Severe Hypercalcemia due to Drowning in an Onsen (Hot Spring)

Area of Science:

• Toxicology
• Internal Medicine
• Environmental Health

Background:

• Hypercalcemia typically results from primary hyperparathyroidism, malignancies, or certain medications.
• The differential diagnosis for hypercalcemia is broad, necessitating thorough patient evaluation.

Observation:

• A 55-year-old woman presented with severe hypercalcemia (serum total calcium 18.7 mg/dL) after being found unresponsive in a hot spring bath.
• The patient exhibited hypoxia and shock, requiring intubation and vasopressor support, with CT revealing aspiration pneumonia.

Findings:

• Standard causes of hypercalcemia, including endocrine disorders, cancers, and drug interactions, were excluded.
• Analysis revealed high calcium concentrations in the hot spring water, leading to the conclusion of accidental ingestion.

Implications:

• This case highlights an unusual cause of hypercalcemia secondary to environmental exposure.
• Accidental ingestion of mineral-rich water should be considered in patients with hypercalcemia, especially in drowning incidents.
• Investigating the composition of ingested substances is vital for accurate diagnosis and management.