VN March 2023

Vetnews | March 2023 37 (GFR), in turn leading to elevated levels of BUN; this same decrease in GFR can lead to elevations of uric acid without primary renal disease being present. It is therefore prudent, in cases of an elevated uric acid level, to rehydrate the patient over 2-3 days before definitively diagnosing renal disease. Persistent hyperuricaemia after fluid therapy, and with haematocrit, total protein and BUN returning to normal, confirms a diagnosis of renal disease. Creatinine is generally accepted as being of little or no value in evaluating renal function in birds. Phosphorous elevations are usually not seen in birds with renal disease. The reproductive system Clinical biochemistries can tell the clinician little about the male reproductive tract; they can however, reveal something about the activity of the female reproductive tract. Oestrogen, produced by developing follicles, induces the production of calcium binding protein and vitellogenesis in the liver. The net result of this activity is an increase in circulating total protein, calcium , and cholesterol. The serum may appear lipaemic. Radiographic evidence of hepatomegaly and increased long bone density can confirm reproductive activity. It should be noted though, that normal calcium and protein does not reflect a lack of reproductive activity. The gastrointestinal system Gastrointestinal disease typicallyonlygives non-specific resultswithclinical biochemistry. Elevations of CK, ASTandLDHarenot uncommon, and are not specific to the intestinal tract. Electrolytes may give more information: Sodium may be elevated with excessive water loss through vomiting or diarrhoea; Chloride may be elevated with vomiting or regurgitation; and Potassiummay be decreased with vomiting/ diarrhoea and elevated with dehydration. There are many other possible causes of electrolyte disturbance, and our understanding of avian electrolyte balance is still in the very early stages. Amylase and lipase have been proposed as useful parameters in the detection of pancreatic disease. There is still considerable discussion of the incidence of pancreatic disease and the specificity of these enzymes. Significant elevations of these enzymes, when accompanied by clinical signs of gastrointestinal dysfunction (vomiting, ileus, diarrhoea, abdominal pain) should lead the clinician to consider pancreatic disease as a differential diagnosis. However, normal levels do not preclude a diagnosis of pancreatic disease, nor do abnormal levels confirm such a diagnosis. Blood glucose Glucose is an essential energy source for nearly every cell in the body. Blood levels are governed by its intake, absorption, the interactions of hormones controlling carbohydrate metabolism (insulin, glucagon, and somatostatin), the body’s metabolism, its ability to store glucose, and its excretion. As disorders of glucose metabolism involve so many organ systems, it is treated here as a separate entity. • Hyperglycaemia may be a normal physiological process e.g. in juvenile birds. However, elevated levels are usually related to increased production or release (eg stress) or failure of tissues to take it up out of the blood (diabetes mellitus). Iatrogenic hyperglycaemia occurs when corticosteroids are administered, or intravenous dextrose is given. Female reproductive disease may also elevate blood glucose, but this may be an indirect result due to inflammation affecting the endocrine pancreas. • Hypoglycaemia may result from poor handling of blood samples i.e. it may be artifactual, rather than factual. However, it is seen in cases with decreased intake (starvation, anorexia), increased usage (septicaemias, neoplasia, and multi-organ failure) or decreased production (liver disease). v Technical I Article >>> 14 SPECIALISED PHARMACEUTICAL COMPOUNDING OF VETERINARY MEDICINES V-Tech is an established ISO-accredited, state-of-the-art facility, ensuring compliance, quality and service you can trust. www. v-tech.co.za Email: pharmacist@v-tech.co.za | WhatsApp: +27 82 314 4510 | Customer Care: 0860 109 779 This article is sponsored by V-Tech