Paroxysmal Hemicrania is a rare primary headache disorder characterized by severe, unilateral (one-sided) head pain that occurs in brief, recurring episodes or attacks. The pain is usually located in the temple, eye, or face and can be accompanied by ipsilateral (same side) autonomic symptoms such as redness of the eye, tearing, nasal congestion, or sweating.

The headaches typically last between 2-30 minutes and occur several times a day, often increasing in frequency over time. The disorder predominantly affects women and tends to begin in middle age. Paroxysmal Hemicrania is considered a type of trigeminal autonomic cephalalgia (TAC) and is thought to be caused by abnormal activation of the trigeminovascular system, which supplies nerves to the head and face.

The disorder is uniquely responsive to indomethacin, a nonsteroidal anti-inflammatory drug (NSAID), with most patients experiencing complete or significant relief at doses of 150-225 mg/day. Failure to respond to indomethacin should raise suspicion for other types of headache disorders.

Trigeminal Autonomic Cephalalgias (TACs) is a group of primary headache disorders characterized by unilateral, severe head pain associated with ipsilateral cranial autonomic features. The International Classification of Headache Disorders, 3rd edition (ICHD-3) classifies TACs into four types:

1. Cluster Headache: Severe, strictly unilateral, orbital, supraorbital, or temporal pain lasting 15 minutes to three hours and occurring in clusters (usually at the same time of day for several weeks or months). The attacks are associated with ipsilateral cranial autonomic symptoms such as conjunctival injection, lacrimation, nasal congestion, rhinorrhea, forehead sweating, eyelid edema, and/or pupillary miosis.
2. Paroxysmal Hemicrania: Short-lasting (2-30 minutes) but recurrent attacks of severe unilateral head pain accompanied by ipsilateral cranial autonomic features. The attacks occur more than five times a day and are often associated with agitation or restlessness during the attack.
3. Short-lasting Unilateral Neuralgiform Headache Attacks (SUNHA): This category includes two subtypes: SUNCT (Short-lasting Unilateral Neuralgiform headache attacks with Conjunctival injection and Tearing) and SUNA (Short-lasting Unilateral Neuralgiform headache attacks with Autonomic symptoms). These disorders are characterized by moderate to severe unilateral head pain lasting 5 minutes to 6 hours, accompanied by cranial autonomic features.
4. Hemicrania Continua: A continuous, strictly unilateral headache of mild to moderate intensity with occasional exacerbations of severe pain. The attacks are associated with ipsilateral cranial autonomic symptoms and/or migrainous features such as photophobia, phonophobia, or nausea.

TACs are considered rare disorders, and their pathophysiology is not entirely understood. However, it is believed that they involve the trigeminal nerve and its connections to the brainstem. Treatment typically involves medications targeting the underlying mechanisms of these headaches, such as triptans for migraine-like features or anticonvulsants for neuralgiform pain. In some cases, invasive procedures like nerve blocks or neurostimulation may be considered.

A cluster headache is a type of primary headache disorder characterized by severe, one-sided headaches that occur in clusters, meaning they happen several times a day for several weeks or months and then go into remission for a period of time. The pain of a cluster headache is typically intense and often described as a sharp, stabbing, or burning sensation around the eye or temple on one side of the head.

Cluster headaches are relatively rare, affecting fewer than 1 in 1000 people. They tend to affect men more often than women and usually start between the ages of 20 and 50. The exact cause of cluster headaches is not fully understood, but they are thought to be related to abnormalities in the hypothalamus, a part of the brain that regulates various bodily functions, including hormone production and sleep-wake cycles.

Cluster headache attacks can last from 15 minutes to several hours and may be accompanied by other symptoms such as redness or tearing of the eye, runny nose, sweating, or swelling on the affected side of the face. During a cluster period, headaches typically occur at the same time each day, often at night or in the early morning.

Cluster headaches can be treated with various medications, including triptans, oxygen therapy, and local anesthetics. Preventive treatments such as verapamil, lithium, or corticosteroids may also be used to reduce the frequency and severity of cluster headache attacks during a cluster period.

SUNCT syndrome, an acronym for Short-lasting Unilateral Neuralgiform headache attacks with Conjunctival injection and Tearing, is a rare and severe type of headache disorder. It is characterized by recurrent episodes of intense, one-sided (unilateral) head pain that typically lasts for a short duration (less than 5 minutes). The headaches are often described as stabbing or piercing and can be triggered by various stimuli such as touch, movement, or temperature changes.

In addition to the head pain, SUNCT syndrome is also associated with autonomic symptoms, including redness (conjunctival injection) and tearing of the eye on the same side as the headache. Other possible autonomic symptoms include sweating, nasal congestion, and pupil changes.

SUNCT syndrome can be challenging to diagnose and treat due to its rarity and severity. It is typically managed with a combination of medications, including anti-epileptic drugs, and in some cases, invasive procedures such as nerve blocks or neurostimulation may be considered.

