CLINICAL, HEMATOLOGIC, AND BIOCHEMICAL FINDINGS IN DOGS AFTER INDUCTION OF SHOCK BY INJECTION OF HEARTWORM EXTRACT

A crude, whole-body extract of female or male heartworms was injected IV into 28 dogs with and 22 dogs without heartworm (HW) infection. The female HW extract caused shock in 22 of 24 dogs with and 12 of 20 dog s without HW infection. The male HW extract induced shock in 4 of 4 do gs with and 1 of 2 dogs without HW infection. Prevalence of shock caus ed by female HW extract was significantly (P < 0.05) higher in dogs wi th than without HW infection; shock developed 5 to 30 minutes after HW injection. These signs were observed: marked decrease in blood pressu re; collapse (initial collapse); paleness of mucous membranes; weak he art sounds; dyspnea; skin coldness; intestinal hyperperistalsis, and d efecation; increases in RBC count, serum total protein concentration, serum osmolality, serum Na and blood glucose concentrations; and decre ases in neutrophil, eosinophil, and platelet counts. Alanine transamin ase, alkaline phosphatase, and lactate dehydrogenase activities increa sed substantially from the time of initial collapse to 24 hours after HW injection. Of 39 dogs with shock, 29 recovered from initial collaps e, but 5 of the 29 subsequently collapsed again (secondary collapse), with bloody diarrhea followed by death. Of these 39 dogs, 6 died durin g initial collapse without bloody diarrhea, and 4 were euthanatized du ring initial collapse. It was confirmed that HW extract had, in fact; induced shock. These clinical, hematologic, and biochemical findings w ere fundamentally similar to those associated with shock resulting fro m administration of drugs, such as diethylcarbamazine and milbemycin D , in microfilaremic dogs with HW infection.