Headache & Migraine

Subarachnoid haemorrhage (SAH) typically presents as a sudden, severe headache that peaks within 1 to 5 minutes (thunderclap headache) and lasts more than an hour; concurrent features often include vomiting, photophobia, and non-focal neurological signs. See CGO on subarachnoid haemorrhage for detailed advice

Examination findings may include:

• altered consciousness/confusion
• meningism (e.g. neck stiffness, muscle aches, photophobia)
• ocular changes (e.g. intraocular haemorrhages)
• focal findings (e.g. unilateral loss of motor function, loss of visual field, aphasia

However, be aware that a patient with subarachnoid haemorrhage MAY EXAMINE NORMALLY – beware of the warning or "sentinal bleed” with full recovery.

Patients with suspected SAH require urgent evacuation for CT imaging. If the option is available then consider bypassing forward medical facilities in favour of direct evacuation to a facility with neurosurgical capability.

If the patient is, or becomes unwell with reduced level of consciousness, use a systematic approach to minimise secondary brain injury by managing airway, respiration and circulation in accordance with standard guidance. Request urgent evacuation with enhanced pre-hospital emergency care support if available.

Otherwise, pending imaging:

Give analgesia and anti-emetics.

Many patients struggle to tolerate adequate oral fluids so ensure adequate hydration with IV crystalloid if needed (up to 3 litres per day depending on oral intake)

Avoid any physical exertion and start stool-softening laxatives to avoid any straining that may precipitate further harm.

If available within 4 days of onset of suspected/confirmed subarachnoid haemorrhage, start Nimodipine 60mg every 4 hours. This should ideally be continued until the diagnosis is excluded or otherwise for 21 days (unless stopped on specialist advice).

Target systolic blood pressure 120-160 mmHg with beta blockers (bisoprolol 5mg OD, titrate up to 20mg OD). If not administering nimodipine then other calcium channel blockers could also be used to optimise blood pressure (amlodipine 5mg OD, titrate up to 10mg OD).

Giant cell (temporal) arteritis early symptoms are often non-specific but the diagnosis should be suspected if personnel are aged 50+ and present with either or both of:

New onset localised headache - usually unilateral in the temporal area, occasionally diffuse or bilateral

Temporal artery abnormality such as tenderness or thickening (present in 45–75% of people with the condition); occasionally the overlying skin is red, and pulsation may be reduced or absent.

Other symptoms and signs suggestive of GCA include:

• Systemic features (low grade fever, fatigue, anorexia, weight loss) affect most people
• Features of polymyalgia rheumatica (bilateral upper arm stiffness, aching, and tenderness; pelvic girdle pain)
• Scalp tenderness in ~50% of people, especially over the temporal and occipital arteries
• Intermittent jaw claudication occurs in nearly 50% of people with GCA, causing pain in the jaw muscles while eating. Occasionally, intermittent claudication affects the arms, tongue, or the muscles involved in swallowing due to involvement of blood vessels which supply these areas.
• Visual disturbances. Permanent partial or complete loss of vision in one or both eyes occurs in up to 20% of people and is a common early symptom. Typically it is described as painless with a feeling of a shade covering one eye, which can progress to total blindness. Double vision and visual field defects may occur. Untreated, the second eye is likely to become affected within 1–2 weeks, although it can be affected within 24 hours.

Management

Do not delay starting steroids in patients with suspected GCA.

Specialist input - UK guidelines recommend specialist opthalmology and/or rheumatology review within 3 days for suspected GCA. While this is unlikely to be possible in the deployed environment, reach back for specialist advice at the earliest opportunity.

Blood tests - although blood tests cannot fully exclude GCA, normal inflammatory markers indicate a low likelihood of disease and may be helpful to support clinical judgement in uncertain cases, so if possible take samples for C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) before starting steroids - but do not delay steroid therapy.

Ultrasound of temporal and axillary arteries is recommended as first line diagnostic imaging for suspected GCA - if possible, seek to evacuate the patient to a facility equipped to undertake this.

