Headache differential

“Doctor I have a headache – am I going to die?”

“Well… eventually…”

As a doctor you have to try and give useful answers to fairly important questions, like, better than this.


Differential diagnoses are one of the most useful tools when it comes to diagnosing symptoms and it’s important to ensure you’ve thought of as many of the potential causes as possible. Here’s a weird way to remember the key causes of a headache in an emergency situation.

Typical Day in A&E

You are on duty in the emergency department and you’re feeling incredibly tense, as someone has just fired off a cluster grenade somewhere in the hospital. You’ve just been called in to see a patient who has a very bad headache, who says he has a history of migraines

As you enter the room, you notice he’s holding a cricket bat and smoking a huge joint. Next to him a washing machine is spinning out of control, pouring smoke all over the room.

You notice a weird tingling stiffness in your neck, when suddenly his head catches fire.

The man stands up and says “To Be Honest mate I’m just gonna go home”, but his head begins to expand and he starts grinding his jaw

You don’t see what happens next because you go blind and pass out.

  • Tension headache
  • Cluster headache
  • Migraine
  • Subarachnoid (feels like being hit with a bat)
  • Drugs
  • CO poisoning 
  • Meningitis
  • Encephalitis
  • TBH – Tumour, TB, Haematoma
  • Temporal arteritis
  • Glaucoma

Step 1: Take a history


  • First and worst headache ever
  • Sudden onset and really bad
  • Unilateral with eye pain
  • Worse on coughing
  • Scalp tenderness
  • Decrease in GCS

– Any trauma?

– Any neck pain?

– Any fever?

– Any loss of consciousness?

– Any decrease in consciousness?

– Any warning signs?

– Any fitting/biting of tongue?

– Any other medical conditions?

– Any changes in vision?

– Any drugs?

– Sudden or gradual onset?

– How severe?

Two crucial questions:

– “Have you been away?”

– “Could you be pregnant?”

Step 2: Do a neuro exam

Step 3: Look in their eyes

Step 4: Get thinking


No signs on examination:

Tension headache

– Migraine

– Cluster

– Post-trauma

– Drugs – particularly nitrates and calcium channel blockers

– CO poisoning

Signs of meningism:

– Meningitis

– Subarachnoid haemorrhage

Decreased consciousness:

– Encephalitis

– Meningitis

– Stroke

– Cerebral abscess

– Subarachnoid haemorrage

– Tumour

– Haematoma

– TB meningitis


– Tumour

– Malignant hypertension

– Benign intracranial hypertension

– CNS infection of >2weeks

Painful jaw/temple:

– Temporal arteritis

Changes in vision:

– Glaucoma


– Paget’s disease

– Sinusitis

– Altitude sickness

– Cervical spondylosis

– Venous sinus occlusion

– Vertebral artery dissection

All of the above information is from the Oxford Handbook of Clinical Medicine 7th Edition

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