G44.53 Primary thunderclap headache

Billable ICD-10-CM code, FY2026.

Applies from G44 Other headache syndromes

Excludes1 (never code together)

• headache NOS (R51.9)

Excludes2 (not included here)

• atypical facial pain (G50.1)
• headache due to lumbar puncture (G97.1)
• migraines (G43.-)
• trigeminal neuralgia (G50.0)

MS-DRG index

Defines the logic of DRG(s) 102-103 in MDC 01.

Approximate ICD-9-CM (GEMs)

• 339.43 Primary thunderclap headache

Code annotations containing back-references to G44.53

Back-references to G44.5

• Type 2 Excludes: G44.1 Vascular headache, not elsewhere classified ("complicated headache syndromes (G44.5-)")

Back-references to G44

• Type 2 Excludes: G43 Migraine ("headache syndromes (G44.-)")
• Type 2 Excludes: G89 Pain, not elsewhere classified ("headache syndromes (G44.-)")
• Type 2 Excludes: R51 Headache ("migraine and other headache syndromes (G43-G44)")

Diagnosis Index entries for G44.53

• Headache › primary › thunderclap
• Headache › thunderclap (primary)

Nearby codes

• G44.40 Drug-induced headache, not elsewhere classified, not intractable
• G44.41 Drug-induced headache, not elsewhere classified, intractable
• G44.5 Complicated headache syndromes
• G44.51 Hemicrania continua
• G44.52 New daily persistent headache (NDPH)
• G44.53 Primary thunderclap headache (this code)
• G44.59 Other complicated headache syndrome
• G44.8 Other specified headache syndromes
• G44.81 Hypnic headache
• G44.82 Headache associated with sexual activity
• G44.83 Primary cough headache