CME INDIA Presentation by Dr. V. Natarajan, MD, DM(Neuro) FRCP (Edin), FAAN, FIAN, Former Professor of Neurology and Head, Institute of Neurology, Madras Medical College; Professor Emeritus Tamil Nadu Dr. MGR Medical University; & Dr. K. Mugundhan, MD, DM(Neuro), FRCP(Glag), FRCP(London), FRCP(Ire), FRCP(Edin), FACP(USA), FICP, FICCDMD, FIMSA, Professor of Neurology and Head, Stanley Medical College, Chennai.

1. The brain is insensitive to pain

The brain is insensitive to pain, as are its coverings the arachnoid and most of the dura and the ependyma. The structures which are sensitive to pain are the following:

  • The intracranial structures are:
    • Arteries
    • Veins and the venous sinuses
    • The Dura adjacent to the Blood vessels
  • The extra cranial structures include:
    • Paranasal sinuses
    • Eyes and orbits
    • Ears, tympanic membrane
    • Teeth, salivary glands, temporo-mandibular joint
    • Cervical nerves, roots, and blood vessels

2. There are more than 300 types of headaches

For practical purposes can be classified as:

  • Primary headaches – which form about 90% of the headaches with no structural or metabolic abnormality.
  • Secondary headaches – which form about 10% and have structural or metabolic abnormalities.

The structural abnormalities can be extracranial or intracranial:

  1. The Extracranial abnormalities include sinusitis, otitis, glaucoma, Temporo-Mandibular Joint (TMJ) disorders.
  2. Intracranial abnormalities include SubArachnoid Haemorrhage (SAH), Cerebral venous sinus thrombosis (CVST), Reversible Cerebral Vasoconstriction Syndrome (RCVS), Dissection of blood vessel, tumour, abscess and meningitis.
  3. The Metabolic causes include Carbon dioxide retention, Carbon Monoxide poisoning.

Approach Flow Chart

Headaches - What A Physician Must Know?
Headaches - What A Physician Must Know?

Never Forget to ask these:

Some crucial points in the history to be asked for are:

Is the headache recurrent? What is the frequency, severity, duration and location of the headache?
Is the headache always similar or are there different types of pain?
Is the pain throbbing, burning, pricking, stabbing, lancinating, a tight sensation or weight placed over the head, aching?
Is the headache associated with nausea, vomiting, photophobia, phonophobia, redness of eyes, tearing, swelling of periorbital region, narrowing of palpebral fissures?
Are there triggers for the headaches? – Stress, lack of sleep, exposure to sunlight, head bath, menses, travel, hunger, weather change, headache on getting up, posture of neck?
Are there additional features like vertigo, tinnitus, confusion, altered sensorium, blackening of vision, seizures?
Also, should enquire about the occurrence of auras which could be visual, sensory, speech or motor symptoms.

Neurological examination

  • Neurological examination should include examination of visual acuity, visual field, ocular fundi and looking out for the presence of focal deficits like motor, language, sensory, ataxia or altered sensorium.
  • If neurological examination is abnormal, it should be considered a secondary headache and the cause of the headache should be found out.
  • If the examination is normal, then most likely it is a primary headache with certain caveats which are considered as red flags.

The red flags go under the rubric snoop

This is a mnemonic for red flags to the diagnosis of primary headache

SSystemic symptoms (fever, weight loss), secondary headache risk factors like HIV, Cancer, pregnancy and postpartum occurrence
NNeurological symptoms or signs namely confusion, altered sensorium, focal neurologic deficits.
OOnset being sudden or abrupt, or in a split second or like a thunderclap
OOlder age and new onset or progressive headache in a person with age more than 50 years (giant cell arteritis)
PNo h/o previous headache or headache which is progressive in intensity: a first headache or a headache which has changed its pattern, with regards its frequency, severity, or clinical features.


