A 50-year-old chronic alcoholic presented with complaints of acute confusion, delirium, ataxia and mild memory loss. On ophthalmoscopic examination, ophthalmoplegia was noted along with hypotension. Serum electrolyte levels were normal. Lab findings revealed increased RBC transketolase activity along with reduced blood lactate levels. CT scan of the brain did not reveal any finding, so MRI of brain was planned. Which of the following enzymes uses the above deficient vitamin as a coenzyme: –
A 50-year-old chronic alcoholic presented with complaints of acute confusion, delirium, ataxia and mild memory loss. On ophthalmoscopic examination, ophthalmoplegia was noted along with hypotension. Serum electrolyte levels were normal. Lab findings revealed increased RBC transketolase activity along with reduced blood lactate levels. CT scan of the brain did not reveal any finding, so MRI of brain was planned. Which of the following enzymes uses the above deficient vitamin as a coenzyme: –
💡 Explanation
**Core Concept**
Thiamine deficiency is a common complication in chronic alcoholics, leading to impaired glucose metabolism, neurological symptoms, and ophthalmoplegia. Thiamine serves as a coenzyme for several essential enzymatic reactions in the brain, particularly in the pentose phosphate pathway.
**Why the Correct Answer is Right**
The patient's symptoms, including acute confusion, delirium, ataxia, and ophthalmoplegia, are classic manifestations of Wernicke's encephalopathy, a condition caused by thiamine deficiency. The increased RBC transketolase activity and reduced blood lactate levels are indicative of thiamine deficiency. Transketolase is a key enzyme in the pentose phosphate pathway, which is dependent on thiamine pyrophosphate (TPP) as a coenzyme. The lack of thiamine leads to impaired glucose metabolism, resulting in reduced lactate production.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the correct enzyme related to thiamine deficiency. While thiamine is involved in various enzymatic reactions, the question specifically asks for the enzyme that uses thiamine as a coenzyme in the context of the patient's symptoms.
**Option B:** This option is incorrect because it does not directly relate to thiamine deficiency. Although thiamine is involved in the metabolism of various compounds, the question specifically asks for the enzyme that uses thiamine as a coenzyme in the context of the patient's symptoms.
**Option C:** This option is incorrect because it does not specify the correct enzyme related to thiamine deficiency. While thiamine is involved in various enzymatic reactions, the question specifically asks for the enzyme that uses thiamine as a coenzyme in the context of the patient's symptoms.
**Clinical Pearl / High-Yield Fact**
Thiamine deficiency can be prevented by administering thiamine before glucose, as glucose can worsen thiamine deficiency. This is a critical principle in managing patients with suspected Wernicke's encephalopathy.