Hyponatremia due to secondary adrenal insufficiency: a case
Hyponatremia is defines as plasma Na+ concentration <135 mm and is a very common disorder in patients admitted in ICU. The causes include euvolemic, hypovolemic, hypervolemic hyponatremia. Among the euvolemic cause, adrenal insufficiency is an important consideration which requires high degree of suspicion in order to detect early and treat properly. Two such cases have been presented the Journal of The Association of Physicians of India.

A 71 yr. old male, known diabetic, presented to ICU with generalised weakness for last 2 weeks along with confusion and irrelavant talk for last 3 days. There is no history of fever, headache, vomiting. On examination patient in altered sensorium. Investigation revealed- Na+-118.5 mg/dl, K+-3.42 mg/dl.

MRI brain-diffuse atrophic changes in brain. Patient was treated with hypertonic saline slowly and over next 48hrs sodium level increased to 120 mg/dl but then it again came down to 116 mg/dl despite treatment with hypertonic saline along with decreased sensorium of the patient. This prompted to again look at blood investigation report which showed to be a case of euvolemic hyponatremia as patient had no edema, normal JVP, normal CVP, urine spot na>20.

Serum cortisol morning (8 am) was sent which revealed level of 25 .2 nmol/l (normal range 123-626 nmol/l), and the evening sample of 23.5 nmol/l (46.2-389 nmol/L). ACTh level sent came to be 13 pg/ml. The patient was now diagnosed to be a case of secondary adrenal insufficiency and treated with hydrocortisone injection. Gradually the sensorium of the patient improved and sodium reached normal level in next 3days.

70 yr old female came to hospital with weakness, reduced appetite for 10 days and decreased sensorium for the last 2 days. Blood investigation revealed Na+116.1mmol/L, K+4.59 mmol/L, urinary osmolality 332.02 mosm/kg.

Serum cortisol morning-78 nmol/L (range 123-626 nmol/l), evening4 0 . 2 n m o l / l ( r a n g e 4 6 . 2 - 3 8 9 nmol/L). Serum ACTH -21 pg/ ml, serum aldosterone-2.17 ng/dl, plasma renin-0.84. Patient was diagnosed to be case of hyponatremia due to adrenal insufficiency treated with hydrocortisone injection following which sensorium improved and sodium level reached to normal range.

Major takeaway:-
• A high degree of suspicion is needed to detect cortisol deficiency especially in elderly group who may present with nonspecific symptoms of weakness, lethargy, reduced appetite and hyponatremia as happened in both the above cases.

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