see also:

• meningitis
• the child with headache
• subarachnoid haemorrhage (SAH)
• migraine
• acute unilateral headache
• cervicogenic headache
• a diagnostic approach to the adult with acute headache
• AFTB lectures - headache

• patients with headache as a prime feature are a worrying group of patients as there are a number of potentially life threatening or morbid conditions that, although uncommon, are easily missed:
  • meningitis
  • subarachnoid haemorrhage - classically, a thunderclap onset in occipital region
  • acutely raised intracranial pressure (ICP) such as due to:
    • subdural haematoma 
      • may be chronic in the elderly after a forgotten fall; decreased mental state usually more significant than headache;
      • have a low index of suspicion in any elderly patient after a fall, especially if they are on anticoagulants such as aspirin or warfarin.
    • extradural haematoma - usually a history of trauma with LOC
    • brain tumour - frontal/vertex headache if above tentorioum; occipital headache if subtentorial; pain on wakening; worse on Valsalva;
    • intracerebral abscess (rare)
    • venous thrombosis (rare)
      • consider in pregnancy, pueperium, tamoxifen¹⁾
  • toxic metabolic headaches:
    • fever > 38.8degC
    • influenza typically presents with severe headaches and then cough
    • hypoxia or hypercapnia are potent cerebral vasodilators
    • carbon monoxide poisoning
    • acute anaemia due to blood loss
  • internal carotid artery dissection
  • vertebral artery dissection - especially after chiropractic manipulation of the neck
  • hypertensive headaches
    • a throbbing occipital headache, usually do not occur unless diastolic > 130mmHg
  • acute glaucoma:
    • orbital pain with N/V and cornea may be oedematous with pupil mid-position, decreased acuity & raised i/ocular pressure.
  • temporal arteritis
    • mainly women aged > 50yrs; this requires starting on prednisolone 60-80mg/d ASAP to prevent optic neuritis and bilateral blindness.
    • untreated, if blindness occurs in one eye, blindness will occur in the other eye within 1-20 days in 75%.
    • maintenance dose of prednisolone usually recommended for a year or more with periodic ESR to assess progress.
• the majority of patients have headaches due to less worrying conditions such as:
  • tension headache
    • chronic tension type headaches are amongst the most common form of daily headaches, often associate with stress, sleep disorders (including OSA)
    • usually frontal
    • need to exclude headache red flags
    • consider amitryptiline esp. if sleep disorder
  • cervicogenic headache
    • see non-traumatic upper neck pain
    • occurs in up to 4% of the population, and perhaps a quarter of those who have had neck trauma
    • up to 70% are due to issues with the C2-3 zygapophyseal joint (innervated by C2 and C3 which can give referred pain to occiput, fronto-temporal and perioribital regions), with the atlanto-axial joint (innervated by C1 and pain is referred to occiput) being the 2nd most common aetiologic focus
    • suggestive features include palpably painful upper cervical joints and restricted range of neck extension
    • lesions cannot be detected on either CT and MRI but these may be done to exclude other pathology
    • many patients also have tension headaches and migraine headaches
  • migraine
  • post-concussion headache
  • analgesic abuse headaches
  • post-ictal headache
  • cluster headaches:
    • mainly young adult males, recurrent, peak pain 10-15min after onset and lasts 45-60min, unilateral, excruciating, non-throbbing and usually retro-orbital with ipsilateral nasal stuffiness and lacrimation. Often nocturnal; 
    • 10min of oxygen at 5-8L/min may abort attacks in 70%
    • instillation of 4% lignocaine into ipsilateral nostril is useful
    • consider verapamil
  • sinusitis
    • BUT be aware that ~20% of patients having CT brain for headache or mild CHI will have a CT report of “chronic sinusitis” - this finding without acute URTI should probably NOT warrant Rx and is probably NOT the cause of an acute headache ²⁾
  • coital headache
    • usually severe, sudden onset headache associated with orgasm and last a few hours
    • be aware that SAH should still be excluded as SAH can occur during coitus
  • CSF leak headache
    • usually postural, worse on standing
    • most occur due to facial/head injury or iatrogenic
    • some are due to benign raised idiopathic intracranial hypertension
    • some are spontaneous and may be cranial or spinal CSF leaks
      • some are due to genetic factors
    • post-LP headaches:
      • usually starts within 48hrs (but not within 1hr) of lumbar puncture or epidural procedures although may be delayed for up to 14 days.
      • bi-cranial, pulsatile, worse in upright position and on movement, median duration is 5 days with early onset usually more severe and longer lasting.
      • see post LP headaches (PLPH)
      • Rx options - simple pain, analgesia and analgesics, methylxanthines such as caffeine, and if severe, an epidural blood patch.
      • Post-lumbar pucture headache. Shah & Thomas. Hospital Physician June 2007 (pdf)
  • high altitude - eg. non-acclimated climbers at altitudes greater than 3000-3600m
  • drug-induced
    • vasodilators such as GTN
    • even inhaled Rx for asthma such as LABA with steroids can cause headaches and nasopharyngitis
  • benign intracranial hypertension (pseudotumour cerebri) 
    • usually, young, obese female with amenorrhoea or irregular cycles or on tetracyclines; 
    • papilloedema present; CT shows slit-like ventricles and no mass effect;
  • trigeminal neuralgia - usually age > 50yrs; brief, excruciating attacks of facial pain;
  • obstructive sleep apnoea headaches - usually morning headaches
  • post-dialysis headaches may be due to:
    • electrolyte and fluid shifts:
      • large shifts in water and electrolytes during dialysis can induce headaches. This includes changes in levels of sodium, magnesium, and calcium.
    • sudden alterations in blood pressure, either intradialytic hypertension or hypotension, are significant contributors.
      • patients with higher pre-dialysis blood pressure values are more likely to experience headaches
    • caffeine withdrawal:
      • dialysis can remove caffeine from the bloodstream, leading to withdrawal symptoms, including headaches, especially in habitual caffeine consumers.
    • dialysate composition:
      • the composition of the dialysate, such as high levels of calcium or magnesium, can contribute to headaches. Acetate dialysate has also been implicated.
    • toxins in Dialysate:
      • contaminants like fluoride or chloramine in the dialysate can cause headaches
    • serotonin levels and cerebral vasoconstriction:
      • acute yet transient alterations in serotonin levels and cerebral vasoconstriction during dialysis can trigger headaches
    • renin-angiotensin-aldosterone system activation:
      • sudden drops in blood pressure can activate the renin-angiotensin system, causing vasoconstriction and contributing to headaches
    • other factors:
      • factors such as hypoxia, anaemia, and disturbances in parathyroid hormone levels have also been associated with dialysis-related headaches

