II. Epidemiology

  1. Rare: <500 cases reported in U.S. in last 25 years
  2. Region
    1. U.S. West of the Mississippi River
    2. More common in mountains

III. Pathophysiology

  1. Cause
    1. Spirochete in Borrelia genus
  2. Vectors
    1. Soft Ticks (Ornithodoros genus)
      1. Other Borrelia species cause Relapsing Fever in Africa and Russia
      2. Borrelia hermsii (reservoir: Squirrels and chipmunks)
      3. Borrelia tunicate (reservoir: Cattle, rodents, pigs)
      4. Borrelia miyamotoi
    2. Body Lice (human to human transmission)
      1. Borrelia recurrentis
  3. Exposure
    1. Mountain cabin with rodents
    2. Cave exploration
    3. Work under buidlings
  4. Relapsing Fever
    1. Infections often involve multiple Borrelia serotypes
    2. As one serotype is cleared, another proliferates
    3. May lie dormant in liver, Spleen, CNS, marrow
    4. Alternating serotypes, dormancy cause Relapsing Fever

IV. Symptoms (follows 7 day incubation period)

  1. Fever
    1. Sudden onset, over 102.5 F (39.2 C)
    2. May rise over 104 F
    3. Pattern
      1. Fever for 3 to 6 days
      2. Febrile period ends with 30 minute crisis period
        1. Brief spike in pulse and Blood Pressure
        2. Sweats occur as the fever abates
      3. Fever recurs every 4 to 14 days
  2. Associated symptoms
    1. Headache
    2. Myalgias and Arthralgias
    3. Chills
    4. Nausea or Vomiting
    5. Abdominal Pain

V. Signs

  1. Hepatomegaly (10%)
  2. Splenomegaly (6%)
  3. Meningitis (2%)
  4. Pneumonitis
  5. Myocarditis
  6. Iridiocyclitis
  7. Cranial Nerve palsy (e.g. Bell's Palsy, deafness)
  8. Altered Level of Consciousness (Delirium, coma)

VI. Labs: Diagnosis

  1. Microscopic exam of blood, CSF other body fluid
    1. Thick and thin smears stained with Wright's or Giemsa
    2. Spirochetes identified
  2. Blood Cultures during febrile period
  3. Immunofluorescence and PCR not widely available

VIII. Labs: If indicated

  1. Myocarditis suspected
    1. EKG with Prolonged QT interval (QTc)
  2. Meningitis suspected
    1. CSF mononuclear Pleocytosis and increased CSF Protein

IX. Management

  1. Tick-Borne Infection
    1. Doxycycline 100 mg oral or IV twice daily for 7-10 days (preferred) OR
    2. Erythromycin 500 mg orally qid for 7-10 days
  2. Louse-borne Infection
    1. Tetracycline 500 mg oral or IV once OR
    2. Erythromycin 500 mg oral or IV once

X. Complications

  1. Jarisch-Herxheimer Reaction (54% of treated cases)
    1. Occurs with treatment
    2. Onset within 2 hours of starting treatment
    3. Observe for 12 to 24 hours after starting treatment
  2. Acute Respiratory Distress Syndrome (ARDS)
  3. Encephalopathy

XI. Prognosis

  1. Mortality <1% in treated cases
  2. Poor prognostic factors
    1. Myocarditis
    2. Altered Level of Consciousness
    3. Poor liver function
    4. Bleeding complications from multiple sites

XII. Prevention

  1. See Prevention of Tick-borne Infection
  2. Spray susceptible buildings with Malathion 0.5%
  3. Keep home free of rodents

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Ontology: Tick-borne relapsing fever (C0035022)

Concepts Disease or Syndrome (T047)
ICD9 087.1
ICD10 A68.1
SnomedCT 186821005, 10301003
English Relapsing fever, tick-borne, Tick-borne relapsing fever NOS, tick-borne relapsing fever (diagnosis), tick-borne relapsing fever, Tick-borne relaps fever, Tick-borne relapsing fever NOS (disorder), Tick-borne relapsing fever, Tick-borne relapsing fever (disorder), tick-borne; relapsing fever, Tick-borne relapsing fever, NOS, Tick-Born Relapsing Fever
Dutch febris recurrens, overgebracht door teken, door teken overgebrachte febris recurrens, teken; febris recurrens, Door teken overgebrachte febris recurrens
French Fièvre récurrente, transmise par tique, Fièvre récidivante transmise par tique
German Rueckfallfieber, von Zecken uebertragen, von Zecken uebertragenes Rueckfallfieber, Durch Zecken uebertragenes Rueckfallfieber
Italian Febbre ricorrente da zecche
Portuguese Febre recorrente transmitida por carraças
Spanish Fiebre recurrente transmitida por garrapatas, fiebre recurrente transmitida por garrapatas, SAI (trastorno), fiebre recurrente transmitida por garrapatas, SAI, fiebre recidivante transmitida por garrapatas (trastorno), fiebre recidivante transmitida por garrapatas
Japanese ダニ媒介性回帰熱, ダニバイカイセイカイキネツ
Czech Typhus recurrens přenášený klíštětem, Návratná horečka přenášená klíštětem
Korean 진드기 매개 재귀열
Hungarian Visszatérő láz, kullancs által terjesztett, Kullancs-által terjesztett visszatérő láz