  • Imaging is required if abnormal neurological findings are present on examination or if the features of headaches are not consistent with a primary headache disorder.
  • Most headache patients do not need neuro imaging as 90 % of them have primary headaches. The likelihood of either a CT or MRI scan identifying an abnormality as the cause of the headache in a person with a normal neurology is less than 2%.

MRI would be the preferred choice of imaging as CT might be inadequate to identify some of these conditions:

  • Vascular disorders like saccular aneurysms, Arteriovenous malformations (AVMs), Sub Arachnoid Hemorrhage (SAH), carotid or vertebral arterial dissections, infarcts, Cerebral Venous Thrombosis (CVT), vasculitis, cerebral vasospasm, subdural and epidural hematomas.
    • Neoplasms, meningeal metastases, pituitary tumour.
    • Corticomedullary lesions (Chiari malformations and foramen magnum tumours).
    • Infections (paranasal sinusitis, meningoencephalitis, cerebritis, and brain abscess).
    • Low cerebrospinal fluid (CSF) pressure syndrome.

Primary Headaches


  • Perhaps the most prevalent type of primary headache is Migraine, although some argue that Tension Type headache may be more common. The challenge in determining which type is more prevalent stems from the fact that many patients experience both types of headaches, and the diagnosis depends on the physician’s interpretation of the patient’s medical history.
  • The criteria outlined in “The International Classification of Headache Disorders 3rd edition Beta version 2013” guide the diagnosis process.
  • In South India, it is estimated that approximately 20% of the population experiences migraine headaches, with children experiencing them at a rate of 18 to 21%, according to Shivpuri.’

Headaches - What A Physician Must Know?

  • Migraine can be classified into Migraine without aura and Migraine with aura Diagnostic criteria for Migraine without aura
    • Recurrent attacks of at least five attacks of 4-72 hours duration (untreated or unsuccessfully treated)
    • The headache has at least two of the following four characteristics:
      • unilateral location
      • pulsating quality
      • moderate or severe pain intensity
      • aggravation by or necessitating avoidance of routine physical activity (eg, walking or climbing stairs)

The headache should be associated with at least one of the following:

  1. nausea and/or vomiting
  2. photophobia
  3. phonophobia
  • Triggers – sunlight, stress, sleep deprivation, head bath, awakening from sleep, travel, change of weather, hunger, strong odours, hormones, food stuffs, exercise are the usual triggers of migraine headache.
  • Diagnostic criteria for Migraine with aura.
  • Features of migraine which is above associated with fully reversible aura of unilateral visual, retinal, sensory, motor symptoms or rarely speech disturbance.
  • These auras usually last for 5 to 60 minutes.

Phases of Migraine

Prodrome or premonitory phase could precede the headache by hours to 2 days and consist of changes in mental state, photophobia and or phonophobia, yawning, drowsiness and general symptoms like stiff neck, craving for food, altered bowel symptoms. Aura phase occurs in about 30% as stated earlier with headache though not necessarily in all. In resolution phase, postdrome symptoms like changes in mood, weakness/tiredness, anorexia, irritability, poor concentration could occur.

Migraine features

Pain in any part of the head or face including upper and lower jaw, teeth, malar eminence.
Can be unilateral in about 60% or bilateral in 40%.
In about 15%, the pain is always one sided.
Migraine which lasts for > 72 hours is called status migrainosus.
If not treated, 80% have fairly severe pain with nausea and the phobias, (photo, phono, osmo).
Cranial autonomic symptoms of forehead sweating, lacrimation, nasal congestion could occur though not necessarily during each attack.
About 70% of migraineurs have a family history of a 1st degree relative being affected with similar headaches.

