Symptoms and signs
Clinical presentation depends on age and location of the DAVF. In general, symptoms are caused by venous hypertension, hemorrhage and mass effect due to variceal growth.
- Poorly understood natural history: The natural history of DAVF is ill understood. Data are heterogeneous and mostly come from retrospective studies in adults.
- 2–8% annual hemorrhage risk in adults: In adults, the yearly bleeding rate for those DAVFs with cortical reflux, variceal growth or those located in the tentorium is estimated to be 2% to 8%. Some authors estimate a much higher bleeding rate (up to 30% per year) for those presenting with cortical venous drainage(6).
- Higher risk if symptomatic: In addition, the above DAVFs also have a higher rebleeding rate in the early period after presentation of up to 35% within the first two weeks(5). Symptomatic cranial DAVFs tend to have worse clinical progression than incidental DAVFs or DAVFs that present with tinnitus only(32), 19% vs 1.6%, respectively. Non-hemorrhagic presentation of DAVFs with cortical venous drainage is approximately 7%. Mortality can be as high as 10% to 30% in children(1).
These patients have a poor prognosis and should be evaluated and treated promptly. The differential diagnosis for this group should include vein of Galen malformation. This group can present with:
- Heart failure: In cases with very high cardiac output, the kidneys and liver might be affected.
- Cyanosis: Blue coloration of the skin, especially on the lips, and mucosa can be seen.
- Cranial bruits and facial vein prominence: Alternative routes of venous drainage through cavernous sinus and facial veins might be seen. These symptoms might increase with Valsalva maneuvers (i.e. crying).
Infant Presentation (first 2 years of life)
- Hydrocephalus: Increased venous pressure can impair CSF absorption and cause non-obstructive hydrocephalus. In addition, large venous varices might obstruct CSF pathways.
- Macrocrania: Progressive enlarging of head circumference with a growth line that does not follow percentile curves.
- Hemorrhage: Intracerebral hemorrhage and subarachnoid hemorrhage.
- Sequelae: These patients tend to do better than neonates but might have neurological sequelae months to years after diagnosis.
Childhood Presentation (after the first 2 years of life)
- Headaches: Headache tends to be one of the most common symptoms. It might manifest as irritability in younger children.
- Focal neurological deficits: This could be secondary to blood steal due to a high flow fistula.
- Syncope: Although rare, children might present with sudden syncope.
- Seizures: Any type of seizure can occur but in general they tend to be generalized seizures.
- Tonsillar herniation: Patients can present with Chiari-like symptoms, generally due to venous hypertension.
- Cavernous sinus fistulas: Those fistulas located at the cavernous sinus can produce proptosis, orbital bruit, visual failure and chemosis.
Patterns of evolution
- Types of patterns: There is no typical pattern of evolution. In cases with hemorrhagic presentation, however, the re-bleeding rate might be significant. Venous cortical drainage and venous varices are also high-risk features. On the other hand, some cases might have a benign pattern with spontaneous resolution.
- Evolution of symptoms: Symptoms evolve depending on the preservation of normal venous drainage on the affected segment. If this is still present, symptoms might be absent or mild. However, when retrograde flow and cortical venous drainage appear, the incidence of events might increase.
- Cases that present with cardiac failure: These patients might need diuretics, inotropic agents (dopamine, dobutamine and digitalis) and vasodilators. However, maintenance of adequate hydration is also important as dehydration might promote an already existing venous thrombosis.
- Cases of hemorrhagic presentation: Especially in younger patients, red cell packs should be available as well as fresh frozen plasma and prothrombin complex.
- Cases with hydrocephalus and high intracranial pressure: Placement of an external ventricular drain is indicated. Large hematomas might require a craniotomy for evacuation.
Preparation for definitive intervention, non-emergent
- Hydration: Because the mainstay treatment is now endovascular, children must be adequately hydrated before going to the angiography suite.
- Blood Products: Should the treatment of choice be open surgery, blood products should be available.
Preparation for definitive intervention, emergent
- Patient stabilization: This should occur before an endovascular procedure or surgery should be performed (see above).
- Standard management for hemorrhage if indicated: If the child presents with intracranial hemorrhage, basic neurosurgical principles must be followed, paying special attention to keep MAPs within their age range limits. Adequate hydration is of utmost importance, especially in infants.
- Antiepileptics for seizure: In the case of seizures, antiepileptic drugs should be started.
- Cardiac consultation if heart failure: In newborns with heart failure, the pediatric cardiology team should be consulted. Fluid overload can be dangerous for these patients.
- Preparation for contrast agent administration: Preparation for non-invasive imaging tests and angiography should be arranged and include: fasting, a basic set of labs with coagulation studies and adequate hydration.
- Preparation for surgery: Blood should be typed and crossed.