Approach to managing a patient with hypophosphataemia and no obvious underlying cause:
First, confirm the hypophosphataemia with repeat serum phosphate measurement to exclude laboratory error.
Conduct a thorough clinical assessment including history and examination to identify potential causes such as malnutrition, alcohol misuse, medications, or symptoms suggestive of renal phosphate wasting or endocrine disorders.
Investigate serum calcium, parathyroid hormone (PTH), vitamin D levels, and renal function to assess for underlying metabolic or renal causes, as abnormalities in these can affect phosphate balance.
Consider referral to a specialist (e.g., endocrinologist or nephrologist) if initial investigations do not reveal a cause or if the hypophosphataemia is severe or symptomatic.
Management should be directed at the underlying cause if identified; if no cause is found and the patient is asymptomatic with mild hypophosphataemia, monitoring may be appropriate.
In symptomatic or severe cases, phosphate supplementation may be considered under specialist guidance, with monitoring of serum phosphate and calcium to avoid complications.
Note: The provided NICE guidelines focus primarily on hyperphosphataemia and chronic kidney disease management and do not specifically address hypophosphataemia management; therefore, clinical judgement and specialist advice are important in these cases NICE NG203,NICE NG132.