Pathophysiology of migraine

The following are postulated as the mechanisms of causation of migraine:

  • Brain stem neuronal hyper excitability.
  • Cortical spreading depression in migraine with aura.
  • Abnormalities of 5HT (5 hydroxy tryptophan), CGRP (calcitonin gene related peptide), NE (Norepinephrine), DA (Dopamine), GABA (Gamma-Aminobutyric acid), NO (Nitric Oxide), Glutamate and endorphins.
  • Trigeminal activation resulting in dilatation of meningeal vessels (throbbing), activation of area postrema causing nausea and vomiting, activation of cortex and thalamus resulting in pain over the head and activation of cervical trigeminal system producing cervical muscle spasm.


Medicines for acute treatment & relief of headache:

  1. Acetaminophen, paracetamol.
  2. NSAIDS – ibuprofen, naproxen sodium, diclofenac.
  3. Ergotamine-not widely used because of adverse effect but is making a comeback.
  4. Triptans – 5 Hydroxy Tryptophan 1B & 1D receptor agonists. 5HT1B receptor agonists have a vasoconstricting effect.

Triptans are at present considered to be the most potent medicine for acute treatment by aborting the headache.

Sumatriptan is the most widely used triptan and is available as tablets and injection & nasal spray with least side effect among the triptan and is given as 50mg & 100mg tablets or 50mg sc injection.

Triptans are preferably given once in 24 hours and is limited to use of 2-3 times per week. However, those who fail to respond to one triptan can be tried on another.

Limitation of Triptans:

  • 5HT1B agonists are to be avoided in individuals with coronary artery disease, peripheral vascular
  • disease, cerebrovascular disease, heart blocks and uncontrolled hypertension in view of its vasoconstricting effect.
  • 5HTIF receptor agonists have been developed and categorised as a new class of Triptans- the DITANS and LASMIDITAN is a second line treatment option in 16 those where triptan has failed or a first line option in person with above mentioned risk factors as it doesnot cause constriction of the blood vessels.
  • CGRP (Calcitonin Gene Related Peptides) antagonists are the newer molecules in the treatment of migraine.
  • GEPANTS are a class of medicines in this group which inhibit the CGRP receptor and Ubrogepant, Rimegepant and Atogepant have been approved by FDA in 209,2020 and 2021.Real world data of its efficacy and safety are awaited.
  • The other class of CGRP antagonists are monoclonal antibodies which are useful for prevention of migraine headaches.

Migraine prevention

Drugs recommended and established as effective for migraine prophylaxis are:

Divalproex / sodium valproate 400 to 1000 mg / day
Metoprolol 47.5 to 200 mg
Propranolol 120 to 240 mg
Topiramate 25 to 200 mg
Flunarizine. 5 to 10 mg (not yet approved by FDA)

Tension type headaches (TTH)

  • This is probably the most commonly diagnosed headache in family practice.
  • These are recurrent episodes of headache lasting 30 minutes to one week.
  • The headaches are typically bilateral, mild to moderate in intensity, non-throbbing and are described as dull, pressure like a tight cap or band without associated nausea or vomit but could have either photo or phonophobia
  • Physical activity has no influence on the headache intensity in the majority and this feature helps differentiating it from migraine.
  • The exact cause of TTH remains elusive, pericranial myofascial mechanisms are probably of importance and sensitisation of pain pathways in the CNS from prolonged nociceptive stimuli seems responsible for conversion of episodic to chronic TTH.
  • It is the least distinct of all headache types though present in 75% of population-based studies.
  • The clinical diagnosis is based chiefly on negative features and many secondary headaches may mimic TTH.
  • Atypical history or abnormal clinical examination would suggest the need for imaging; however, the vast majority with typical history and normal examination do not need further investigation.
  • Differentiating chronic TTH from chronic migraine may be difficult at times, as the features could overlap and many a time both can co-exist.
  • The mnemonic POUND helps separate migraine from TTH; P – pulsatile quality; O – duration of 4 – 72 hours; U – being unilateral; N – nausea being associated; D – disabling intensity of pain.

