Metaldehyde toxicosis in dogs is characterised by prolonged seizure activity and it is a common cause of seizures in poisoned dogs. Management can be difficult and often several sedatives or anaesthetic agents are required to control seizures and prevent the onset of complications such as pyrexia and multiorgan failure. Treatment can be intensive and prolonged.
A recent study compared the use of haemodialysis for severe metaldehyde intoxication in 11 dogs with 7 dogs managed conventionally and fund that haemodialysis significantly decreases the requirement for anaesthesia and length of hospitalization in dogs with metaldehyde intoxication. In the study diagnosis was based on clinical signs and toxicological analysis or presence of turquoise material in the gastrointestinal content. Dialysis was performed for median (range) 180 minutes (150–420 minutes) with a median of 2.28 L/kg blood volume processed. In the haemodialysis group, anaesthesia was discontinued at a median of 3.0 hours (1.5–6.7 hours) after starting dialysis. The conventional-group received general anaesthesia for a median of 17.5 hours (7.0–30.5 hours). No further anticonvulsive treatment was necessary for the haemodialysis group. Time to hospital discharge was shorter in dialysed dogs (median 18 hours 15–41 hours) compared to conventionally treated dogs (median 89 hours; 61–168 hours; P = 0.0014). Aspiration pneumonia was reported in 5 conventionally treated dogs and none of the dialysed dogs (P = 0.001). Five dialysed dogs developed haematoma at the dialysis catheter site. One dog in each group was euthanased; one of the conventionally treated dogs was euthanased due to severe aspiration pneumonia. One dog in the haemodialysis-treated group was euthanased after 3 hours of haemodialysis and 1 hour after isoflurane administration was discontinued because it did not recover from anaesthesia and developed non-responsive mydriasis, prolonged aPTT and severe hypernatraemia.
Serial quantitative metaldehyde analysis was performed in one dog treated with haemodialysis and during the course of treatment (3 hours) the concentration decreased steadily showing an 81% reduction.
The survival rate in these dogs did not differ between the groups and were comparable to those previously reported, and of course this was only a small study. Reduced anaesthesia time and fewer complications are positive outcomes, however, as they reduce morbidity, hospitalisation time and treatment costs.