Diagnostic imaging findings in a referral population of dogs diagnosed with immune-mediated haemolytic anaemia: 50 cases (2015-2018)

Thoracic and abdominal diagnostic imaging findings in dogs diagnosed with immune-mediated polyarthritis: 71 cases (2011-2023)

OBJECTIVES

To describe thoracic and abdominal imaging findings in dogs with immune-mediated polyarthritis and to evaluate their impact on the decision to commence immunosuppressive therapy.

MATERIALS AND METHODS

Retrospective case series describing imaging findings in dogs with immune-mediated polyarthritis across modalities, including thoracic radiographs, abdominal ultrasound, computed tomography, and where available, echocardiography. Additionally, two internal medicine clinicians reviewed the signalment, clinical signs, clinicopathological findings and diagnostic imaging results on two separate occasions, reaching a consensus for each dog on whether immunosuppression would be their treatment of choice or whether their recommendations would be altered by the results of diagnostic imaging.

RESULTS

Seventy-one dogs met the inclusion criteria. Abnormal diagnostic imaging findings were identified in 25.4% (18/71) of dogs. Thoracic radiography did not identify significant imaging findings in any of the dogs. Lymphadenomegaly was the most commonly reported finding on computed tomography (32/40) and abdominal ultrasound (13/34). Neoplasia was identified in three dogs (3/71). Four (4/13) dogs had echocardiography findings consistent with endocarditis. Immunosuppression without performing diagnostic imaging would have been considered in 41 of 71 (57.7%) dogs, based on the signalment, presenting signs, results of physical examination and clinicopathological testing. Of these, 10 dogs (24.3%) had diagnostic imaging findings suggestive of an underlying trigger, therefore changing the clinician's decision to proceed with immunosuppression.

CLINICAL SIGNIFICANCE

Abdominal imaging and echocardiography should be prioritised over thoracic radiography, in dogs with immune-mediated polyarthritis. Signalment, presenting complaint, physical examination findings and clinicopathological results are not reliable predictors of abnormal diagnostic imaging findings in dogs with immune-mediated polyarthritis.

Comparison of timing of relapse in dogs with nonassociative immune-mediated hemolytic anemia, thrombocytopenia, or polyarthritis

BACKGROUND

Relapse is a clinical concern in dogs diagnosed with immune-mediated hemolytic anemia (IMHA), thrombocytopenia (ITP), or polyarthritis (IMPA). The average time to relapse is unknown, and evidence that vaccination is associated with disease relapse is lacking.

HYPOTHESIS/OBJECTIVES

Compare the incidence of relapse in groups of dogs with IMHA, ITP, or IMPA over a 24-month period after diagnosis and compare proportions of dogs that received vaccines in those dogs that did and did not relapse.

ANIMALS

One hundred sixty client-owned dogs (73 with IMHA, 55 with ITP, 32 with IMPA).

METHODS

Medical records of dogs were reviewed with the goal of following cases for a minimum of 2 years. Incidence of relapse was calculated for each disease, and relapse rates in dogs that were or were not vaccinated after diagnosis were compared.

RESULTS

Relapse rates at 12 months differed significantly among disease groups (P = .02), with a higher rate for IMPA (35%) compared to IMHA (11%) or ITP (11%). Relapse rate at 24 months was 41% for IMPA, 18% for IMHA, and 23% for ITP. Ninety percent of IMPA relapses occurred in the first 12 months after diagnosis, compared with 56% for IMHA and 50% for ITP. Vaccine administration after diagnosis was not associated with relapse (P = .78).

CONCLUSIONS AND CLINICAL IMPORTANCE

Risk of disease relapse in IMPA is highest in the first year after diagnosis, with a higher relapse rate compared with IMHA and ITP. The role of vaccination in disease relapse remains unclear.

Diagnostic Utility of Thoracic Radiography and Abdominal Ultrasonography in Canine Immune-Mediated Polyarthritis: 77 Cases

Thoracic radiography and abdominal ultrasonography are part of standard diagnostic investigations in cases of canine immune-mediated polyarthritis (IMPA). However, the clinical importance of thoracic and abdominal imaging towards the management of canine IMPA currently remains unknown. The primary aim of this study was to describe the findings documented on thoracic radiography and abdominal ultrasonography in dogs diagnosed with IMPA, and to evaluate the diagnostic utility of thoracic radiography and abdominal ultrasonography in the initial approach and management of these cases. Seventy-seven dogs diagnosed with IMPA who underwent thoracic radiography and abdominal ultrasonography at a single referral hospital between 2008 and 2022 were included. The diagnostic imaging studies of these 77 dogs were reviewed by one blinded board-certified diagnostic imaging specialist for quality assurance. The medical records, including the diagnostic imaging reports of these dogs, were then reviewed by three blinded board-certified internal medicine specialists. Using a modified version of a previous question and scoring system, the three internal medicine specialists then generated an answer for the overall diagnostic utility and a diagnostic utility score for thoracic radiography and abdominal ultrasonography for each case. The abnormal findings identified in radiography and ultrasonography were described. In the cases where the findings were considered significant enough to immediately affect the case management, the results of the further investigations that were subsequently performed were also described. No abnormalities were detected in thoracic radiography for 30 cases, and none were detected in abdominal ultrasound for 6. The majority of the internists considered thoracic radiography to be not useful in the overall case management at the time of IMPA diagnosis in 70 cases, and considered abdominal ultrasonography to be not useful in the overall case management in 57 cases. The majority of the internists agreed on the utility of thoracic radiography in 95% of the cases, and in 61% of the cases for abdominal ultrasonography. The most common finding in the thoracic radiography was a mild bronchial pulmonary pattern, and the most common in the abdominal ultrasonography was mild lymphadenomegaly. Therefore, although thoracic radiography and abdominal ultrasonography identified numerous abnormal findings in this population of dogs, in the majority of the cases, the findings were deemed not useful towards the overall case management at the time of the initial diagnosis of IMPA. Thus, the use of thoracic radiography and abdominal ultrasonography should be taken into careful consideration when considering initial diagnostic investigations for canine IMPA.