Hyponatraemia is the most common inpatient referral to endocrinology services, and is frequently seen in cases of community-acquired pneumonia (CAP).

This prospective clinical study by Cuesta et al. aimed to determine whether hyponatraemia was linked to syndrome of inappropriate antidiuresis (SIAD) in CAP, and if it was best managed by fluid restriction. Of 1723 patients with CAP, 143 (8.3%) had hyponatraemia (sodium <130mmol/l); 66 (46%) had SIAD, 60 (42%) had hypovolaemic hyponatraemia, 13 (9%) had hypervolaemia hyponatraemia, and 4 (3%) had hyponatraemia due to glucocorticoid deficiency (GD). Sodium, plasma arginine vasopressin and antidiuresis fell with antibiotic usage in the SIAD group, without fluid restriction. Persistent hyponatraemia suggested underlying lung disease, such as bronchiectasis. It is noteworthy that 3% of patients had GD, reflecting the prevalence of inhaled steroid use, which needs managing with glucocorticoid replacement.

The authors suggest that fluid restriction therefore may not be the most appropriate management technique in CAP and SIAD, and that isotonic fluid may be appropriate, noting management should be based on careful patient assessment.

Read the full article in Clinical Endocrinology doi:10.1111/cen.13937