Diagnosis of Muscular Spasm
The diagnosis for muscular spasm depends entirely on the anatomical location and underlying etiology—coronary artery spasm is diagnosed as variant angina (Prinzmetal's angina), cricopharyngeal spasm is coded under esophageal disorders, and skeletal muscle spasm secondary to upper motor neuron lesions requires coding the primary neurologic condition first with M62.838 as a secondary diagnosis. 1
Context-Specific Diagnostic Terminology
The term "muscular spasm" is not a single diagnosis but rather a clinical finding that requires anatomical and etiological specification:
Coronary Artery Spasm
- Variant angina (Prinzmetal's angina) is the formal diagnosis when coronary artery spasm occurs 2
- Diagnosis requires documentation of ST-segment elevation during transient chest discomfort that resolves when symptoms abate 2
- Typically occurs at rest in early morning hours and responds exquisitely to nitroglycerin 2
- Requires cardiovascular system codes, not musculoskeletal codes 1
Skeletal Muscle Spasm from Neurologic Disease
- Code the underlying neurologic condition first (e.g., I63.9 for cerebral infarction in stroke patients) 1
- Add M62.838 as secondary diagnosis for the resulting muscle spasm 1
- Common in upper motor neuron lesions including stroke, multiple sclerosis, tumors, and trauma 3
Cricopharyngeal Spasm
- Coded distinctly under esophageal disorders when causing dysphagia 1
- Related to proximal muscle dysfunction and can be evident on videofluoroscopy 2
Distinguishing True Muscle Cramps from Other Conditions
True Muscle Cramps
- Painful, sudden, involuntary muscle contractions that are generally self-limiting 4
- Originate from peripheral nerves 5
- Can be exercise-induced, idiopathic, or symptomatic of underlying disease 4
Muscle Contractures (Not True Cramps)
- Defined as shortening of muscle resulting in inability to relax normally 4
- Generally myogenic in origin 4
- Electromyographically silent, unlike true cramps 6
- Example: Brody's disease 6
Clinical Pitfalls
Critical distinction: Coronary artery spasm must never be coded with musculoskeletal codes—this represents a fundamentally different pathophysiologic process requiring cardiovascular coding 1. Similarly, catheter-induced spasm during angiography is not an indicator of vasospastic disease and should not be diagnosed as variant angina 2.
The diagnosis of muscular spasm requires identifying the specific anatomical location and underlying cause rather than using a generic "muscle spasm" diagnosis 1.