What are the symptoms of an abdominal Arteriovenous Malformation (AVM)?

Symptoms of Abdominal Arteriovenous Malformations

Abdominal AVMs most commonly present with gastrointestinal bleeding manifesting as acute hemorrhage, chronic bleeding with transfusion-dependent anemia, or occult bleeding causing iron deficiency anemia. 1, 2

Primary Clinical Presentations

Gastrointestinal Bleeding (Most Common)

• Major hemorrhage is the predominant presentation across all age groups with abdominal AVMs 2
• Chronic bleeding leading to severe, transfusion-dependent anemia that may require multiple blood transfusions 1
• Occult bleeding presenting as obscure gastrointestinal bleeding (OGIB) with progressive anemia but no obvious source 1
• Bleeding can range from intermittent minor episodes to life-threatening acute hemorrhage 2

Location-Specific Symptoms

Small Intestinal AVMs:

• Often present with obscure gastrointestinal bleeding that is difficult to localize 1
• May cause transfusion-dependent anemia during pregnancy due to increased physiologic demands 1
• Can lead to severe physical deterioration requiring urgent intervention 1

Gastric AVMs:

• May be completely asymptomatic and discovered incidentally during screening endoscopy 3
• Can present without any history of gastrointestinal bleeding 3
• May appear as submucosal tumors on endoscopic examination 3

Colonic AVMs (Type 1):

• Typically occur in patients 55 years or older 2
• Localized to the right side of the colon 2
• Not palpable or visible at operation, making diagnosis challenging 2

Rectal AVMs:

• Can present with persistent anal bleeding 4
• May cause bleeding from associated internal hemorrhoids 4
• Associated dizziness from resultant anemia 4

Secondary Manifestations

Systemic Symptoms from Blood Loss

• Dizziness and lightheadedness from acute or chronic anemia 4
• Fatigue and weakness from chronic blood loss 1
• Hemodynamic instability in severe cases requiring urgent resuscitation 1

Rare Complications

• Encephalopathy can develop in severe cases with massive blood loss, even without underlying liver disease 1
• High-output cardiac failure in neonates (though this is more typical of other anatomic locations) 5

Age-Related Patterns

Younger Patients (Type 2 AVMs):

• Symptoms typically begin before 50 years of age 2
• Lesions are larger and occasionally visible at operation 2
• More commonly located in the small intestine 2
• Likely congenital in origin 2

Older Patients (Type 1 AVMs):

• Present at 55 years or older 2
• Solitary, localized lesions 2
• Right-sided colonic location predominates 2

Hereditary Hemorrhagic Telangiectasia (Type 3):

• Multiple punctate angiomas throughout the GI tract 2
• Classical findings of hereditary hemorrhagic telangiectasia syndrome 2
• Family history may be present 2

Important Clinical Pitfalls

• Pregnancy can exacerbate bleeding from abdominal AVMs due to increased blood volume and hormonal changes, potentially leading to life-threatening transfusion-dependent anemia 1
• Many abdominal AVMs are not visible or palpable during surgery, requiring preoperative imaging localization 2
• Diagnosis requires high clinical suspicion as symptoms may be nonspecific or the lesion completely asymptomatic 3
• Contrast-enhanced CT angiography and selective angiography are essential for diagnosis, as physical examination and routine endoscopy may miss these lesions 1, 2, 4