Keynote Message

• Decreased or abnormal appetite behaviors (termed “dysrexia”) and loss of weight and muscle mass are a common problem in CKD.
• Nutrition is a key component of management of CKD as weight loss and poor body condition are associated with a poorer prognosis. Additionally, poor appetite is perceived as a significant quality of life concern and can cause emotional distress to the owner and prompt end-of-life decisions.
• Diets formulated for renal diseases typically have reduced phosphorus and modified protein. These diets have been shown to benefit the patient, but will not perform optimally if the patient is not eating their caloric needs.
• Nutritional assessment, including weight, body condition score, muscle mass score, and caloric intake, should be performed for CKD patients at each visit. A nutritional plan should be formulated for each patient. Tools for assessment have been made available by the WSAVA global nutritional initiative (www.wsava.org/nutrition-toolkit).
• Complications of CKD, such as hypertension, anemia, hypokalemia, dehydration and constipation, may affect appetite and should be identified and addressed when applicable. Concurrent disease, such as chronic enteropathy, osteoarthritis, hyperthyroidism, etc., should be identified and addressed.
• Poor appetite and nausea in CKD may be due to appetite dysregulation and effects of uremic toxins. Anti-nausea and appetite stimulant therapy can be helpful in the management of CKD patients. Transdermal mirtazapine has recently been approved for use in Europe for managing unintended weight loss in cats.
• Placement of esophagostomy tube may help long-term management to allow assisted feeding, water and medication administration.

Key References

1.  Freeman LM. Cachexia and sarcopenia: emerging syndromes of importance in dogs and cats. J Vet Intern Med. 2012;26:3–17. doi: 10.1111/j.1939-1676.2011.00838. www.ncbi.nlm.nih.gov/pubmed/22111652

2.  Quimby JM, Lunn KF. Mirtazapine as an appetite stimulant and anti-emetic in cats with chronic kidney disease: a masked placebo-controlled crossover clinical trial. Vet J. 2013;197:651–655. doi: 10.1016/j.tvjl.2013.05.048. www.ncbi.nlm.nih.gov/pubmed/23838205

3.  Poole M, Quimby JM, Hu T, Labelle D, Buhles W. A double-blind, placebo-controlled, randomized study to evaluate the weight gain drug, mirtazapine transdermal ointment, in cats with unintended weight loss. J Vet Pharmacol Ther. 2019;42:179–188. doi: 10.1111/jvp.12738. www.ncbi.nlm.nih.gov/pubmed/30506924

4.  Quimby JM, Benson KK, Summers S, et al. Assessment of compounded transdermal mirtazapine as an appetite stimulant in cats with chronic kidney disease. J Feline Med Surg. 2020;22:376–383. doi: 10.1177/1098612X19851303. www.ncbi.nlm.nih.gov/pubmed/31161850

5.  Ross S. Utilization of feeding tubes in the management of feline chronic kidney disease. Vet Clin North Am Small Anim Pract. 2016;46:1099–1114. doi: 10.1016/j.cvsm.2016.06.014. www.ncbi.nlm.nih.gov/pubmed/27499006