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The RVC’s small animal Internal Medicine Service has considerable experience managing chronic kidney disease (CKD) and hyperthyroidism, including cases where they occur concurrently.

CKD is the most common condition affecting older cats and, as 10% of geriatric cats develop hyperthyroidism, it is not surprising that these conditions are often found together.

Alluding to treatment challenges, Senior Lecturer in Small Animal Internal Medicine, Rosanne Jepson, said: “Treatment of cats with concurrent CKD and hyperthyroidism can be a real challenge for vets and lead to a diagnostic dilemma. Despite extensive investigations for suitable biomarkers, assessment of kidney function in the hyperthyroid cat can only accurately be performed once the cat has been treated for hyperthyroidism and euthyroidism achieved.

“The effect of hyperthyroidism leading to an increase in glomerular filtration rate (GFR) means that even novel biomarkers, such as symmetric dimethylarginine, will be affected in some way by the hyperthyroid state. Additionally, the presence of concurrent disease, such as CKD, can result in ‘sick euthyroid syndrome’, making it more challenging to reach the hyperthyroid diagnosis.”

These complex situations require clinicians to have a systematic understanding of when to perform and how to interpret key diagnostic tests, both for assessing renal function and diagnosing hyperthyroidism.

Balance

ÐÂÔÂÖ±²¥¨Ensuring that balance is maintained when prescribing for these two conditions is a difficult task. New data suggests that clinicians should try to avoid the development of iatrogenic hypothyroidism due its negative consequences on the kidneys and survival.

In relation to hyperthyroidism, specialist facilities at RVC Small Animal Referrals include technetium scanning and the radioactive iodine unit. Technetium scans help localise overactive thyroid tissue, which can be present anywhere from the base of the tongue to the cranial mediastinum.

This means RVC vets can identify overactive tissue that is not immediately apparent on physical examination (i.e. cats with no palpable goitre) and where this tissue is present in the thorax. For cats with thyroid carcinoma, it may also, occasionally, give information about active metastatic disease.

Radioactive iodine remains the gold standard treatment for hyperthyroidism and RVC Small Animal Referrals is one of a handful of places in the UK where this treatment option is available. More than 95% of cats referred to the service are cured of their hyperthyroidism. Cats remain at the facility for a minimum of two weeks after treatment.

Veterinary nephrology and urology

RVC Small Animal Referrals is the only centre in the UK to have experts who sub-specialise in veterinary nephrology and urology. Dr Rosanne Jepson, co-director of the RVC dialysis unit, and Professor Harriet Syme, board member of the International Renal Interest Society (IRIS), provide specialist clinical expertise in the field of canine and feline nephrology and urology. 

The nephrology and urology expertise available at the RVC is strengthened by the transdisciplinary approach to case management. The Internal Medicine Service works particularly closely with the Emergency and Critical Care, Diagnostic Imaging and Soft Tissue Surgery ÐÂÔÂÖ±²¥ on such cases. The onsite Diagnostic Laboratories team provides rapid assessment and interpretation of diagnostic samples for patients hospitalised at RVC Small Animal Referrals. We welcome requests for advice about any nephrology and hyperthyroidism cases.

The RVC’s nephrology and urology clinic supports pets with kidney disease and urinary-tract disorders. This service offers the following diagnostic and therapeutic modalities:

• GFR assessment
• Diagnostic imaging of the urinary tract
• Non-invasive cystoscopy
• Laser lithotripsy for urinary stones
• Percutaneous cystolithotomy (minimally invasive surgical stone retrieval)
• Cystoscopic laser ablation of ectopic ureters

The clinic also offers renal biopsy, subureteral bypass, ureteral stent placement and dialysis options for acute kidney injury.

For small animal referrals, please call 01707 666399 
Email: qmhreception@rvc.ac.uk