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Amyotrophic lateral sclerosis
von Hippel-Lindau disease
Acoustic neuroma (schwannoma)
Adult brain tumors
Pediatric brain tumors
Transient ischemic attack
Cavernous sinus thrombosis
Spinocerebellar ataxia (NORD)
Tethered spinal cord syndrome
Lewy body dementia
Normal pressure hydrocephalus
Acute disseminated encephalomyelitis
Central pontine myelinolysis
JC virus (Progressive multifocal leukoencephalopathy)
Idiopathic intracranial hypertension
Opsoclonus myoclonus syndrome (NORD)
Restless legs syndrome
Early infantile epileptic encephalopathy (NORD)
Cauda equina syndrome
Treponema pallidum (Syphilis)
Vitamin B12 deficiency
Concussion and traumatic brain injury
Spinal muscular atrophy
Carpal tunnel syndrome
Thoracic outlet syndrome
Lambert-Eaton myasthenic syndrome
Adult brain tumors: Pathology review
Central nervous system infections: Pathology review
Cerebral vascular disease: Pathology review
Congenital neurological disorders: Pathology review
Dementia: Pathology review
Demyelinating disorders: Pathology review
Headaches: Pathology review
Movement disorders: Pathology review
Neurocutaneous disorders: Pathology review
Neuromuscular junction disorders: Pathology review
Pediatric brain tumors: Pathology review
Seizures: Pathology review
Spinal cord disorders: Pathology review
Traumatic brain injury: Pathology review
Arterio refers to the arteries, which are the the blood vessels that take blood away from the heart. Venous refers to the veins, which carry blood toward the heart. Mal means “badly,” so an arteriovenous malformation, or AVM, is some sort of “bad” or abnormal formation between the arteries and veins.
Typically, oxygen-rich blood is carried to the body’s tissues via arteries. Large arteries split into smaller and smaller arteries, and feed into capillary beds, where cells exchange oxygen for carbon dioxide. The capillaries then feed into larger and larger veins, which carry deoxygenated blood away from the tissues. Normally, arterial blood is under a high-pressure system, and as it goes through smaller and smaller vessels, and ultimately into the capillary bed, pressure in the vessels becomes significantly lower, and blood drains into the lower pressure systemic veins. So, this capillary bed dampens the arterial flow a bit.
With AVM, this whole capillary bed isn’t there, and a group of arteries directly link up with a group of veins instead. The vessels in the AVM can start to tangle up and are called a nidus, which is Latin for “nest.” When a single artery and a single vein link up abnormally like this, it’s called an arteriovenous fistula.
In AVM, the arteries and the veins are both under high systolic blood pressures because there are no capillaries to dampen the pressure, which means that the AVM can expand in size over time and can put pressure on the surrounding tissue. This pressure on surrounding capillaries can pinch them shut and prevent that functional tissue from getting blood flow. Also, the high pressure causes the arteries supplying blood to dilate and the veins to thicken and undergo fibrosis. Vessel walls are also prone to forming aneurysms, which are these balloon-like protrusions. Because the vessel walls are weakened and stretched out, they are also at risk for ripping and tearing.
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