Relapsing Fever Clinical Presentation

Updated: Oct 13, 2021
  • Author: Geneva E Guarin, MD, MBA; Chief Editor: Michael Stuart Bronze, MD  more...
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The hallmark of both louse-borne relapsing fever (LBRF) and tickborne relapsing fever (TBRF) is two or more episodes of high fever (usually >39°C and up to 43°C), headaches, and myalgias. The clinical manifestations are also similar. The mean incubation time is 7 days (range, 4-18 or more days). [40]  

Fever occurs in conjunction with spirochetemia. In TBRF, the initial febrile episode lasts an average of 3 days (range, 12 h to 17 d), [35] with an average of 7 days between the initial episode and first relapse. In LBRF, the first febrile episode usually lasts longer, 5.5 days on average (range, 4-10 d), with an average of 9 days between the first episode and first relapse. Patients may feel well between episodes, but the febrile periods are characterized by crises marked by labile blood pressures and pulse as well as rigors and further increase in temperature. The crisis phase lasts for approximately 15 to 30 minutes.The risk of death is greatest during and immediately following the period of hypotension. [5]

Other symptoms of relapsing fever include chills, arthralgias, myalgias, nausea, vomiting, abdominal pain, mental status changes (and other neurologic symptoms [below]), nonproductive cough, diarrhea, dizziness, headache, neck stiffness, photophobia, rash, and dysuria.

Adult respiratory distress syndrome (ARDS) may occur during TBRF crises. [19]

Neurologic symptoms occur more often in TBRF and can include facial paralysis, hemiplegia, radiculopathy, and myelitis. In both TBRF and LBRF, delirium, and, in some cases, coma, can ensue. Case reports of meningoencephalitis have been described in recently discovered B miyamotoi infection in immunocompromised individuals. [41]

LBRF is associated with a higher incidence of jaundice, petechiae, hemoptysis, epistaxis, and CNS involvement. [35]

On average, individuals with TBRF experience 3 relapses, while those with LBRF experience only one. [5] Fever tends to be milder with relapses, which result from antigenic variation of the spirochete's outer-surface proteins. [2]



Physical exam findings in patients with relapsing fever include mental status changes, petechiae, hepatomegaly, splenomegaly, abdominal tenderness, jaundice, eschars, abnormal lung function, possible neurologic deficits (cranial nerve palsies, focal deficits), conjunctival suffusion, and the ocular findings listed above. [5, 31]

Petechiae and ecchymoses are more common in patients with LBRF than in those with TBRF. [42, 43] Bleeding results from a combination of thrombocytopenia, impaired clotting factor production, and vessel occlusion from spirochetes, red cells, and platelets.

Although patients typically present with polyarthralgia, joint tenderness and swelling are unusual findings.

The organomegaly and lung and CNS abnormalities are more commonly associated with LBRF, secondary to direct invasion of spirochetes. Rash is reported more often in patients with TBRF. [31]

Myocarditis is common in both TBRF and LBRF. On cardiac examination, gallops may be auscultated.

As noted above, neurologic findings are more common in TBRF and result from direct spirochetal CNS invasion. Both meningitis and meningoencephalitis have been reported and can lead to resultant hemiplegia or aphasia. Bell palsy (unilateral or bilateral) has also been reported in TBRF, due to seventh or eighth cranial nerve involvement.

In LBRF, CNS symptoms result from spirochetemia rather than direct spirochetal invasion. Findings include mental status changes, neck stiffness, and subarachnoid hemorrhage.



See Background.