Differentials
Common
Tension headache
History
often associated with emotional stressors, depression, insomnia; headache may be described as tight and band-like or vice-like, bilateral, steady, aching, non-pulsatile, constricting pain (not severe)
Exam
pericranial tenderness is common, otherwise examination may be normal
1st investigation
- none:
diagnosis is clinical
Other investigations
Migraine
History
unilateral, pulsing, or throbbing pain, migraine with aura: nausea, vomiting, visual phenomenon (flashing lights, zig-zag lines), photophobia, phonophobia, may have transient focal neurological deficits; aura symptoms last <60 minutes; one study uses a helpful mnemonic, POUNDing: Pulsatile quality, duration of 4 to 72 hOurs, Unilateral location, Nausea or vomiting, and Disabling intensity (score of 5: migraine is likely; 3-4: migraine is possible; 1-2: migraine is unlikely)
Exam
if migraine with aura, may see focal neurological deficit on examination, otherwise examination normal
1st investigation
- none:
diagnosis is clinical
Other investigations
Acute sinusitis
History
frontal headache, nasal congestion, mucopurulent nasal discharge, fever; headache aggravated by bending forwards, coughing, or sneezing
Exam
sinus tenderness, reproducible pain on percussion of frontal and maxillary sinuses strongly indicates acute bacterial sinusitis
1st investigation
- none:
diagnosis is clinical
Other investigations
Otitis media
History
common in children; presents with otalgia, irritability, decreased hearing, anorexia, vomiting, or fever, usually in the presence of an ongoing viral respiratory infection
Exam
bulging, opacified tympanic membrane with decreased mobility; membrane may be white, yellow, pink, or red; diagnosis is generally made with conventional otoscopy
1st investigation
- otoscopy:
bulging, opacified tympanic membrane
Other investigations
- pneumatic otoscopy:
confirms presence of an effusion
- tympanometry:
confirms presence of an effusion
Menstrual headache
History
episodic headache, monthly/cyclical occurrence, around time of menses
Exam
usually normal
1st investigation
- none:
diagnosis is clinical
Other investigations
Medication withdrawal
History
recent medication changes, usually hypertension medication or antihistamines, caffeine, pseudoephedrine, opiates, corticosteroids
Exam
usually normal
1st investigation
- none:
diagnosis is clinical
Other investigations
Medication overuse headache
History
overuse headache considered if patient with a pre-existing headache disorder is taking simple analgesia (e.g., paracetamol, aspirin, non-steroidal anti-inflammatory drugs [NSAIDs]) on ≥15 days per month, or opioid, ergot, triptan, or combination analgesia on ≥10 days per month; patients either develop a new type of headache or experience a deterioration of the pre-existing headache
Exam
usually normal
1st investigation
- none:
diagnosis is clinical
Other investigations
Cervical paraspinal muscle tenderness
History
tight and band-like or vice-like headache, bilateral, steady, aching, non-pulsatile, constricting pain (not severe)
Exam
muscle tenderness on palpation, may be impaired movement of cervical spine
1st investigation
- none:
diagnosis is clinical
Other investigations
Dental caries/wisdom tooth impaction
History
pain on drinking or eating sweet, hot, or cold foods or fluids; wisdom tooth pain has characteristic 'horseshoe' distribution with intense, throbbing, unilateral pain; seen in young adults
Exam
dental caries visible, enamel soft on probing, dental abscess may cause breath odour, enlarged cervical nodes, fever, and swollen jaw
1st investigation
- none:
diagnosis is clinical
Other investigations
- dental x-ray:
impacted teeth, cavities, abscesses, periodontal disease
Temporomandibular disorders
History
temporomandibular joint pain, noise in the joint (clicking, popping, or crepitus with/without locking), masticatory muscle tenderness, limited mandibular movement; headache in the temporal region, otalgia and/or tinnitus without a significant ear disorder; associated symptoms, such as myalgia and arthralgia, depression and anxiety may be present
Exam
