Management of Cramps in Hemodialysis Patients
Reduce dialysate temperature to 34-35°C and administer hypertonic saline (23.4% NaCl) for acute cramps, while implementing preventive strategies including slower ultrafiltration rates, increased dialysate sodium, and midodrine pretreatment for recurrent cases. 1, 2
Immediate Treatment of Active Cramps
When a patient develops muscle cramps during dialysis, the most effective acute intervention is administering hypertonic saline (23.4% NaCl) as an intravenous bolus, which rapidly reverses the plasma and muscle cell hypo-osmolality that triggers cramping 2, 3. This approach relieves cramps quickly without compromising ultrafiltration or putting the patient at risk 2.
Additional acute measures include:
- Place patient in Trendelenburg position to improve venous return 4
- Administer supplemental oxygen during cramping episodes to alleviate symptoms 1
- Temporarily reduce or stop ultrafiltration if cramps are associated with hypotension 4
Preventive Dialysis Prescription Modifications
Temperature Management
Lower dialysate temperature from 37°C to 34-35°C to increase peripheral vasoconstriction and prevent cramps 1, 5. This intervention is effective even in patients with excessive weight gains 5. However, monitor for symptomatic hypothermia, which occurs in some patients and may range from mild to intolerable 5, 1.
Ultrafiltration Rate Optimization
Extend treatment time to reduce ultrafiltration rate below 6 mL/h/kg 6. The American Journal of Kidney Diseases emphasizes that excessive ultrafiltration rates exceed vascular refilling capacity and trigger both hypotension and cramps 6. For patients with large interdialytic weight gains, consider isolated ultrafiltration sessions 1.
Sodium Management
Increase dialysate sodium concentration to 148 mEq/L, particularly early in the dialysis session 1, 4. Implement sodium profiling with higher sodium concentrations at treatment initiation and gradual reduction throughout the session to maintain vascular stability 1, 4. Be vigilant for side effects including increased thirst, interdialytic weight gain, and hypertension 1, 4.
Pharmacological Interventions
Midodrine for Prevention
Administer midodrine 30 minutes before dialysis initiation to increase peripheral vascular resistance and enhance venous return 1, 5. This α1-adrenergic agonist reduces hypotensive events and associated cramps, with comparable hemodynamic benefits to hypothermic dialysis 5. The medication is well-tolerated with few side effects 5.
Baclofen for Persistent Cramps
For patients with persistent muscle cramps despite other interventions, prescribe baclofen starting at 10 mg/day with weekly increases up to 30 mg/day 1. This muscle relaxant addresses the underlying tonic muscle activity that increases throughout dialysis in patients prone to cramping 7.
Avoid Quinine
Do not use quinine sulfate, as the FDA has ordered cessation of marketing for unapproved formulations and advised against off-label use for cramps 8.
Anemia Correction
Raise hemoglobin to levels recommended by NKF-K/DOQI guidelines (approximately 11 g/dL) to improve oxygen-carrying capacity and reduce cramp frequency 1, 5. This strategy is particularly beneficial for patients with cardiovascular or respiratory disease 5.
Patient Behavioral Modifications
Counsel patients to avoid food intake immediately before or during hemodialysis, as eating causes decreased peripheral vascular resistance that may precipitate both hypotension and cramps 5, 4.
Ensure appropriate fluid intake limitation between sessions to reduce interdialytic weight gain and prevent the need for aggressive ultrafiltration 5, 6.
Engage patients in education about adherence to the complete prescribed dialysis session, as premature termination due to cramps results in inadequate dialysis delivery and worse outcomes 1.
Medication Review
Individually evaluate antihypertensive medications in problematic patients, as the literature shows contradictory findings regarding their contribution to intradialytic cramps and hypotension 5. While some studies demonstrate strong correlations, others do not 5.
Alternative Physical Interventions
For select patients with recurrent lower extremity cramps, consider sequential compression devices applied to both legs at 40 mmHg during treatment to improve venous return and prevent stagnant venous flow 9. This noninvasive approach showed complete resolution of cramping in a small case series 9.
Critical Monitoring Points
- Assess for symptomatic hypothermia when using cooler dialysate, as this limits tolerability in some patients 1
- Monitor interdialytic weight gain and blood pressure when using higher sodium dialysate 1
- Evaluate nutritional status, as poor nutrition may contribute to cramping 1
- Ensure dialysis adequacy and complete prescribed sessions to prevent complications 1