7.2 Acute & Chronic Headaches, Giant Cell Arteritis & CNS Infections

Acute & Chronic Headaches, Giant Cell Arteritis & CNS Infections

In accordance with NICE guideline CG150 (Headaches in over 12s) and NICE guideline NG240 (Meningitis and neurological infections), headache is one of the most frequent presenting complaints in acute and primary care. The central clinical challenge is distinguishing common, benign primary headache disorders from life-threatening secondary causes such as central nervous system infections, intracranial vasculitis, or raised intracranial pressure.

---

The SNOOP Red Flag Assessment Framework

Every patient presenting with a new or altered headache must be systematically screened for secondary red flags before diagnosing a primary headache syndrome.

---

Primary Headache Disorders

1. Migraine

• Pathophysiology: Neurovascular disorder driven by trigeminovascular activation, neurogenic sterile inflammation, and release of calcitonin gene-related peptide (CGRP). Cortical spreading depression underlies the migraine aura.
• Clinical Presentation: Episodic headache lasting 4–72 hours. Classically unilateral, pulsating/throbbing, moderate-to-severe intensity, aggravated by routine physical activity. Associated with nausea, vomiting, photophobia, and phonophobia.
• Aura: Present in ~25% of patients. Fully reversible focal neurological symptoms (most commonly visual scintillating scotomas or fortification spectra, sensory tingling marching across the hand/face, or transient dysphasia) that develop gradually over ≥5 minutes and last 5–60 minutes, typically followed by the headache phase.
• Acute Abortive Treatment: Combination therapy is first-line: a 5-HT₁B/1D receptor agonist (oral triptan, e.g. Sumatriptan 50–100 mg) co-administered with an NSAID (e.g. Naproxen 500 mg or Ibuprofen 400 mg) or Paracetamol 1 g, plus an oral prokinetic antiemetic (Metoclopramide 10 mg or Prochlorperazine 10 mg) to treat gastric stasis. Contraindications to Triptans: Coronary artery disease, previous myocardial infarction, ischaemic stroke, peripheral vascular disease, or uncontrolled hypertension (due to coronary and cerebral vasoconstrictive potential).
• Prophylactic Therapy: Indicated if attacks occur ≥2 times per month or cause significant disability. First-line options include:
  • Propranolol (80–160 mg daily; avoid in asthma and peripheral vascular disease)
  • Topiramate (50–100 mg daily; highly effective, but contraindicated in pregnancy for migraine prevention and in women of childbearing potential unless the conditions of the MHRA (2024) Pregnancy Prevention Programme, including highly effective contraception, are met, because of oral clefts, low birth weight and possible neurodevelopmental effects)
  • Candesartan (angiotensin II receptor antagonist; excellent alternative if beta-blockers contraindicated)
  • Amitriptyline (tricyclic antidepressant, taken nocte; beneficial in co-existing tension headache or sleep disturbance)

2. Tension-Type Headache (TTH)

• Most Common Primary Headache: Bilateral, non-pulsating, 'tight band-like' or pressing discomfort across forehead and occiput. Mild-to-moderate intensity; not aggravated by routine physical exertion.
• Distinguishing Features: No nausea, no vomiting, and no more than one of photophobia or phonophobia (never both).
• Management: Simple analgesia (paracetamol, ibuprofen, or aspirin). Avoid combination analgesic preparations, codeine/opioids, and triptans to prevent medication-overuse transformation.

