Hyponatremia is the Most Likely Electrolyte Abnormality Following TURP Surgery
The correct answer is D. hyponatremia, which is the most common and significant electrolyte abnormality associated with Transurethral Resection of the Prostate (TURP) surgery. 1
Pathophysiology of TURP-Related Hyponatremia
Hyponatremia occurs during TURP through a specific mechanism:
- During TURP, irrigation fluid is used to distend the bladder and wash away blood and tissue debris
- This irrigation fluid can be absorbed into the bloodstream through opened prostatic venous sinuses during resection 1
- The absorbed hypotonic irrigation fluid causes dilution of serum sodium, leading to dilutional hyponatremia
- This condition, known as "TURP syndrome," can be life-threatening when severe 2
Risk Factors for TURP Syndrome
Several factors increase the risk of developing hyponatremia during TURP:
- Prolonged resection time (especially with monopolar TURP)
- Large prostate size requiring more extensive resection
- High irrigation pressure
- Open prostatic sinuses/vessels during resection 1
- Multiple cystoscopic applications in the same session 2
Clinical Presentation
TURP syndrome with hyponatremia typically presents with:
- Neurological symptoms: confusion, dizziness, seizures, coma
- Cardiovascular symptoms: bradycardia, hypotension, hypertension
- Respiratory symptoms: hypoxemia, pulmonary edema
- Laboratory findings: serum sodium < 130 mmol/L 1, 3
Prevention Strategies
The American Urological Association guidelines recommend several approaches to reduce the risk of TURP syndrome:
- Limiting resection time, particularly with monopolar TURP 4
- Using bipolar TURP techniques which allow for longer resection times with reduced risk of hyponatremia and TURP syndrome 4
- Maintaining low irrigation pressure
- Regular monitoring of electrolytes during lengthy procedures 1
Management of TURP-Related Hyponatremia
When hyponatremia occurs:
- Immediate cessation of the procedure if symptoms develop intraoperatively
- Careful correction of hyponatremia with hypertonic saline (3% NaCl) for severe cases
- Caution to avoid too-rapid correction which can lead to central pontine myelinolysis
- Hemodynamic support with vasopressors if hypotension occurs 1, 3
Other Electrolyte Abnormalities in TURP
While hyponatremia is the primary concern, other electrolyte abnormalities may occur but are less common:
- Hyperkalemia can occasionally occur as reported in some cases 3
- Hypocalcemia has been reported but is not the primary concern 5
- Lactic acidosis may develop in severe cases, especially with certain irrigation fluids 6
Bipolar vs. Monopolar TURP
The AUA guidelines specifically note that bipolar TURP has a reduced risk of hyponatremia and TURP syndrome compared to monopolar TURP, which allows for:
- Longer resection times
- Surgery on larger prostates
- Reduced risk of complications 4
This is an important consideration when planning TURP procedures, especially for patients with larger prostates or those requiring longer resection times.