Clinical characteristics of two-hundred thirty-two dogs (2006-2018) treated for suspected anaphylaxis in Perth, Western Australia

Acute hepatic rupture causing hemoperitoneum in a dog with anaphylaxis

A 2-year-old spayed female Siberian Husky was presented with a history of acute onset lethargy, collapse, haematochezia and vomiting. The patient was severely tachycardic and hypotensive. Point-of-care ultrasound revealed gallbladder wall thickening and peritoneal effusion consistent with haemorrhage on subsequent abdominocentesis. Despite attempted medical stabilization over the course of several hours, including blood products and multiple autotransfusions, the patient progressed to cardiopulmonary arrest. The dog was successfully resuscitated but was subsequently euthanized. Necropsy revealed a severe, acute hemoperitoneum secondary to rupture of the left lateral liver lobe. A tear in the hepatic capsule was identified along with a large hematoma. A single adult nematode, consistent with Dirofilaria immitis, was found in a pulmonary vessel in the right caudal lung lobe. The remaining necropsy findings were supportive of the clinical diagnosis of anaphylaxis. This report details a case, with necropsy findings, supporting a diagnosis of anaphylaxis and severe, refractory hemoperitoneum resulting from hepatic rupture. Acute hepatic rupture should be considered in cases of anaphylaxis-related hemoperitoneum.

Modified rush venom immunotherapy in dogs with Hymenoptera hypersensitivity

BACKGROUND

Hymenoptera envenomation occurs frequently in people and dogs and can trigger anaphylaxis. Venom immunotherapy (VIT) is the only preventive treatment for Hymenoptera hypersensitivity and is indicated for people with severe adverse reactions to insect stings. Rush VIT is an accelerated VIT protocol in people. This has not been reported in dogs.

OBJECTIVES

The objective of the study was to evaluate the safety of modified rush VIT.

ANIMALS

Twenty client-owned dogs with Hymenoptera hypersensitivity based on a history of adverse reactions to Hymenoptera envenomation and a positive intradermal test to honey bee and/or paper wasp venom.

MATERIALS AND METHODS

Dogs received incremental doses of venom via subcutaneous injection one day per week for three consecutive weeks until the maintenance dose was achieved. Vital signs were recorded every 30 min prior to venom administration. Adverse reactions were categorised as localised or grade I-IV systemic reactions.

RESULTS

Nineteen of 20 dogs (95%) completed rush VIT. One dog experienced a grade III systemic adverse reaction and was withdrawn from the study. No adverse reactions occurred in 10 of 20 dogs (50%). Localised and grade I-II systemic reactions occurred in nine of 20 dogs (45%), including nausea (n = 5), injection site pruritus (n = 3) and diarrhoea and lethargy (n = 1).

CONCLUSIONS AND CLINICAL RELEVANCE

Modified rush VIT in dogs was well-tolerated and should be considered for dogs with Hymenoptera hypersensitivity. Larger studies are needed to evaluate the efficacy of VIT in dogs for preventing hypersensitivity reactions to insect stings.

Sensitivity of a Hymenoptera serological immunoglobulin (Ig)E assay for the diagnosis of venom hypersensitivity in dogs

BACKGROUND

Hymenoptera envenomation with honey bee (Apis mellifera) and paper wasp (Polistes spp.) may cause life-threatening anaphylaxis in dogs. In human patients, clinical history, intradermal testing (IDT) and measurement of allergen-specific serological immunoglobulin (Ig)E (sIgE) are used to support a diagnosis of Hymenoptera venom hypersensitivity. The utility of venom allergen-specific sIgE has not yet been evaluated for this purpose in dogs.

OBJECTIVES

The objective of the study was to investigate the sensitivity (sn), specificity (sp) and positive predictive value (PPV) of honey bee and paper wasp serological titres using a commercially available sIgE assay [VARL (Veterinary Allergen Reference Laboratory) Liquid Gold] against clinical history for a diagnosis of Hymenoptera hypersensitivity in dogs.

MATERIALS AND METHODS

Honeybee and paper wasp IgE serum titres were measured in 15 client-owned dogs with a diagnosis of Hymenoptera venom hypersensitivity based on a history of anaphylaxis, owner observation of Hymenoptera, and positive IDT to bee and/or wasp; and in 10 client-owned dogs with no known history of anaphylaxis or Hymenoptera exposure and a negative IDT to bee and wasp.

