A 30 year old manic patient was prescribed haloperidol 3month back. For last two days he has become restless and kept pacing in he room for a day. On examination he was found to have tremors of hand. He is most likely to be suffering from:
**Core Concept**
Haloperidol is a typical antipsychotic medication that can cause extrapyramidal side effects (EPS) due to its blockade of dopamine D2 receptors in the nigrostriatal pathway. This blockade disrupts the normal balance between dopamine and acetylcholine in the striatum, leading to various motor symptoms.
**Why the Correct Answer is Right**
The patient's symptoms of restlessness, pacing, and tremors of the hand are indicative of akathisia, a type of EPS. Akathisia is characterized by subjective feelings of restlessness and a compelling need to be in constant motion. It is thought to result from the blockade of dopamine D2 receptors in the ventral striatum, particularly in the nucleus accumbens. This blockade disrupts the normal balance between dopamine and acetylcholine, leading to an increase in acetylcholine release and a subsequent increase in motor activity.
**Why Each Wrong Option is Incorrect**
**Option A:** is incorrect because this option is not a recognized side effect of haloperidol. The patient's symptoms are not suggestive of a sedative or anxiolytic effect, which would be more characteristic of a benzodiazepine or a barbiturate.
**Option B:** is incorrect because this option is not a common side effect of haloperidol. The patient's symptoms are not suggestive of a gastrointestinal or cardiovascular effect, which would be more characteristic of a medication such as metoclopramide or propranolol.
**Option C:** is incorrect because this option is not a recognized side effect of haloperidol. The patient's symptoms are not suggestive of a hallucinogenic or deliriant effect, which would be more characteristic of a medication such as LSD or PCP.
**Option D:** is incorrect because this option is not a recognized side effect of haloperidol. The patient's symptoms are not suggestive of a hepatotoxic or nephrotoxic effect, which would be more characteristic of a medication such as acetaminophen or gentamicin.
**Clinical Pearl / High-Yield Fact**
Akathisia is a common side effect of typical antipsychotics like haloperidol, and it can be treated with beta-blockers such as propranolol or with anticholinergic medications like benztropine. It's essential to recognize the symptoms of akathisia early on and start treatment to prevent worsening of the condition.
**Correct Answer:** . Tardive dyskinesia is characterized by involuntary movements of the face and limbs, and it is a long-term side effect of typical antipsychotics like haloperidol.