Presentation

In general, after an incubation period of 1-6 days, the history suggests a severe and rapidly progressive sepsis.

Recent travel in the Southwestern and Pacific Coast regions of the United States, particularly in New Mexico, Arizona, California, and Utah, should raise suspicion of a fleabite. Although imported plague is rare, similar suspicion should exist for any recent travel to endemic areas outside the United States. Fewer than 10% of patients recall a prior fleabite.

Close contact with any potentially infected host or rural environment should raise suspicion for the plague. Historically, the rat has been believed to be the main plague host; however, currently in the United States, the ground and rock squirrels are the most common hosts. In recent years, the domestic cat has emerged as a prominent host that transmits the plague to veterinarians.^[13]

A sudden increase in the incidence of severe pneumonia in previously healthy individuals should raise concern for pneumonic plague possibly deployed as a bioterrorism weapon.

Symptoms include the following:^{[14, 2]}

• Fever
• Chills
• Myalgias
• Sore throat
• Headache
• Weakness
• Malaise
• Enlarged, painful, swollen lymph node
• Abdominal pain - Only presenting symptom more common in a patient presenting with septicemic plague (primary blood-borne plague) versus one presenting with bubonic plague
• Nausea, vomiting (bloody at times)
• Constipation, diarrhea, and black or tarry stools
• Gastrointestinal complaints (may precede a bubo)
• Cough, which may be productive of bloody sputum
• Shortness of breath
• Stiff neck (if meningitic infiltration by plague bacillus has occurred)

In general, after an incubation period of 1-6 days, the plague presents with the physical findings of severe and rapidly progressive sepsis with or without features of pneumonia. Multiple organ involvement occurs. Pneumonic plague may present only as a severe pneumonia.

• Temperature of 37-40.9°C, tachycardia, tachypnea, and hypotension, if in late septic shock
• Inguinal bubo (60%), axillary (30%), cervical (10%), or epitrochlear (10%) (Bubo is usually no greater than 5 cm, extremely tender, erythematous, and surrounded by a boggy hemorrhagic area; patient often flexes, abducts, and externally rotates the hip near an involved inguinal node to reduce pain at the site.) Children are more likely to have a cervical or submandibular bubo.^[2] Images below show a bubo and a necrotic ulcer. A suppurative, bubo of the femoral lymph node (shown here), the most common site of the erythematous, tender, swollen, nodes in a plague victim. The next most common lymph node regions involved are the inguinal, axillary, and cervical areas. The child in the image below has an erythematous, eroded, crusting, necrotic ulcer at the presumed primary inoculation site on the left upper quadrant. This type of lesion is uncommonly found in patients with plague. Bubo location is primarily a function of the region of the body in which an infected flea inoculates plague bacilli. Courtesy of Jack Poland, PhD, CDC, Fort Collins, CO. A suppurative, bubo of the femoral lymph node, shown in the image above, is the most common site of the erythematous, tender, swollen, nodes in a plague victim. The next most common lymph node regions involved are the inguinal, axillary (shown here), and cervical areas. The child in this photo has an erythematous, eroded, crusting, necrotic ulcer at the presumed primary inoculation site on the left upper quadrant. This type of lesion is uncommonly found in patients with plague. Bubo location is primarily a function of the region of the body in which an infected flea inoculates plague bacilli. Courtesy of Jack Poland, PhD, CDC, Fort Collins, CO.

Dermatologic findings

A maculopapular lesion may be found at the site of the fleabite; however, such lesions commonly are found at autopsy implying that, in the United States, the diagnosis often is not determined until it is too late.

Acral cyanosis, ecchymosis (shown in the image below), petechiae, and digital gangrene are seen with Y pestis septicemia (from disseminated intravascular coagulation [DIC]).

The medieval epithet "Black Death" is thought to have originated from the deeply cyanotic skin, ecchymoses, and/or acral necrosis associated with terminal septicemic and pneumonic plague.

The initially rose-colored purpuric lesions most likely gave rise to the child's nursery rhyme "Ring Around the Rosy."

• "Ring around the rosy" - Rose-colored purpuric macules (may be caused by the Y pestis enzyme that acts alternately as a plasminogen activator or coagulase at various temperatures or may be due to DIC)
• "Pocket full of posies" - Sweet-smelling flowers that those tending the sick would carry to ward off the stench of disease
• "Ashes, ashes" - Impending mortality or "A-choo, a-choo" - The sneezing and coughing of pneumonic plague
• "All fall down" - Death

Rare cases of ecthyma gangrenosum–like lesions and carbuncles due to blood-borne Y pestis have been described.

Other findings

• Diffuse crackles, diffuse areas of dullness to percussion (secondary to patchy consolidation of pneumonic plague), and hemoptysis
• Diffuse abdominal tenderness, with or without guarding, splenomegaly, hematochezia, or heme-positive stools
• Nuchal rigidity and diffuse muscle and joint tenderness
• Various degrees of mental status changes, ranging from mild confusion or agitation to delirium and coma
• Seizures
• Bleeding from any body site or cavity (eg, hematemesis, hematochezia, hemoptysis)
• Gangrene and necrosis (shown in the images below) of areas such as the digits, penis, and nares (ascribed to peripheral thrombosis secondary to DIC) Acral necrosis of nose, lips, fingers (shown here) and toes (image below) and residual ecchymoses over both forearms in a patient recovering from bubonic plague that disseminated to blood and lungs. At one time, the patient's entire body was ecchymotic. Reprinted from McGovern TW, Friedlander AM. Plague. In: Sidell FR, Takafuji ET, Franz DR, eds. Medical Aspects of Chemical and Biological Warfare. Chapter 23 in: Zajtchuk R, Bellamy RF, eds. Textbook of Military Medicine. Washington, DC: US Department of the Army, Office of the Surgeon General, and Borden Institute; 1997: 493. Government publication, no copyright on photos. Acral necrosis of nose, lips, fingers (image above) and toes (shown here) and residual ecchymoses over both forearms in a patient recovering from bubonic plague that disseminated to blood and lungs. At one time, the patient's entire body was ecchymotic. Reprinted from McGovern TW, Friedlander AM. Plague. In: Sidell FR, Takafuji ET, Franz DR, eds. Medical Aspects of Chemical and Biological Warfare. Chapter 23 in: Zajtchuk R, Bellamy RF, eds. Textbook of Military Medicine. Washington, DC: US Department of the Army, Office of the Surgeon General, and Borden Institute; 1997: 493. Government publication, no copyright on photos.
• Pharyngitis culture positive for Y pestis has been seen in endemic areas in household contacts of those with bubonic plague. These patients also have associated cervical lymphadenopathy.

The etiologic agent is Y pestis, a facultative anaerobic, intracellular, gram-negative bacillus. The following are some epidemiologic factors that suggest an increased likelihood of infection with the plague:^[3]

• Rural or nonurban residency, especially in geographic areas with known plague foci
• Contact with sick animals, small rodents, or other possible hosts
• Wilderness activities (eg, camping, hiking, sleeping on ground, hunting)
• Fleabite
• Recent plague in the community
• Occupation as a veterinarian
• Summer months
• Sudden influx of previously healthy patients with severe pneumonia, especially if geographically clustered