**Question:** Lithium toxicity is treated by following methods except:-

A. Hyperventilation
B. Administration of activated charcoal
C. Hemodialysis
D. Lumbar puncture

**Core Concept:** Lithium is an effective mood stabilizer used in the treatment of bipolar disorder. However, when taken in excessive amounts, it can lead to lithium toxicity, potentially causing serious complications. Treatment options for lithium toxicity involve managing the electrolyte imbalances, renal function, and neuropsychiatric symptoms.

**Why the Correct Answer is Right:** Lithium toxicity is primarily managed by optimizing electrolyte levels, renal function, and neuropsychiatric symptoms. Hyperventilation (option A) is not specifically targeted at treating lithium toxicity but rather aims to reduce the concentration of hydrogen ions, which could potentially worsen the situation by exacerbating acidosis.

**Why Each Wrong Option is Incorrect:**

B. Administration of activated charcoal (option B) is usually employed in gastrointestinal poisoning to adsorb toxins, not lithium. In the context of lithium toxicity, it would not effectively bind to and neutralize lithium ions.

C. Hemodialysis (option C) is a renal replacement therapy that can remove excess lithium from the bloodstream, effectively lowering lithium levels. This is a crucial intervention in managing lithium toxicity.

D. Lumbar puncture (option D) is typically performed in the context of cerebrospinal fluid (CSF) studies, not in treating lithium toxicity. It is not a suitable method for removing lithium from the blood or treating the renal dysfunction associated with lithium toxicity.

**Clinical Pearl:** Hemodialysis is the primary method for treating lithium toxicity, ensuring the removal of excess lithium from the bloodstream, while avoiding other methods like hyperventilation, activated charcoal, or lumbar puncture.

**Correct Answer:** D (Lumbar Puncture)