Treatment of TTH

Treatment can be divided into pharmacological and non-pharmacological

  • Most persons with infrequent TTH might take self-administered OTC (over the counter) analgesics.
  • For those with frequent episodic TTH simple analgesics and NSAIDs are the mainstays in acute therapy.
  • Tricyclic Antidepressants (TCAs) are effective for chronic TTH and another option is Mirtazepine, a serotenergic and noradrenergic antidepressant.
  • The role of muscle relaxants in prevention of chronic TTH is debatable. Centrally acting muscle relaxant like Tizanidine may have some benefit.
  • Botulinum toxin is not recommended for chronic TTH.
  • Non pharmacological management include physical therapy, biofeedback, life style changes and psychological treatment.

Trigeminal-autonomic cephalgias (TAC)

  • TACs are a group of primary headache disorders with pain and / or autonomic features in the distribution of trigeminal nerve.
  • The TACs include cluster headache (CH), paroxysmal hemicrania (PH), hemicrania continua (HC), and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT), and short-lasting unilateral neuralgiform attacks with cranial autonomic symptoms (SUNA) but without tearing.
  • The TACs are uncommon, but are disabling and have a major impact on the patient’s quality of life.
  • These headache disorders are eminently treatable with highly selective drugs that are generally not used for Migraine or TTH.
  • Misdiagnosis is common and there could be a delay of several years before the correct diagnosis is made.
  • The TACs consist of severe headache attacks accompanied by prominent oculocephalic autonomic features ipsilateral to the headache.
  • The general diagnostic characteristics of this group are unilateral head pain predominantly affecting the Ophthalmic division of the trigeminal nerve associated with cranial autonomic symptoms with increased parasympathetic and decreased sympathetic activity.

Other primary headaches

Primary thunderclap headache

  • A severe headache of sudden onset reaching maximum intensity in less than a minute, is called a thunderclap headache.
  • However, a secondary cause of such a headache must be excluded especially that of sub arachnoid haemorrhage which could be a cause in 25 %, before concluding that this headache is primary.
  • Reversible cerebral vasoconstrictor syndrome, cervical artery dissection, spontaneous intracranial hypotension and cerebral venous thrombosis are other causes which need to be considered and excluded in persons with a sudden onset, severe headache.

Primary headache associated with sexual activity

  • Sexual activity could produce a bilaterally diffuse, or occipital headache lasting from 1 minute to 24 hours of severe intensity, which can be preorgasmic or orgasmic.
  • Orgasmic headache could be explosive in onset like a thunderclap and is followed by a severe generalised headache.
  • The lifetime prevalence is about 1%.
  • Secondary causes mentioned above for thunderclap headache need to be excluded and 5% of aneurysmal SAH can occur during sex in 5%.
  • Triptans are effective, and can be taken prior to sexual activity or also after occurrence for relief if not taken earlier. Indomethacin and topiramate also can be taken for prevention.

Primary exercise headache

  • Typically a bilateral throbbing headache lasting from minutes to hours related to  sustained physical exercise and usually not associated with nausea or vomiting is considered to be a primary exercise induced headache.
  • Occurs in about 10% of the population usually in the age range of 20 to 40 years.
  • Secondary pathology like space occupying lesions (SOLs) and vascular abnormalities should be excluded.
  • Indomethacin, propranolol and naproxen can be used for prevention.

Hypnic headache

  • This is a rare type of headache that occurs only during sleep and awakens the sufferer at a consistent time usually between 1 am to 4 am and can occur during daytime naps also.
  • Is not accompanied by nausea or autonomic symptoms and can be unilateral or bilateral, throbbing or non-throbbing, and can be mild or severe in intensity.
  • The duration can range from minutes to hours and can occur frequently but is usually once in a day.
  • Usually occurs in persons over 50 years and more often in females.
  • The best treatment is caffeine taken before going to sleep apart from lithium and indomethacin.

