Suspected immune-mediated polysynovitis and serositis in a horse

Fluid Analysis in the Equine Patient: Cerebrospinal, Synovial, and Peritoneal Fluids

Fluid analysis is an important part of the diagnostic work-up of equine patients presenting with disorders of the nervous system, musculoskeletal system, and abdominal cavity. Proper specimen handling and processing are paramount for complete and accurate interpretation of fluid samples. Normal cerebrospinal fluid is a low-cellularity, low-protein fluid requiring specific sample handling to ensure accurate results. Joint and abdominal fluid analyses are completed in practice or submitted for analysis to a reference laboratory. This article discusses fluid sample handling and processing considerations for the equine practitioner and reviews cytologic evaluation of normal and abnormal cerebrospinal, synovial, and peritoneal fluid samples.

Detection of IgM-rheumatoid factor and anti-citrullinated protein antibodies in healthy horses and their comparison

Rheumatoid factor (RF) is used in human and veterinary medicine in the form of IgM RF traditionally to support the diagnosis of rheumatoid arthritis (RA). In the latest diagnostic criteria, presence of anti - citrullinated protein antibodies (ACPA) was added to the grading system for the diagnosis of RA in humans. A change which is not integrated or routinely used in veterinary medicine. The criteria changed partly because of RF's diagnostic shortcomings, which include its increased titer detection in humans with non-rheumatoid diseases, inability to predict the disease and increased titers over the limit in the older population. Clinical signs similar to human RA were reported in horses in a condition known as idiopathic polysynovitis. Similarities in the clinical presentation to RA raised a question to the usability of RF and ACPA in horses. In our study, sixty clinically healthy horses, ranging from 3 days to 30 years of age, were evaluated for their serum levels of IgM RF. 55 of these horses were tested for ACPA, using methods of ELISA measuring Anti - CFG (Anti citrullinated fibrinogen antibody). The results of the study demonstrated the existence of an age-dependent increase in the level of IgM RF up to the age of about 9 years and ACPA's independence of the horse's age as well as both markers independence of the horse sex.

Medical and surgical management of an intra-abdominal abscess of hepatic origin in a horse

CASE DESCRIPTION

A 4-year-old Arabian-cross mare was examined because of a 48-hour history of pyrexia, lethargy, and signs of abdominal discomfort.

CLINICAL FINDINGS

On initial evaluation, the horse was in good body condition, but febrile, tachycardic, tachypneic, and icteric and had signs of colic. Findings on CBC and serum biochemical analysis indicated marked systemic inflammation and hepatocellular damage. Serial abdominal ultrasonographic examinations revealed progressive, localized hepatic parenchymal abnormalities in the left ventral aspect of the abdomen in proximity to the left liver lobes, and eventual identification of an irregularly marginated, hyperechoic walled region of heterogenous echogenicity consistent with an encapsulated hepatic abscess.

TREATMENT AND OUTCOME

Medical treatment was initiated with administration of doxycycline and flunixin meglumine. After 7 days, the horse's clinical signs and hematologic values improved. After 14 days, the horse was discharged from the hospital and prescribed continuation of doxycycline treatment for 14 days. One week following hospital discharge, the horse was reevaluated for recurrent signs of colic and pyrexia. The horse was sedated, and the region overlying the caudal aspect of the seventh rib was desensitized with an inverted L nerve block by local infiltration with 2% lidocaine. While the horse was standing and sedated, drainage of an encapsulated intra-abdominal abscess was followed by rib resection and removal of a portion of necrotic left lateral liver lobe. The development of a pneumothorax following rib resection represented the only major surgical complication. Twelve months later, the horse was clinically normal and had returned to its previous level of performance.

CLINICAL RELEVANCE

Rib resection in standing sedated horses, together with appropriate medical management, should be considered an option for removal of well-encapsulated cranially located intra-abdominal abscesses that are adherent to the ventrolateral aspect of the body wall in horses.