RESULTS

Analysis of receiver operating characteristic (ROC) curves demonstrate that a VARL score cut-off of one of six for honeybee yields Sn, Sp and PPV of 40%, 60% and 60%, respectively, and two of six for wasp yields Sn, Sp and PPV of 25%, 78% and 60%, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Owing to the poor sensitivity and PPV of sIgE assays for both bee and wasp hypersensitivity in dogs with known envenomation and anaphylaxis, the use of sIgE cannot be recommended as a tool for venom identification.

Evaluation of hemostatic derangements associated with canine anaphylaxis and the relationship to syndrome severity

OBJECTIVE

To describe hemostatic derangements associated with canine anaphylaxis and to assess for association with syndrome severity.

DESIGN

Prospective observational study.

SETTING

University teaching hospital.

ANIMALS

Twenty-seven client-owned dogs, recruited from November 2018 to January 2022, diagnosed with anaphylaxis of varying severity were included. Study inclusion required presentation <6 hours after initiation of clinical signs, no medications or history of illness within the prior 2 weeks, lack of comorbidities expected to affect hemostasis, and lack of a disease state that could alternatively explain the clinical presentation.

INTERVENTIONS

Blood samples were collected within the first hour of presentation for CBC, serum biochemistry, prothrombin time (PT), activated partial thromboplastin time (aPTT), and viscoelastic coagulation testing for use with a cartridge-based point-of-care device.

MEASUREMENTS AND MAIN RESULTS

Clotting time and clot formation time were prolonged, alpha angle and maximum clot firmness were decreased, PT and aPTT were prolonged, and platelet counts were lower in severe cases compared to mild and moderate cases. There were no differences for any parameter between mild and moderate cases. The presence or absence of abdominal effusion was not associated with hemostatic status.

CONCLUSIONS

Global hemostatic derangements consistent with hypocoagulability are a prominent feature of severe anaphylaxis in dogs and should be considered for routine evaluation.

Retrospective evaluation of hypersensitivity reactions and anaphylaxis in dogs (2003-2014): 86 cases

OBJECTIVE

To characterize anaphylactic reactions in dogs, including clinical signs, severity, treatments, prognosis, and estimated incidence. To determine whether glucocorticoids influence clinical recovery and survival.

DESIGN

Retrospective study between January 1, 2003 and April 28, 2014.

SETTING

University teaching hospital.

ANIMALS

Eighty-six dogs treated for a type I hypersensitivity reaction. Nineteen dogs fulfilled the criteria for anaphylaxis, and 67 dogs had mild cutaneous reactions.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The estimated incidence was 0.04% for anaphylaxis and 0.15% for mild hypersensitivity reactions. The female:male ratio (2.3:1) was significantly higher (P = 0.032) compared to our source population (ratio of 1:1.158). Vaccines were the most frequent trigger for anaphylaxis (57.9%) and mild hypersensitivity reactions (28.4%). Seventy-four (86%) dogs had cutaneous signs, and 11 (57.9%) dogs with anaphylaxis had no cutaneous signs reported. Forty-two (48.8%) dogs received both an H1 antagonist and a glucocorticoid, 34 (39.5%) dogs received an H1 antagonist only, and 6 (6.9%) dogs received a glucocorticoid only. The majority of the dogs survived, and 1 was euthanized due to complications. Clinical signs associated with nonsurvival included respiratory signs (P = 0.006), particularly respiratory distress (P < 0.00001) and cyanosis (P < 0.00001), and circulatory shock (P = 0.005). The analysis of the interaction between etiology, clinical signs, treatment, and outcome did not show any association between pairs of variables.

CONCLUSIONS

In the current study, anaphylaxis had a relatively good prognosis, and cutaneous signs were not always present. Based on the present data, the use of glucocorticoids to treat mild type I hypersensitivity reactions and anaphylaxis in dogs was not associated with clinical improvement or survival.

Allergy, inflammation, hepatopathy and coagulation biomarkers in dogs with suspected anaphylaxis due to insect envenomation

Objectives

To compare concentrations of biomarkers of; allergy [mast cell tryptase (MCT) and histamine], inflammation [interleukin (IL)-6,-10, and-18, CXCL8, CCL2, keratinocyte chemoattractant (KC), C-reactive protein (CRP)], endothelial glycocalyx shedding (hyaluronan), coagulation [prothrombin time, activated partial thromboplastin time, fibrinogen concentration, and von Willebrand Factor antigen, protein C (PC) and antithrombin (AT) activity], and hepatopathy [alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and total bilirubin] between dogs with anaphylaxis after suspected insect exposure, dogs with critical illness, and healthy dogs.

