Bubonic plague differential diagnosis

Differential diagnosis

The differential diagnosis of the plague can be broken down into three different categories based on the form of the disease.

Bubonic plague

• Streptococcal or staphylococcal adenitis (Staphylococcal aureus, Staphylococcal pyogenes)
  • Purulent or inflamed lesion often noted distal to involved nodes (i.e., pustule, infected traumatic lesion).
  • Involved nodes more likely to be fluctuant.
  • Associated ascending lymphangitis or cellulitis may be present (generally not seen with plague).

• Tularemia (Francisella tularensis)
  • Ulcer or pustule often present distal to involved nodes.
  • Clinical course rarely as fulminant as in plague.
  • Systemic toxicity uncommon.

• Cat scratch fever (Bartonella henselae)
  • History of contact with cats; usually history of cat scratch.
  • Indolent clinical course; progresses over weeks.
  • Primary lesion at site of scratch often present (small papule, vesicle).
  • Systemic toxicity not present.

• Mycobacterial infection, including scrofula (Mycobacterium tuberculosis and other Mycobacterium species)
  • With scrofula, adenitis occurs in cervical region.
  • Usually painless.
  • Indolent clinical course.
  • Infections with species other than M. tuberculosis. more likely to occur in immunocompromised patients.

• Lymphogranuloma venereum (Chlamydia trachomatis)
  • Adenitis occurs in the inguinal region.
  • History of sexual exposure 10-30 days previously.
  • Suppuration, fistula tracts common.
  • Although LGV buboes may be somewhat tender, exquisite tenderness usually absent.
  • Although patients may appear ill (headache, fever, myalgias), systemic toxicity not present.

• Chancroid (Hemophilus ducreyi)
  • Adenitis occurs in the inguinal region.
  • Ulcerative lesion present.
  • Systemic symptoms uncommon; toxicity does not occur.

• Primary genital herpes
  • Herpes lesions present in genital area.
  • Adenitis occurs in the inguinal region.
  • Although patients may be ill (fever, headache), severe systemic toxicity not present.

• Primary or secondary syphilis (Treponema pallidum)
  • Enlarged lymph nodes in the inguinal region.
  • Lymph nodes generally painless.
  • Chancre may be noted with primary syphilis.

• Strangulated inguinal hernias
  • Evidence of bowel involvement.

Pneumonic plague

• Inhalational anthrax (Bacillus anthracis)
  • Widened mediastinum and pleural effusions seen on CXR or chest CT.
  • Not true pneumonia; minimal sputum production.
  • Hemoptysis uncommon (if present, suggests diagnosis of plague).

• Tularemia (Francisella tularensis)
  • Clinical course not as rapid or fulminant as in pneumonic plague.

• Mycoplasmal pneumonia (Mycoplasma pneumoniae)
  • Rarely as fulminant as pneumonic plague.

• Pneumonia caused by Chlamydia pneumoniae
  • Rarely as fulminant as pneumonic plague.

• Legionnaires' disease (Legionella pneumophila or other Legionella species)
  • Rarely as fulminant as pneumonic plague.
  • Community outbreaks of Legionnaires' disease often involve exposure to cooling systems.
  • Legionellosis and many other diseases caused by bacterial agents (S aureus, S pneumoniae, H influenzae, K pneumoniae, M catarrhalis) usually occur in persons with underlying pulmonary or other disease or in the elderly.

• Psittacosis (Chlamydia psittaci)
  • Rarely as fulminant as pneumonic plague.
  • Result of bird exposure.

• Other bacterial agents (e.g., Staphyloccocus aureus, Streptococcus pneumoniae, Haemophilus influenzae, Klebsiella pneumoniae, Moraxella catarrhalis)
  • Rarely as fulminant as pneumonic plague.
  • Usually occur in persons with underlying pulmonary or other disease or in the elderly.

• Influenza
  • Influenza generally seasonal (October-March in United States) or involves history of recent cruise ship travel or travel to tropics.

• Hantavirus
  • Exposure to excrement (urine or feces) of mice with hantavirus.

• RSV
  • RSV usually occurs in children (although may be cause of pneumonia in elderly); tends to be seasonal (winter/spring).

• CMV
  • CMV usually occurs in immunocompromised patients.

• Q fever (Coxiella burnetii)
  • Exposure to infected parturient cats, cattle, sheep, goats.
  • Severe pneumonia not prominent feature.

Septicemic plague

• Meningococcemia
  • More likely to have evidence of meningitis (but not always present).

• Septicemia caused by other Gram-negative bacteria.
  • Underlying illness usually present.

Chest X Ray

Some other infectious diseases can be differentiated by looking at chest x ray images. For example, SARS, Hantavirus syndrome, and Anthrax all need to be ruled out because they do present with some similar Symptoms. An example of a chest x ray for Hantavirus and Anthrax is shown.