A 52-year-old man undergoing transurethral resection of prostate (TURP) under spinal anesthesia with 3 mL of 0.5% bupivacaine receives 2 L of 1.5% glycine irrigation fluid intraoperatively. At 45 minutes post-procedure, he develops restlessness, confusion, and visual disturbances. His blood pressure is 168/95 mmHg, heart rate 102/min, and serum sodium is 118 mEq/L. What is the most appropriate immediate management?

Explanation

## Clinical Diagnosis: TURP Syndrome with Hyponatremic Encephalopathy **Key Point:** TURP syndrome is caused by excessive absorption of hypotonic irrigation fluid, leading to acute hyponatremia (Na⁺ < 120 mEq/L) and cerebral edema. Symptomatic hyponatremia with neurological signs (confusion, visual disturbances, restlessness) requires urgent hypertonic saline correction. ### Pathophysiology Glycine (and other hypotonic irrigants) absorbed systemically dilute plasma osmolality, causing water shift into the intracellular space and cerebral edema. The patient's serum Na⁺ of 118 mEq/L with acute neurological symptoms is a medical emergency. ### Management Algorithm ```mermaid flowchart TD A[TURP Syndrome Suspected]:::outcome --> B{Symptomatic?}:::decision B -->|Yes: Neuro signs| C[Measure serum Na+]:::action B -->|No: Asymptomatic| D[Fluid restriction + monitoring]:::action C --> E{Na+ < 120 & acute?}:::decision E -->|Yes| F[3% NaCl 100 mL IV bolus over 10 min]:::action E -->|No: Chronic| G[Slow correction: 10-12 mEq/L per 24 hrs]:::action F --> H[Repeat Na+ in 2-4 hrs]:::action H --> I[Target: Na+ 120-125 mEq/L acutely]:::outcome J[Seizures occur?]:::urgent --> K[Diazepam 5-10 mg IV + airway support]:::action ``` ### Rationale for 3% Hypertonic Saline | Feature | Rationale | |---------|----------| | **Concentration** | 3% NaCl creates osmotic gradient, draws water OUT of brain cells | | **Dose** | 100 mL bolus = ~15 mEq Na⁺; raises serum Na⁺ by ~2–3 mEq/L acutely | | **Speed** | Over 10 minutes to prevent central pontine myelinolysis (CPM) from overcorrection | | **Monitoring** | Recheck Na⁺ every 2–4 hours; target correction rate = 4–6 mEq/L in first 24 hrs | **High-Yield:** Symptomatic hyponatremia (Na⁺ < 120 with seizures, altered mental status, visual changes) is a **medical emergency** requiring hypertonic saline. Asymptomatic hyponatremia (Na⁺ 120–130) is managed conservatively with fluid restriction and slow correction. **Clinical Pearl:** Glycine is preferred for TURP because it is non-electrolytic (allowing monopolar resection), but it is neurotoxic if absorbed systemically. Sorbitol and mannitol are alternatives but are hyperglycemic and hyperosmolar, respectively. **Warning:** Overcorrection of hyponatremia (> 10 mEq/L per 24 hrs) risks central pontine myelinolysis, a demyelinating syndrome causing permanent neurological disability. Correct slowly unless symptomatic with seizures. ### Why NOT Mannitol Alone? Mannitol is an osmotic diuretic that can worsen hyponatremia by increasing urine output without replacing sodium. It is useful for cerebral edema in hypernatremia but is second-line here. Hypertonic saline directly corrects the osmolal gradient and is first-line for symptomatic hyponatremia.