Pathophysiology of Cluster Headache

    The pathophysiology of cluster headache is still remains unclear. However, there are several theories regarding the pathophysiology of Cluster headache. One theory is that the focus of the pathophysiology of cluster headache is located in the carotid artery which stimulates intracavernous pericarotis plexus. 

     This plexus stimulation received from branches 1 and 2 of the trigeminal nerve, superior cervical ganglia / SCG (sympathetic) and ganglia sphenopalatinum / SPG (parasympathetic). It is estimated, irritative focus in and around plexus carry impulses to the brain stem and cause pain in the periorbital region, retroorbital and forehead. Polisynaptic relationships in stimulating brain stem neurons in the intermediolateral columns of the spinal cord (sympathetic) and superior salivatorius nucleus (parasympathetic). Preganglioner fibers from nucleus carries impulses to stimulate the SCG (sympathetic) and resulted in the secretion of sweat on the forehead, as well as stimulation of the SPG (parasympathetic) for secretion of tears (lacrimation) and water nose (rinorrhea). There is another theory about the dysfunction of the hypothalamus, where there is a disturbance or alteration in the circadian rhythm of the patient. Besides regulatory changes hypothalamic hormones. Otherwise activation also occurs substantia grisea of the ipsilateral hypothalamus of pain, resulting in activation of the ipsilateral cranial autonomic to pain, and thalamus as the generator of cluster  headache.

      Unlike migraine and tension-type headache, cluster headache is generally not associated with triggers such as food, hormonal changes or stress. But in some people with cluster headache is a heavy drinker and a Severe smoker. Once the cluster period begins , the consumption of alcohol can trigger severe headaches within a few minutes. For this reason a lot of people with cluster headache abstain from alcohol during the cluster period. Triggers are the use of drugs such as nitroglycerin, which is used in patients with heart disease.

      The onset of cluster periods often after disruption of normal sleep patterns, such as during holidays or when starting a new job or a new work. Some people with cluster headache also apnea during sleep, a condition in which the walls of the throat collapse while the so repeatedly obstruct the airway during sleep .

Increased Sensitivity of Line Nerves

        Severe pain in cluster headache centered behind or around the eyes, in an area that is innervated by the trigeminal nerve, a major pain pathway. Stimulation of this nerve produces an abnormal reaction of the arteries that supply blood to the head. It will dilate blood vessels and cause pain.

         Some symptoms of cluster headache such as watery eyes, runny or stuffy nose and, eyelids hard and raised involving the autonomic nervous system. Nerves that are part of this system form a line at the base of the brain. When the trigeminal nerve in the activation, causing pain in the eyes, the autonomic nervous system is also activated by the so-called trigeminal autonomic reflex. The researchers believe that there is still an unknown process that involves inflammation or abnormal blood vessel activity in this region may be involved causing headaches.

Abnormal function of the hypothalamus

       Attacks usually occur in clusters like setting clock 24 hours a day. Cycle period clusters often follow seasonal patterns in one year. This pattern suggests that the body's biological clock involved. In the human biological clock located in the hypothalamus is located deep in the brain. Of the many functions of the hypothalamus, this section controls the sleep wake cycle and other internal rhythms. Abnormalities of the hypothalamus may explain the existence and timing of the cluster headache cycle. Studies have found increased activity in the hypothalamus during the occurrence of cluster headache. This increased activity is not found in people with migraine headaches such as.

      The study also found that people who have abnormal levels of certain hormones, including melatonin and testosterone, the hormone levels increased during the period of the cluster. Changes in these hormones are believed to be due to problems in the hypothalamus. Other researchers have found that people with cluster headache has a larger hypothalamus than those who do not have a cluster headache. It is still not known why this is such abnormalities.



Source
1. Picture: http://www.medscape.org/viewarticle/416383_7