Cramping

Etiology

  • Approximately 20% of dialysis sessions are accompanied by muscle cramps1
  • Cramps are more pronounced in patients who require high ultrafitration rates and are possibly dialyzed below their dry weight. They are presumably related to reduction in muscle perfusion that occurs in response to hypovolemia.  Compensatory vasoconstrictive responses may shunt blood centrally during treatment, and could play a role in promoting muscle cramps.
  • Changes in intra or extracellular balance of potassium and concentration of ionized calcium can disturb neuromuscular transmission and produce cramps.
  • Peripheral vascular disease, although common in dialysis patients, may not be associated with increased prevalence of intradialytic cramps2 which confirms that processes related to the dialytic treatment are responsible for the cramps.

Differential Diagnosis

While the majority of cramps are associated with dialysis treatment, the differential diagnosis is extensive and includes the following conditions:

  • Changes in intra or extracellular balance of potassium and concentration of ionized calcium can disturb neuromuscular transmission and produce cramps
  • Idiopathic cramps
  • Contractures (occurring in conditions such as metabolic myopathies, and thyroid disease)
  • Tetany (due to hypocalcemia or alkalosis)
  • Dystonias (occupational cramps, anti-psychotic medications)
  • Other leg problems such as restless leg syndromes and periodic leg movements, must be distinguished from cramps3

Treatment and Prevention

  • Many of the treatment strategies are similar to those used to treat intradialytic hypotension
  • Physical maneuvers such as massage of the calf muscles and dorsiflexion of the foot are not very helpful
  • Immediate treatment is to increase intravascular volume by interrupting or slowing ultrafiltration and administering saline, mannitol or glucose. In addition to effecting an intravascular shift of water, hypertonic solutions may directly improve blood flow to the muscles.
  • Use of dialysate sodium, potassium or calcium modeling.  The concept of individualization of dialysate composition seems to be a good preventive method.
  • Careful reassessment of the dry weight, counseling the patient to reduce interdialytic weight gain and using bicarbonate dialysis
  • Carnitine4,  quinine5, prazocin, vitamin E, vitamin C and Japanese herbal extract have been tested with variable results

References:

  1. Wilkinson R, Barber SG, Robson V. Cramps, thirst and hypertension in hemodialysis patients — The influence of dialyzate sodium concentration. Clin Nephrol 7:101-105, 1977
  2. Brass EP, Adler S, Sietsema K, Amato A, Esler A, Hiatt WR. Peripheral arterial disease is not associated with an increased prevalence of intradialytic cramps in patients on maintenance hemodialysis. Am J Nephrol 22:491-496, 2002
  3. Riely JD, Antony SJ. Leg cramps: Differential diagnosis and management. Am Fam Physician 52:1794-1798, 1995
  4. Ahmad S. L-carnitine in dialysis patients. Semin Dial 14:209-217, 2001 Review.
  5. Mandal AK, Abernathy T, Nelluri SN, Stitzel V. Is quinine effective and safe in leg cramps? J Clin Pharmacol  35:588-593, 1995