• Headaches of sudden, severe onset (thunderclap) – worse than previous headache
• Headache exacerbated by coughing, sneezing or straining
• Headache provoked by postural change (stooping or bending)
• Headache associated with eye movement and blurred vision
• Headaches with new-onset neurological signs (sensory changes, weakness, diplopia, Horner’s Syndrome, visual field defects)
• Headaches associated with stiff neck, generalised aches/pains, rash, malaise, altered consciousness or confusion
• Headaches that have changed dramatically in quality, nature or site
• Headaches failing to respond to appropriate therapy

• the patient with strongly suspected bacterial meningitis:
  • urgent IV antibiotic Rx 
  • +/- IV fluid/inotrope support if evidence of septic shock - purpura, poor capillary refill or hypotension.
  • investigations such as CT and LP as time allows
• the patient with decreased mental state:
  • assessment of A,B,C's +/- airway support (eg. intubation if GCS < 8)
  • FBE, U&E, RBG, dextrostix, +/- blood cultures if high fever, +/- ABG's.
  • rapid assessment for localising neurology (eg. stroke, SAH) 
  • rapid assessment for possible sepsis with early IV antibiotics/antivirals administered if clinically indicated.
  • early CT scan once stabilised, and if normal, then LP may be indicated, although this can usually be delayed.
  • differential diagnosis includes:
    • intracranial event:
      • stroke, SAH, meningitis, encephalitis (eg HSV), brain tumour
      • intracranial thrombosis,  
      • traumatic brain injury - concussion, subdural or extradural haemorrhage
    • general conditions:
      • hypertensive encephalopathy
      • drug overdose
      • metabolic conditions - hypoglycaemia, DKA, hyperosmolar coma, hyponatraemia, hypoxia, hypercapnia
• the patient with neurologic symptoms:
  • although hemiplegic migraine may be the cause, one needs to exclude a stroke, space occupying lesion or aneurysm
  • early CT brain 
  • do not use ergotamine or sumatriptan as these vasoconstrict and may exacerbate ischaemia

• see below for indications for brain CT scan.

• thunderclap headaches are those with rapid time to peak headache intensity (seconds to five minutes)
• these patients need to have subarachnoid haemorrhage (SAH) excluded - preferably with a CT brain within 6 hours of onset
• other serious causes which usually have focal neurology include:
  • intracerebral haemorrhage
  • carotid or vertebral artery dissection
• other less serious causes include:
  • orgasm headaches
  • primary exercise headache (esp. in hot weather or at high altitude - need to consider altitude sickness or high altitude cerebral oedema in such cases)
  • primary thunderclap headache
  • trigeminal-autonomic cephalgias
  • hypnic headache - a rare recurrent headache that awakes one from sleep usually between 1-3am

• this is unlikely to be migraine
• FBE, ESR, U&E, RBG, CRP, check BP
  • if ESR or CRP is high, consider temporal arteritis, meningitis, sinusitis, other infection (eg. pneumonia)
• consider CT brain

• send bloods for FBE, RBG (+/- blood cultures if high fever)
• before embarking on CT brain and lumbar puncture (LP) (assuming there is true neck stiffness not just soreness):
  • consider CXR to exclude pneumonia as a cause
  • consider painful Cx lymphadenopathy as cause of neck pains - could it be infectious mononucleosis?