New Daily Persistent Headache (NDPH)

  • NDPH is a rare, idiopathic, persistent headache with a continuous, unremitting headache with a pin pointed onset and lasting for more than 3 months.
  • The headache is usually bilateral ranging from mild to severe and is present in any head region.
  • The age of onset ranges from 6 years to 70 years and is usually preceded by stress, infection, surgery.
  • NDPH is a diagnosis of exclusion after excluding a host of differential diagnosis like SOL, spontaneous intracranial hypotension and idiopathic intracranial hypertension, RCVS, cervical artery dissection, cerebral venous thrombosis, arterio venous malformation, sinusitis, meningitis, chiari malformation and temporal arteritis.
  • The headache is treated like Migraine or TTH, which it resembles.

Nummular headache

  • It is a recently described circumscribed head pain of mild to moderate intensity and is pressure like in nature with a remitting or chronic course.
  • It is a primary headache with no underlying lesion usually demonstrated.
  • Occurs in one precisely localised site in a small rounded area outlined with paresthesia, hyperesthesia, or dysesthesia on the affected area usually in the parietal region.
  • The particular topography suggests a probable epicranial source in a few terminal branches of the cutaneous nerves of the scalp.
  • Paracetamol would suffice for relief in most patients with this type of headache as it is not frequent.

Secondary Headaches

Secondary headaches are headaches with an underlying cause.

Post traumatic headache (PTH)

  • It is quite common after mild traumatic brain injury.
  • The onset should be within 7 days of trauma to quantify for a PTH.
  • This headache most often resembles Migraine or Tension Type headache and can also manifest as occipital, supra or infra orbital neuralgia, or temporo-mandibular disorder being localized rather than being diffuse or at multiple sites.
  • Is a persistent headache reported in 50 to 75% for 3 months and up to a year in a third of the patients. Noted to persist even up to 25% at 4 years.
  • These headaches are treated with medicines as used in for the primary headache which it resembles.

Alcohol hangover headache

  • May be associated with physical symptoms like anorexia, tremulousness, diarrhoea, dizziness, fatigue; sympathetic symptoms like tachycardia and sweating; cognitive and mood symptoms like decreased attention and concentration, anxiety, irritability.
  • Typically, it is a throbbing headache occurring on the morning after alcohol consumption and peaks when the blood alcohol concentration (BAC) is zero and continues upto 24 hours.
  • More common in mild to moderate drinkers and alcohol can also trigger migraine and cluster headache.
  • The effects may be decreased by drinking in moderation and sipping slowly, eating greasy foods before taking alcohol and taking honey in tomato juice and food rich in fructose and by ensuring good sleep.

High altitude headache (HAH)

  • Ascent to an altitude above 200 metres can produce acute mountain sickness with a bilateral headache of mild or moderate intensity in many, and resolves within 24 hours of descent to below 200 metres.
  • It can be associated with nausea, photophobia, vertigo and poor concentration.
  • The risk of HAH can be reduced with the use of aspirin taken three times at 4 hours interval and 1 hour before ascent, 4 doses in total. Ibuprofen three times a day starting 6 hours before ascent can also be given. Acetazolamide 125 mg every 12 hours starting a day prior to ascent is also effective.
  • This headache can be treated with paracetamol, ibuprofen and antiemetics.

Post Lumbar puncture headache

Post Dural Puncture headaches (PDPH) are typically bilateral frontal, occipital, or generalized throbbing or pressure – like headaches, worse when upright.
Occurs within 6 to 72 hours of the procedure and in the majority lasts less than 5 days.
Can be associated with nausea, vomiting, dizziness, neck stiffness and visual symptoms.
Younger (18 to 30) age group, female gender, prior chronic or recurrent headaches, large diameter needle are risk factors.
Bed rest, oral caffeine, normal saline infusion helps. Persistent headaches are treated with blood patch over the site of the dural puncture.

Spontaneous intracranial hypotension (SIH) or low CSF volume headaches

  • SIH results from spontaneous CSF leaks, typically at the spinal level (thoracic) and seldom at skull base level and can occur at all ages.
  • The headache occurs while upright and is relieved on lying down and hence can appear or get relieved on change of posture.
  • This headache usually has the characteristics of Tension Type headache and can evolve into a non-orthostatic chronic daily headache.
  • Can also occur as exertional headache, cough headache, acute thunderclap onset, second-half-of- the-day headaches, intermittent headaches.

