Category: Pituitary Disorders/Neuroendocrinology
Objective : Central pontine myelinolysis (CPM) is a neurological disorder affecting the pons due to damage of myelin sheath of nerves. It is characterized by dyarthria, acute paralysis, dysphagia etc. Cause is iatrogenic or treatment induced.
Methods : n/a
Results : n/a
22 y/o male presented with increased somnolence, dullness and anorexia since 4 days. He had abnormal behavior, change in voice and hiccoughs for 1 day. He was prescribed antihistaminic and steroid nasal spray for allergic rhinitis about 2 weeks ago. After taking these medications, he developed sleepiness and altered sensorium.
On examination, patient was dull, drowsy, moving all limbs, had a puffy face. Vitals were normal and he looked mildly dehydrated. Labs- Hb 11.3 g/dl, Ser. creatinine 0.8 mg/dl, BUN 21 mg/dl, ser. Na 92.1 mEq/L, K 3.9 mEq/L, Cl 101 mEq/L, T4 3.6 mcg/dl (4.7‑9.5), TSH 11.9 mIU/ml (0.25‑5.0), and urine for spot sodium 44 mEq/L (40‑220). USG abdomen showed minimal ascites. Diagnosis made was primary hypothyroidism with severe hyponatremia. Patient was treated with hypertonic saline (1.6% NaCl) at 30 ml/h with supportive treatment. After 24 hr ser Na improved to 111.6 mEq/L, it further improved to 122.1, 125.7, 137.6 mEq/L over next 3 days respectively. He was discharged on L‑thyroxine after 5 days. A week later patient developed weakness of limbs, difficulty in walking, dribbling of saliva, staring look and slurring speech. On exam, patient was drowsy with stiffness of limbs, facial tics, coarse tremors, dysarthria and ataxic gait. Labs: ser. Na 135.4 mEq/L, K 3.89 mEq/L, cortisol 1.0 mcg/dl (5‑25), ACTH 15.1 pg/ml (10‑46), FSH 3.94 mIU/ml (2.70‑17.30), prolactin 3.89 ng/ml (0.0‑15), and testosterone 3.17 (2.70‑17.30).
MRI brain showed bilateral symmetrical hyperintensity in lentiform and caudate nucleus on fluid attenuated inversion recovery and T2‑weighted images suggestive of osmotic myelinolysis. Patient was started on oral hydrocortisone and thyroid replacement therapy. Gradually, he improved but remained clumsy. After 2 months cortisol remained low, serum TSH became normal. He continued to improve neurologically. After 4 years of treatment, he is almost living normal life. Pituitary hormones are normal, but 8 am cortisol remained low (0.8 mcg/dl). Presently, he is on 10 mg hydrocortisone BD and 75 mcg L‑thyroxine.
CPM is a devastating illness with considerable morbidity and mortality. Prevention is important as current treatment only rarely leads to full recovery. Avoid hypernatremia while correcting hyponatremia. Patients who survive CPM require extensive and prolonged neurorehabilitation. Pituitary function should be evaluated when hormonal deficiency is suspected.