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  3. Clinical entry: Tick paralysis

Clinic: Tick paralysis

Examine for venom effects

Local Effects

  • Pain
  • reddness
  • swelling

Neurological effects

  • Ascending flaccid paralysis:
    • Paralysis of the legs
    • Paralysis of aupper extremities and trunk.
    • Bulbar paralysis with cranial nerve deficits.
    • Cyanosis, shallow breathing, respiratory arrest (respiratory paralysis).
    • Loss of consciousness and generalized convulsions caused by hypoxaemia in patients who have respiratory paralysis.  

Species-specific envenoming pattern

The assessment of the envenoming pattern is based on the data from publication in which the identification of the tick is clearly specified and in accordance with accepted criteria.

     Neurological effects 

North America

Dermacentor andersoni

Dermacentor variabilis 

(Ixodes scapularis)

  
Australia Ixodes holocyclus  

Neurological effects

Onset of neurological symptoms after the tick had already been attached for several days (Gregson 1973, Hamilton 1940). Progressive course.

Symptoms

In some patients irritability may be apparent 12–24 h before paralysis becomes obvious.
Tingling in the extremities, the face or the perioral region. 
Paralysis usually begins in the legs. At first the gait is affected, then there is a complete loss of strength in the legs. 1–2 days later the paralysis also affects the upper extremities and the trunk. 
Bulbar palsy ensues, with cranial nerve deficits. 
Finally paralysis of the respiratory musculature occurs. The causes of death are thus respiratory failure and aspiration pneumonia.

Findings

Signs of peripheral paralysis. Deep tendon reflexes cannot be elicited.

Course of the disease after removal of the tick

There appear to be differences in the clinical course of tick paralysis in North America and Australia.

  • In North America patients experience full recovery within 3–4 days as long as paralysis was not too far advanced at the time the tick was removed. 
  • In Australia the symptoms may only peak up to 48–72 h after removal of the tick or after the tick falls off by itself (Pearn 1977). The clinical course of Australian tick paralysis generally appears to be more acute than that of North American paralysis.

Important differential diagnoses

Lyme borreliosis, caused by B. burgdorferi and carried by Ixodes sp. Neurological symptoms occur weeks after the tick bite, in contrast to several days with tick paralysis.
Other neurological disorders (polyradiculitis = Landry-Guillain-Barré syndrome, polyneuropathies, poliomyelitis).

See also list of differential diagnoses in Diaz (2010).
There is a particular risk that tick paralysis may not be considered initially and valuable time may be lost before the tick can be located and removed so as to enable spontaneous recovery. 

Clinical management

First Aid

  • Remove ticks as soon as possible. It is imperative to also look carefully for ticks in less obvious places, such as the scalp.  

Local treatment

Bite site

Tetanus prophylaxis
Standard wound care 


Systemic supportive treatment

A general understanding of emergency medicine is required, or can be found in emergency medicine guidelines, e.g. ABCDE approach, WHO-ICRC Basic Emergency Care.

Follow ABCDE approach

WHO-ICRC Basic Emergency Care: approach to the acutely ill and injured

Obey Tick paralysis - specific features

see 'Species-specific envenoming pattern' above.

Key issues: 

  • Remove ticks as soon as possible. It is imperative to also look carefully for ticks in less obvious places, such as the scalp. 
  • Intensive medical care if symptoms progress. Early endotracheal intubation. Artificial respiration.
  • Neurophysiological investigations: marked reduction in the amplitude of the motor response and early appearance as well as persistence of fibrillations (Donat and Donat 1981).

Specific treatment (antivenoms)

Australia 

No antivenom available for humans.

Veterinary antivenom for use in animals.

North America

No antivenom available for humans. 

Species-specific evidence

North America

Dermacentor andersoni, D. variabilis

Rarely, Ixodes scapularis, the vector of Lyme disease, is causing tick paralysis in North America.

  • Abbott (1944)
    Description of the clinical picture.

Reviews

  • Diaz JH. A 60-year meta-analysis of tick paralysis in the United States: a predictable, preventable, and often misdiagnosed poisoning. J Med Toxicol. 2010 Mar;6(1):15-21. PMID: 20186584; PMCID: PMC3550436. https://doi.org/10.1007/s13181-010-0028-3
  • Edlow JA. Tick Paralysis-A Rare but Important Tick-Borne Disease. JAMA Intern Med. 2024 Nov 1;184(11):1394-1395. PMID: 39312219. https://doi.org/10.1001/jamainternmed.2024.4797

Australia

Ixodes holocyclus

Reviews

  • Grattan-Smith PJ, Morris JG, Johnston HM, Yiannikas C, Malik R, Russell R, Ouvrier RA. Clinical and neurophysiological features of tick paralysis. Brain. 1997 Nov;120 ( Pt 11):1975-87. PMID: 9397015. https://doi.org/10.1093/brain/120.11.1975

Global impact

  • Deng Y-P, Fu Y-T, Elsheikha HM, Cao M-L, Zhu X-Q, Wang J-L, Zhang X, Xie S-C, Yao C, Liu G-H. Comprehensive analysis of the global impact and distribution of tick paralysis, a deadly neurological yet fully reversible condition. Clin Microbiol Rev. 2024 Dec 10;37(4):e0007424.  Epub 2024 Oct 23. PMID: 39440956; PMCID: PMC11629633. https://doi.org/10.1128/cmr.00074-24