3. Cluster Headache

• Epidemiology: Trigeminal autonomic cephalalgia (TAC) affecting men substantially more than women (3:1), commonly presenting between ages 20 and 40, with strong correlation to heavy cigarette smoking.
• Clinical Presentation: Strictly unilateral, excruciating, sharp, 'hot poker in the eye' piercing pain centered around the orbit, supraorbital ridge, or temple. Attacks last 15 to 180 minutes, occurring 1–8 times daily, often waking the patient from sleep at identical times ('alarm clock headache'). During an attack, patients are restless and agitated, pacing the room (in sharp contrast to migraineurs who seek quiet, dark seclusion).
• Ipsilateral Autonomic Manifestations: Conjunctival injection, lacrimation, nasal congestion, rhinorrhoea, forehead and facial sweating, miosis, and partial ptosis (Horner's syndrome).
• Acute Abortive Management:
  • 100% High-flow Oxygen: 12–15 L/min administered through a non-rebreather face mask with a reservoir bag for 15–20 minutes.
  • Subcutaneous Sumatriptan 6 mg (or nasal zolmitriptan 5 mg). Oral analgesics and oral triptans are completely ineffective due to their slow onset of action relative to the attack's brevity.
• Prophylactic Maintenance: Verapamil (calcium channel blocker; titrated up with baseline and serial ECG monitoring to detect PR interval prolongation and heart block). Short-course oral prednisolone is used as a temporary tapering bridge while titrating verapamil.

4. Medication-Overuse Headache (MOH)

• Diagnostic Criteria: Headache present on ≥15 days per month in a patient with a pre-existing headache disorder, resulting from the regular overuse of acute headache medications for >3 months:
  • Paracetamol or NSAIDs taken on ≥15 days per month
  • Triptans, opioids, ergots, or combination analgesics taken on ≥10 days per month
• Clinical Presentation: Daily, dull, diffuse, non-specific headache present upon awakening in the morning.
• Management: NICE CG150 advises stopping all overused acute headache medicines abruptly for at least 1 month; consider specialist referral (and a slower, supervised withdrawal) for people overusing strong opioids. Patients must be warned of a transient withdrawal exacerbation (rebound headache, nausea, sleep disturbance) lasting 1–3 weeks before meaningful clinical improvement occurs.

---

Giant Cell Arteritis (Temporal Arteritis)

Giant Cell Arteritis (GCA) is a systemic granulomatous vasculitis targeting large and medium-sized arteries, particularly branches of the external carotid artery (temporal, ophthalmic, and posterior ciliary arteries).

• Patient Demographics: Exclusively occurs in individuals aged >50 years (peak incidence 70–80 years); females > males (3:1). Closely linked to Polymyalgia Rheumatica (PMR) in ~50% of cases (bilateral morning stiffness and aching in shoulder and pelvic girdles lasting >45 minutes).
• Cardinal Clinical Features:
  • New-onset, severe, localized headache (often temporal or occipital)
  • Scalp tenderness (pain on brushing hair or resting head on a pillow)
  • Jaw claudication (fatigue and cramping pain in masseter muscles provoked by chewing or talking; highly specific/pathognomonic for GCA ischaemia)
  • Visual disturbances: Amaurosis fugax (transient painless monocular visual loss), diplopia, or sudden profound permanent visual loss due to Anterior Ischaemic Optic Neuropathy (AION) from occlusion of posterior ciliary arteries.
  • Examination: Tender, thickened, nodular, or pulseless superficial temporal artery. Fundoscopy may show a pale, edematous optic disc.
• Diagnostic Investigations:
  • Markedly elevated inflammatory markers: ESR > 50 mm/h (frequently >80–100 mm/h) and elevated serum CRP.
  • Temporal Artery Biopsy (TAB): Confirmatory gold standard demonstrating transmural granulomatous inflammation, mononuclear infiltrate, disruption of the internal elastic lamina, and multinucleated giant cells. Because of 'skip lesions', biopsy length should be ≥1.5–2.0 cm. A negative biopsy does not exclude GCA.
  • Temporal artery ultrasound: Shows the characteristic hypoechoic 'halo sign' representing vessel wall oedema.

