CPD ACCREDITED ARTICLE
TREATMENT
Tailor treatment to the IRIS stage of disease:
➤ ➤ IRIS stage 1 – identify underlying disease process
and apply steps to eliminate this disease
➤ ➤ IRIS stage 2-3 – Address factors leading to
progression of CKD – appropriate nutrition,
control proteinuria, hypertension and
hyperparathyroidism.
➤ ➤ IRIS stage 3-4 – also give supportive therapy,
dehydration , acidosis, anaemia, hypokalaemia
Renal diet
Feeding a renal diet provides the most positive long
term effect on outcome of CKD. The diets are protein
restricted, phosphate restricted, sodium restricted and
supplemented with Omega 3 fatty acids, potassium
and vitamin B and containing blood alkalinising
agents. Two separate studies showed survival times
of 20.8 months vs 8.7 and 16 months vs 7 months in
cats on renal diet and on normal maintenance diets.
Uraemic episodes were significantly minimised.
The studies also showed a reduced morbidity and
mortality rate in the renal diet group over the test
period with 0% uraemic episodes vs 26% in the
maintenance diet group and 0% mortality vs 22% in
the maintenance diet group. Increased survival is
presumed to be due to the attenuation of the severity
of the secondary renal hyperparathyroidism as well as
lessening the severity of uraemia.
Early intervention is recommended when creatinine
is >150umol/L. Acceptance of the diet increases prior
to the development of clinical signs as there is less
nausea.
of angiotensin I to angiotensin II. Thus they will
decrease GFR and increase RBF.
In mammals
however, alternative pathways (ACE ESCAPE) exist for
angiotensin II generation. In a trial using benazepril
at 0.5mg/kg -1mg/kg per day on cats with naturally
occurring CKD compared to a placebo in 61 cats over
180 days benazepril significantly reduced proteinuria.
There was also a non-significant trend for a lower
creatinine at the endpoint in the treatment group as
well as a higher quality of life score. Non- progression
of the CKD IRIS stage excluding stage 4 patients, was
93% in the benazepril group and 73% in the placebo
group (p =.196). The study was underpowered , too
few animals and treated for too short a period and
differences in survival time which were no significant
in the current study may have gained significance
ARBs: Semintra is licensed for reduction of proteinuria
associated with CKD. It selectively blocks the
Angiotensin II 1 receptor and spares the beneficial
Angiotensin II 2 receptor. There is also no ACE escape.
A study comparing 240 client owned cats treated with
either angiotensin converting enzyme inhibitor (ACEi)
benazepril or angiotensin receptor blocker (ARB)
telmisartan (Semintra®) was significantly superior to
ACEi in decreasing proteinuria.
With any drug affecting the RAAS system a 5-7 d
post treatment check is essential to evaluate for the
presence of azotaemia and serum potassium which
may increase due to a decreased GFR.
Supportive Therapy IRIS Stage 3-4
In advanced CKD treatment need to be aimed
at managing hydration, weight loss/nausea,
hypokalaemia, any urinary tract infections, and
anaemia.
Blood pressure
Start treatment when SBP is greater than 160 –
170mmHG or if evidence of hypertensive retinopathy
(haemorrhage/detachment) is present. Only start
treatment when the CKD is stable. Amlodipine at 0.25-
0.5mg/kg oid is the recommended treatment. ACE
inhibitors are ineffective for systemic hypertension as
they drop SBP by only 10 – 15 mmHg. Telmisartan at
1-3mg/kg oid or divided bid significantly decreased
SBP in normal cats (130 to 105/90 mmHg) within the
second week of treatment.
Proteinuria
The major detrimental renal effects of angiotensin
II are mediated by AT1 receptors: vasoconstriction,
increased systolic blood pressure, cell proliferation
and fibrosis and proteinuria. AT2 receptors modulate
renoprotective actions of angiotensin II such as
vasodilation, natriuresis, inhibition of renin secretion
and anti-inflammatory, anti-ischaemic and anti-fibrotic
effects.
ACE inhibitors: ACE inhibitors prevent the conversion
Dehydration progresses CKD. Cats in uraemic episodes
need IV fluid administration: aim for euvolaemia and
resolution of clinical signs and NOT for decreasing
creatinine. Encourage water intake using water
fountains and using a broth (water from poached fish/
chicken). If this doesn’t work the subcutaneous fluids
is a possible next step: 50 – 100ml Ringers lactate
SQ oid.
Appetite
Manage nausea, which will increase food and water
intake. Maropitant – 0.5mg/kg oid, Ondansetron,
Mirtazepine (0.5mg/kg q 48 to ¼ tab q 72). Uraemic
gastropathy and acidity is not a feature of CKD in cats
so antacids and ulsanic are not indicated. Constipation
is a common problem in cats with CKD and can also
add to the nausea and inappetance. Fluid balance
(supplementation) and hypokalaemia need to be
addressed in these patients. Check for periodontal
and dental disease. Rather risk a general anaesthetic
to fix the mouth, this will then result in improved
appetite as there is less oral pain.
Issue 05 | NOVEMBER 2018 | 9