Subacute combined degeneration of spinal cord is caused by deficiency of?
High-Yield Explanation
ANSWER: (D) Vitamin B12REF: Harrison s 17th ed p- 2595SUBACUTE COMBINED DEGENERATION (VITAMIN B12 DEFICIENCY)Demyelination of neurons of the posterior column and lateral column of the spinal cord due to deficiency of vit. B12. It is a treatable myelopathy.Characterised by:Pyramidal tract involvement:Loss of reflexes due to an associated peripheral neuropathy in a patient who also has Babinski sign.Weakness and spasticity.Increased tendon reflex and clonusSpastic gaitLateral column involvement:Subacuteparesthesias in the hands and feetLoss of vibration and position sensation,Progressive spastic and ataxic weakness.III. Other features: Optic atrophy and irritability or other mental changes Diagnosis:Macrocytic red blood cellsLow serum concentrationElevated serum levels of homocysteine and methylmalonic acid.Treatment is by replacement therapy, beginning with 1000 micro gm of intramuscular vitamin B12 repeated at regular intervals or by subsequent oral treatment