Tick Paralysis
Tick paralysis occurs when an engorged and gravid (egg-laden) female tick (update 8/16- also male ticks) produces a neurotoxin (poison) in its salivary glands and transmits it to the host while feeding. Tick paralysis is the only tick-borne disease that is not caused by an infectious agent.
Tick paralysis is most commonly seen in children under 16 and typically affects girls more than boys. It is transmitted by over 40 species of ticks worldwide (five in North America, including the deer tick, lone star tick and dog ticks). It has been responsible for killing countless pets and farm animals.
Ticks in the USA that can cause tick paralysis are widely distributed; therefore, the potential for exposure exists in every state.
Tick paralysis is chemically induced by the tick and the "poison" can only continue to cause symptoms while the tick is attached. Once the tick is removed the symptoms usually diminish or disappear. In some cases profound paralysis can develop and it can become fatal before a person becomes aware of a tick’s presence.
Symptoms
Symptoms- Symptoms of tick paralysis usually begin 4 to 6 days after a tick becomes attached (often found on the scalp and along the hairline on the head). Fatigue, ataxia, wide-based gait, numbness of the legs and muscle pains are common. Paralysis can rapidly develop- from the lower to the upper extremities- and is often followed by tongue and facial paralysis.
Fever is rare, and constitutional symptoms, which sometimes precede the paralysis, can include dizziness, nausea, vomiting, tremors, paraesthesias, restlessness, irritability and myalgia. Reflexes in affected areas are reduced or absent. Sensory abnormalities, primarily numbness and tingling in the face and limbs are frequently reported by patients. Bulbar palsy and ophthalmoparesis have also been reported.
Ocular disturbances, tachycardia, autonomic dysfunction and new hypertension have been reported. The differential diagnosis includes entities that are infectious or caused by toxins of infectious agents, such as epidural abscess, some causes of transverse myelitis and botulism. It can also mimic polio and has been misdiagnosed as cellulitis.
Large distal syrinx and arachnoid cysts have been reported in the literature. (Arachnoid cysts are cerebrospinal fluid-filled sacs that are located between the brain or spinal cord and the arachnoid membrane.)
Cranial nerve involvement, hyporeflexia and respiratory depression have also been noted in patients. The most severe complications are convulsions, respiratory failure and death.
Tick paralysis is often misdiagnosed as Guillain-Barre syndrome (particularly the Miller Fisher's subtype). As a general rule, aimed more towards patient safety, doctors should never definitively diagnose Guillain-Barré syndrome without first searching the entire body for a tick.
In Australia tick paralysis symptoms can linger after the removal of a tick bite for a greater length of time than comparative cases in the United States.
Diagnosis
Diagnosis- Lab tests are not able to detect tick paralysis. Symptoms are used to diagnosis the illness and diagnosis is dependent on physician experience and awareness. If symptoms lessen after a tick is removed it can help confirm the diagnosis.
Treatment
Treatment- Treatment involves removing the feeding tick as soon as possible and being sure to remove all of the mouthparts since they contain the salivary glands which may continue to infect the patient even after the body of the tick has been removed. Once the tick is removed the patient usually recovers rapidly.
Last Updated- February 2019
Lucy Barnes