Treatment of patient symptoms becomes a higher priority in the later stages of CKD when the decreased renal function has a
more pronounced effect on the patient's quality of life. In addition to phosphorus restriction and protein reduction, dietary
management includes omega-3 fatty acid supplementation, salt reduction, and alkalinization—all of which are designed to reduce
patient symptoms and slow disease progression. Acceptance of a renal diet is enhanced with early initiation (while the patient
still has a good appetite) and gradual implementation. Vomiting and anorexia are common patient symptoms in dogs with later
stage CKD and can often result in decreased caloric intake. Causes of vomiting and anorexia include: 1) stimulation of chemoreceptor
trigger zone by uremic toxins, 2) decreased excretion of gastrin and increased gastric acid secretion, and 3) gastrointestinal
irritation secondary to uremia. Vomiting may be treated with metoclopramide, which blocks the chemoreceptor trigger zone.
Metoclopramide also increases gastric motility and emptying without causing gastric acid secretion, and is one of the drugs
of choice for vomiting associated with renal failure. H2-receptor blockers (e.g., famotidine or ranitidine) have been shown to effectively decrease gastric acid secretion, which may attenuate vomiting in
dogs with CKD. Oral ulcers, stomatitis, and glossitis may occur as a result of gastritis and vomiting or the effect of uremic
toxins on mucosal membranes and will often also result in anorexia. If vomiting has been controlled but anorexia persists,
placement of a feeding tube (esophagostomy or gastrostomy tube) will often facilitate the maintenance of caloric intake and
hydration status. In many stage III and IV dogs without feeding tubes, fluid therapy with polyionic solutions, given intravenously
or subcutaneously in the hospital or subcutaneously by owners at home (10-50 ml/kg every one to three days), will help improve
the patient's quality of life.
Dr. Grauer is professor and Jarvis chair of small animal internal medicine at Kansas State University in Manhattan, Kan. Dr.
Grauer's expertise involves small animal urinary system diseases and disorders.