SIH headache

  • This headache can be associated with neck stiffness or pain, nausea/vomiting, photo/ phonophobias, decreased hearing, tinnitus, or a sense of imbalance.
  • MRI Brain is abnormal in up to 80% and the most common abnormality is diffuse pachymeningeal enhancement.
  • The opening pressure of CSF on lumbar puncture is often low but could be normal as well with no specific attributes.
  • Treatment is like that of post dural puncture headaches.

Medication overuse headache (MOH)

  • Headache occurring for more than 15 days a month as a consequence of taking analgesics regularly for more than 3 months for relief of headache, is termed Medication Overuse Headache (MOH).
  • Is present in 1 to 2% of persons with Migraine or Tension Type headache and is diagnosed more often in headache clinics.
  • Treatment includes tapering off the over used medications usually analgesics and substituting with preventives.
  • Naproxen 500 mg twice daily can be given alone or in combination with Tizanidine for relief.

Reversible Cerebral Vasoconstriction Syndrome (RCVS)

  • This syndrome is characterised by multiple thunderclap headaches associated with nausea and vomiting with photophobia as a predominant manifestation.
  • Occurs more often in women in the age range of 20 to 50 years and occurs postpartum or after exposure to vasoactive drugs like cannabis, SSRI, Triptans, IVIg.
  • The defining feature of RCVS is vasoconstriction of cerebral vessels demonstrated on angio which reverses within 1 to 3 months.
  • Complications include cervical artery dissection, ischaemic or haemorrhagic stroke, cortical SAH, PRES (posterior reversible encephalopathy syndrome) and seizures.
  • Nimodipine, nifedipine and verapamil can be useful though there are no placebo-controlled trials for these medicines.


Trigeminal Neuralgia (TN)

The pain is on one side of the face and it should have at least 3 of the 4 below mentioned features to qualify for it to be a TN:
The pain should be paroxysmal and recurrent lasting for less than a second to 2 minutes.
Should be severe in intensity.
It should be electric shock like, shooting, stabbing, or sharp in quality.
Usually is precipitated by tactile stimuli like washing, toweling, chewing.
Snot be associated with a clinical neurological deficit.
It usually occurs in the 5th or 6th decade and is quite often caused by compression of the nerve by superior cerebellar artery, though secondary causes such as multiple sclerosis, neoplasms, and basilar artery aneurysm have to be considered.
The pain is most often in the Maxillary divison (V2) of the trigeminal nerve or in the Mandibular divison(V3).

Glossopharyngeal neuralgia

  • Causes severe stabbing pain on one side of the throat near the tonsils with occasional radiation to the ear.
  • Lasts from less than a second to 2 minutes.
  • Precipitated by swallowing, coughing, talking, or yawning.
  • Most have an artery pressing on the nerve as it exits the medulla and travels in the subarachnoid space. Other causes include tumours, MS, Paget’s disease, Sjögren’s syndrome.
  • Most often occurs in the 5th or 6th decade.

Occipital Neuralgia

The distribution of pain in the face according to the branches of the trigeminal nerve causing the pain.
Can involve the greater occipital nerve or lesser occipital nerve.
Paroxysms of electrical pain in the distribution of the nerve and could be referred to suboccipital, hemicranial, temporal, frontal, orbital, periorbital, or retro orbital distribution.
Lesser occipital neuralgia occurs over the lateral scalp superior and posterior to the ear and sometimes in the ear.
Tenderness over the involved nerve can be elicited with reproduction of symptoms.
Could be associated with hyperesthesia, dysesthesia, or paresthesia over the scalp area.
Primary and secondary headaches including temporal arteritis can mimic occipital neuralgia.

