Headache is one of the most common neurological symptoms seen in emergency medicine and general clinical practice. While many headaches are benign, some can be life-threatening and require immediate intervention.
This comprehensive guide simplifies the types, causes, warning signs, diagnosis, and treatment approaches—based on the clinical chart you provided (featuring conditions like SAH, HTN encephalopathy, meningitis, migraine, etc.).
Introduction: Why Are Headaches Clinically Important?
Headache is a common complaint across all age groups. Most cases are due to benign, self-limited conditions, such as tension headache or migraine. However, a small but dangerous subset (~5%) represent neurological or systemic emergencies that can lead to disability or death if missed.
Therefore, clinicians must learn to quickly determine:
- Is this headache dangerous?
- Are red flags present?
- Does the patient need emergency imaging, lumbar puncture, or admission?
The Red Flags of Dangerous Headaches
The chart highlights several red-flag symptoms that strongly suggest a serious underlying cause:
Major Red Flags
- First or “different” headache from usual pattern
- Worst headache of life (thunderclap)
- Sudden onset (seconds to minutes)
- Syncope/fainting with headache
- Neck stiffness
- Neurological deficit (weakness, vision loss, slurred speech)
- Significant trauma
- Fever or rash
- Ill-appearance
These signs require urgent evaluation, often with CT scan, lumbar puncture, or emergency labs.
Classification: Dangerous vs. Benign Headaches
Your chart divides headaches into two broad categories:
A. Dangerous Causes (5%) – Must Not Miss
These headaches can be life-threatening.
1. Acute Glaucoma
Clues:
- Unilateral pain
- Blurry vision
- Fixed, mid-dilated pupil
Workup: Refer to Eye Complaints
Treatment: Ophthalmology consultation, pressure-lowering medications
2. Carotid Artery Dissection
Clues:
- Unilateral headache
- Neck pain
- Trauma or sudden neck movement
Workup: CTA/MRA, ultrasound
Treatment: Anticoagulation, neurosurgery consultation
3. Carbon Monoxide (CO) Poisoning
Clues:
- Weakness
- Nausea/vomiting
- Exposure (home heater, car exhaust)
Workup: Co-oximetry, venous blood gas
Treatment: 100% oxygen; hyperbaric oxygen if severe
4. Encephalitis
Clues:
- Fever
- AMS (Altered Mental Status)
- Seizures
Workup: CT → Lumbar puncture
Treatment: IV antibiotics + antivirals, isolation
5. Hypertensive Encephalopathy
Clues:
- Very high BP (dBP > 120)
- AMS
- Vision changes
Workup: End-organ labs
Treatment: Controlled BP lowering → MAP ↓ ≤ 25%
6. Meningitis
Clues:
- Fever
- Stiff neck
- Photophobia
- Rash
Workup: CT → Lumbar puncture
Treatment: Steroids before antibiotics, isolation
7. Preeclampsia / Postpartum Hypertension
Clues:
- 20 weeks gestation to 6 weeks postpartum
- High BP
- Headache
Workup: LFTs, CBC, urinalysis
Treatment: Magnesium sulfate, BP control, OB/GYN consult
8. Idiopathic Intracranial Hypertension (Pseudotumor Cerebri)
Clues:
- Overweight young female
- Visual symptoms
Workup: CT
Treatment: Lumbar puncture, acetazolamide
9. Subarachnoid Hemorrhage (SAH)
Clues:
- Sudden, worst headache of life
- May present with syncope
- Vomiting
Workup: CT ± LP
Treatment: BP control, neurosurgery consult
10. Temporal (Giant Cell) Arteritis
Clues:
- Age >55
- Tender temporal artery
- Jaw claudication
Workup: ESR
Treatment: Immediate steroids to prevent blindness
11. Traumatic Intracranial Hemorrhage
Clues:
- Head trauma
- Elderly
- Alcohol use
Workup: CT head
Treatment: Neurosurgery consult
B. Benign Causes (95%) – Most Common in ED & Clinics
1. Cluster Headache
Clues:
- Sudden, severe unilateral orbital pain
- Tearing, red eye
- More common in men, smokers, 40s
Treatment:
- 100% oxygen
- Triptans
2. Migraine
Clues:
- Unilateral throbbing pain
- Nausea/vomiting
- Photophobia
Treatment:
- NSAIDs
- Metoclopramide
- IV fluids
- Triptans
3. Sinusitis
Clues:
- URI symptoms
- Sinus tenderness
- Congested or opacified sinuses
Treatment:
- Nasal spray
- Decongestants
- ± Antibiotics
4. Tension Headache
Clues:
- Bilateral “band-like” tightness
- Stress-related
- No neurological symptoms
Treatment:
- Pain control
- Good sleep/relaxation
Diagnostic Approach to Headache
A structured approach helps identify dangerous cases early.
