Megacolon in cats: Current insights and future directions

Feline megacolon represents a critical manifestation of severe and intractable constipation, resulting in persistent colonic dilation and hypomotility. It is commonly observed in middle-aged to older male domestic shorthair cats; however, cats of any age, sex, or breed may present with this condition. Idiopathic megacolon remains the most common form. Other primary factors contributing to megacolon involve untreated long-term constipation stemming from pelvic fractures, spinal cord injuries, or congenital deformities. Clinical presentation includes dehydration, weight loss, chronic constipation (obstipation), and periodic abdominal straining. Physical examination often reveals a dilated and firm colon upon abdominal palpation. Diagnosis mainly relies on abdominal radiography, occasionally supplemented by additional imaging modalities. Traditional medical treatment comprising laxatives, enemas, prokinetic drugs, and rehydration therapy with dietary fibers proves effective in early or reversible cases, while novel cellular and gene-based therapies warrant investigation. Chronic irreversible cases, however, necessitate surgical management. Subtotal colectomy remains the treatment of choice for megacolon refractory to medical management. Early diagnosis and appropriate treatment can reasonably improve prognosis, but delayed interventions may result in suboptimal outcomes. In cases where treatment proves ineffective and the condition deteriorates, euthanasia is considered. Currently, there is a lack of specific biomarkers for diagnosing and predicting the pathogenesis and progression of the disease. While effective drug combinations remain challenging, surgery can potentially lead to postoperative complications, indicating the requirement for more specific treatment and management. This narrative review summarizes current knowledge of feline megacolon and highlights future research avenues.