7 Key Symptoms of Arteriovenous Malformation You Should Know

Arteriovenous malformation (AVM) is a rare condition characterized by abnormal connections between arteries and veins, bypassing the normal capillary system. These tangles of blood vessels can occur anywhere in the body but are most concerning when they develop in the brain or spine. AVMs can disrupt normal blood flow and oxygen circulation, potentially leading to serious complications. While some people with AVMs may never experience symptoms, others may face life-threatening situations. Understanding the symptoms of arteriovenous malformation is crucial for early detection and appropriate medical intervention.

The symptoms of AVM vary significantly depending on the location, size, and severity of the malformation. Some individuals may live their entire lives without knowing they have an AVM, while others experience sudden and severe symptoms. Recognition of these warning signs can be life-saving, as untreated AVMs carry risks of bleeding, stroke, and permanent neurological damage.

1. Severe and Persistent Headaches

Headaches are one of the most common symptoms reported by individuals with arteriovenous malformation, particularly when the AVM is located in the brain. These headaches often differ from typical tension headaches or migraines in their characteristics and intensity.

The headaches associated with AVM tend to be:

• Localized: Pain often occurs on one side of the head, typically corresponding to the location of the malformation
• Severe and throbbing: The pain can be intense and pulsating, similar to migraine headaches but often more persistent
• Progressive: Headaches may worsen over time as the AVM grows or if there is bleeding
• Resistant to standard pain relievers: Over-the-counter medications may provide minimal or no relief

These headaches occur because the abnormal blood vessels create increased pressure and turbulent blood flow in the surrounding brain tissue. The brain tissue itself doesn’t feel pain, but the stretching of blood vessel walls and surrounding membranes triggers pain receptors. Some patients describe a constant, dull ache that occasionally intensifies into severe episodes. If you experience new, unusual, or increasingly severe headaches, especially those accompanied by other neurological symptoms, seeking immediate medical evaluation is essential.

2. Seizures and Convulsions

Seizures represent one of the most alarming and common presenting symptoms of arteriovenous malformation, particularly in younger patients. Approximately 20-25% of people with brain AVMs experience seizures as their first noticeable symptom.

AVM-related seizures can manifest in various forms:

• Focal seizures: These affect only one part of the brain and may cause twitching, numbness, or unusual sensations in specific body parts
• Generalized seizures: These involve the entire brain and can cause loss of consciousness, full-body convulsions, and muscle rigidity
• Absence seizures: Brief episodes of staring or loss of awareness that may be mistaken for daydreaming

Seizures occur because the abnormal blood vessels irritate the surrounding brain tissue, disrupting normal electrical activity. The brain tissue around the AVM may not receive adequate oxygen and nutrients due to the disrupted blood flow, making neurons more excitable and prone to abnormal firing patterns. Additionally, if the AVM has bled even slightly, the presence of blood breakdown products can further irritate brain tissue and lower the seizure threshold.

The onset of seizures in a previously healthy individual, especially in late childhood, adolescence, or early adulthood, should prompt investigation for possible AVM. These seizures may be difficult to control with standard anti-seizure medications until the underlying AVM is addressed.

3. Neurological Deficits and Weakness

Neurological deficits refer to the loss or impairment of normal brain and nervous system functions. These symptoms can develop gradually or appear suddenly, depending on whether the AVM is slowly affecting surrounding tissue or has caused acute bleeding.

Common neurological deficits associated with AVM include:

• Muscle weakness: Weakness may affect one side of the body (hemiparesis) or specific limbs, making it difficult to perform everyday tasks like walking, grasping objects, or maintaining balance
• Paralysis: In severe cases, complete loss of movement in affected body parts may occur
• Coordination problems: Difficulty with fine motor skills, balance, and coordinated movements
• Numbness or tingling: Altered sensations in the face, arms, or legs

These deficits occur because the AVM diverts blood flow away from normal brain tissue, creating areas of chronic ischemia (insufficient blood supply). The brain regions responsible for motor control and sensory processing may not receive adequate oxygen and nutrients, leading to functional impairment. The specific type of weakness or deficit depends on which area of the brain is affected by the AVM.

Neurological deficits may fluctuate, sometimes improving temporarily before worsening again. Progressive or sudden onset of weakness should be treated as a medical emergency, as it may indicate AVM rupture or significant expansion.

4. Vision Problems and Visual Disturbances

Vision problems are particularly common when an arteriovenous malformation affects areas of the brain responsible for processing visual information, such as the occipital lobe, or when the AVM is located near the optic pathways.

Visual symptoms can include:

• Blurred or double vision: Difficulty focusing or seeing two images instead of one
• Visual field defects: Loss of vision in specific areas of the visual field, such as peripheral vision or half of the visual field in both eyes
• Visual hallucinations: Seeing flashing lights, geometric patterns, or other visual phenomena that aren’t actually present
• Difficulty with depth perception: Problems judging distances or spatial relationships
• Partial or complete vision loss: In severe cases, particularly after AVM rupture

The abnormal blood vessels can compress or damage the optic nerves or the visual processing centers in the brain. Additionally, the altered blood flow patterns can create areas of reduced oxygen delivery to visual pathways. Some patients experience temporary visual disturbances that come and go, while others may develop progressive vision loss.

