PURPOSE: Clinical manifestations of hyponatremia often occur when plasma sodium levels fall below 120 m.eq/litre. We present here the clinical features, types, course, prognosis and management of patients with severe hyponatremia (defined as plasma sodium < 110 meq/litre).
METHODS: Twenty-six consecutive patients (14 men and 12 women) with severe hyponatremia were analyzed. Parameters assessed were: demographic data, duration of symptoms, duration of hospitalization, ventilatory requirement and the systemic and neurological features. The type of hyponatremia was classified as hypovolemic, euvolemic and hypervolemic. Time to achieve normal sodium levels was assessed.
RESULTS: Age ranged from 3 days to 78 years (mean 59.19+17.22). Duration of symptoms ranged from 1–15 days (mean 4.23+3.52). Alteration of sensorium (encephalopathy), seen universally, ranged from mild confusion and drowsiness to coma. Other features were: nausea-6, vomiting-12, malaise-15, seizures-4, and headache-5. Two patients developed pulmonary edema and two developed septicemia while in the hospital. Five developed hospital acquired respiratory infection. Ventilatory assistance was needed in four. Type of hyponatremia was hypovolemic-8, euvolemic-16 and hypervolemic-2. Cranial MR imaging, done in 22, revealed cerebral edema in 3 and hypertensive and ischemic changes in 9. MRI was normal in ten. EEG, done in 15 was normal in three. Abnormalities seen were: poor alpha index, background slowing to theta and abundant beta activity. CSF analysis done in 6 was normal. Hypertonic(3%) saline was used in only 13 (100 ml in 11 and 200 ml in 2). Hyponatremia was corrected over 1–8 days (mean 4.03+1.56). Patients stayed in the hospital for 5 –33 days (mean 10.61 + 6.13). One developed osmotic disequilibrium syndrome and died while 25 were normal at discharge and at 3 months follow up.
CONCLUSION: Hyponatremia is of diverse causes and results in various neurological complications. Hypertonic saline is not universally required in the management even with severe hyponatremia.
CLINICAL IMPLICATIONS: Hyponatremia, even when severe, has a relatively benign course with good prognosis. Cautious correction with avoidance of overtly vigorous therapies including hypertonic saline administration is advocated in the management.
DISCLOSURE: Ramesh Babu Kesavan, None.