---

Central Nervous System Infections

1. Acute Bacterial Meningitis

• Microbiology:
  • Adults & Children: Streptococcus pneumoniae (most common overall) and Neisseria meningitidis (young adults, students; associated with non-blanching petechial or purpuric rash, septic shock, and Waterhouse-Friderichsen syndrome [adrenal haemorrhage]).
  • Elderly (>60 years) & Immunocompromised: Streptococcus pneumoniae, Neisseria meningitidis, plus Listeria monocytogenes (Gram-positive bacillus; inherently resistant to all cephalosporins).
• Clinical Presentation: Classical triad of high fever, headache, and neck stiffness (nuchal rigidity), accompanied by altered mental status, photophobia, and positive meningeal signs (Kernig's sign: knee extension resistance with hip flexed at 90°; Brudzinski's sign: passive neck flexion triggers spontaneous knee/hip flexion).
• Pre-Hospital / GP Emergency Protocol: In suspected meningococcal disease (meningitis or septicaemia with a characteristic non-blanching petechial rash), administer intramuscular or intravenous Benzylpenicillin (1.2 g in adults) or Ceftriaxone (2 g) immediately without delaying urgent ambulance transfer to hospital.
• In-Hospital Emergency Protocol:
  1. Take blood cultures and check capillary blood glucose immediately.
  2. Proceed to urgent lumbar puncture unless specific neuroimaging red flags are present.
  3. Do not delay empirical antibiotics for a lumbar puncture or CT scan. If LP is delayed, administer antibiotics immediately after drawing blood cultures.
  4. Empirical Antibiotic Therapy: Intravenous Ceftriaxone 2 g twice daily (or Cefotaxime 2 g every 6 hours).
  5. Add Intravenous Ampicillin 2 g every 4 hours (or Amoxicillin 2 g 4-hourly) in patients aged >60 years, pregnant women, or the immunocompromised to cover Listeria monocytogenes.
  6. Adjunctive Corticosteroids: Administer Intravenous Dexamethasone 10 mg every 6 hours just before or simultaneously with the first dose of antibiotics (continued for 4 days if Streptococcus pneumoniae is confirmed; discontinue if non-pneumococcal). Dexamethasone significantly reduces sensorineural hearing loss, neurological sequelae, and mortality in pneumococcal meningitis.

Indications for CT Head BEFORE Lumbar Puncture

To avoid tentorial or tonsillar herniation (coning), an urgent CT head must precede lumbar puncture only if one or more of the following are present:

1. New focal neurological deficits (e.g. hemiparesis, dilated unreactive pupil, cranial nerve VI/VII palsy)
2. Papilloedema on fundoscopy
3. New-onset continuous or recurrent seizures
4. Significantly depressed conscious level (GCS 12 or less)

These are the UK Joint Specialist Societies (2016) indications. Some international guidance (for example the IDSA) also lists severe immunocompromise, but in the UK this alone is not a reason to delay LP. If CT is needed, antibiotics and dexamethasone must be given first. Patients without these specific signs should undergo prompt lumbar puncture without pre-procedure CT scanning.

Cerebrospinal Fluid (CSF) Analysis Interpretation

2. Viral Encephalitis

• Microbiology: Herpes Simplex Virus Type 1 (HSV-1) accounts for >90% of adult viral encephalitis. HSV-1 exhibits marked tropism for the temporal and inferior frontal lobes, producing necrotising, haemorrhagic encephalitis.
• Clinical Presentation: Acute fever, headache, altered consciousness, rapid personality and behavioural changes (disinhibition, psychosis, emotional lability), expressive dysphasia, and focal temporal lobe seizures (e.g. olfactory hallucinations, lip-smacking automatisms).
• Diagnostic Workup:
  • CSF Analysis: Lymphocytic pleocytosis, normal glucose, mildly elevated protein; CSF HSV PCR is the gold standard diagnostic test.
  • MRI Brain: Hyperintensity on T2/FLAIR restricted to the temporal and orbitofrontal lobes, with asymmetric cortical oedema.
  • EEG: Periodic lateralised epileptiform discharges (PLEDs) over the temporal lobes.
• Emergency Treatment: Immediate intravenous Aciclovir 10 mg/kg three times daily (every 8 hours) for 14–21 days. Therapy must be started immediately upon clinical suspicion. Maintain adequate IV hydration and monitor renal function to prevent aciclovir-induced crystalline nephropathy.