Tick Paralysis in dogs & cats
Most local tick cases occur between July and January, with a peak in Spring. It takes at least 3-4 days for signs to appear after the adult tick first attaches to the susceptible animal. The gland producing the tick toxin is located just behind the head, and it is preferable to pluck the tick off briskly rather than to apply any chemical. If all else fails, simply cut the tick off at the head, level with the skin surface with scissors. If no symptoms are apparent, observe the animal closely for the next 1-2 days after the tick(s) have been removed. First signs can include wobbly hind legs, loss of voice or a "groan", vomiting, and difficulty in breathing. It is important at this stage to not give anything by mouth as pneumonia may result. Keep the animal quiet and cool. A fluid shift occurs in severely affected animals with tick paralysis. Fluid accumulates in the lungs due to a direct effect of toxin on heart muscle. The majority of animals have oesophageal muscle weakness. The combination of a poor gag reflex, saliva pooling, and a dilated and filling oesophagus, has the potential to cause severe upper respiratory distress. Regurgitation induces a harsh groan as dogs attempt pharyngeal clearing with upper airway paralysis.
MANAGEMENT of patients may involve:
A simple blood test (called a PCV or "packed cell volume") to assess the degree of fluid shift; and in severe cases an X-Ray of the chest to determine the degree of lung oedema.
Tick antiserum is given slowly via an intravenous catheter; however, improvement in signs will normally take 12-24 hours. Patients will usually worsen prior to this turnaround. Other drugs are important in this initial period.
These are designed to:
• relieve fluid accumulation in the lungs
• reduce respiratory distress by sedating the animal
• dry up secretions in the mouth and upper airways
• combat infection in the lungs resulting from aspiration of vomitus &/or saliva
Intravenous fluids may be required to prevent dehydration if recovery is prolonged and high molecular weight fluids (colloids) are useful in clearing fluid from the lungs. Eye protectants are useful to guard against drying out of the corneas and potential ulceration; especially if any local eyelid paralysis is evident with a tick attached around the skull area. In conclusion, it is difficult to give an accurate prognosis on recovery at initial consultation, as many variable factors influence the degree of worsening prior to the "turnaround" time some many hours after dosing with antiserum. The important message is to begin treatment as early as possible, and to not wait to see if your pet may improve by the next day.