Disorders associated with headache

Headaches may be primary, when the headache itself is the disease e.g. in migraine, or it may be secondary to other processes like increased intracranial pressure, meningitis, dehydration, sinusitis etc.

(I) Migraine: It is a recurrent, often disabling headache of neurovascular origin more commonly seen in females. It has a genetic predilection. It is often associated with prodromal symptoms and an aura before the onset of the actual headache. An aura is defined as any neurological symptom that arises before the headache of migraine. More than 90% of auras are visual, consisting either of positive phenomena (flicker, “fortification figures”, flashes of light) or of negative phenomena (such as hemianopsia). Sometimes non-visual aura symptoms are seen, such as tingling on the face, arm or leg on one side of the body, or aphasia. Prodrome precedes several hours before with hypothalamus (fatigue, depression, irritability, food cravings, and yawning), brainstem (muscle tenderness and neck stiffness), cortex (abnormal sensitivity to light, sound, and smell), and limbic system (depression and anhedonia) features. The headache typically throbs, intensifies with an increase in intracranial pressure, and presents itself in association with nausea, vomiting, and abnormal sensitivity to light, noise, and smell. It can also be accompanied by abnormal skin sensitivity (allodynia) and muscle tenderness.

Depending on presentation, migraine can be classified as in the table below. It can also be classified as migraine with and without aura. Chronic migraine is defined as headaches that have been present on at least 15 days per month for at least 3 consecutive months.

Types of migraine

Migraine aura is caused by cortical spreading depression, a slowly propagating wave of depolarization/excitation followed by hyperpolarization/inhibition in cortical neurons and glia. The initial membrane depolarization is associated with a large efflux of potassium; influx of sodium and calcium; release of glutamate, ATP, and hydrogen ions; neuronal swelling, breakdown of the blood–brain barrier and inflammation.

Headache in migraine is caused by a complex interaction between the cortical, subcortical structures with the meninges, blood vessels and peripheral nervous system. The trigeminocervical complex consists of the trigeminal nucleus along with the dorsal horn of C1–C2 segments of the spinal cord. It consists of peripheral axons from the trigeminal ganglion that reach the meninges and intracranial arteries and converge centrally in the trigeminocervical complex releasing, among other transmitters, calcitonin gene-related peptide (CGRP). Brainstem nuclei—including the rostral ventral medulla, the locus coeruleus, the superior salivatory and cuneiform nucleus—modulate trigeminovascular pain transmission and autonomic responses in migraine. The hypothalamus has direct and indirect anatomical connections to the thalamus, trigeminovascular neurons and sympathetic and parasympathetic brainstem nuclei, supporting its role in nociceptive and autonomic modulation in migraine patients. Preganglionic parasympathetic neurons in the superior salivatory nucleus release acetylcholine, vasoactive intestinal peptide, and nitric oxide from meningeal terminals of postganglionic parasympathetic neurons in the sphenopalatine ganglion , leading to dilation of intracranial blood vessels, plasma protein extravasation, and local release of inflammatory molecules capable of activating pial and dural branches of meningeal nociceptors. In familial migraines, genetic mutations in proteins that participate in the regulation of glutamate neurotransmission and synaptic plasticity predispose to generalized neuronal hyperexcitability and migraine.

(II) Tension headache: It is of moderate intensity, holocranial (entire head) or band like or occipitofrontal , dull or pressing headache often precipitated by stress, more commonly in females. Chronic stress, low cortisol levels and hippocampal atrophy , spasm of neck and scalp muscles may be seen. It is the most common headache in adults.

(III) Cluster headache: It presents as severe pain in the orbital and periorbital area that is associated with conjunctival redness, lacrimation, nasal congestion, rhinorrhea, facial sweating, miosis, ptosis of eyelid edema. It tends to appear in clusters of up to eight times a day. Posterior hypothalamus area is activated during an episode. Substance P and histamine have been implicated as pain mediators of cluster headache. It is more common in males and may be precipitated by alcohol. Patients may have suicidal tendencies.

(IV) Trigeminal neuralgia or tic douloureux: It is a chronic pain condition that affects the trigeminal or Vth cranial nerve. The typical or “classic” form of the disorder (called “Type 1” or TN1) causes extreme, sporadic, sudden burning or shock-like facial pain that lasts anywhere from a few seconds to as long as two minutes per episode. These attacks can occur in quick succession, in volleys lasting as long as two hours. The “atypical” form of the disorder (called “Type 2” or TN2), is characterized by constant aching, burning, stabbing pain of somewhat lower intensity than Type 1. Pain can be present along the ophthalmic, maxillary or mandibular branches of the trigeminal nerve. The intense flashes of pain can be triggered by vibration or contact with the cheek (such as when shaving, washing the face, or applying makeup), brushing teeth, eating, drinking, talking, or being exposed to the wind. Pain is often accompanied with facial spasms or tics.

Trigeminal neuralgia is more common in 60-70 year old females. Focal trigeminal nerve demyelination, arterial or venous compression, compression or damage to the trigeminal nerve, neoplasms etc can cause trigeminal neuralgia. Most cases are idiopathic. Patients suffering from multiple sclerosis or hypertension are at increased risk of trigeminal neuralgia. It may lead to depression and suicidal tendencies.

(V) Mixed headaches: Headaches with characters of migraine and tension headaches are called mixed headaches.

(VI) Ice pick headache: Also called as primary stabbing headache, it is associated with brief stabs or jabs of pain, mostly in the frontal or temporal area. It is more common in women. It may be associated with nausea, vomiting and photophobia. No accompanying autonomic phenomena (as seen in cluster headaches) are seen. Some cases are secondary to herpes zoster, stroke, meningioma or multiple sclerosis.

(VII) Temporal arteritis or Giant cell arteritis: Seen in older females, presents with headache, claudication of the jaw, visual disturbances and scalp tenderness. Fever, elevated ESR and fatigue may be present. Involvement of the opthalmic artery may cause blindness. It is more common in individuals with Northern European ancestry.

(VIII) Medication overuse headaches: Medication overuse headache is defined as a headache of 15 days or more per month that is regarded as a consequence of regular overuse of headache medication in a patient with a pre-existing headache. It is more common in women, in those with anxiety and depression. Use of caffeine containing over-the-counter combination analgesics, tranquilizers, triptans or opioids for the treatment of migraine is associated with greater risk of medication overuse headache.