Table 1.

Studies showing hyponatraemia in non-dehydrated patients with respiratory infections

Study	No of patients	Age	Diagnosis	Exclusions	Serum sodium level (mmol/l)	Serum or urine osmolality	Symptoms associated with low sodium level
Dhawan et al 19922	100	1 month-12 years	Pneumonia	Clinical dehydration	31 patients had Na <130	Serum dilute in 29, concentrated in 2 (probable dehydration)	4 died, Na <125 mmol/l
Shann et al 19851	73	≥1 month	Pneumonia	Clinical dehydration	33 patients had Na <134	—	Hyponatraemia 2-3 times more frequent with severe pneumonia
Rivers et al 19815	4	6-8 weeks and 6 months	3 bronchiolitis, 1 pneumonia	—	3 patients had Na 114-124	Concentrated urine, or not maximally dilute urine	Seizures in one patient with bronchiolitis