Neurology & Pain Management Coding Alert

Don’t overlook the possibility for newborns. 

Myasthenia gravis is a chronic autoimmune neuromuscular disease characterized by weakness and rapid fatigue of any of the muscles under your voluntary control (especially the eyes, throat, mouth, and limbs). When the condition affects multiple muscle groups throughout the body, it’s known as generalized myasthenia gravis. 

ICD-9 includes two diagnoses for myasthenia gravis in adults, based on whether the patient experiences acute exacerbation: 

• 358.00 – Myasthenia gravis without (acute) exacerbation 
• 358.01 – Myasthenia gravis with (acute) exacerbation. 

The patient will always carry the myasthenia gravis diagnosis, but the exacerbation could be present at one visit and not the next. 

When you begin using ICD-10 in October, your diagnosis choices for myasthenia gravis will remain the same. You’ll make a direct shift to G70.00 for myasthenia gravis without acute exacerbation, or G70.01 for the condition with acute exacerbation. 

Extra code: An additional diagnosis will apply to patients with a congenital form of the condition: G70.2 (Congenital and developmental myasthenia). 

A corresponding diagnosis for congenital myasthenia gravis is not found in ICD-9. 

Neonatal note: Babies can also be diagnosed with myasthenia gravis, which you currently report with 775.2 (Neonatal myasthenia gravis). This diagnosis will change to P94.0 (Transient neonatal myasthenia gravis) in ICD-10. 

Explanation: Transient neonatal myasthenia gravis occurs in 10 to 15 percent of infants born to women with myasthenia gravis. The symptoms appear a few hours after the birth in two-thirds of babies and usually disappear within 18 days. Sucking, swallowing and respiratory difficulties are the most common symptoms.  The condition generally resolves spontaneously, but supportive management and administration of medication prior to feedings is sometimes necessary until the condition resolves.

Terminology:  The name myasthenia gravis, which is Latin and Greek in origin, literally means “grave muscle weakness.” The disease is caused by a defect in the transmission of nerve impulses from the nerve to the muscle it innervates. Often the condition is more pronounced in muscles that control eye and eyelid movement, facial expression, chewing, talking and swallowing.