Indomethacin is a non-steroidal anti-inflammatory drug (NSAID) that is commonly used to reduce pain, inflammation, and fever. It works by inhibiting the activity of certain enzymes in the body, including cyclooxygenase (COX), which plays a role in producing prostaglandins, chemicals involved in the inflammatory response.

Indomethacin is available in various forms, such as capsules, suppositories, and injectable solutions, and is used to treat a wide range of conditions, including rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, gout, and bursitis. It may also be used to relieve pain and reduce fever in other conditions, such as dental procedures or after surgery.

Like all NSAIDs, indomethacin can have side effects, including stomach ulcers, bleeding, and kidney damage, especially when taken at high doses or for long periods of time. It may also increase the risk of heart attack and stroke. Therefore, it is important to use indomethacin only as directed by a healthcare provider and to report any unusual symptoms or side effects promptly.

Primary headache disorders are a group of headaches that are not caused by an underlying medical condition or structural problem. They are considered to be separate medical entities and include:

1. Migraine: A recurring headache that typically causes moderate to severe throbbing pain, often on one side of the head. It is commonly accompanied by nausea, vomiting, and sensitivity to light and sound.
2. Tension-type headache (TTH): The most common type of headache, characterized by a pressing or tightening sensation around the forehead or back of the head and neck. It is usually not aggravated by physical activity and does not cause nausea or vomiting.
3. Cluster headache: A rare but extremely painful type of headache that occurs in clusters, meaning they happen several times a day for weeks or months, followed by periods of remission. The pain is usually one-sided, centered around the eye and often accompanied by redness, tearing, and nasal congestion.
4. New daily persistent headache (NDPH): A type of headache that starts suddenly and persists every day for weeks or months. It can be similar to tension-type headaches or migraines but is not caused by an underlying medical condition.
5. Trigeminal autonomic cephalalgias (TACs): A group of primary headache disorders characterized by severe pain on one side of the head, often accompanied by symptoms such as redness, tearing, and nasal congestion. Cluster headaches are a type of TAC.
6. Other primary headache disorders: These include rare conditions such as hemicrania continua, paroxysmal hemicrania, and short-lasting unilateral neuralgiform headache attacks.

Primary headache disorders can significantly impact a person's quality of life and ability to function. Treatment typically involves medication, lifestyle changes, and behavioral therapies.

A headache is defined as pain or discomfort in the head, scalp, or neck. It can be a symptom of various underlying conditions such as stress, sinus congestion, migraine, or more serious issues like meningitis or concussion. Headaches can vary in intensity, ranging from mild to severe, and may be accompanied by other symptoms such as nausea, vomiting, or sensitivity to light and sound. There are over 150 different types of headaches, including tension headaches, cluster headaches, and sinus headaches, each with their own specific characteristics and causes.

A migraine disorder is a neurological condition characterized by recurrent headaches that often involve one side of the head and are accompanied by various symptoms such as nausea, vomiting, sensitivity to light and sound, and visual disturbances. Migraines can last from several hours to days and can be severely debilitating. The exact cause of migraines is not fully understood, but they are believed to result from a combination of genetic and environmental factors that affect the brain and blood vessels. There are different types of migraines, including migraine without aura, migraine with aura, chronic migraine, and others, each with its own specific set of symptoms and diagnostic criteria. Treatment typically involves a combination of lifestyle changes, medications, and behavioral therapies to manage symptoms and prevent future attacks.

Headache disorders refer to a group of conditions characterized by recurrent headaches that cause significant distress and impairment in daily functioning. The most common types of headache disorders are tension-type headaches, migraines, and cluster headaches.

Tension-type headaches are typically described as a dull, aching sensation around the head and neck, often accompanied by tightness or pressure. Migraines, on the other hand, are usually characterized by moderate to severe throbbing pain on one or both sides of the head, often accompanied by nausea, vomiting, sensitivity to light and sound, and visual disturbances.

Cluster headaches are relatively rare but extremely painful, with attacks lasting from 15 minutes to three hours and occurring several times a day for weeks or months. They typically affect one side of the head and are often accompanied by symptoms such as redness and tearing of the eye, nasal congestion, and sweating on the affected side of the face.

Headache disorders can have a significant impact on quality of life, and effective treatment often requires a multidisciplinary approach that may include medication, lifestyle changes, and behavioral therapies.

The ophthalmic nerve, also known as the first cranial nerve or CN I, is a sensory nerve that primarily transmits information about vision, including light intensity and color, and sensation in the eye and surrounding areas. It is responsible for the sensory innervation of the upper eyelid, conjunctiva, cornea, iris, ciliary body, and nasal cavity. The ophthalmic nerve has three major branches: the lacrimal nerve, frontal nerve, and nasociliary nerve. Damage to this nerve can result in various visual disturbances and loss of sensation in the affected areas.