Headaches and sinus disease

  • A widely accepted definition of sinus disease has not been established.
  • Inflammation of the sinus is almost always preceded by rhinitis and hence the preferred term is rhino sinusitis.
  • Acute adult rhinosinusitis is of sudden onset and lasts for up to 4 weeks.
  • The examination should include anterior rhinoscopy, otoscopy, and oropharyngeal and neck examinations.
  • The task force identified major and minor clinical symptoms and signs for clinical diagnosis. Two or more major factors or one major and two minor factors are essential.

Major factors

  • Purulence in nasal cavity
  • Facial pain
  • Nasal obstruction
  • Fever
  • Hyposmia

Minor factors

  • Headache
  • Halitosis
  • Fatigue
  • Dental pain
  • Cough
  • Ear pain

  • The task force indicated that most cases can be diagnosed clinically.
  • Imaging of the sinuses and diagnostic nasal endoscopy is only for difficult cases.
  • CT scan is considered the gold standard for the diagnosis of chronic sinusitis.
  • In Frontal sinusitis, the headache is directly over the sinus and radiates to the vertex.
  • Maxillary sinusitis, the pain is over the Antral area radiating to upper teeth or forehead.
  • Ethmoidal sinusitis produces pain between and behind the eyes and in Sphenoidal sinusitis, the pain is in occipital, vertex and frontal region.

CME INDIA Learning Edge

When to investigate?

The ‘ Red Flags’ to consider for investigation are:
Acute or sudden onset of headache or the first or worst headache.
New onset and late onset of headache.
Progressive or worsening headache.
Headache with neurologic symptoms or signs.
  • Secondary headaches could simulate primary headaches or could occur in a person with a preexisting primary headache. Headaches seen in practice may not match with textbook descriptions. 
  • There is no investigation protocol that can be used individual for all headache patients and the investigation has to be customized for each depending on the provisional diagnosis.
  • Misdiagnosis could happen as we attribute all headaches to common conditions like migraine, hypertension, sinusitis, cervical spondylosis.
  • When a person presents with a headache the first goal should be to find out whether the headache is primary or secondary. This is done based on the description of the headaches outlined above.
  • Apart from Migraine and Tension Type headaches which in its typical presentation can be identified, the other primary headaches may have to be an exclusion diagnosis after excluding an underlying structural cause.
  • The significant causes which we would need to consider can be grouped for convenience as under: Raised Intracranial tension –
Space occupying lesions like – tumours, haematomas, abscess, granulomas. Hydrocephalus, cerebral venous sinus thrombosis, and Idiopathic Intracranial hypertension. The headaches are usually subacute or chronic and are rather persistent than being episodic. Associated symptoms and focal deficits apart from the sometimes only finding of papilledema would suggest the diagnosis.
Vascular causes – haemorrhages – Sub Arachnoid Haemorrhage (SAH) and Parenchymal haemorrhage (ICH), infarcts usually in the posterior circulation, Vasculitis like Giant Cell Arteritis (blindness), Reversible cerebral vasoconstrictor syndrome (RCVS), Cervical arterial dissections (Horner’s) are of acute to subacute onset and could be associated with focal deficits and signs as mentioned above.
Infective causes like meningitis, encephalitis, granulomas are usually associated with constitutional symptoms of fever, malaise, neck stiffness, seizures.
Following Trauma, post traumatic headaches are common and the trauma could de novo cause headache but more often exacerbates or unmasks the underlying migraine or Tension Type headache.
Low pressure headache as in post lumbar puncture and in spontaneous intracranial hypotension (SIH).


  4. Kulkarni GB, Rao GN, Gururaj G, Stovner LJ, Steiner TJ. Headache disorders and public ill-health in India: prevalence estimates in Karnataka State. J Headache Pain. 2015;16:67. doi: 10.1186/s10194-015-0549-x. Epub 2015 Jul 22. PMID: 26197976; PMCID: PMC4510104.

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