Acute headache is a common complaint that you'll see whilst on the wards or in the acute take. Although most causes of headache are completely benign, the scope article is to help you identify which headaches may have life threatening or permanent consequences if missed.  Most of these serious causes you will not be expected to manage on your own, remember your job is to Escalate and get help! As always, if a patient is in pain it is helpful to give them analgesia in advance/early on in your review - you'll get a better history & the pain might even have gone by the time you arrive.

Here is a few differentials that should be lurking on the back of your mind’ (This list is by no means exhaustive! certainly there are even more differentials but these are major causes that should not be missed)
  • Subarachnoid Haemorrhage (SAH)
  • Benign intracranial hypertension
  • Venous sinus thrombosis
  • Temporal Arteritis
  • Glaucoma
  • Carbon Monoxide Poisoning 
  • Malignant Hypertension
  • Infective Causes -  meningitis, brain abscess
Also consider the common causes of headaches in hospital (if you're on the ward)
  • Tension/stress/anxiety/poor sleep related
  • Dehydration/hunger
  • Referred pain from dental/ear/sinus
The Secret is in history
Stick with your SOCRATES acronym and you will be able to elicit any red flag you need to know about

SITE
  • Benign Intracranial Hypertension – classically bi-temporal in location
  • Temporal Arteritis -  usually over the temples, pain can be reproduced on palpation
  • SAH – back of head is common site but do not use location as an excluding factor for SAH
  • Glaucoma – may be confined behind the eye but more commonly can be associated with a  frontal or generalized headache
ONSET
Timing can be very non discriminatory and will not necessarily yield a solid diagnosis but should help complete the picture of your top differentials. Beware of the new headache in those above 50 or below the age of 5. Notice that the emphasis on NEW headache. Those with migraine complaining of headache that feels NEW from their usual headache, warrants your attention.
  • Venous Sinus thrombosis - usually progressive and persistent, can be present for over two days, or can even present in a similar sudden onset nature as a SAH
  • SAH – Sudden in nature, over a matter of seconds
  • Temporal Arteritis – gradual onset worsening over the course of a week or longer 
  • Glaucoma – commonly presents in the evening, pain is severe and rapidly progressive
  • Benign Intracranial Hypertension -  generally worse in the morning
CHARACTER
  • SAH - Thunderclap nature, sometimes patients will even feel as if they have been kicked in the head
  • Temporal Arteritis – patients may use the terms ‘throbbing’ or ‘pulsatile’ pain
RADIATION

ASSOCIATED SYMPTOMS 
  • Fever, neck stiffness, photophobia – think meningitis/abscess
  • Vomiting – non-specific symptoms, but suggestive or raised ICP which warrants high suspicion
  • Reduced level of consciousness – worrying sign, this warrants escalation
  • History of Trauma – think subarachnoid, subdural, extradural, concussion
  • Seizures – non specific, but a major red flag that definitely needs imaging and investigating
  • Jaw claudication – think temporal arteritis
  • Amorosis Fugax/Blurred vision/Coloured Haloes (especially around lights) – painless temporary vision loss, think Temporal arteritis or glaucoma
TIMING 
See onset section

EXACERBATING/RELIEVING FACTORS
DO NOT BE FOOLED – a headache that is relieved by simple analgesics does not exclude a SAH
Headache made worse on coughing/straining/sneezing physical activity (generally anything that increased intracranial pressure) think about Benign Intracranial Hypertension or SOL

SEVERITY
  • SAH - "worst headache ever"
Important Risk Factors & Past Medical History

Subarachnoid Haemorrhage
  • Female gender higher risk
  • Hypertension
  • Positive family history
  • Polycystic kidney disease
Venous Thrombo-Embolism  –
  • Recent Neurosurgery/Head or Facial Injury/ Dural Puncture
  • Pregnancy and contraceptive use
  • Severe dehydration
  • Major Infection – sepsis or endocarditis or TB
Space Occupying Lesion
  • History of any previous malignancy (particularly lung, breast, thyroid, melanoma, kidney, prostate) should make you concerned of brain tumours caused by extracranial primaries. 
Infection
  • Immuno-compromised patients are at risk of a brain abcess
    • Consider HIV (increased risk of toxoplasmosis), organ transplants or immunosuppressants (candida species)
Benign Intracranial Hypertension
  • Typically in a young female patient who is overweight
  • Oral contraception
  • Anabolic steroids
  • Obesity
  • Tetracyclines
Major Red Flags – These always warrant further investigation
  • Seizure or abnormal GCS
  • Vomiting
  • Sudden onset severe headache/ thunderclap nature
  • Neck stiffness (someone with meningism will have a truly stiff neck where they can only move it mm before wincing of pain)
  • Pyrexia
  • Immunocompromise (ie HIV and immunosuppressive drugs) or Malignancy 
  • Abnormal findings on examination – Look for Horner’s syndrome, opthalmaplegia, abnormal tone/reflexes, papillo-edema
Resources/References/Useful Links:
By Dr Catherine Chan CT2