A 28-year-old woman with first-episode psychosis is started on risperidone 4 mg daily. After 2 weeks, she develops severe restlessness, inability to sit still, and an overwhelming urge to move her legs. She denies suicidal or homicidal ideation, and her psychotic symptoms are improving. Vital signs are normal. What is the most likely diagnosis and the most appropriate management?

Explanation

## Diagnosis: Akathisia **Key Point:** Akathisia is an acute extrapyramidal side effect characterized by subjective restlessness, inability to sit still, and an irresistible urge to move. It occurs within days to weeks of starting or increasing antipsychotics and is distressing but not life-threatening. ### Clinical Presentation of Akathisia - **Subjective:** inner restlessness, anxiety, sense of impending doom - **Objective:** inability to sit still, pacing, leg movements, fidgeting - **Onset:** acute, within 1–4 weeks of antipsychotic initiation or dose increase - **Key feature:** Patient is aware of the abnormal sensation (unlike other EPS) ### Differential Diagnosis: Acute EPS | Condition | Onset | Features | Vital Signs | Management | |-----------|-------|----------|-------------|-------------| | **Akathisia** | Days–weeks | Restlessness, urge to move, anxiety | Normal | Reduce dose, β-blocker, benzodiazepine | | **Acute dystonia** | Minutes–hours | Muscle spasm, torticollis, oculogyric crisis | Normal | Anticholinergic (benztropine) | | **Parkinsonism** | Days–weeks | Tremor, rigidity, bradykinesia | Normal | Anticholinergic or reduce dose | | **NMS** | Days–weeks | Fever (>38.5°C), rigidity, altered mental status, ↑CK | **Abnormal** | **Discontinue, ICU, supportive care** | **High-Yield:** Akathisia is often mistaken for anxiety or worsening psychosis and may lead to non-compliance. It is NOT relieved by anticholinergics (unlike acute dystonia/parkinsonism). ### Management Algorithm ```mermaid flowchart TD A["Acute restlessness + urge to move<br/>within 1-4 weeks of antipsychotic"]:::outcome A --> B{"Vital signs normal?<br/>No fever, rigidity, ↑CK?"}:::decision B -->|Yes| C["Likely Akathisia"]:::outcome B -->|No| D["Rule out NMS"]:::urgent C --> E["Step 1: Reduce antipsychotic dose"]:::action E --> F["Step 2: Add propranolol 20-40 mg TDS<br/>or benzodiazepine"]:::action F --> G["Step 3: If severe, switch to SGA<br/>with lower akathisia risk"]:::action D --> H["Discontinue antipsychotic,<br/>ICU admission, supportive care"]:::urgent ``` **Clinical Pearl:** Propranolol (β-blocker) is the most effective pharmacological treatment for akathisia, working via unknown mechanism (not purely sympathetic). Doses: 20–40 mg three times daily. **Mnemonic: "AKATHISIA = RESTLESS" - **A**cute onset - **K**eeps moving (inability to sit) - **A**nxiety, agitation - **T**reatment: reduce dose, **β-blocker** - **H**ours to weeks (onset) - **I**nner urge to move - **S**ubjective sensation - **I**mmediate relief with propranolol - **A**ntipsychotic-induced **Warning:** Do NOT give anticholinergics for akathisia—they are ineffective and may worsen it. Anticholinergics are for acute dystonia/parkinsonism, not akathisia. [cite:KD Tripathi 8e Ch 12; Harrison 21e Ch 387]