What is the relationship between urostomy and metabolic acidosis?

From the Guidelines

Patients with a urostomy are at high risk of developing hyperchloremic metabolic acidosis due to the intestinal reabsorption of chloride and loss of bicarbonate, and thus require careful management to prevent morbidity and mortality. To manage this condition, it is crucial to focus on preventing sodium loss and maintaining electrolyte balance, as emphasized in the ESPEN guidelines on parenteral nutrition 1.

• The guidelines highlight the importance of restricting oral hypotonic drinks and encouraging the use of glucose–saline replacement solutions with a sodium concentration of 90 mmol/l or more to prevent sodium loss.
• Additionally, patients with stomal losses should be cautioned against consuming plain water and instead encouraged to drink oral rehydration solutions (ORS) whenever they are thirsty, as plain water can exacerbate sodium loss and contribute to acidosis.
• The management of acidosis in patients with a urostomy also involves monitoring and correcting magnesium deficiency, as significant losses of magnesium can occur in the intestinal effluent and urine, leading to hypomagnesemia and associated complications such as calcium and potassium deficiency 1.
• Regular monitoring of electrolytes, including serum bicarbonate, chloride, and sodium levels, is essential to promptly identify and manage any imbalances that could lead to or exacerbate metabolic acidosis.
• It is also important for patients to be aware of the symptoms of acidosis, such as fatigue, weakness, increased respiratory rate, and confusion, and to seek medical attention if these symptoms develop.
• Overall, the goal of management is to prevent the development of metabolic acidosis and its complications, thereby improving the quality of life and reducing morbidity and mortality in patients with a urostomy.

From the Research

Urostomy and Acidosis

• Urostomy care is crucial in managing patients with a urostomy, and home care clinicians should have the knowledge and skills to manage their care 2.
• However, there is no direct evidence linking urostomy to acidosis in the provided studies.
• Metabolic acidosis is associated with accelerated progression of chronic kidney disease (CKD), and treatment with sodium bicarbonate can improve kidney and patient survival 3.
• Sodium citrate and sodium bicarbonate have similar effects on renal function and serum bicarbonate correction in patients with metabolic acidosis and CKD, but sodium bicarbonate is associated with higher rates of medication discontinuation due to adverse events 4.
• Hyperchloremia, an electrolyte abnormality associated with metabolic acidosis, can be prevented and managed through optimal fluid management, including the use of balanced crystalloids for fluid resuscitation 5, 6.
• The kidney plays an important role in regulating chloride concentration, and hyperchloremia can occur when the capacity to handle excessive chloride is overwhelmed or when serum bicarbonate is low 6.