pain may be triggered by jaw movement or pressure on the masticatory muscles, and may be associated with jaw click or reduced jaw movement; maximal mandibular opening is 35 to 55 mm, movement may be reduced to <35 mm; there may be an uncorrected deviation on maximum mouth opening; wear facets are indicative of bruxism
1st investigation
- none:
diagnosis is clinical; requires dental referral
More
Acute hydrocephalus
History
sudden severe headache, vomiting, lethargy
Exam
may be normal
1st investigation
- CT brain without contrast:
enlarged ventricles
Other investigations
- lumbar puncture:
may show elevated intracranial pressure
Uncommon
idiopathic intracranial hypertension (pseudotumor cerebri)
History
typically female, obese, aged 20 to 30 years; nausea, vomiting, headaches, transient visual disturbances, some association with medication use (cimetidine, corticosteroids, danazol, isotretinoin, levothyroxine, lithium, minocycline, nalidixic acid, nitrofurantoin, tamoxifen, tetracycline, or trimethoprim-sulfamethoxazole)
Exam
papilloedema
1st investigation
- CT brain without or with contrast:
negative
Other investigations
- lumbar puncture:
elevated intracranial pressure
More
Brain tumour
History
may present with unexplained weight loss, focal neurological deficits; history of cancer; headache that awakens patient from sleep or is present upon awakening, decreases after being awake for several hours, is aggravated by exertion or Valsalva
Exam
focal neurological deficits
1st investigation
- CT brain without or with contrast:
ring-enhancing lesions with or without surrounding oedema
More
Other investigations
- MRI brain without and with gadolinium:
ring-enhancing lesion
More
Hypertensive encephalopathy
History
acute-onset headache, nausea, vomiting, may have altered mental status or visual disturbance
Exam
elevated BP, mean arterial pressure >150 to 200 mmHg
1st investigation
- CT brain:
negative
More
Other investigations
Eclampsia/pre-eclampsia
History
third trimester pregnancy or peripartum, pedal oedema, weight gain (>2.2 kg/week), visual disturbance (blurred vision, flashing lights); seizures distinguish eclampsia
Exam
BP >140/90 mmHg
1st investigation
- CT brain:
negative
Other investigations
- urinalysis:
proteinuria (300 mg/24 hours or 1 g/mL)
- FBC:
low Hb if haemolysis present, low platelets
- liver function tests:
hyperbilirubinaemia, elevated LDH, elevated aspartate aminotransferase
Pituitary apoplexy
History
headache (usually sudden-onset), nausea, vomiting, altered mental status, 2:1 male predominance, most commonly seen in ages 37 to 57 years; most cases occur when a rapidly growing, non-functioning pituitary adenoma infarcts, or haemorrhages
Exam
visual deficits: diplopia, ptosis, changes in visual field
1st investigation
- MRI brain:
pituitary haemorrhage
Other investigations
- CT brain:
pituitary haemorrhage
More
Venous sinus thrombosis
History
diffuse progressively severe headache, nausea, vomiting, seizures, hypercoagulable states
Exam
papilloedema, visual field deficits, cranial nerve palsies, focal neurological deficits
1st investigation
- CT brain with contrast:
delta sign (dense triangle from hyperdense thrombus) within the superior sagittal sinus
Other investigations
- MRI with magnetic resonance venography (MRV):
venous sinus thrombus
More
Epidural haematoma
History
blunt trauma to temporoparietal aspect of skull, classic presentation of loss of consciousness followed by period of lucidity and subsequent neurological deterioration; may have headache, vomiting, lethargy
Exam
physical examination may be normal, depending upon location, size, and presence or absence of mass effect, ipsilateral pupillary dilatation
1st investigation
- CT brain without contrast:
lenticular/biconvex hyperdensity
Other investigations
Subarachnoid haemorrhage (SAH)
History
may present with a 'thunderclap' headache (sudden onset of severe headache) or 'sentinel' headache (mild headache preceding the severe one); usually seen in women aged 40 to 60 years
Exam
nuchal rigidity
1st investigation
- CT brain without contrast:
blood in the area of the circle of Willis
More
Other investigations
- lumbar puncture:
xanthochromia or grossly blood-stained
More
Subdural haematoma
History
more likely with history of alcohol misuse, anticoagulants, frequent falls, seizure disorder; may present with altered mental status, seizures, coma
