Differential Diagnosis for Restless Legs Syndrome
The differential diagnosis for restless legs syndrome includes leg cramps, venous stasis, peripheral neuropathy, vascular disease (intermittent claudication), arthritis, positional discomfort, muscle aches (myalgia), leg edema, neuroleptic-induced akathisia, radiculopathy, venous varicosities, and habitual foot tapping. 1, 2
Primary Mimics That Must Be Excluded
The most critical conditions to differentiate from RLS are those that can superficially meet all four diagnostic criteria but represent distinct pathology:
Venous Stasis
- This is a critical mimic, particularly in patients with prolonged standing history 2
- Look for visible varicosities, dependent edema, and skin changes consistent with chronic venous insufficiency 1
- Unlike RLS, venous stasis symptoms typically improve with leg elevation rather than movement 2
Peripheral Neuropathy
- Perform a thorough neurological examination to identify sensory deficits, diminished reflexes, or radiculopathy 1, 2
- Small fiber neuropathy can trigger RLS or mimic its symptoms 3
- The physical examination may reveal abnormalities in neuropathy, whereas primary RLS typically has a normal neurological exam 1
Vascular Disease (Intermittent Claudication)
- Claudication pain is exercise-induced and relieved by rest, the opposite pattern of RLS 1
- Check for diminished peripheral pulses and vascular bruits 1
Arthritis
- Joint-specific pain with tenderness on palpation distinguishes arthritis from RLS 1
- Arthritis pain is typically localized to joints rather than the diffuse leg discomfort of RLS 1
Additional Conditions in the Differential
Leg Cramps
- Cramps are sudden, painful muscle contractions that are distinct from the urge to move in RLS 1
- Cramps typically resolve spontaneously or with stretching, whereas RLS requires sustained movement 1
Neuroleptic-Induced Akathisia
- Akathisia involves a generalized urge to move the whole body, not just the legs 1, 3
- Akathisia lacks the uncomfortable leg sensations characteristic of RLS 3
- Medication history is critical—look for antipsychotic or antidepressant use 3
Positional Discomfort and Muscle Aches (Myalgia)
- These conditions lack the circadian pattern of RLS (evening/nighttime worsening) 1
- Positional discomfort resolves with position change alone, not requiring sustained movement 1
Leg Edema
- Edema presents with visible swelling and pitting on examination 1
- Unlike RLS, edema-related discomfort does not follow a circadian pattern 1
Radiculopathy
- Radiculopathy typically follows a dermatomal distribution with positive straight leg raise or other provocative maneuvers 1
- Pain radiates from the back down the leg in a specific nerve root pattern 1
Habitual Foot Tapping
- This is a behavioral pattern without the uncomfortable sensations or urge to move that characterize RLS 1
- Habitual movements are voluntary and not driven by discomfort 1
Key Distinguishing Features of True RLS
To confirm RLS and exclude mimics, all five essential criteria must be met:
- Urge to move the legs, usually accompanied by uncomfortable sensations (crawling, creeping) 1, 2
- Worsening with rest or inactivity (sitting, lying down) 1, 2
- Relief with movement (walking, stretching) that persists as long as activity continues 1, 2
- Circadian pattern with evening/nighttime predominance 1, 2
- Not solely accounted for by another medical or behavioral condition 1, 2
Critical Pitfall to Avoid
Without performing a proper differential diagnosis, 16% of subjects who do not have RLS will be misclassified as having RLS if you only ask about the four symptom criteria. 1 This emphasizes why criterion #5 (excluding mimics) was formalized in the 2012 diagnostic criteria 1
Secondary Causes to Investigate
Once mimics are excluded, evaluate for secondary RLS causes: