What are the symptoms of tularemia?

Symptoms of Tularemia

Tularemia classically presents with sudden onset of fever, chills, headache, lymphadenopathy, myalgia, malaise, and fatigue, with pulse-temperature dissociation occurring in 42% of cases. 1

Core Clinical Features

The disease manifests after an incubation period of 1–21 days (mean 4–5 days) and varies in severity depending on the route of inoculation, the bacterial subspecies involved, number of organs affected, and host immune status. 1

Universal Symptoms (Present Across All Forms)

• Sudden onset of high fever and chills - characteristic of the acute phase 1
• Severe headache - a prominent early symptom 1
• Myalgia (muscle pain) and malaise - contributing to the flu-like presentation 1, 2
• Profound fatigue - often disproportionate to other findings 1
• Pulse-temperature dissociation - a classic finding where the pulse rate is lower than expected for the degree of fever, occurring in 42% of cases 1

Clinical Syndrome-Specific Presentations

The symptoms vary significantly based on the route of transmission, resulting in six distinct clinical syndromes: 1, 2, 3

Ulceroglandular Form (49-75% of cases)

• Skin ulcer or eschar at the site of organism entry (tick bite, animal contact, or insect bite) 1
• Tender regional lymphadenopathy - lymph nodes draining the entry site become prominently enlarged 1
• The skin lesion may be inconspicuous or healed by the time medical care is sought 1
• Lymph nodes progress to suppuration in approximately 30% of patients 4

Glandular Form (12.5-15.9% of cases)

• Tender lymphadenopathy without visible skin lesion - the ulcer is either absent or has already healed 1, 5
• Otherwise identical systemic symptoms to ulceroglandular form 1

Oculoglandular Form

• Conjunctivitis with purulent discharge 2
• Periauricular or cervical lymphadenopathy 2
• Ocular pain and photophobia 2

Oropharyngeal Form

• Pharyngitis or tonsillitis 1, 2
• Cervical lymphadenopathy 1
• Stomatitis and oral ulceration 2
• Acquired through ingestion of contaminated water or food 1, 2

Pneumonic/Pulmonary Form

• Pneumonia with cough and chest pain 1, 6
• Dyspnea in severe cases 6
• May present with fever and general illness with no respiratory symptoms despite pulmonary involvement 6
• Radiological changes vary widely and may include hilar enlargement that can mimic lymphoma 6
• Acquired through inhalation of contaminated aerosols 1, 2

Typhoidal Form

• High fever with no localizing signs 1, 2
• Severe systemic illness without obvious lymphadenopathy or skin lesions 2
• Can occur after infection via any route 2
• May be life-threatening if not recognized early 4

Important Clinical Pitfalls

Do not exclude tularemia based on absence of a visible skin lesion - the glandular form accounts for 12.5-15.9% of cases and the ulcer may have healed before presentation. 5

Consider tularemia in atypical pneumonia or acute febrile illness with no local symptoms when there is a history of exposure to hares, rodents, or tick bites, or residence in an endemic region. 6

Early diagnosis is critical - treatment delays beyond 2-3 weeks after disease onset are associated with higher rates of treatment failure, relapse, and need for surgical intervention. 4

The clinical presentation is less specific in respiratory forms, making diagnosis particularly challenging when the disease has been rarely encountered in a region. 6

Human-to-human transmission does not occur, so isolation beyond standard precautions is not required. 2