Clinical Connections  –  Summer 2020

Tackling IMHA from all angles
Immune-mediated haemolytic anaemia (IMHA) causes severe anaemia when the immune system attacks and destroys normal red blood cells. It is the most common autoimmune disease in dogs across Europe and North America. It is more common in younger and middle age dogs but it can also occur in elderly dogs. Although the cause of the disease is currently unknown - it appears to be partially related to genetic background
High mortality rate Despite treatment, up to half of affected dogs unfortunately still do not survive the disease. Many others experience considerable distress.
• Cocker spaniels • English springer spaniels • Maltese terrier
• pale or yellow gums • extreme weakness and lethargy • loss of appetite • jaundice (yellow discolouration) of whites of the eyes • discolouration of urine (becomes red or dark brown)

Ollie, a seven-year-old male Shih Tzu, presented to the RVC Small Animal Hospital. On presentation, his mucus membranes were pale, with a normal capillary refill time and bounding pulses. Otherwise, physical examination was largely unremarkable.
Diagnostic tests
A complete blood cell count (CBC) on presentation revealed a markedly regenerative anaemia (PCV of 12%) with signs of immune mediated destruction (moderate spherocytosis), and neutrophilia with left shift. An In saline agglutination test was strong positive. A serum biochemistry profile revealed mild hypercholesterolaemia (7.38mrnol/L, ref 3.2 - 6.2), moderate hyperbilirubinaemia (31.9 umol/L, ref 0.1 - 4.2), mild increases in ALT (139.0 U/L, ref 19.8 -124), and ALP activities (221 U/L, ref 0 - 130).
Ollie was initially stabilised by matched pRBC transfusion, and after further investigation (bicavitary imaging and serological testing for infectious diseases) did not reveal an underlying trigger factor, he was started on immunosuppressive dose of prednisolone, azathioprine and clopidogrel. His response was monitored by regular physical examinations, CBC, biochemistry profiles and quality of life assessment
After seven days of hospitalisation Ollie’s PCV started to increase and he was discharged for continued treatment at home. He continued to be re-examined on a regular basis by the RVC team, and immunosuppressive therapy was successfully tapered and ceased over a period of 16 weeks, while also assessing his quality of life during this period.

Standardised treatment protocols exist for dogs with IMHA, but perhaps this ‘one size fits all’ approach is no longer appropriate. We are analysing left-over blood samples from dogs with IMHA to assess novel markers of disease severity that could be used in future to refine and individualise treatment. It is hoped this study will provide new and clinically useful tools to monitor the progress of dogs with IMHA. Therapeutic approaches could be refined then for individual animals to maximise positive outcomes whilst minimising side effects. Results are due at the end of 2021.
Referring vets can nominate clients to participate by contacting Dr Barbara Glanemann, Senior Lecturer in Small Animal Medicine
Call: +44 (0)1707 666333 Email: general/IMHA

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