Severe hyperphosphatemia induced by a phosphate-containing oral laxative

Area of Science:

• Nephrology
• Gastroenterology
• Geriatrics

Background:

• Oral phosphate laxatives are commonly used for bowel preparation.
• The elderly population may have undiagnosed renal insufficiency, affecting phosphate excretion.
• Drug misuse and compliance issues are more prevalent in older adults.

Observation:

• An 84-year-old woman developed severe hyperphosphatemia (serum phosphate 10.3 mmol/L) after unintentionally overdosing on an oral phosphate laxative.
• The patient presented with confusion, a potential symptom of severe electrolyte imbalance.
• Her ionized calcium was critically low (0.56 mmol/L), indicating potential for complications.

Findings:

• This case highlights the risk of acute hyperphosphatemia and hypocalcemia from phosphate laxative overdose in the elderly.
• Underlying renal impairment, even with normal creatinine, can exacerbate phosphate retention.
• The potential for medication misuse in the elderly necessitates careful prescribing and monitoring.

Implications:

• Clinicians must exercise caution when prescribing oral phosphate laxatives to elderly patients.
• Assessment of renal function in the elderly should consider phosphate handling capacity.
• Patient education and monitoring are crucial to prevent accidental overdose and adverse events.