We report a case of severe hypokalaemia and moderate hypophosphataemia from clay ingestion. A 60-year-old woman presented with flaccid paralysis. Investigations revealed a serum potassium level of 1.8 mmol/L, phosphate level of 0.56 mmol/L and creatine kinase level of 30 747 IU/L. She had marked proximal and distal muscle weakness due to severe hypokalaemia and concurrent hypophosphataemia, which likely contributed to the onset of rhabdomyolysis. The patient subsequently admitted to significant pica, most likely secondary to an associated iron deficiency. We conclude that the ingested clay acted as a potassium and phosphate binder. Although we did not investigate the content of the clay in this case, it has been reported that clay can bind potassium in vitro and is rich in minerals such as aluminium that could play a role in the binding of phosphate, although the exact mechanism remains unclear. The patient recovered fully and outpatient follow-up at 6 months and again at 40 months confirmed no electrolyte abnormality, myopathy nor any further geophagia.

BMJ case reports

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BMJ Case Rep