Differentiating nocturnal leg cramps and restless legs syndrome

Abstract

Leg pain and discomfort are common complaints in any primary physician’s clinic. Two common causes of pain or discomfort in legs are nocturnal leg cramps (NLC) and restless leg syndrome (RLS). NLC present as painful and sudden contractions mostly in part of the calf. Diagnosis of NLC is mainly clinical and sometimes involves investigations to rule out other mimics. RLS is a condition characterized by the discomfort or urge to move the lower limbs, which occurs at rest or in the evening/night. The similarity of RLS and leg cramps poses the issue of errors in diagnosing and differentiating the two. In this paper we review the pathopysiology of each entity and their diagnosis as well as treatment. The two conditions are then compared to appreciate the differences and similarities. Finally, suggestions are recommended for complete assessment.

Keywords::

• movement disorder
• nocturnal leg cramp
• periodic limb movement
• restless leg syndrome
• willis ekbom disease

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Leg pain and discomfort are common complaints in any family physician’s clinic.

• The similarity of restless leg syndrome (RLS) and leg cramps poses a dilemma in diagnosing and differentiating the two.

• Although RLS and nocturnal leg cramps (NLC) both pose the risk of fulfilling the criteria for diagnosis as defined by the International RLS study group, there are a few key features that may help to differentiate the two.

• RLS symptoms are mainly apparent in rest as they are initiated during rest and not a specific limb position.

• The discomfort felt by RLS is at least partially or completely relieved by movement and not a simple change in posture.

• RLS sensations are also differentiated from NLC sensations as they involve deep inner sensations versus painful muscle contractions, respectively.

• NLC sensations usually involve pain and the feeling of muscle tightening, whereas RLS sensations are rather hard for patients to describe and have been called ‘creepy, crawly, tingly or a deep ache’.

• Sleep dysfunction is a key consequence of the symptoms of RLS. When RLS is suspected, more specific questions should be asked. The Hopkins telephone diagnostic interview provides additional probing questions beyond the four basic RLS criteria that can help in differentiating RLS from mimics like NLC.

• Patient history is important in revealing important differentiating criteria, and primary care physicians play an important role in rightly diagnosing and treating NLC and RLS.