Meanwhile - start prednisolone

For suspected GCA without visual symptoms: prednisolone 60mg orally once daily

For suspected GCA with visual symptoms: prednisolone 60mg orally once daily and either aspirin or clopidogrel 75 mg once daily

Prednisolone will normally be continued for at least 4 weeks before reducing, so can and should continue until the patient is evacuated and seen by a rheumatology specialist.

In the unlikely event of weaning prednisolone while deployed (following specialist advice) reduce by 10 mg every two weeks until a dose of 20 mg daily is reached, then continue to wean by 5 mg a month until 10 mg daily, then by 1 mg daily a month until stopped.

Without specialist imaging, it is difficult to differentiate raised intracranial pressure from other conditions that cause headache. Features of concern include:

• Severe headache associated with postural change (bending over) or coughing
• Loss of vision (field > central)
• Transient blurred vision
• Double vision
• Photophobia 
• Pulsatile tinnitus (‘whooshing noise’ in ears in time with the pulse)

Management:

If raised intracranial pressure is suspected, the patient requires evacuation for CT imaging then specialist opinion and possible lumbar puncture depending on imaging findings.

Pending evacuation, nurse with the head of the bed elevated to 45 degrees.

If there is a high index of suspicion of raised ICP based on the clinical presentation (or findings from CT or other investigations) and the patient's condition deteriorates:

Hyperosmolar therapy may be given on neurosurgical advice, or without delay if the patient becomes obtunded and shows signs of coning (Cushing's Triad of bradycardia, hypertension and irregular breathing). Remember to follow a systematic approach to manage the patient's airway, respiration and circulation, and seek urgent neurosurgical advice if possible. Depending on availability, options include:

Mannitol 1 g/kg, to be administered over 30-60 minutes; this may be repeated after 4 hours.

Hypertonic (5%) saline 6ml/kg to a maximum of 350ml, to be administered over 10 minutes (3ml/kg in children).

Steroids may be of benefit if the presentation is thought likely to be associated with vasogenic oedema around a tumour. Give dexamethasone 8 mg orally or intravenously or IV, continuing twice daily. If dexamethasone is not available then 8 mg is equivalent to approximately 40mg methylprednisolone or 50mg prednisolone.

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Carbon monoxide is a colourless, odourless, tasteless gas produced by incomplete combustion. In severe cases, it causes irreversible brain damage and can be fatal. Deployed operations carry a heightened risk of exposure from heating and cooking systems as well as vehicle engines.

Following a brief exposure, patients may present with:

• Headache
• Dizziness & flushing
• Muscle pain
• Nausea, vomiting
• Personality changes
• Vertigo
• Flu-like symptoms with tiredness

In addition, prolonged exposure may be associated with:

• Confusion
• Hypotension
• Reduced level of consciousness
• Movement issues, weakness
• Seizures

Management:

The immediate management for suspected or confirmed carbon monoxide poisoning is to:

- REMOVE THE PATIENT from the suspected source and

- APPLY OXYGEN using the highest flow mechanism available - ideally a non-rebreathe mask with a reservoir bag.

Oxygen saturations are unlikely to be reliable - most pulse oximeters are not able to distinguish between carboxyhaemoglobin and oxyhaemoglobin, and will give a false reading, although there are specialist pulse oximetry devices available that can be used to measure carboxyhaemoglobin.

Following the application of oxygen and a full primary survey, a neurological assessment and cognitive function test should be performed to assess severity of presentation and monitor improvement.

Evacuate the patient, if possible, to a facility where blood gas analysis can be undertaken. Carboxyhaemoglobin levels >30% indicate severe poisoning (but levels <30% do not exclude this).

Patients with suspected or confirmed carbon monoxide poisoning require evacuation to a deployed hospital facility for assessment and monitoring if:

• they present with or develop confusion, reduced level of consciousness, seizures or any neurological deficit
• carboxyhaemoglobin greater than baseline (2% in non-smokers, 5% in smokers but up to 10% in very heavy smokers)
• symptoms persist after >2 hrs treatment or worsen at any point after starting treatment

Use crystalloid fluid to maintain hydration.

