What is tick paralysis?

Tick Paralysis: A Potentially Fatal but Treatable Neurotoxic Condition

Tick paralysis is a rare but potentially fatal neurotoxic condition caused by a neurotoxin secreted in the saliva of engorged female ticks, characterized by ascending flaccid paralysis that resolves rapidly after tick removal. 1

Clinical Presentation and Pathophysiology

Tick paralysis develops due to a specific neurotoxin released by feeding ticks, with symptoms typically appearing within 2-6 days of tick attachment. The classic presentation follows a predictable pattern:

• Initial symptoms: Unsteady, ataxic gait
• Progression: Symmetric ascending flaccid paralysis
• Advanced symptoms: Involvement of upper extremities within hours
• Late symptoms: Cranial nerve involvement and bulbar palsy

The progression is typically rapid and can lead to respiratory failure if the tick remains attached. Unlike infectious tick-borne diseases, tick paralysis is purely toxin-mediated and resolves quickly after tick removal.

Key Diagnostic Features

Tick paralysis is often misdiagnosed as Guillain-Barré syndrome (particularly Miller Fisher variant) due to similar presentation with:

• Ataxia
• Areflexia
• Ascending paralysis
• Cranial nerve involvement

However, important distinguishing features include:

• More rapid progression than Guillain-Barré syndrome
• Normal cerebrospinal fluid protein levels
• Complete resolution within hours to days after tick removal 1
• No need for immunotherapy or plasmapheresis

Atypical Presentations

While the classic presentation involves ascending paralysis, several atypical presentations have been documented:

• Isolated involvement of the upper trunk of brachial plexus 2
• Multiple cranial neuropathies with visual loss and proptosis 3
• Unilateral weakness with bulbar palsy 4

These variant presentations can make diagnosis even more challenging and highlight the importance of a thorough skin examination in any patient with acute or subacute neurological symptoms, especially during tick season.

Diagnostic Approach

The diagnosis of tick paralysis is clinical and confirmed by:

1. Finding and removing the attached tick
2. Observing rapid clinical improvement after tick removal
3. Electrophysiological studies may show reduced compound muscle action potentials without conduction slowing 2

Importantly, the tick may be in an obscure location and easily missed on initial examination. There have been reports of ticks visible on neuroimaging studies that were initially overlooked 5, emphasizing the need for meticulous skin examination.

Treatment and Prognosis

The definitive treatment for tick paralysis is simple but critical:

• Complete removal of the attached tick
• Supportive care until recovery occurs

The prognosis is excellent with proper treatment:

• Initial improvement typically occurs within hours of tick removal
• Complete neurological recovery generally occurs within approximately 1.5 days 1
• No long-term sequelae if treated promptly

Prevention

Prevention strategies include:

• Wearing protective clothing in tick-endemic areas
• Using tick repellents
• Performing regular "tick checks" after outdoor activities
• Prompt removal of attached ticks before symptoms develop

Clinical Pitfalls to Avoid

1. Failure to perform a thorough skin examination in patients with acute neurological symptoms
2. Misdiagnosis as Guillain-Barré syndrome leading to unnecessary treatments
3. Incomplete tick removal, which may not resolve symptoms
4. Overlooking ticks in hidden areas (scalp, gluteal fold, axilla)
5. Failing to consider tick paralysis in adults (though more common in children)

Tick paralysis should be considered in any patient presenting with acute ataxia and ascending paralysis, particularly during tick season in endemic areas, as prompt diagnosis and tick removal can prevent significant morbidity and mortality.