What are the symptoms of Arteriovenous Malformations (AVMs) in different body systems?

Symptoms of Arteriovenous Malformations by Body System

AVMs present with dramatically different symptoms depending on their location, with many patients remaining asymptomatic (25-58%) until life-threatening complications occur, making location-specific symptom recognition critical for preventing mortality from hemorrhage, stroke, or organ failure. 1

Pulmonary (Lung) AVMs

Respiratory and Hypoxemia Symptoms

• Hypoxemia occurs in 27-71% of patients, manifesting at rest or during exercise 1
• Orthodeoxia (worsening hypoxemia when upright) and platypnea (worsening dyspnea when upright) are characteristic presentations, occurring because 65-83% of pulmonary AVMs are located in the lower lung lobes 1
• Dyspnea on exertion is common due to impaired gas exchange from right-to-left shunting 1

Neurological Complications from Paradoxical Embolism

• Transient ischemic attacks and cerebral strokes occur in 3.2-55% of patients due to loss of the pulmonary capillary bed's filtering function 1
• Cerebral abscesses develop in 0-25% of cases from systemic infections bypassing pulmonary filtration 1

Hemorrhagic Complications

• Massive hemoptysis and hemothorax are rare (0-2%) but represent life-threatening emergencies 1
• Pregnancy dramatically increases risk due to hormonal and hemodynamic changes causing rapid AVM growth with higher rupture risk 1

Brain (Cerebral) AVMs

Hemorrhagic Presentation

• Hemorrhage is the most common initial presentation (50-60% of all cases, >75% in children), representing the primary cause of mortality and morbidity 2, 3
• Mortality from first hemorrhage ranges 10-30%, with 10-20% of survivors experiencing permanent disability 4, 2
• Annual hemorrhage risk is approximately 2-3% per year for unruptured AVMs, increasing fivefold after initial rupture 4, 2, 3
• Recurrent hemorrhage risk is highest in the first year (6-32.9%) following initial bleeding 2

Seizure Presentation

• Seizures occur in 20-25% of adult cases as the presenting symptom 2, 5
• Seizures result from cortical irritation by the AVM and hemosiderin deposits from microhemorrhages 4

Headache and Other Symptoms

• Headaches present in approximately 15% of cases 2
• Neurological deficits may occur from mass effect or steal phenomenon affecting surrounding brain tissue 5, 3

Critical Risk Factors for Hemorrhage

• Prior hemorrhage is the strongest predictor of future bleeding 4, 2
• Small AVM size paradoxically increases hemorrhage risk 4, 2
• Presence of intranidal aneurysms, deep venous drainage, and periventricular location all increase rupture risk 4, 2

Hand and Extremity AVMs

Visual and Vascular Findings

• Visible clusters of abnormal vessels without solid mass, accompanied by warmth and pulsatile swelling are the hallmark presentation 6, 7
• Fast-flow on Doppler ultrasound showing arterialized flow in draining veins confirms the diagnosis 6
• The affected hand or digits feel warm to touch with palpable pulses even when ischemic 6

Progressive Ischemic Changes (Critical Warning Pattern)

The hand paradoxically shows inadequate blood flow despite increased vascular flow through the AVM, progressing through distinct stages: 6

1. Pale/blue and/or cold hand without pain (early stage)
2. Pain during exercise or activity (claudication)
3. Pain at rest (critical ischemia)
4. Ulcers, necrosis, or gangrene of fingertips (end-stage)

Surgical Emergency Presentation

• Fingertip necrosis shows initially slow progression over weeks, followed by rapid final deterioration leading to gangrene 6
• This represents a surgical emergency requiring immediate vascular surgery referral, as delay can result in catastrophic gangrene and hand amputation 6

Critical Diagnostic Pitfall

• The presence of a warm hand with palpable pulses does NOT exclude severe ischemia—this paradoxical finding occurs with steal phenomenon and represents a critical diagnostic trap that can delay life-saving intervention 6

Head and Neck AVMs (Region-Specific)

Cosmetic and Functional Manifestations

• Abnormal skin or mucosal findings with visible vascular abnormalities 7
• Progressive lesions that can worsen over time 7
• Region-specific complications affecting cosmetic appearance, ingestion, respiratory function, and neuronal function 7

Severe Complications

• Hemorrhage from mucosal or cutaneous surfaces 7
• Ischemia from steal phenomenon 7
• High-output heart failure in severe, extensive cases 7

Associated Systemic Condition: Hereditary Hemorrhagic Telangiectasia (HHT)

Multi-System Involvement

• 70-90% of pulmonary AVMs occur with HHT, an autosomal dominant disorder 1, 4
• HHT type 1 (endoglin mutation) presents with cerebral and pulmonary AVMs 1
• HHT type 2 (ALK1 mutation) presents with pulmonary hypertension and hepatic AVMs 1
• SMAD4 mutation (1-2% of HHT patients) associates with juvenile polyposis syndrome 1

General AVM Characteristics Across All Systems

Natural History

• AVMs can remain clinically silent for decades before becoming symptomatic 2, 3
• Most symptoms depend on size, number, type (complex versus simple), and flow through the malformations 1
• AVMs are congenital lesions that can be evolutive (progressive), leading to worsening complications over time 8, 9, 3

Common Pitfall in Diagnosis

• 25-58% of patients are completely asymptomatic before catastrophic complications occur, emphasizing the importance of screening in high-risk populations (especially HHT patients) 1