Bubonic plague differential diagnosis

There are many diseases that resemble the basic signs and symptoms of bubonic plague. Since bubonic plague has the ability to kill the majority of a population, it is an extremely concerning diagnosis. It is very important to check for these other diseases before a final diagnosis of bubonic plague is made. There are many other bacterial infections that could be mistaken for the bubonic plague.

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.