June 18, 2013

Migraines in ICD-10: Avoiding Big Headaches

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A migraine is a common neurological disorder that often manifests as a serious headache. Usually unilateral and pulsating in nature, the headache results from abnormal brain activity along nerve pathways and brain chemical (neurotransmitter) changes. These affect blood flow in the brain and surrounding tissue and may trigger an "aura" or warning sign (visual, sensory, language, motor, etc.) before the onset of pain.

Migraine headaches frequently are accompanied by autonomic nervous system symptoms, such as nausea, vomiting, and sensitivity to light and/or sound. Triggers can include caffeine withdrawal, stress, lack of sleep, smoking, missed meals, certain foods, loud noises and bright lights.

Migraine variants usually affect children and young adults. The neurological disorder also can result in  symptoms other than a headache. These symptoms can include prolonged visual aura, atypical auras, confusion, abdominal pain, cyclic vomiting, vertigo, hemiplegia/hemiparesis and dysarthria (speech problems).

In ICD-10-CM, migraines are classified to category G43, with 12 four-character subcategories for the following:

G43.0- Migraine without aura

G43.1- Migraine with aura

G43.4- Hemiplegic migraine

G43.5- Persistent migraine aura without cerebral infarction

G43.6- Persistent migraine aura with cerebral infarction

G43.7- Chronic migraine without aura

G43.A- Cyclical vomiting

G43.B- Ophthalmoplegic migraine

G43.C- Periodic headache syndromes in child or adult

G43.D- Abdominal migraine

G43.8- Other migraine

G43.9- Migraine unspecified

Migraine codes have fifth characters that further differentiate the condition as not intractable (0) or intractable (1). When reviewing documentation, the following terms are considered to be equivalent to intractable: pharmacoresistant, pharmacologically resistant, treatment resistant, refractory, medically refactory, and poorly controlled. And migraine codes, except codes for some migraine variants (G43.A-, G43.B-, G43.C-, and G43.D-), also can have a sixth character that identifies the migraine as occurring with status migrainosus (1) or without status migrainosus (9). Status migrainosus refers to a migraine that has lasted more than 72 hours.

It should be noted that lower-half migraine and migrainous neuralgia are terms that refer not to migraines in category G43, but to cluster headache syndrome. These are reported with codes in category G44.

Conditions that may cause or be associated with migraines should be reported additionally. Migraines can represent an adverse effect of some drugs; drugs that are known to trigger migraines include nitroglycerine and oral contraceptives. So a migraine without aura, not intractable, without status migrainosus, diagnosed as an adverse effect of nitroglycerin (initial visit) would require two codes: G43.009 for the migraine and T46.3x5A Adverse effect of coronary vasodilators.

Migraines with aura rarely may be complicated by a seizure. According to the International Headache Society, for a diagnosis of migraine seizure, the seizure must occur within one hour of the onset of the aura. To report this condition, the appropriate code from subcategory G43.1- is assigned with a code for the seizure – which, depending on the diagnosis, could be either a code from category G40 Epilepsy and recurrent seizures, or code R56.9 Unspecified convulsions.

Codes for persistent migraine aura with cerebral infarction (G43.6-) require an additional code from category I63 for the cerebral infarction. For menstrual migraines (G43.82-, G43.83-), an additional code is required for associated premenstrual tension syndrome (N94.3).

About the Author

Lauri Gray, RHIT, CPC, has worked in the health information management field for 30 years. She began her career as a health records supervisor in a multi-specialty clinic. Most recently she has worked as a clinical technical editor of coding and reimbursement print and electronic products. She has also taught medical coding at the College of Eastern Utah. Areas of expertise include: ICD-10-CM, ICD-10-PCS, ICD-9-CM diagnosis and procedure coding, physician coding and reimbursement, claims adjudication processes, third-party reimbursement, RBRVS and fee schedule development. She is a member of the American Academy of Professional Coders (AAPC) and the American Health Information Management Association (AHIMA).

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