1. History
Focus on:
- Onset (sudden vs gradual)
- Location (uni vs bilateral)
- Severity & progression
- Associated symptoms (N/V, vision changes, fever)
- Trauma history
- Pregnancy status
2. Physical Examination
The chart suggests thorough documentation of:
- Fever
- Neck stiffness
- Photophobia
- Pupils
- Full neurological exam
Identify:
- Focal deficits
- Papilledema
- Meningeal signs
- Rash (meningococcemia)
3. Investigations
Based on suspicion:
| Investigation | When to Use |
|---|---|
| CT head | trauma, SAH suspicion, focal deficits |
| LP | meningitis, SAH with negative CT |
| CTA/MRA | suspected dissection or vascular disorders |
| Blood tests | infection, metabolic issues, pregnancy |
| ESR | suspected giant cell arteritis |
Management Principles for Headaches
Step 1: Rule Out Emergencies
Use red flags to identify cases needing:
- CT scan
- LP
- Immediate BP control
- IV antibiotics
- Neurosurgical referral
Step 2: Symptomatic Relief
For benign cases:
- NSAIDs (ibuprofen, ketorolac)
- Acetaminophen
- Antiemetics (metoclopramide, ondansetron)
- Triptans (migraine)
- Oxygen therapy (cluster)
Step 3: Preventive Strategies
For recurrent headaches:
- Sleep optimization
- Hydration
- Stress control
- Avoid triggers (caffeine, perfumes, fasting)
- Preventive medications (migraine prophylaxis)
Pearls & Pitfalls (From Your Chart)
- Acute headache + syncope = SAH until proven otherwise
- Hypertension rarely causes headache (unless >180/120 with neurological symptoms)
- New onset headache in age >50 is concerning (think giant cell arteritis)
- Never miss meningitis—treat quickly
- Sudden & severe headache needs immediate attention
Summary Table
| Category | Condition | Key Clue | Action |
|---|---|---|---|
| Dangerous | SAH | Worst sudden headache | CT ± LP |
| Dangerous | Meningitis | Fever + stiff neck | Steroids → IV antibiotics |
| Dangerous | Encephalitis | Fever + AMS | CT + LP + antivirals |
| Dangerous | Giant cell arteritis | Age >55 + jaw pain | ESR + steroids |
| Dangerous | Pre-eclampsia | Pregnancy + high BP | Magnesium + OB consult |
| Benign | Migraine | Unilateral + N/V | NSAIDs + antiemetics |
| Benign | Sinusitis | URI + sinus tenderness | Nasal spray, decongestants |
| Benign | Tension | Bilateral band-like | Pain control |
FAQs About Headache
1. When is a headache an emergency?
When it is sudden, severe, associated with fever, neurological deficits, or occurs after trauma.
2. Can high blood pressure cause headache?
Only at extremely high levels, usually with other symptoms like AMS or vision changes.
3. Do all headaches need imaging?
No. Only red-flag headaches require CT/MRI.
4. What is the most dangerous type of headache?
Subarachnoid hemorrhage, often described as the "worst headache of life."
5. When should migraines be treated in the ED?
If severe, prolonged, or accompanied by vomiting or dehydration.
6. What makes sinus headaches different?
They are associated with nasal congestion, facial pressure, and sinus tenderness.
7. What medication should be avoided in acute glaucoma?
Pupil-dilating agents; urgent eye pressure reduction is required.
8. Which age group is red-flagged for new headaches?
New headaches in age ≥50 require evaluation for serious causes.