In the deployed hospital environment, invasive ventilation may be required to maximise oxygen delivery (in addition to ensuring a secure airway in the obtunded patient). If there is persistent metabolic acidosis then sodium bicarbonate 1.26% IV may be of benefit, administered in aliquots until pH normalises. Monitor serum potassium closely as administration of sodium bicarbonate may worsen hypokalaemia. Current UK toxicological advice does not recommend hyperbaric oxygen therapy.

Acute closed angle glaucoma is an eyesight-threatening emergency due to the rapid, severe rise in intraocular pressure.

Typical presentation includes sudden, severe eye pain and headache. The pain is frequently sufficiently severe to cause nausea, vomiting, and abdominal pain.

The patient may experience blurred or hazy vision, and is likely to present with unilateral red eye and a mid-dilated, non-reactive pupil.

Be aware that although glaucoma is often non-traumatic in the civilian population, in the military context it is usually precipitated by blunt injury causing hyphema or damage to normal pressure-controlling structures in the eye.

See Opthalmology CGO for "Painful Loss of Vision" for more information on diagnosing and managing acute closed angle glaucoma.

Tension-type headaches are episodes of headache that may last from 30 minutes to 7 days. 

These are not associated with nausea or vomiting, but the headache has at least two of the following features:

• Bilateral location
• Pressing, tightening, non-pulsating quality, pain may spread to neck
• Mild or moderate intensity
• Not aggravated by routine physical activity
• Often associated with depression/stress/anxiety 

Initial management should use simple analgesics supported with reassurance and an explanation of symptoms. Explore possible triggers and consider the possibility of medication overuse headache (see below).

Consider a single dose of one of: 

• Paracetamol (1g)
• Ibuprofen (400mg but can increase to 600mg if needed)
• Aspirin (900mg)

If insufficient then a short regular course of naproxen 500mg bd with PPI ccover may be helpful.

If headaches are severe, frequent & persist then, if available, trial amitriptyline, starting at low dose of 10mg at night. This can be increased at increments of 5-10mg to up to 75mg each evening.

Explore the possibility of mixed headaches.

Migraine without aura is defined as at least five attacks fulfilling the following criteria:

• Headache lasting 4–72 hours untreated
• Headache with at least two of the following characteristics:
  • Unilateral location
  • Pulsating quality
  • Moderate or severe pain intensity
  • Aggravation by, or causing avoidance of, routine activities of daily living
• Headache with associated symptoms, including at least one of:
  • Nausea and/or vomiting
  • Photophobia (sensitivity to light)
  • Phonophobia (sensitivity to sound)

Migraine with aura is most likely encountered as one or more fully reversible aura symptoms (visual in 90%, but may include sensory features, such as paresthesia, or dysphasia) accompanied by or followed by headache. Aura typically has a gradual onset and lasts 5-60 minutes.

Consider the possibility of a stroke or transient ischaemic attack with atypical aura (duration greater 60 minutes, or including motor weakness, double vision, visual symptoms affecting only one eye, or impaired balance) or aura occurring for the first time in a person using the combined oral contraceptive (COC) pill

Menstrual-related migraine is diagnosed in women/girls who experience migraine predominantly during the period from two days before until three days after the start of menstruation over at least two of three consecutive menstrual cycles.

Initial Management

Avoid opioids. Initially trial a single dose of simple analgesia taken as soon as headache develops:

• Ibuprofen (400mg, if ineffective increase to 600mg)
• Paracetamol (1g)
• Aspirin (900mg)

If migraine is felt probable or confirmed, trial oral sumatriptan which may be taken along or in combination with simple analgesia.

If the above is ineffective or not available then trial an anti-emetic such as prochlorperazine or ondansetron even if the patient is not experiencing nausea, and give 1 litre of intravenous crystalloid over 60 mins.

Treatment is generally effective within 2 hours, so if symptoms have not improved then consider an alternative analgesic.

