Cystic hygromas most often occur in the neck where they are known as nuchal hygromas.A severe venous malformation is known as a lymphaticovenous malformation that also involves the lymph vessels. Arteriovenous malformation
Arteriovenous malformations occur between an artery and a vein. In the brain a cerebral arteriovenous malformation causes arterial blood to be directly shunted into the veins as there is an absence of a capillary bed. This carries a high risk of an intracranial hemorrhage. See also
Arteriovenous fistula
Lymphohemangioma
Telangiectasia
Vascular disease


== References ==
Dorzolamide, sold under the brand name Trusopt among others, is a medication used to treat high pressure inside the eye, including in cases of glaucoma. It is used as an eye drop. Effects begin within three hours and last for at least eight hours. It is also available as the combination dorzolamide/timolol.Common side effects include eye discomfort, eye redness, taste changes, and blurry vision. Serious side effects include Steven Johnson syndrome. Those allergic to sulfonamides may be allergic to dorzolamide. Use is not recommended in pregnancy or breastfeeding. It is a carbonic anhydrase inhibitor and works by decreasing the production of aqueous humour.Dorzolamide was approved for medical use in the United States in 1994. It is available as a generic medication. In 2017, it was the 281st most commonly prescribed medication in the United States, with more than one million prescriptions. It is a second-generation carbonic anhydrase inhibitor. Medical uses
Dorzolamide hydrochloride is used to lower excessive intraocular pressure in open-angle glaucoma and ocular hypertension. This drug is able to cross the cornea, reach the ciliary body of the eye, and produce systemic effects on the carbonic anhydrase enzyme within the eye. Side effects
Ocular stinging, burning, itching and bitter taste. It causes shallowing of the anterior chamber and leads to transient myopia. As a second generation carbonic anhydrase inhibitor, Dorzolamide avoids systemic effects associated with first generation carbonic anhydrase inhibitors such as Acetazolamide, Methazolamide, and Dichlorphenamide. Pharmacodynamics
Dorzolamide lowers intraocular pressure by about 20%.