Investigations
1st investigations to order
clinical diagnosis
Test
The diagnosis of MOH is clinical.[1]
If you suspect MOH based on the history, ask the patient to keep a headache diary or calendar.[10][30] This is a key tool to quantify headache frequency, intensity, and use of acute medication and thereby confirm that the diagnostic thresholds for MOH have been reached.[1]
Make a diagnosis of MOH if the patient meets all three of the criteria set out in the 2018 International Classification of Headache Disorders (ICHD-3):[1]
Headache on ≥15 days per month on a background of a pre-existing primary headache disorder.
Regular overuse for >3 months of acute treatments (at any dose) for the pre-existing headache disorder. Overuse is defined by: use of simple analgesics on ≥15 days per month (paracetamol, aspirin, or other non-steroidal anti-inflammatory drug [NSAID], alone or in any combination); or use of a triptan, opioid, or ergot derivative on ≥10 days per month; or use of a combination of analgesics from different classes on ≥10 days per month.
No other ICHD-3 headache diagnosis better accounts for the symptoms.
There are no specific neuroimaging studies, blood tests or biomarkers needed to confirm the diagnosis. Such investigations are only indicated if there are red flags or other symptoms or signs that indicate the need to rule out an alternative diagnosis.[45]
Result
fulfils the ICHD-3 criteria
Investigations to consider
MRI brain
Test
Neuroimaging is not needed for patients who meet the ICHD-3 diagnostic criteria for MOH and have no red flags in their history or examination.[1][45]
MRI (either without contrast, or both without and with contrast) is the recommended investigation for most patients with secondary headache who have one or more red flags (e.g., history of cancer; headache aggravated by postural changes or Valsalva manoeuvre; papilloedema).[45] It is also recommended for any child with a secondary headache.[45]
Result
normal in MOH; otherwise may indicate an alternative cause for the secondary headache
CT brain
Test
Neuroimaging is not needed for patients who meet the ICHD-3 diagnostic criteria for MOH and have no red flags in their history or examination.[1][45]
CT without contrast may be appropriate if intracranial hypertension is suspected or there are other red flags (e.g., neurological deficits, or a history of cancer or immunocompromise).[45]
Result
normal in MOH; otherwise may indicate an alternative cause for the secondary headache
CRP/erythrocyte sedimentation rate (ESR)
Test
Laboratory tests are not needed for patients who meet the ICHD-3 diagnostic criteria for MOH and have no red flags in their history or examination.[1][45]
Check inflammatory markers (CRP and ESR) if there are any red flags to indicate suspicion for giant cell arteritis or systemic infection.
Result
normal in MOH; if elevated, may indicate an alternative diagnosis (e.g., giant cell arteritis, infection)
lumbar puncture (LP)
Test
Investigations are not needed for patients who meet the ICHD-3 diagnostic criteria for MOH and have no red flags in their history or examination.[1][45]
High opening cerebrospinal fluid (CSF) pressure may suggest the presence of idiopathic intracranial hypertension (also known as pseudotumor cerebri), while low CSF pressure may indicate intracranial hypotension.
May also be considered if an infective cause is suspected.
Result
normal in MOH; otherwise may indicate an alternative cause for the secondary headache
cerebrospinal fluid (CSF) culture
Test
Investigations are not needed for patients who meet the ICHD-3 diagnostic criteria for MOH and have no red flags in their history or examination.[1][45]
If there is suspicion for a systemic or central nervous system infection, culture and microscopy of CSF may identify the infecting micro-organism.
Result
normal in MOH; otherwise may indicate an alternative cause for the secondary headache
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