ICD-10 Code G46.5 – Pure Motor Lacunar Syndrome (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G46.5 – Pure motor lacunar syndrome
What it is
Pure motor lacunar syndrome is a small-vessel stroke syndrome that causes weakness on one side of the body without major sensory loss, language problems, or visual field deficits. It reflects a lacunar infarct in a deep brain pathway.
Clinical signs
Typical findings include unilateral face, arm, and leg weakness, often with dysarthria. Clinical features vary; refer to documentation if the record does not clearly describe a pure motor deficit pattern.
When to use this code
Use G46.5 when the provider documents pure motor lacunar syndrome or a lacunar stroke with isolated motor weakness. Apply it when the note supports a stroke syndrome rather than a vague history of weakness. Check documentation if the diagnosis is uncertain or if another stroke type is specified.
Do not use for
Do not use this code for generalized weakness, hemiplegia without a stroke syndrome, or sensory-only lacunar presentations. Do not assign it when the chart identifies a different cerebrovascular syndrome. Check documentation.
Coding tip
Code G46.5 only when the provider links the motor deficit to a lacunar stroke syndrome.