G44.321Chronic post-traumatic headache, intractable

G44.321 is the ICD-10-CM diagnosis code for chronic post-traumatic headache, intractable. It belongs to category G44 (other headache syndromes), block G40-G47 (episodic and paroxysmal disorders) and chapter 6 (diseases of the nervous system). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.

Within G44.32 (chronic post-traumatic headache), G44.321 is specifically for chronic post-traumatic headache, intractable. Related codes cover not intractable (G44.329).

It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.

In MS-DRG v44.0, it is part of the grouping logic for DRG 102 (Headaches with MCC, relative weight 1.1201) and DRG 103 (Headaches without MCC, relative weight 0.822), in MDC 01 (Diseases and Disorders of the Nervous System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.

It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.

Before ICD-10, this condition was coded in ICD-9-CM as 339.22 (chronic post-traumatic headache).