• the longer the duration of headache without change in its severity or character, the more benign it is likely to be.
• increasing frequency, severity, especially if nocturnal and/or associated with vomiting, the more one should consider an intracranial tumour with rising intracranial pressure as a cause - do not do LP on these patients - do a CT brain (although this does not exclude raised ICP) and look for CLINICAL signs of raised intracranial pressure and consult with seniors.

• patients with PH migraine who present with their typical features of migraine and no red flags for other conditions should be moved to a quiet room with low level of lighting and treated for migraine depending on severity of attack, medications already used and contraindications
• see Mx of acute migraine

• 1st line: paracetamol +/- codeine, rest, Rx cause
• 2nd line: non-steroidal anti-inflammatory drugs (NSAIDs)
• 3rd line: aspirin with oral maxolon +/- codeine
• 4th line: iv maxolon 20mg + antihistamine appears to be better than parenteral ketorolac and probably safer
• AVOID opiates and opioids

• these headaches respond well to indomethacin but not as well to other non-steroidal anti-inflammatory drugs (NSAIDs)
• paroxysmal and continuous hemicranias
• valsalva-induced headache
• primary stabbing headache or ice-pick headache
• a select group of trigeminal-autonomic cephalgias
• hypnic headache

• raises possibilities of infections:
  • meningo-encephalitis including viral vector borne
  • malaria
  • dengue fever
  • influenza, COVID-19 coronavirus (2019-nCoV / SARS-CoV-2)
  • other infections
• ask about possible trauma whilst on holiday, especially in context of alcohol intake
  • delayed presentation of chronic subdural haemorrhage

• if not photophobic then consider fundoscopy to exclude papilloedema
  • if a retinal camera is available then this may be the preferred option
  • using an ophthalmoscope can be difficult, especially in those with pin point pupils which may need mydriatics to dilate them first if there are no contra-indications to this and they are not planning to drive home before it wears off
  • for those with chronic headaches which could be benign raised idiopathic intracranial hypertension, fundoscopy is more important and may require the neurology team to review and they may also require measuring of opening pressures on lumbar puncture (LP) - this can generally be delayed until ward admission under neurology if ED resources do not allow it
• if they actually have eye pain and a red eye then eye examination to exclude glaucoma, viral conjunctivitis, foreign body, etc is important
  • see acute atraumatic painful red eye(s)

• see also indications for head CT scan for non-“headache” patients
  • eg. head injury in the adult patient
• sudden onset headache (esp. occipital) suggestive of sub-arachnoid haemorrhage:
  • CT as soon as possible within 6 hrs of onset, then if normal, may require lumbar puncture (LP) if CT done more than 6hrs after onset.
    • if CT is delayed more than 6 hours and fails to show SAH:
      • lumbar puncture (LP) after 12 hours from onset looking for xanthochromia
      • if LP is not possible then a CT Circle of Willis angio to exclude an aneurysm may be indicated to reduce risk of missing a treatable cause of SAH
• headache with acute unexplained impaired mental state or new neurology
• possible meningitis:
  • eg. meningism, fever, headache
  • empirical antibiotics, then CT ASAP & if normal, usually requires LP
• head trauma with reasonable risk of intracranial haemorrhage such as:
  • patient on anticoagulants
  • ongoing vomiting
  • decreased mental state
  • penetrating injury or possible fracture base of skull
  • see under head injury in the adult patient for more details
• “migraine” patient with red flag features that may warrant a CT scan (EEG is seldom helpful):
  • aura symptoms always at same side of body (should alternate)
  • aura symptoms with acute onset without spread or with either very brief (<5min) or prolonged (>60min) duration
  • brainstem aura
  • acute change in migraine characteristics
  • acute, substantial increase in attack frequency
    • NB. ask about substance misuse
  • first or worst “migraine”
  • onset above age 50yrs
  • aura without headache
  • high fever
  • 2nd or 3rd TM pregnancy (risk of venous dural thrombosis)
  • immunosuppression
  • abnormal neurologic examination:
    • ie. new focal deficit such as “hemiplegic migraine”, altered mental status, or altered cognitive function
    • increases probability of abnormal CT by 3x and a PPV of 39%
    • CT should be performed ASAP.
• new onset seizures with headache
• HIV / AIDS patients with new type of headache
• age > 60 yrs with acute or recent onset unexplained headache
• long standing headaches without past CT scan to exclude pathology, particularly if new features such as vomiting that may indicate rising intracranial pressure or complication of an intracerebral tumour.