Focal cerebral ischemia – A stroke occurring in a localized area that can either be acute or transient. This may be due to a variety of medical conditions such as an aneurysm that causes a hemorrhagic stroke, or an occlusion occurring in the affected blood vessels due to a thrombus (thrombotic stroke) or embolus (embolic stroke). Focal cerebral ischemia constitutes a large majority of the clinical cases in stroke pathology with the infarct usually occurring in the middle cerebral artery (MCA). Global cerebral ischemia – A complete stoppage of blood flow to the brain. Cerebral infarction – A "stroke",  caused by complete oxygen deprivation due to an interference in cerebral blood flow which affects multiple areas of the brain.Cerebral hypoxia can also be classified by the cause of the reduced brain oxygen:
Hypoxic hypoxia – Limited oxygen in the environment causes reduced brain function. Divers, aviators, mountain climbers, and fire fighters are all at risk for this kind of cerebral hypoxia. The term also includes oxygen deprivation due to obstructions in the lungs. Choking, strangulation, the crushing of the windpipe all cause this sort of hypoxia. Severe asthmatics may also experience symptoms of hypoxic hypoxia. Hypemic hypoxia – Reduced brain function is caused by inadequate oxygen in the blood despite adequate environmental oxygen. Anemia and carbon monoxide poisoning are common causes of hypemic hypoxia. Ischemic hypoxia ( or "stagnant hypoxia") – Reduced brain oxygen is caused by inadequate blood flow to the brain. Stroke, shock, cardiac arrest and heart attack may cause stagnant hypoxia.
In rats treated with estradiol, iodine deficiency has been shown to lead to changes similar to benign breast changes that are reversible by increased iodine in the diet. In a few studies, iodine supplementation had beneficial effects (such as reducing the presence of breast cyst, fibrous tissue plaques and breast pain) in women with fibrocystic breast changes.Protective effects of iodine on breast cancer have been postulated from epidemiologic evidence and described in animal models. In view of the antiproliferative properties of iodine in breast tissue, molecular iodine supplementation has been suggested as an adjuvant in breast cancer therapy. Risk factors
Following is a list of potential risk factors that may lead to iodine deficiency:
Low dietary iodine
Selenium deficiency
Pregnancy
Exposure to radiation
Increased intake/plasma levels of goitrogens, such as calcium
Sex (higher occurrence in women)
Smoking tobacco
Alcohol (reduced prevalence in users)
Oral contraceptives (reduced prevalence in users)
Perchlorates
Thiocyanates
Age (for different types of iodine deficiency at different ages)

Pathophysiology
Iodine accounts for 65% of the molecular weight of T4 and 59% of T3. There is a total of 15–20 mg of iodine in the human body, primarily concentrated in thyroid tissue and hormones. Thirty percent of iodine is distributed in other tissues, including the mammary glands, eyes, gastric mucosa, choroid plexus, arterial walls, the cervix, and salivary glands. In the cells of these tissues, iodide enters directly by sodium-iodide symporter (NIS). Venturi S, Guidi A, Venturi M (1996). "[Extrathyroid iodine deficiency disorders: what is the real iodine requirement?]"". Le Basi Razionali della Terapia. 16: 267–275. Pellerin P (1961). "La tecnique dautoradiographie anatomique a la temperature de lazote liquide".