ICD Body System
Diseases of the nervous system and sense organs [320 - 389]
Date amended:
External
Statements of Principles
Current RMA Instruments

Reasonable Hypothesis SOP

57 of 2018

Balance of Probabilities SOP

58 of 2018

Changes from previous Instruments

ICD Coding
  • ICD-9-CM Codes: 346.2
  • ICD-10-AM Codes: G44.0
Brief description

Cluster headache manifests as unilateral, typically severe headache attacks, occurring in clusters.  In the episodic form attacks occur over a period of weeks followed by a remission that may last for months.  There is also a chronic form, without significant remission periods.  Attacks are typically accompanied by autonomic symptoms (usually involving the eye, nose or facial skin).  Whilst rare, cluster headache is the most common form of a group of headache entities, known as the trigeminal autonomic cephalalgias.

Confirming the diagnosis

This diagnosis is made on clinical grounds, using diagnostic criteria.  Neuroimaging is not required (but may be undertaken to exclude a cranial lesion) and other tests are not diagnostically helpful.  Specialist opinion will generally be required.

The relevant medical specialist is a neurologist.

Additional diagnoses that are covered by SOP
  • Cluster headache following head trauma
  • Histamine cephalgia
  • Horton’s neuralgia
Conditions that are excluded from SOP
  • Headaches due to intracranial structural anomalies - code to anomaly
  • Headaches due to systemic disease - code to underlying disease
  • Hemicrania continua #
  • Migraine*
  • Paroxysmal hemicrania#
  • Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) #
  • Short-lasting unilateral neuralgiform headache attacks with cranial autonomic symptoms (SUNA) #
  • Trigeminal neuralgia*

* another SOP applies

# non-SOP condition

Clinical onset

Clinical onset will be based on when typical cluster headache symptoms, as per the SOP definition, first manifest.   

Clinical worsening

Cluster headache is an enduring condition in most patients.  Preventive therapies can suppress attacks over the duration of a cluster period.  Therapies aimed at preventing onset of cluster episodes are generally ineffective. Worsening may be evidenced by an increase in the frequency, severity or duration of cluster episodes.