Exam
may be normal, depending upon location, size, and presence or absence of mass effect, or patients may have altered mental status, focal deficits, seizures, pupillary abnormalities, or coma
1st investigation
- CT brain without contrast:
half-moon or crescent-shaped clot overlying the hemispheric convexity
More
Other investigations
- MRI brain:
subdural fluid collection
More
Meningitis
History
higher likelihood in HIV or immunocompromised, classic triad of fever, headache, stiff neck; other symptoms are nausea, vomiting, seizures, focal deficits, photophobia, rash; meningococcal sepsis presents with hypotension, altered mental state, and purpuric or petechial rash
Exam
meningeal signs: Brudzinski's sign (hip flexion with neck flexion), Kernig's sign (painful knee extension with hip flexed), papilloedema with increased intracranial pressure
1st investigation
- CT brain without contrast:
negative
More
Other investigations
- lumbar puncture:
bacterial: low glucose, elevated protein, polymorphonuclear predominance; viral: normal glucose, normal protein, monocyte predominance
Brain abscess
History
headache, fever, vomiting, focal neurological deficit, may be immunocompromised
Exam
papilloedema
1st investigation
- CT brain with contrast:
rings of enhancement surrounding low-density centre and surrounded by white matter oedema
Other investigations
- MRI brain:
shows ring-enhancing lesion
More
Carbon monoxide poisoning
History
non-specific early signs and symptoms; may be exposure to furnace (in old house), space heaters, house fires, car exhaust, or gas stoves; flu-like symptoms, other household members with similar symptoms or recently deceased pets, morning headaches, dizziness, ataxia, confusion, nausea/vomiting, may present in late autumn/early winter
Exam
poor co-ordination, memory loss, wheeze, hyperventilation
1st investigation
- carboxyhaemoglobin level:
obtained from arterial blood gas analysis; upper limit of normal 3% non-smokers, 10% smokers
More
Other investigations
- O2 saturation:
often normal
- pulse CO-oximeter:
elevated carbon monoxide
Concussive syndrome/trauma
History
history of recent head trauma, possible loss of consciousness, dizziness, fatigue, reduced concentration, insomnia, psychomotor slowing
Exam
physical examination may be normal or may reveal evidence of trauma, scalp laceration, or contusion
1st investigation
- none:
diagnosis is clinical
Other investigations
- CT brain:
negative
More
Acute mountain sickness/hypoxia
History
occurs with ascent to altitude >2500 metres; symptoms include headache, anorexia, nausea, vomiting, lightheadedness, fatigue, dizziness, and sleep disturbance; headache tends to be diffuse and constant, often worsening with straining, lifting, or coughing
Exam
mental state changes, papilloedema, retinal haemorrhages
1st investigation
- none:
diagnosis is clinical
Other investigations
Cluster headaches
History
more often in men aged >20 years, severe, unilateral orbital, supra-orbital, or temporal pain lasting 15 to 180 minutes, reddened eyes, excessive lacrimation, nasal congestion, facial swelling; frequent attacks occur in clusters lasting weeks or months, followed by periods of remission; patients characteristically pace the floor during attacks
Exam
conjunctival injection, lacrimation, facial swelling, miosis, ptosis, rhinorrhoea
1st investigation
- brain and pituitary MRI without and with intravenous contrast:
normal in primary cluster headache; abnormal results might indicate secondary causes (e.g., tumour, cavernous sinus pathology)
Other investigations
Paroxysmal hemicrania
History
unilateral severe orbital, supra-orbital, and/or temporal pain lasting 2 to 30 minutes; distinguished from cluster headache by duration of attack and complete remission with indometacin; no male predominance
Exam
conjunctival injection, lacrimation, rhinorrhoea, eyelid oedema, facial sweating, miosis, ptosis
1st investigation
- none:
diagnosis is clinical
Other investigations
Trigeminal neuralgia
History
paroxysms of severe unilateral pain in the trigeminal nerve distribution lasting seconds, no pain between paroxysms, may be history of herpetic episode or multiple sclerosis; pain has an ‘electric shock-like’ quality; triggered by innocuous stimuli in the distribution of the trigeminal nerve
