May be described as the worst headache of the patients life. Depending on the location of bleeding, may be associated with new fixed neurologic deficit. In unruptured brain AVMs, the risk of spontaneous bleeding may be as low as 1% per year. After a first rupture, the annual bleeding risk may increase to more than 5%. Seizure or brain seizure (46%) Depending on the place of the AVM, it can cause loss of vision in one place. Headache (34%)
Progressive neurologic deficit (21%)
May be caused by mass effect or venous dilatations. Presence and nature of the deficit depend on location of lesion and the draining veins. Pediatric patients
Heart failure
Macrocephaly
Prominent scalp veins

Pulmonary arteriovenous malformations
Pulmonary arteriovenous malformations are abnormal communications between the veins and arteries of the pulmonary circulation, leading to a right-to-left blood shunt. They have no symptoms in up to 29% of all cases, however they can give rise to serious complications including hemorrhage, and infection. They are most commonly associated with hereditary hemorrhagic telangiectasia. Genetics
Can occur due to autosomal dominant diseases, such as hereditary hemorrhagic telangiectasia. Pathophysiology
Arteries and veins are part of the vascular system. Arteries carry blood away from the heart to the lungs or the rest of the body, where the blood passes through capillaries, and veins return the blood to the heart. An AVM interferes with this process by forming a direct connection of the arteries and veins. AVMs can cause intense pain and lead to serious medical problems.
Additionally or alternatively, flow-dependent or other contrast-free magnetic resonance imaging techniques can be used to determine the location and other properties of the vasculature.AVMs can occur in various parts of the body:

brain (cerebral AV malformation)
spleen
lung
kidney
spinal cord
liver
intercostal space
iris
spermatic cord
extremities – arm, shoulder, etc.AVMs may occur in isolation or as a part of another disease (for example, Von Hippel-Lindau disease or hereditary hemorrhagic telangiectasia).AVMs have been shown to be associated with aortic stenosis.Bleeding from an AVM can be relatively mild or devastating. It can cause severe and less often fatal strokes. If a cerebral AVM is detected before a stroke occurs, usually the arteries feeding blood into the nidus can be closed off to avert the danger. However, interventional therapy may also be relatively risky. Treatment
Treatment for brain AVMs can be symptomatic, and patients should be followed by a neurologist for any seizures, headaches, or focal neurologic deficits. AVM-specific treatment may also involve endovascular embolization, neurosurgery or radiosurgery. Embolization, that is, cutting off the blood supply to the AVM with coils, particles, acrylates, or polymers introduced by a radiographically guided catheter, may be used in addition to neurosurgery or radiosurgery, but is rarely successful in isolation except in smaller AVMs. Gamma knife may also be used.Treatment of lung AVMs is typically performed with endovascular embolization alone, which is considered the standard of care. Epidemiology
The estimated detection rate of AVM in the US general population is 1.4/100,000 per year. This is approximately one fifth to one seventh the incidence of intracranial aneurysms.