Visual symptoms associated with AVM can sometimes be mistaken for migraines with aura, but they tend to be more persistent and may not follow the typical pattern of migraine visual disturbances. Any unexplained vision changes, especially when accompanied by other neurological symptoms, warrant immediate medical attention.

5. Speech and Language Difficulties

When an arteriovenous malformation affects language centers in the brain, typically located in the left hemisphere for most people, various speech and language problems can develop. These symptoms can significantly impact daily communication and quality of life.

Speech and language difficulties may manifest as:

• Aphasia: Difficulty understanding or producing language, including trouble finding the right words or comprehending what others say
• Dysarthria: Slurred or slow speech due to weakness or lack of coordination in the muscles used for speaking
• Word-finding difficulties: Pausing frequently while speaking as the person struggles to recall specific words
• Reading and writing problems: Difficulty with written language comprehension or production
• Verbal comprehension issues: Trouble following conversations or understanding complex instructions

These language impairments occur when the AVM disrupts normal function in Broca’s area (responsible for speech production) or Wernicke’s area (responsible for language comprehension), or the connections between these regions. The abnormal blood flow patterns can deprive these critical language centers of adequate oxygen and nutrients.

Language difficulties can be particularly distressing for patients and may develop gradually or appear suddenly if bleeding occurs. The severity can range from mild word-finding difficulties to complete inability to communicate verbally. Early recognition of these symptoms is important for prompt diagnosis and management.

6. Cognitive and Concentration Problems

Arteriovenous malformations can significantly impact cognitive functions, affecting a person’s ability to think clearly, remember information, and maintain focus. These subtle symptoms may develop gradually and sometimes go unrecognized until they become more severe.

Cognitive symptoms associated with AVM include:

• Memory impairment: Difficulty forming new memories or recalling information, affecting both short-term and long-term memory
• Concentration difficulties: Trouble maintaining attention on tasks, easily distracted, or unable to focus for normal periods
• Mental confusion: Episodes of disorientation, difficulty processing information, or unclear thinking
• Executive dysfunction: Problems with planning, organizing, decision-making, and problem-solving
• Slower processing speed: Taking longer to understand information or respond to questions
• Mental fatigue: Feeling mentally exhausted after cognitive tasks that were previously manageable

These cognitive changes occur because the AVM disrupts normal blood flow patterns in the brain, creating areas of chronic underperfusion. Brain regions responsible for higher-order thinking, memory formation, and executive functions require substantial oxygen and glucose to function optimally. When an AVM diverts blood away from these areas, cognitive performance suffers.

Family members or coworkers may notice these changes before the affected individual does, reporting that the person seems “different” or is not performing as well as usual. Students may experience declining academic performance, while working adults might struggle with tasks that were once routine. These symptoms can significantly impact quality of life and should not be dismissed as normal aging or stress.

7. Pulsatile Tinnitus and Unusual Sounds

Pulsatile tinnitus is a distinctive symptom that some people with arteriovenous malformation experience, particularly when the AVM is located near the ear or involves major blood vessels in the head and neck region. Unlike regular tinnitus, which presents as ringing or buzzing, pulsatile tinnitus has a rhythmic quality synchronized with the heartbeat.

Characteristics of AVM-related pulsatile tinnitus include:

• Whooshing or rushing sounds: A rhythmic noise that pulses in time with the heartbeat, often described as hearing blood flow
• Clicking or thumping sounds: Some patients describe hearing repetitive clicking or thumping noises
• One-sided occurrence: The sound is typically heard in one ear, corresponding to the location of the AVM
• Variation with activity: The sound may become louder during physical exertion, when lying down, or during times of increased blood pressure
• Constant or intermittent: Some people hear the sound continuously, while others experience it episodically

This symptom occurs because the abnormal, high-flow connections between arteries and veins create turbulent blood flow. The turbulence generates vibrations and sounds that can be transmitted through bone and tissue to the inner ear structures. The sound essentially represents the person hearing their own blood flowing through the abnormal vessels.

While pulsatile tinnitus can have various causes, its presence should prompt medical evaluation, especially when accompanied by other neurological symptoms. Unlike common tinnitus, pulsatile tinnitus associated with AVM may be audible to a physician using a stethoscope placed over the affected area (this is called a bruit). This objective finding can be an important clue in diagnosis.

The constant sound can be distressing and may interfere with concentration, sleep, and overall quality of life. Some patients report that the sound becomes louder during quiet moments, making it particularly bothersome at night.

