Paralysis Progresses as the Clock Ticks

Introduction: A child who presents with acute ascending paralysis triggers a meticulous history, physical exam, and the development of a wide differential diagnosis as treatment delay in many causative conditions can be fatal. In a child with acute ataxic ascending paralysis, an automatic consideration is Guillain- Barre Syndrome unless the possibility of a tick bite is mentioned. Differentials then shift towards consideration of the infectious diseases that ticks carry. The question quickly becomes which clinical, laboratory, or imaging test will yield the key information in order to save a life.

Case Description: A 6-year-old female with past medical history of resolved mild extremity hypotonia and resolved delayed speech presented to the ER. The patient went to sleep the previous night at her baseline but awoke in the morning with profound weakness, ataxia and the inability to walk without assistance. On physical exam she was calm and cooperative. Vitals were appropriate for age. Significant findings included horizontal nystagmus, dysmetria with finger to nose testing, 3/5 abduction of her bilateral upper extremities, and 4/5 in bilateral lower extremities with absent Patellar and Achilles reflexes. Biceps and triceps reflexes were 1+ bilaterally. Her exam was otherwise unremarkable. Lab workup including CBC, CMP, TSH, CRP, PT/INR, UDS, Ethanol were unremarkable however lactic acid was 2.7 and alkaline phosphatase was 287. Chest X-ray and non-contrast CT head were unremarkable. Subsequently two engorged ticks were discovered at base of the patient’s skull by her mother. She reported that the patient had been playing in a treehouse over the previous days. The ticks were removed, and the patient was observed without intervention. The patient returned to her previous baseline prior to discharge home on Hospital Day 2.

Discussion: Tick paralysis is caused by a botulism-like toxin produced in the salivary glands of 8% of tick species which is transmitted to the host by attachment day 3-5. Most cases have been reported in young children, particularly girls under 10 years of age in North America and Australia. Symptoms involve acute, flaccid, ascending paralysis which can lead to death with involvement of respiratory muscles mimicking Guillain- Barre and cerebellar ataxia. Patients have normal labs, imaging, and sensory exams. Treatment involves prompt removal of the ticks and supportive measures while toxin levels decrease. In some cases, the tick detaches spontaneously resulting in clinical resolution without diagnosis or intervention. This contributes an overall lack of incidence data for tick paralysis, however as this case demonstrates a comprehensive skin exam should be considered in at-risk patients.

Conclusion: Tick paralysis is a rare, potentially fatal condition, which should be considered in all children presenting with acute ascending paralysis. At-risk patients should undergo a comprehensive skin exam.