Detecting acute kidney injury in horses by measuring the concentration of symmetric dimethylarginine in serum

ECEIM consensus statement on equine kidney disease

The aim of this consensus statement is to summarize and appraise scientific evidence and combine this with the clinical experience of a panel of experts to optimize recommendations on how to recognize and manage kidney disease in horses.

Doppler renal resistivity index in horses: A systematic review

BACKGROUND

The resistivity index (RI) evaluates haemodynamic based on arterial resistance. Alterations in renal blood flow are important for the early detection of kidney damage, as perfusion might be one of the first affected aspects.

OBJECTIVES

To retrieve published studies on equine renal RI to develop a standardised method of renal ultrasonographic examination and to evaluate the current reference range for the renal RI in horses.

STUDY DESIGN

Systematic review.

METHODS

An electronic search in Science Direct, PubMed, Scopus and Web of Science databases was performed in February 2023 using the terms 'RI' OR 'resistivity index' OR 'IP' OR 'pulsatility index' AND (kidney OR renal) AND (equine OR horse) in titles, keywords and abstracts. The studies were screened for inclusion based on pre-determined criteria and data on the variables of interest were collected from included studies. The SYRCLE risk of bias tool was used to assess the methodological quality.

RESULTS

The electronic searches identified 134 studies, of which 5 were eligible for inclusion in this review. The studies had been conducted in healthy non-sedated horses through the transabdominal technique. The upper limit of normality for the renal RI was 0.58 ± 0.06 for the right kidney of untrained horses, which is considerably lower than the value of 0.70 currently used for humans, cats and dogs. There were heterogenous outcomes among the studies: two of the five demonstrated a difference between the right and left renal RI values, and one of the five showed an increased renal RI in elderly horses compared with foals and adult horses.

MAIN LIMITATIONS

Data regarding the RI in horses are still scarce.

CONCLUSIONS

Additional studies that establish a reference range for the renal RI in horses are needed and there is a need to ensure consistency of techniques.

Survival of formalin intoxication in a 13-year-old Thoroughbred gelding

BACKGROUND

Formalin intoxication via the gastrointestinal route has not been previously reported in the horse. Whereas ingestion of formalin in humans, although rare, is well documented. Majority of human cases are either accidental, suicidal or homicidal and often lead to fatality, with a reported lethal formaldehyde dose equating to 0.12 - 0.16 g/kg bwt.

OBJECTIVES

To describe a single case report of the clinical management of an adult horse referred to a veterinary teaching hospital following accidental administration of 10% formalin via nasogastric tube.

METHODS

A 13-year-old Thoroughbred gelding originally presented to the referring veterinarian for colic where 1.8 L of 10% formalin was accidentally administered instead of mineral oil via nasogastric intubation, a potentially lethal dose of formaldehyde (0.12 g/kg bwt). Approximately 20-hours following 10% formalin administration the horse was admitted to the referral hospital with moderate tachycardia, occasional ectopic beats, tacky and hyperaemic mucous membranes, delayed capillary refill time, reduced borborygmi, and pronounced digital pulses. Diagnostic investigations included laboratory blood analysis, urinalysis, electrocardiogram, abdominal ultrasound, palpation per rectum and gastroscopy.

RESULTS

Patient assessment found evidence of toxicity to the gastrointestinal tract, hypovolaemia and risk for laminitis. Intensive care included fluid and electrolyte therapy, anti-inflammatories and analgesia, continuous digital cryotherapy, gastro-protectants and other methods of gastrointestinal support. The horse was discharged from hospital on day 14 with no long-term complications and the client-veterinarian relationship was preserved.

DISCUSSION

In human cases of ingestion, gastrointestinal injury is typically accompanied by severe metabolic acidosis and multiple organ dysfunction syndrome due to toxicity of other body systems that can contribute to non-survival. Formaldehyde toxicity in the present case predominantly affected the gastrointestinal tract, most likely a direct result of the route of administration. Aside from gastrointestinal injury, primary toxicity of other body systems was not confirmed. To prevent this medical error recurring, the referring veterinary clinic revised their labelling and storage of 10% formalin.

CONCLUSION

This is the first report of systemic formalin intoxication in the horse. Following a high dose of 10% formalin (0.12 g/kg bwt formaldehyde) enterally, the horse survived having received intensive supportive care based on human guidelines for ingested formalin.