Main Causes of Arteriovenous Malformation

Understanding the causes of arteriovenous malformation can help individuals better comprehend this complex condition, though it’s important to note that AVMs are generally not preventable. The causes include:

Congenital Development: The vast majority of AVMs are congenital, meaning they develop during fetal development in the womb. During normal embryonic development, the vascular system forms through a complex process where arteries and veins differentiate and capillaries develop to connect them. In AVM formation, this process is disrupted, resulting in direct connections between arteries and veins without the normal capillary bed. The exact cause of this developmental error remains unclear, and most cases occur sporadically without a clear hereditary pattern.

Genetic Factors: While most AVMs occur randomly, certain genetic conditions increase the risk of developing vascular malformations. Hereditary hemorrhagic telangiectasia (HHT), also known as Osler-Weber-Rendu syndrome, is an inherited disorder that causes AVMs to develop in multiple organs. Individuals with this condition have mutations in genes responsible for blood vessel formation. Other rare genetic syndromes may also be associated with increased AVM risk, though these account for a small minority of cases.

Trauma or Injury: Although rare, some AVMs may develop following head injury or trauma. These acquired AVMs can form as part of the healing process when blood vessels regenerate abnormally after damage. However, this represents a very small percentage of all AVMs, and the vast majority are present from birth, even if not diagnosed until later in life.

Unknown Factors: Despite advances in medical understanding, the precise triggers that cause the developmental abnormality leading to AVM formation remain largely unknown. Researchers continue to investigate potential environmental, genetic, and molecular factors that may contribute to AVM development. There is no evidence that maternal behaviors during pregnancy, such as diet or activities, cause AVMs to form.

It’s important to emphasize that AVMs are not caused by anything the patient or their parents did or didn’t do. They are not the result of lifestyle choices, infections, or environmental exposures in most cases.

Frequently Asked Questions

Can arteriovenous malformation go away on its own?

No, AVMs do not resolve spontaneously. Once formed, they typically persist throughout life unless treated. Some small AVMs may remain stable and never cause symptoms, while others may grow over time or rupture. Medical monitoring or intervention is usually necessary for diagnosed AVMs.

Are all AVMs life-threatening?

Not all AVMs are immediately life-threatening, but they do carry risks. The danger level depends on the AVM’s size, location, and characteristics. Brain AVMs pose the highest risk due to potential bleeding that could cause stroke or death. Many people with small, stable AVMs live normal lives with appropriate monitoring, while others require treatment to prevent complications.

At what age do AVM symptoms typically appear?

Although AVMs are present from birth, symptoms most commonly appear between ages 10 and 40, with peak diagnosis in the 20s and 30s. However, AVMs can be discovered at any age, including in elderly individuals who have never experienced symptoms, or in young children. Some remain asymptomatic throughout life and are only discovered incidentally during imaging for unrelated conditions.

Can you inherit arteriovenous malformation from your parents?

Most AVMs are not inherited and occur sporadically without any family history. However, certain genetic syndromes like hereditary hemorrhagic telangiectasia (HHT) can be passed down through families and increase AVM risk. If you have a family history of AVMs or HHT, genetic counseling may be beneficial.

Is it possible to have an AVM without any symptoms?

Yes, many people have asymptomatic AVMs that are discovered incidentally during brain imaging performed for other reasons. Studies suggest that a significant number of AVMs never cause symptoms throughout a person’s lifetime. However, even asymptomatic AVMs carry some risk of future bleeding or complications, which is why medical evaluation and monitoring are important once an AVM is discovered.

How is arteriovenous malformation diagnosed?

AVM diagnosis typically involves advanced imaging techniques. Magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) can visualize the abnormal blood vessels and their structure. Computed tomography (CT) scans may be used, especially in emergency situations. Cerebral angiography, where contrast dye is injected into blood vessels, provides the most detailed images and is considered the gold standard for AVM evaluation. Diagnosis is typically made by neurologists, neurosurgeons, or interventional neuroradiologists.

Can physical activity or stress cause an AVM to rupture?

While extreme physical exertion or severe stress can theoretically increase blood pressure and potentially contribute to AVM rupture, most ruptures occur spontaneously without any identifiable trigger. There is no evidence that normal daily activities, moderate exercise, or typical life stress causes AVMs to bleed. However, individuals with known AVMs should discuss activity restrictions with their healthcare provider, as recommendations may vary based on individual circumstances.

What should I do if I experience sudden severe headache or neurological symptoms?

Sudden severe headache, especially if described as “the worst headache of your life,” combined with neurological symptoms like weakness, vision changes, seizures, or altered consciousness, requires immediate emergency medical attention. Call emergency services or go to the nearest emergency room immediately. These symptoms could indicate AVM rupture or bleeding, which is a medical emergency requiring urgent treatment.

References:

• Mayo Clinic – Arteriovenous Malformation
• National Institute of Neurological Disorders and Stroke – Arteriovenous Malformation
• Johns Hopkins Medicine – Arteriovenous Malformation
• American Association of Neurological Surgeons – Arteriovenous Malformations
• NHS – Arteriovenous Malformation