Design

This was a single center prospective clinical observational comparative biomarker study that included 25 dogs with anaphylaxis (evidence of insect exposure, acute dermatological signs, and other organ involvement), 30 dogs with other critical illness, and 20 healthy dogs. Differences across groups in biomarker concentrations were tested using one-way ANOVA or Kruskal-Wallis test, with significant P values (<0.05) reported for pairwise differences detected by post-hoc tests. Logistic regression models were used to calculate the area under the receiver operator characteristic curve (AUROC) for discrimination between anaphylaxis and non-anaphylactic illness.

Results

Histamine concentration was significantly higher in the anaphylaxis group than the healthy (P < 0.001) and critically ill groups (P < 0.001), whereas no differences in MCT were detected amongst groups. Biomarker concentrations that were increased relative to healthy dogs in both the anaphylaxis and critically ill groups included IL-10 (P < 0.001 and P = 0.007, respectively), CCL2 (P = 0.007 and P < 0.001, respectively) and AST (both P < 0.001), whereas only the critically ill group had significantly increased CRP (P < 0.001), IL-6 (P < 0.001), KC (P < 0.001), ALP (P < 0.001), and fibrinogen (P = 0.016) concentrations, compared to the healthy group. Only dogs with anaphylaxis had significantly higher hyaluronan (P = 0.021) and ALT (P = 0.021) concentrations, and lower PC (P = 0.030) and AT (P = 0.032) activities, compared to healthy dogs. Both CRP and histamine concentration showed good discrimination between anaphylaxis and other critical illness, with an AUROC of 0.96 (95% CI 0.91-1) and 0.81 (95% CI 0.69-0.93), respectively.

Conclusions

This preliminary study in dogs with anaphylaxis after suspected insect exposure, found evidence of an early innate immune response, glycocalyx shedding and anticoagulant consumption. Both CRP and histamine showed potential clinical utility for differentiation between anaphylaxis and other critical illness.

Evaluation of quick sequential organ failure scores in dogs with severe sepsis and septic shock

OBJECTIVES

To evaluate the prognostic utility of the quick sequential organ failure assessment score in dogs with severe sepsis and septic shock presenting to an emergency service, and evaluate the clinical value of the quick sequential organ failure assessment score to predict severe sepsis and septic shock.

MATERIALS AND METHODS

The quick sequential organ failure assessment score was calculated by evaluating respiratory rate (>22 breaths per minute), arterial systolic blood pressure (≤100 mmHg) and altered mentation. The quick sequential organ failure assessment scores with respiratory rate cut-offs of greater than 22, greater than 30 and greater than 40 were compared. Cases were defined as dogs presented to the emergency room and met at least 2 systemic inflammatory response syndrome criteria, had documented infection, and at least one organ dysfunction. A control population of dogs included animals with non-infectious systemic inflammatory response syndrome.

RESULTS

Forty-five dogs with severe sepsis and septic shock and 45 dogs with non-infectious systemic inflammatory response syndrome were included in the final analysis. The quick sequential organ failure assessment provided poor discrimination between survivors and non-survivors for severe sepsis and septic shock (area under receiving operating characteristic curve, 0.51; 95% confidence interval, 0.35 to 0.67). Discrimination remained poor when quick sequential organ failure assessment greater than 30 and quick sequential organ failure assessment greater than 40 scores were calculated (area under receiving operating characteristic curve, 0.56; 95% confidence interval, 0.39 to 0.72, and 0.54; 95% confidence interval, 0.36 to 0.71). The quick sequential organ failure assessment of at least 2, quick sequential organ failure assessment greater than 30 of at least 2 and quick sequential organ failure assessment greater than 40 of at least 2 produced sensitivity and specificity to detect severe sepsis and septic shock of 66.7% and 64.5%, 62.2% and 71.1%, 44.4% and 80%, respectively.

CONCLUSION AND CLINICAL SIGNIFICANCE

Scoring systems utilised in emergency rooms should have high sensitivity to reduce missed sepsis cases and treatment delays. The use of the quick sequential organ failure assessment for severe sepsis and septic shock demonstrated poor mortality prediction and low sensitivity to detect canine patients with severe sepsis and septic shock and should not be used alone when screening for sepsis.