Preliminary evaluation of hepatitis A virus cell receptor 1/kidney injury molecule 1 in healthy horses treated with phenylbutazone

OBJECTIVES

To investigate if hepatitis A virus cell receptor 1/kidney injury molecule 1 (HAVCR1/KIM1) in urine is detectable concurrently with increases in serum creatinine concentrations in horses receiving a recommended dose of phenylbutazone (PBZ) for 7 days.

DESIGN

Preliminary study.

METHODS

Ten clinically healthy horses with normal physical examination and laboratory work were randomly assigned to PBZ or placebo groups (5 each). The PBZ group received PBZ at 4.4 mg/kg mixed with corn syrup orally every 12 hours. The placebo group received corn syrup orally every 12 hours. Both groups were treated for 7 days. Kidney ultrasonography was performed, and venous blood and urine samples were collected prior to commencement and at the end of treatment. Samples from 1 additional healthy horse, 3 horses with acute kidney failure, and 1 horse with chronic kidney failure were also evaluated.

RESULTS

None of the 10 horses had detectable HAVCR1/KIM1 in urine at baseline. Serum creatinine concentrations in placebo group did not increase, and HAVCR1/KIM1 was undetectable in urine. At the end of treatment, 3 of 5 horses receiving PBZ developed increases in serum creatinine of >26.5 μmol/L (>0.3 mg/dL), and HAVCR1/KIM1 was detectable in urine, despite normal findings on kidney ultrasonography in all horses.

CONCLUSIONS

HAVCR1/KIM1 is detectable in urine and is associated with increases in serum creatinine concentrations of >26.5 μmol/L in horses following treatment with PBZ for 7 consecutive days. Thus, HAVCR1/KIM1 might aid in the early detection of acute kidney injury in horses.

EVALUATION OF SYMMETRIC DIMETHYLARGININE AS AN ENDOGENOUS MARKER OF RENAL DISEASE IN GREATER FLAMINGOS (PHOENICOPTERUS ROSEUS)

Detection of renal disease in birds is currently reliant on biochemical measures such as uric acid, which is only elevated after significant renal compromise has occurred. Symmetric dimethylarginine (SDMA) production has not been previously evaluated in birds and no reference intervals (RI) for measurement exist in avian species. This study aimed to develop an RI for SDMA in greater flamingos (Phoenicopterus roseus) and evaluate the association between SDMA levels and renal disease. Blood from 60 flamingos was collected for RI development and the RI of SDMA was found to be 11.8-34.2 µg/dl. Symmetric dimethylarginine showed a strong positive correlation with uric acid, a moderate positive correlation with creatine kinase, and moderate negative correlations with total protein, albumin, and glucose. No correlation was found with pododermatitis score or body condition. Using the SDMA RI, six clinical cases were included for assessment of the clinical relevance of SDMA in renally compromised patients. All birds that were euthanized had elevated SDMA levels and severe renal or systemic pathology on necropsy.

Biomarkers of Kidney Disease in Horses: A Review of the Current Literature

Creatinine only allows detection of kidney disease when 60 to 75% of the glomerular function is lost and is therefore not an ideal marker of disease. Additional biomarkers could be beneficial to assess kidney function and disease. The objectives are to describe new equine kidney biomarkers. This systematic review assesses the available literature, including the validation process and reference values, following which the authors suggest recommendations for clinical use. SDMA may have some potential as equine kidney biomarker, but there is currently a lack of evidence that SDMA offers any advantage compared to creatinine in detecting Acute Kidney Injury (AKI). Cystatin C and podocin show potential as biomarkers for kidney disease (including detecting AKI earlier than creatinine) and should be studied further. NGAL has potential as a biomarker of kidney disease (including detecting AKI earlier than creatinine), and potential as an inflammatory marker. Literature on MMP-9 does not allow for conclusive statements about its potential as a biomarker for kidney disease. The future may show that NAG has potential. For all biomarkers, at this stage, available scientific information is limited or too scarce to support clinical use, and only SDMA can be measured for clinical purposes. In conclusion, there are multiple new biomarkers with the potential to diagnose kidney problems. However, there are only a few studies available and more data is needed before these biomarkers can be applied and recommended in our daily practice.