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G44.81 ICD-10-CM Code: Hypnic headache

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Inpatient Payment Groups (MS-DRG)

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0, Appendix B.

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Official Registry Overview & Definition

Hypnic headache is a billable ICD-10-CM diagnosis code (G44.81).

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for G44.81 in the official ICD-10-CM tabular list.

Excludes1 — Not Coded Here

Conditions generally not reported together with this code (Excludes1) -- an error unless the two conditions are documented as unrelated to each other (ICD-10-CM Official Guidelines, Section I.A.12.a).

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Indexed Clinical Terms (1)

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code.

  • Headache, hypnic

Frequently Compared Codes

The official Excludes notes on G44.81 name these codes. Each comparison page covers when the two can — or must not — be reported together.

Change history

No changes recorded for this code — unchanged since the FY2016 baseline of the change ledger.

Verify Before Coding

  • No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim.

Relationships & Classification

Other codes that name G44.81 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

3 Excludes2 notes: G43 (via G44.-), G44.1 (via G44.8.-), G89 (via G44.-).

Potential MS-DRG Relationships (FY2026)

Not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity.

Named in the grouper logic of 2 MS-DRGs: DRG 102 (MDC 01), DRG 103 (MDC 01).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):NVS010 — Headache; including migraine (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Headache; including migraine).

G44.309 — Post-traumatic headache, unspecified, not intractable, G44.311 — Acute post-traumatic headache, intractable, G44.319 — Acute post-traumatic headache, not intractable, G44.321 — Chronic post-traumatic headache, intractable, G44.329 — Chronic post-traumatic headache, not intractable, G44.40 — Drug-induced headache, not elsewhere classified, not intractable, G44.41 — Drug-induced headache, not elsewhere classified, intractable, G44.51 — Hemicrania continua, G44.52 — New daily persistent headache (NDPH), G44.53 — Primary thunderclap headache, G44.59 — Other complicated headache syndrome, G44.82 — Headache associated with sexual activity, G44.83 — Primary cough headache, G44.84 — Primary exertional headache, G44.85 — Primary stabbing headache, G44.86 — Cervicogenic headache, G44.89 — Other headache syndrome, R51 — Headache, R51.0 — Headache with orthostatic component, not elsewhere classified, R51.9 — Headache, unspecified, +70 more

Contextual Map

Every relationship of G44.81 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

  • G00-G99 — Chapter 6: Diseases of the Nervous System (G00-G99) (G00-G99) [Hierarchy]

Referenced by Excludes2 notes

  • G43 — Migraine [Excludes2](via G44.-): “headache syndromes (G44.-)” · check together
  • G44.1 — Vascular headache, not elsewhere classified [Excludes2](via G44.8.-): “other specified headache syndromes (G44.8-)” · check together
  • G89 — Pain, not elsewhere classified [Excludes2](via G44.-): “headache syndromes (G44.-)” · check together

Clinical classification (CCSR)

  • NVS010 — Headache; including migraine [CCSR]

Potential MS-DRG

  • DRG 102 — HEADACHES WITH MCC [MS-DRG]: “HEADACHES WITH MCC (MDC 01)”
  • DRG 103 — HEADACHES WITHOUT MCC [MS-DRG]: “HEADACHES WITHOUT MCC (MDC 01)”

MDC crossing · procedures (8892)

  • MDC 01 — Diseases and Disorders of the Nervous System [MDC crossing]: “Diseases and Disorders of the Nervous System — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs.”
  • 0016070 — Bypass Cerebral Ventricle to Nasopharynx with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Nasopharynx with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016071 — Bypass Cerebral Ventricle to Mastoid Sinus with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Mastoid Sinus with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016072 — Bypass Cerebral Ventricle to Atrium with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Atrium with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016073 — Bypass Cerebral Ventricle to Blood Vessel with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Blood Vessel with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • 0016074 — Bypass Cerebral Ventricle to Pleural Cavity with Autologous Tissue Substitute, Open Approach [Same-MDC procedure]: “Bypass Cerebral Ventricle to Pleural Cavity with Autologous Tissue Substitute, Open Approach — grouped in MDC 01, the procedure side of this code's crossing.” · check together
  • and 8887 more

Index entries

  • Headache, hypnic[Index term]

Nearest codes (40)

  • G44 — Other headache syndromes [Sibling]
  • G44.059 — Short lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), not intractable [Sibling]
  • G44.09 — Other trigeminal autonomic cephalgias (TAC) [Sibling]
  • G44.091 — Other trigeminal autonomic cephalgias (TAC), intractable [Sibling]
  • G44.099 — Other trigeminal autonomic cephalgias (TAC), not intractable [Sibling]
  • G44.1 — Vascular headache, not elsewhere classified [Sibling]
  • G44.2 — Tension-type headache [Sibling]
  • G44.20 — Tension-type headache, unspecified [Sibling]
  • and 32 more

Nearest Codes in This Family

Official ICD-10-CM classifications closest to G44.81 in its code family, with their registry titles.

  • G44.51 — Hemicrania continua
  • G44.52 — New daily persistent headache (NDPH)
  • G44.53 — Primary thunderclap headache
  • G44.59 — Other complicated headache syndrome
  • G44.8 — Other specified headache syndromes
  • G44.82 — Headache associated with sexual activity
  • G44.83 — Primary cough headache
  • G44.84 — Primary exertional headache
  • G44.85 — Primary stabbing headache
  • G44.86 — Cervicogenic headache

View all codes in the G44 family