Introduction
Pancreatitis is commonly encountered in people, dogs and cats, but the
clinical presentation can vary from subclinical or mild nonspecific
clinical signs to severe life-threatening disease (Mansfield 2012a).
Acute and chronic forms are recognised, although these may occur
concurrently. Understanding of the pathophysiology of acute pancreatitis
is largely extrapolated from human clinical studies and experimental
animal models (Bjørnkjær-Nielsen and Bjørnvad 2021). It is believed to
result from the activation of trypsinogen and release of cathepsin-B and
other pancreatic enzymes within acinar cells, leading to the activation
of the apoptotic cascade inflammation, which is manifested by neutrophil
migration to the pancreas as well as probable complement activation and
a “cytokine storm” that further contributes to inflammation (Mansfield
2012b; Talukdar et al 2016).
Ante-mortem diagnosis of acute pancreatitis is difficult owing to the
presence of nonspecific clinical signs and the lack of definitive
diagnostic tests, including enzyme biomarkers (Johnson et al 2019). The biomarker ineffectiveness relates to low amylase activity of
the equine pancreas (Harris and Gow 1892; Lorenzo-Figueras et al 2007), lack of tissue specificity of conventional lipase assays (Tietz
and Shuey 1993) and instability of trypsin (Grulke et al 2003).
In the absence of any one specific clinical sign or combination of signs
that have been identified as pathognomonic for acute pancreatitis in
dogs and cats (Xenoulis 2015), diagnosis is often based on a combination
of clinical signs (such as anorexia, vomiting, weakness, and abdominal
pain) and clinical pathology findings (Cridge et al 2021).
In most previously reported cases, the confirmation of pancreatitis in
horses and donkeys has been established by post-mortem examination
(Yamout et al 2012). The
1,2-o-dilauryl-rac-glycero-3-glutarate-(6′-methylresorufin) ester (DGGR)
lipase assay has been shown to be specific for pancreatic lipase and has
recently been validated for horses (Johnson et al 2019; Peters
and Howard 2023). In the study by Johnson et al (2019) from
Ireland, venous blood was collected and analysed for pancreatic (DGGR)
lipase from 109 hospitalised horses (including 33 horses with various
types of gastrointestinal disease, 22 of which had colic); 85% (28/33)
of these horses had increased pancreatic lipase concentration. In
another study from Switzerland (Lanz et al 2022), increased
DGGR-lipase concentration above published reference limits was
demonstrated in 30.2% of 192 horses with signs of colic, and was above
2x the upper reference limit (URL) in 15.6%. The median DGGR-lipase
concentration in horses with large bowel displacement or torsion was
significantly higher than the median concentration for horses with large
bowel impaction, gastric impaction, dilation, or ulceration. DGGR-lipase
concentration > 2x URL was significantly associated
with surgical treatment, strangulating disease, and non-survival.
The aims of this study were to evaluate serum DGGR lipase concentrations
in horses and donkeys presented to an equine hospital in the UK with
gastrointestinal disease. The objectives were similar to a recently
published study from Switzerland (Lanz et al 2022): to evaluate
the prevalence of elevated DGGR lipase concentrations in horses
presented for gastrointestinal disease, and to investigate any
associations between DGGR lipase concentration at admission of cases to
our hospital and the cause of colic, the outcome (survival or
non-survival), and the treatment type (medical or surgical).