http://tinyurl.com/bk7hnClinical Syndrome(s)
The illness
Depending on the route of infection, there are six forms of tularemia: typhoidal, ulceroglandular, glandular, oculoglandular, oropharyngeal and pneumonic tularemia. These categories serve only to describe the predominant symptom in each syndrome; overlapping symptoms are common in all six forms. Incubation period is approximately 3-5 days but can range from 1 to 21 days (13) .
Ulceroglandular tularemia (21-87% of cases in the United States) (14, 15)
As the name implies, this form is characterized by a skin ulcer and an enlarged and tender lymph node enlargement. The skin lesion starts as a red painful papule which becomes necrotic and produces a tender ulcer with a raised border. The skin ulcer generally represents the site of entry of the bacteria, either through a bite or contact with infected tissue on a pre-existing cut (14) . See Figure 2.
Figure 2. Skin lesions of tularemia. (
http://phil.cdc.gov/phil/default.asp )
Glandular tularemia (3 to 20% of cases in the United States) (15)
Glandular tularemia is distinguished from ulceroglandular tularemia when tender, enlarged lymphadenopathy is present without evident skin lesions. In either case, the lymph node can be fluctuant and may spontaneously drain purulent material. Surgical drainage should be considered if spontaneous drainage does not occur.
Other illnesses may mimic glandular tularemia and include:
* Bacterial lymph node infection
* Cat-scratch disease (Bartonella hensellae)
* Syphillis
* Chancroid
* Lymphogranuloma venereum
* Tuberculosis
* Non-tuberculosis mycobacterial infection
* Toxoplasmosis
* Sporotrichosis
* Rat-bite fever
* Herpes Simplex Virus infection
Other potential agents of bioterrorism include
* Anthrax
* Plague
Oculoglandular tularemia (0 to 5% of cases) (15)
When F. tularensis gains entry to the conjunctiva through direct contact from contaminated hands or splashes, the illness is called oculoglandular tularemia. The presentation is typically unilateral complaints of photophobia and excessive tearing and physical exam can reveal eyelid swelling, redness of the conjunctiva and less commonly conjunctival ulcerations.
Pharyngeal tularemia ((0 to 12% of cases) (15)
When the skin ulcer of tularemia is located in the oropharynx, typically occurring after eating or drinking contaminated foods or water, the syndrome is called pharyngeal tularemia. Patients may present with sore throat with ulcers and exudates seen in the pharynx or tonsils. When patients come from areas where tularemia is endemic, and present with severe sore throat not responsive to penicillin therapy, the possibility of tularemia should be entertained.
Typhoidal tularemia (5-30% of cases) (15)
Patients presenting with a febrile illness caused by F. tularensis but without lymph node enlargement or skin or eye ulcers, are described as having typhoidal tularemia. The mode of transmission may include direct contact with infected animals or tissue, bites from arthropods or inhaling aerosolized bacteria.
Pneumonic tularemia (7-20% of cases) (15)
Patients with this form of tularemia present with pneumonia as the predominant symptom. The route of transmission may be through inhalation of aerosolized bacteria or from seeding of the lung through the blood stream from another source, such as a skin ulcer.
Naturally occurring primary pneumonic tularemia can be seen in certain high-risk professions, such as sheep shearers, farmers and laboratory workers. (6) (16) Common symptoms include fever, dry cough, substernal chest pain and pleuritic chest pain. Chest radiographs may reveal enlarged hilar nodes lobar infiltrates and pleural effusion.
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