Exam
often unremarkable
1st investigation
- none:
diagnosis is clinical
More
Other investigations
Acute angle-closure glaucoma
History
acute, unilateral eye and/or forehead pain, blurred vision, halos around lights, injected sclera, nausea/vomiting, age >50 years
Exam
mid-dilated pupils, decreased visual acuity, increased intra-ocular pressure, diagnosis is made by noting characteristic changes in the optic nerve head, with or without visual field loss
1st investigation
- gonioscopy, examination of anterior chamber angle:
gonioscopy of both eyes should be performed on all patients in whom angle closure is suspected
More
Other investigations
- slit-lamp examination:
shallow anterior chamber; and signs of glaucoma: corneal oedema, lens changes, and corneal endothelial loss
- tonometry:
>21 mmHg suspicious
Giant cell arteritis
History
age >50 years, female predominance, may have history of polymyalgia rheumatica, may present with painless monocular vision loss, flu-like symptoms, jaw claudication
Exam
unilateral blindness, tenderness to temporal area, funduscopic examination may show optic nerve oedema
1st investigation
- erythrocyte sedimentation rate (ESR):
elevated in GCA
More - CRP:
elevated in GCA
More - FBC:
patients with GCA may have a normochromic, normocytic anaemia with a normal WBC count and elevated platelet count; mild leukocytosis may occur
More - vascular ultrasonography:
mural inflammatory changes in GCA
More - temporal artery biopsy:
histopathology typically shows granulomatous inflammation in GCA
More
Other investigations
- FDG-PET scan of head to mid-thigh:
mural inflammation or luminal changes of extracranial arteries in patients with suspected GCA; may demonstrate FDG uptake in the large vessels (aorta and major branches) in GCA
More - high-resolution MRI of cranial arteries:
mural inflammation or luminal changes of extracranial arteries in patients with suspected GCA
More
Zika virus infection
History
recent travel to or residence in an endemic area; many patients are asymptomatic, any symptoms are mild and last for several days to a week; common features are acute onset of fever with arthralgia, conjunctivitis, myalgia, and headache
Exam
non-specific clinical findings, resembling viral or flu-like illness, maculopapular rash
1st investigation
- reverse transcription-polymerase chain reaction (RT-PCR) on blood or urine:
positive for viral RNA
- enzyme-linked immunosorbent assay (ELISA):
positive for virus-specific antibodies
Other investigations
Chikungunya
History
recent travel to or residence in an endemic area; common features are fever, bilateral joint pain; less common features are headache, photophobia, myalgia, arthritis, nausea/vomiting
Exam
conjunctivitis, maculopapular rash
1st investigation
- enzyme-linked immunosorbent assay (ELISA):
positive for virus-specific IgM or IgG antibodies
- indirect immunofluorescence:
positive for IgM or IgG antibodies
Other investigations
- real-time polymerase chain reaction (PCR), real-time loop-mediated isothermal amplification (RT-LAMP), or conventional reverse transcription-PCR (RT-PCR) assay:
positive for viral genetic material
Dengue fever
History
recent travel to or residence in an endemic area; high fever and at least two of the following: severe headaches, severe retro-orbital pain, arthralgia, muscle and/or bone pain, rash, mild bleeding manifestations (e.g., nose or gum bleed, petechiae, easy bruising), low white blood cell count
Exam
rash, mild bleeding manifestations (e.g., nose or gum bleed, petechiae, easy bruising)
1st investigation
Other investigations
- non-structural protein 1 (NS1) detection:
positive
More
Stroke
History
neurological deficit, nausea, vomiting, vertigo, altered mental status; headache is rarely the presenting or prominent feature of ischaemic stroke
Exam
neurological deficit
1st investigation
- CT brain without contrast:
hyperattenuating lesion in haemorrhagic stroke; hypoattenuating (dark) lesion in ischaemic stroke, although may not show up within the first 24 to 48 hours of ischaemic stroke
Other investigations
Use of this content is subject to our disclaimer