Chronic hypovolemic hyponatriemia is typical for Addisonian crisis and may provoke brain edema but its rapid correction may lead to myelinolysis. We report 2 newly diagnosed cases of primary adrenal insufficiency (PAI) associated with severe hyponatriemia which correction was complicated by osmotic myelinolysis.
Case 1: Twenty four-year-old female was admitted with vomiting, sopor, shock. Serum sodium was 83, glucosae 3.6 mmol/l. Serum cortisol 34 nmol/l and ACTH 307 pmol/l confirmed PAI. Hydrocortisone and saline were administered. Within 2 h apnoe, mechanical ventilation began, than coma revealed. 3% saline infusion was added: 400 ml during 4 h giving sodium rise to 107 mmol/l. Saline infusion continued and within 24 h serum sodium was 117 mmol/l (37 mmol/l rise per day). Magnetic resonance imaging (MRI) didnt reveal the reason for persisting coma. Diagnosis of central pontine myelinolysis was considered and was confirmed later by MRI. Patient dies after 18 months lasting coma.
Case 2: Fifty four years female was admitted with abdominal pain, vomiting, hypotension, hyperpigmentation. Serum sodium was 104, glucose 4.6 mmol/l, cortisol 190 nmol/l; plasma ACTH 246 pmol/l, renin 40 ng/ml. Saline infusion begins and additionally 450 ml 3% saline during 10 h was administered giving sodium rise to 116 mmol/l. Than saline was infused and to the next day sodium level was 122 mmol/l (increase −18 mmol/24 h). After 34 days of compensation parkinsonian signs appeared. MRI revealed extrapontine myelinolysis. After 3 months of treatment full neurological recover.
These cases highlight the importance of careful correction of hyponatriemia in PAI. Fatal pontine myelinolysis in case 1 developed due to overzealous correction of chronic hyponatriemia without necessary control and not in line with current recommendation: possible rate of correction is 8 mmol/l during the first and 810 during second days and only at first hours 11.5 mmol/l per hour increase is possible.