Tick paralysis
From IDWiki
Background
- Non-infectious disease caused by saliva injected during tick bite
Epidemiology
- Most common in Pacific Northwest of the US and Canada, and in Australia
- In North America, most commonly caused by Dermacentor variabilis or Dermacentor andersoni from April to June
- In Australia, most commonly caused by Ixodes holocyclus (marsupial ixodid tick), and may be more severe
Pathophysiology
- Unclear mechanism for Dermacentor ticks
- Ixodes holocyclus produces a botulinum-like neurotoxin
Clinical Manifestations
- Ascending neuromuscular paralysis with preserved sensation
- Can cause ataxia
- Often misdiagnosed as Guillain-Barré syndrome until an engorged tick is found, often hidden in hair
Differential Diagnosis
Feature | Tick Paralysis | Guillain-Barré syndrome | Cervical Spine Lesion | Poliomyelitis |
---|---|---|---|---|
Onset | acute and rapid, within 24 to 28 hours | slower, over days to weeks | abrupt or gradual | days to weeks |
Ataxia | present | absent | absent | absent |
DTRs | hypo- or areflexia | hypo- or areflexia | variable | hypo- to areflexia |
Plantar reflex | downgoing | downgoing | upgoing | downgoing |
Sensation | unaffected | mildly affected | affected | unaffected |
Meningismus | no | rarely | no | yes |
Fever | no | rarely | no | yes |
CSF protein | normal | high | normal or high | high |
CSF WBCs | normal | normal | elevated | |
CSF differential | normal | <10 mononuclear cells | variable | lymphocytosis |
Time to recovery | rapid ≤24 hours after tick removal | weeks to months | variable | months to years |
Permanent sequelae | none | possible | possible | possible |
- Botulism causes descending paralysis
Management
- Removal of tick with forceps; recovery typically within 24 hours