Further Care

Use the mnemonic SEEDS to discuss lifestyle changes that can reduce environmental triggers and help manage migraine: • Sleep • Exercise • Eat (food & hydration) • Diary • Stress 

Plan to review the patient after 2-8 weeks - but advise to return for immediate review if the headache changes in nature and/or if any red flag features develop.

At review, discuss frequency of attacks, effectiveness of treatment, adverse effects and lifestyle improvements. If treatment has been effective, is being used appropriately and is well tolerated, it is likely to be appropriate to simply continue.

If not, reconfirm the diagnosis and consider the need for specialist assessment. If available then either try an alternative triptan or a combination therapy with an oral triptan and an NSAID or an oral triptan and paracetamol.

Prevention

For menstrual migraine, naproxen 250 mg BD or ibuprofen 400 mg TDS can be taken for five days, coinciding with the start of the period.

For other migraines, consider preventative treatment if migraine attacks have a significant impact on quality of life and daily function; for example, if they occur frequently (more than once a week on average), if they are prolonged and severe despite optimal acute treatment, or if the patient is at risk of medication-overuse headache due to frequent use of acute drugs.

Options for prevention include propranolol (start 40mg bd, increase to 80mg bd if needed), or amitriptyline 10 mg nightly.

Diagnosis

Episodic headaches, for example associated with factors such as stress and fatigue on operations, can evolve into a chronic headache that is associated with medication overuse.

Patients typically describe daily or near-daily headaches that are often present upon waking, improve with pain medication but return as the medicine wears off. Associated symptoms include nausea, irritability, restlessness, difficulty concentrating, and memory issues. Patients with comorbidities including anxiety and depression are at heightened risk.

A detailed medication history is crucial - and must take account of over-the-counter analgesia, simple analgesics and opioid medication. Usage thresholds are taking simple analgesics on 15 or more days per month, or triptans/opioids on more than 10 days per month.

Management 

The only treatment is withdrawal: education & communication is critical as headaches will initially worsen 

If due to simple analgesia – complete cessation; if due to opioids – gradually wean until stop.

If the patient struggles with weaning process, low dose amitriptyline may be used to support (10mg nocte).

Diagnosis

At least five attacks of severe unilateral orbital, supraorbital or temporal pain lasting between 15 minutes to 3 hours

At least one of the following ipsilateral symptoms or signs:

• Conjunctival injection and/or lacrimation.
• Nasal congestion and/or rhinorrhoea.
• Eyelid swelling.
• Forehead and facial sweating.
• Forehead and facial flushing.
• Sensation of fullness in the ear.
• Miosis (excessive pupillary constriction) and/or ptosis.
• Occur in series, usually lasting between 2 weeks and 3 months

Management 

Oxygen – give high-flow oxygen for 10-20 minutes for acute attacks.

Avoid paracetamol, non-steroidal anti-inflammatory drugs, opioids, or oral triptans for the acute treatment of cluster headache. Subcutaneous sumatriptan 6mg is an effective treatment but unlikely to be available on deployed operations. For new onset cluster headaches, seek reach back for specialist neurologist advice.

Diagnosis 

Pain in the distribution of the trigeminal nerve (usually in the cheek or lower jaw) that is:

• Severe
• Unilateral
• Short-lived — lasting a few seconds to 2 minutes and stopping suddenly.
• Recurrent
• Episodic
• Provoked by factors such as light touch to the face, eating, talking, or exposure to cold air

Some people with trigeminal neuralgia may also have autonomic features such as conjunctival injection, lacrimation, nasal congestion or rhinorrhoea, eye lid oedema, ptosis, or facial sweating.

Management 

Carbamazepine: Initiate therapy at 100 mg up to twice daily and titrate in steps of 100–200 mg every 2 weeks, until pain has been relieved.

Once the pain is in remission, the dosage should be gradually reduced to the lowest possible maintenance level, or the drug can be discontinued until a further attack occurs.

Neurology advice or review should be sought if the patient has recurrent episodes of pain which is severe and/or limits their participation in daily activities.