Persistent pit viper envenomation in three dogs

The effects of hyperbaric oxygen therapy on snake-bite-associated wounds in dogs

OBJECTIVE

To assess the effect of hyperbaric oxygen therapy (HBOT) on Crotalinae envenomation-induced wound swelling and severity and pain in dogs, and to describe the safety and complications of HBOT.

DESIGN

Prospective, randomized, controlled, blinded study (2017-2021).

SETTING

University teaching hospital, private veterinary practice.

ANIMALS

Thirty-six client-owned dogs presenting within 24 hours of a confirmed or suspected naturally occurring Crotalinae snake bite injury were enrolled between 2017 and 2021.

INTERVENTIONS

In addition to the standard of care treatment, dogs received 2 interventions with either HBOT (n = 19) or control (n = 16) within 24 hours of hospital admission. Dogs receiving HBOT were pressurized over 15 minutes (1 psi/min), maintained at a target pressure of 2 atmosphere absolute (ATA) for 30 minutes, and decompressed over 15 minutes. Control dogs received 1 ATA for 1 hour. Local wound swelling, wound severity score, and pain score were assessed at admission, before and after each intervention, and at hospital discharge.

MEASUREMENTS AND MAIN RESULTS

There was no significant difference in wound swelling (P = 0.414), severity score (P = 1.000), or pain score (P = 0.689) between HBOT and control groups. Pain decreased significantly over time regardless of the study intervention (P < 0.001). There were no major adverse effects associated with either study intervention.

CONCLUSIONS

HBOT did not significantly alter the short-term recovery from Crotalinae envenomation in this study population. However, the study might be underpowered to detect a significant treatment effect.

Neurologic and hematologic sequalae following a timber rattlesnake (Crotalus horridus) envenomation in a dachshund

A 2-year-old female Dachshund had a witnessed timber rattlesnake envenomation. Although rattlesnake envenomations are a common, potentially life-threatening event in companion animals, timber rattlesnake envenomations in the dog are rarely reported. This dog described in this case report had significant hematologic and neurologic clinical derangements consistent with Types A and B rattlesnake venom and a suspected hypersensitivity reaction to the venom. This patient was treated aggressively with antivenom and fully recovered without any persistent neurologic signs at follow-up.

A review of 95 pit viper envenomations in Northcentral Florida (2018-2020)

The medical records of 95 pit viper envenomations in client-owned dogs presented to an academic emergency hospital in the Southeastern United States during the period spanning 2018 and 2020 were retrospectively examined. This study's primary objectives were to record the clinical abnormalities and treatment responses associated with envenomation and their relation to outcome. Approximately 80% of the bites involved the head region associated with varying degrees of hemorrhagic lymphedema. Some of the most common additional symptoms observed were; hypotension (10%), cardiac dysrhythmias (17%), and coagulopathy (21%). Treatment in most cases consisted of intravenous fluids, antivenom, and analgesic drugs. Blood products were used as indicated for anemia and persistent bleeding. The average dose of the F('ab')₂ was 1-2 vials. Additional vials (3-22) were administered as needed to counteract persistent or recurrent coagulopathy and hemolysis. Only 3% of the dogs had mild clinical signs of Type 1 hypersensitivity during their treatment period. Antihistamine use at the tertiary hospital was restricted to the three dogs showing signs of a suspected allergic reaction in response to antivenom administration; these patients received diphenhydramine intramuscularly. A glucocorticoid drug was used in only one dog prior to referral but not subsequently. Ninety dogs had a good outcome, while five died. Historically, pit viper envenomation in dogs in the southeastern United States has been a potentially life-threatening problem. Most dogs will survive if treated promptly and appropriately with adequate amounts of intravenous fluids, and antivenom titrated on severity of clinical presentation.

Pit viper envenomation in pediatric dogs: 5 cases

Treatment of pit viper envenomated puppies (≤6  months old) with antivenom was well tolerated, similar to adult dogs. However, therapeutic guidelines should be established to direct use and prove efficacy in this population.

Effect of dilution of canine blood samples on the specificity of saline agglutination tests for immune-mediated hemolysis

BACKGROUND

Saline agglutination tests (SATs) are widely recommended for diagnosis of immune-mediated hemolytic anemia in dogs, but there are frequent false-positive results.

OBJECTIVES

Specificity of SATs will improve at higher saline-to-blood ratios.

ANIMALS

One hundred fifty dogs treated at a veterinary referral hospital with hematocrits ≤30%.

METHODS

Prospective diagnostic accuracy study. Immune-mediated hemolysis (IMH) was considered present if a gel direct antiglobulin test (DAT) was positive and there was clinical evidence of hemolysis (n = 9), absent if another mechanism for anemia was identified and the DAT was negative or there was no hemolysis (n = 138), and if IMH status was unclear, dogs were excluded (n = 3). Saline agglutination tests were prepared at 1 : 1, 4 : 1, 9 : 1, and 49 : 1 saline-to-blood ratios, and microscopic agglutination was considered a positive result.

RESULTS

Specificity for IMH increased from 29% (95% confidence interval 20-38) at a 1 : 1 dilution to 97% (93-99) at a 49 : 1 dilution. Sensitivity was 88% (47-100) at 1 : 1 and 4 : 1 dilutions and 67% (30-93%) at 9 : 1 and 49 : 1 dilutions. Diagnostic accuracy increased from 33% (24-42) at 1 : 1 dilution to 95% (90-98) at 49 : 1 dilution.

CONCLUSIONS AND CLINICAL IMPORTANCE

If performed using a 49 : 1 saline-to-blood ratio, SATs achieve high specificity for IMH. Based on a gold standard of positive DAT and evidence of hemolysis, lower saline-to-blood ratio results should not be used because false-positive results are common.