Phosphates chronic constipation

A 13-year-old boy with Costello syndrome (neonatal macrosomia with subsequent slow growth, developmental delay, coarse facial dysmorphisms, gingival hyperplasia, skeletal anomalies, and hypertrophic cardiomyopathy) and chronic constipation developed signs and symptoms of acute renal insufficiency, after having received four phosphate-containing enemas (125 ml containing sodium... 

Aluminium hydroxide reacts with HCl to form aluminium chloride this in turn reacts with intestinal secretions to produce insoluble salts, especially phosphate. The chloride is released and reabsorbed so systemic acid-base balance is not altered. It tends to constipate. Sufficient aluminium may be absorbed from the intestine to create a risk of encephalopathy in patients with chronic renal failure. Hypophosphataemia and hypophosphaturia may result from impaired absorption due to phosphate binding. 

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