Review Question - QID 104315

Osmotic demyelination syndrome (ODS), previously called central pontine demyelonisis, can occur when hyponatremia is corrected too quickly.

The pons is the most commonly affected part of the brain in ODS, but extra-pontine cases have been well documented. Signs and symptoms of ODS develop two to six days after correction of hypo-osmolarity and include quadriparesis, dysarthria, dysphagia and other pseudobulbar symptoms. There are few effective therapies for ODS; thus, prevention is important.

Goh discusses the management of hyponatremia. Factors that effect the immediate treatment of hyponatremia include the presence of symptoms, the degree of hyponatremia and whether the condition is acute (< than 48hrs) or chronic. In all patients with hyponatremia, the cause should be identified and treated. Some causes include congestive heart failure, diuretics use, SIADH, brain injury and endocrine deficiencies.

Stern et al, as part of a multicenter perspective study, investigated the neurological sequalae after treatment of severe hyponatremia. They concluded that chronicity of hyponatremia and a high rate of correction (>12mmol/L per day) in the first 48 hours of treatment were significantly associated with complications.

Incorrect answers:
Answer 1: Lateral medullary syndrome (Wallenberg syndrome) is a stroke characterized by vertigo, ipsilateral deficits in pain/temp over face, ataxia, dysarthria and contralateral deficits in pain and temperature over trunk and limbs.
Answer 2: Medial medullary syndrome (Dejerine syndrome) is a very rare stroke caused by occlusion of the anterior spinal artery resulting in infarction of the medial medulla oblongata. It causes alternating hemiplegia.
Answer 3: Hypercalcemia can be caused by hyperparathyroidism (or PTHrp secreting tumor) and is associated with nephrolithiasis, bone pain, abdominal pain, and confusion (stones, bones, groans and psychiatric overtones)
Answer 4: Hypocalcemia can be caused by Vitamin D deficiency or hypoparathyroidism, and is associated with muscle cramps, confusion, tingling in the lips and fingers.