SHARES
Headaches can be uncomfortable, disabling and painful, but you usually don’t have to worry about them. However sometimes it is a sign that something is wrong.
Amongst the many patients who come to the clinic with headache, picking out the ones who are suffering from life-threatening secondary headache is always a challenge.
After ruling out patients with acute traumatic brain injury from high-speed motor vehicle injuries or falls, we will then need to identify or exclude the life-threatening causes of headache with a detailed history and physical examination.
“How quick was the onset of the headache?” – the best question to ask
Often most people will say YES when you ask them if this is the worst headache of their life. The question with the best yield would often be ‘how quick was the onset of the headache?’ and ‘what was the provocation for the headache?’, compared to their usual chronic headaches, if any. It may be helpful to draw a graph with a steep upstroke in minutes, in comparison to a less steep slope of a gradual onset headache over a couple of hours/days.
A Steep Curve – Rapid onset
A steep curve is very suggestive of secondary headache. Generally, headache precipitated by exercise, straining, or orgasms is concerning for a Subarachnoid Headache (SAH). Intracranial Hemorrhage (ICH) or Cerebral Venous Sinus Thrombosis (CVT) will present as headache, aggravated by a change in position, which is often worse when lying flat on your back.
A Gradual Curve
We sometimes encounter patients with a dull headache of gradual onset and non-specific giddiness, on a background of poorly controlled high blood pressure. Acute onset of such a headache, associated with altered level of consciousness, visual loss or disturbances and possibly seizures points to the possibility of Posterior Reversible Encephalopathy Syndrome (PRES).
PRES is a form of reversible hypertensive emergency. The causes are failure to maintain adequate and stable blood flow in the brain (cerebral autoregulatory failure) and accumulation of fluid or swelling (vasogenic oedema). This is commonly associated with general brain dysfunction due to significantly high blood pressure (hypertensive encephalopathy), chemotherapy drugs and eclampsia (severe high blood pressure during pregnancy resulting in seizures).
The mainstay of treatment of this hypertensive crisis is by lowering the Mean Arterial Pressure (MAP) by no more than 25% in the first hour and titrating the drugs based on the improvement of symptoms.
Therefore it is important not to dismiss the onset of such headaches but consult your doctor to check you up.
A Very Gradual Curve
More insidious headaches which change over time would raise concerns such as brain tumours. For patients who have a serious infection with altered mental state, a headache and neck pain would alert you to the possibility of meningitis (acute inflammation of the protective membranes covering the brain and spinal cord), especially if the patient has a compromised or weak immune system.
Older patients should be screened carefully for visual disturbances or eye pain to rule out temporal arteritis and acute glaucoma.
Examination
Physical examination in detail of the cranial nerves, neurological function, head, neck and fundus will narrow a doctor’s differential diagnoses further. Eye or ocular ultrasound at the bedside can pick up raised Intra-Cranial Pressure (ICP) when the optic nerve sheath diameter is >5mm in adults which is predictive of intracranial pressure of >20mmHg. When your doctor suspects that there is an increase of Intracranial pressure, the doctor will order a CT brain scan before performing a lumbar puncture.
Figure 1: Measurement of Optic Nerve Sheath Diameter (ONSD) 3mm behind the globe. Measurement >5mm is considered dilated – refer (B) blue line.
Further Note on Bleeding within the Skull (Intracranial Hemorrhage)
The greatest fear for all clinicians would be missing the diagnosis of a spontaneous subarachnoid hemorrhage (SAH), which has a mortality rate of up to 50%. It is sometimes possible to pick up a history of sentinel headache a day or a few weeks before the actual episode. Sentinel headache is, in essence, a sudden, intense, and persistent headache, preceding SAH.
When working up a patient for a possible SAH, physicians investigate further with these options bearing in mind the time-dependent factors.
- CT scans conducted within 6 hours of symptom onset have a sensitivity of 100% (97%-100%) to confirm the diagnosis; and a negative predictive value of 100% (99.5%-100%) to confirm you truly do not have the disease. (Perry et al).
- Xanthochromia (presence of bilirubin in the cerebrospinal fluid) on a Lumbar Puncture will take 2-12 hours to develop.
- Additional CT Angiogram or MRI may be helpful if SAH still cannot be excluded.
- Magnetic resonance angiography (MRA) and magnetic resonance venography (MRV) of your brain will unveil rarer underlying causes. Examples include cervical artery dissection, vertebral artery dissection or cerebral venous thrombosis which may present as decreased alertness or seizures. The MRA and MRV are specifically designed to examine your blood vessels of the brain.
Managing the Benign Stuff
Thankfully most patients who come to us have a primary headache. Your doctor will help you manage your condition.
- Acute migraine attacks: Prescibe simple paracetamol, NSAIDs or caffeinated analgesics like Cafergot. The trick is to take the analgesics at the first sign of migraine onset or when the aura starts to occur.
- Certain patients with accompanying vomiting might need intravenous analgesics (IV) and antiemetic like prochlorperazine.
- Advise you to avoid triggers like chocolate, alcohol, stress, and changes in sleep pattern.
- Check other causes for example for anxiety, depression or sleep apnoea.
- Keep a headache diary with over the counter drug use to monitor the frequency of migraine attacks. Assess the need for prophylactic medication, such as beta-blockers or antiepileptics
Important Takeaway
Headaches are caused by many factors. However most headaches are not serious and are benign. However get medical attention immediately if you have a different headache or experience severe pain . Tell your doctor how it developed, describing all the symptoms along with it.
This article is contributed by Dr Cheah Si Oon
Dr Cheah Si Oon
MBBS (S’pore), M.Med (Emerg Med), MRCSEd (A&E), FAMS
For More Information, contact Urgent Care Clinic International.
Further Reading: Headache and Migraine: How are they Different and Treated?
Reference:
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Perry JJ, Stiell IG, Sivilotti ML, et al. Sensitivity of computed tomography performed within six hours of the onset of headache for diagnosis of subarachnoid haemorrhage: prospective cohort study. 2011;343:d4277. (Prospective; 3132 patients)
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