National Sleep Foundation

Chapter 7: Sleep-Related Movement Disorders

Assessment and Diagnosis of Sleep-Related Leg Cramps

Diagnosis is made based on patient history of nocturnal leg cramps that include sudden, involuntary muscle tightening and/or hardness, which can be relieved by forcefully stretching the muscles.62 It is important to differentiate Sleep-Related Leg Cramps from other conditions, such as Restless Legs Syndrome, Periodic Limb Movement Disorder, or peripheral neuropathy.63

References 

62 Allen RE, Kirby KA, “Nocturnal Leg Cramps,” Am Fam Physician. 2012 Aug 15;86(4):350-355.
63 Monderer RS, Wu WP, Thorpy MJ, “Nocturnal leg cramps,” Curr Neurol Neurosci Rep. 2010 Jan;10(1):53-9.