Arteriovenous malformation (AVM)
is an abnormal connection between arteries and veins, bypassing the capillary system. This vascular anomaly is widely known because of its occurrence in the central nervous system, but can appear in any location. Although many AVMs are asymptomatic, they can cause intense pain or bleeding or lead to other serious medical problems.
AVMs are usually congenital and belong to the RASopathies.
The genetic transmission patterns of AVM, if any, are unknown.
AVM is not generally thought to be an inherited disorder, unless in the context of a specific hereditary syndrome.
Signs and symptoms
Symptoms of AVM vary according to the location of the malformation.
Roughly 88%[1]of people affected with AVM are asymptomatic; often the malformation is discovered as part of an autopsy or during treatment of an unrelated disorder, in rare cases its expansion or a micro-bleed from an AVM in the brain can cause epilepsy, neurological deficit or pain.
The most general symptoms of a cerebral AVM include
headache and epilepsy, with more specific symptoms occurring that normally depend on the location of the malformation and the individual.
Such possible symptoms include.
Difficulties with movement coordination, including muscle weakness and even paralysis;
vertigo (dizziness);
Difficulties of speech (dysarthria) and communication, such as aphasia;
Difficulties with everyday activities, such as
apraxia;
Abnormal sensations (numbness, tingling, or spontaneous pain);
Memory and thought-related problems, such as
confusion, dementia or hallucinations.
Cerebral AVMs may present in a number of ways
Hemorrhage (45% of cases) Acute onset of severe headache. May be described as the worst headache of the patient's life. Depending on the location of hemorrhage, may be associated with new fixed neurologic deficit.
In unruptured brain AVMs, the risk of spontaneous hemorrhage 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 place of 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 deficit depend on location of lesion and the draining veins.
Pediatric patients
Heart failure
Macrocephaly
Prominent scalp veins
Pulmonary arteriovenous malformations.
In the lungs, pulmonary arteriovenous malformations have no symptoms in up to 29% of cases.
Diagnosis
AVMs are diagnosed primarily by the following methods:
CT scan
MRI scan
Magnetic resonance angiography (MRA)
AVMs can occur in various parts of the body:
brain,
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 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 or particles or glue 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.
The Spetzler-Martin grading system developed at the Barrow Neurological Institute is utilized by neurosurgeons to determine operative versus nonoperative management of AVMs.
is an abnormal connection between arteries and veins, bypassing the capillary system. This vascular anomaly is widely known because of its occurrence in the central nervous system, but can appear in any location. Although many AVMs are asymptomatic, they can cause intense pain or bleeding or lead to other serious medical problems.
AVMs are usually congenital and belong to the RASopathies.
The genetic transmission patterns of AVM, if any, are unknown.
AVM is not generally thought to be an inherited disorder, unless in the context of a specific hereditary syndrome.
Signs and symptoms
Symptoms of AVM vary according to the location of the malformation.
Roughly 88%[1]of people affected with AVM are asymptomatic; often the malformation is discovered as part of an autopsy or during treatment of an unrelated disorder, in rare cases its expansion or a micro-bleed from an AVM in the brain can cause epilepsy, neurological deficit or pain.
The most general symptoms of a cerebral AVM include
headache and epilepsy, with more specific symptoms occurring that normally depend on the location of the malformation and the individual.
Such possible symptoms include.
Difficulties with movement coordination, including muscle weakness and even paralysis;
vertigo (dizziness);
Difficulties of speech (dysarthria) and communication, such as aphasia;
Difficulties with everyday activities, such as
apraxia;
Abnormal sensations (numbness, tingling, or spontaneous pain);
Memory and thought-related problems, such as
confusion, dementia or hallucinations.
Cerebral AVMs may present in a number of ways
Hemorrhage (45% of cases) Acute onset of severe headache. May be described as the worst headache of the patient's life. Depending on the location of hemorrhage, may be associated with new fixed neurologic deficit.
In unruptured brain AVMs, the risk of spontaneous hemorrhage 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 place of 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 deficit depend on location of lesion and the draining veins.
Pediatric patients
Heart failure
Macrocephaly
Prominent scalp veins
Pulmonary arteriovenous malformations.
In the lungs, pulmonary arteriovenous malformations have no symptoms in up to 29% of cases.
Diagnosis
AVMs are diagnosed primarily by the following methods:
CT scan
MRI scan
Magnetic resonance angiography (MRA)
AVMs can occur in various parts of the body:
brain,
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 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 or particles or glue 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.
The Spetzler-Martin grading system developed at the Barrow Neurological Institute is utilized by neurosurgeons to determine operative versus nonoperative management of AVMs.
