Presentation of Cerebral Arteriovenous Malformations in Children

Symptoms and Signs

Intracranial hemorrhage due to AVM

• 75% to 85% present with hemorrhage: An estimated 75% to 85% of pediatric patients with AVMs present with intracranial hemorrhage (38,65). In children, 30% to 50% of spontaneous intracranial hemorrhage is associated with AVMs (2).
• Estimates of hemorrhage risk: Annual risk of initial hemorrhage is estimated to be between 2% and 4%, though the risk of subsequent hemorrhage is higher, between 6% and 18% (50,66,67,68). Current data do not support the claim that pediatric AVM, versus adult AVM, is associated with increased risk of subsequent hemorrhage (69).
• Considerable mortality from hemorrhage: The mortality rate from hemorrhage is estimated to be 25% per event (7,65), with a roughly 1% mortality rate per year when accounting for the annual risk of initial hemorrhage (70).

Symptoms and signs at presentation

• Seizures
• Headache
• Focal neurological deficits
• Decline in cognition or developmental delay
• Mass effect or ischemia
• AVM and vascular steal: AVMs produce deficits through mass effect or from cerebral ischemia due to diversion of blood from the normal cerebral circulation to the AVM (vascular steal phenomenon) (56).

Patterns of evolution

• Hemorrhage acute: An acute presentation (within minutes or hours) is observed when symptoms are due to hemorrhage or seizures. A chronic presentation (occurring over months) is observed when symptoms are related to headaches or vascular steal (49).

Intervention at Presentation

Initial therapeutic maneuvers depend on the presentation of the child. For the healthy child (for example, if an AVM is discovered incidentally) or for the child who presents with chronic symptoms (seizure or developmental delay), immediate interventions may not be necessary (apart from antiepileptic medication if seizures are present). The following steps are warranted for the child who presents with an ICH. Severity of presentation can vary greatly, and treatment must be individually tailored.

Stabilization

• Vascular access: Place at least two large-bore IVs and an arterial line, along with a bladder catheter. Perform airway intubation if the child is unable to protect their airway. Place a nasogastric tube with the intubation.
• Blood pressure control: Antihypertensive agents, such as nicardipine, labetalol, and hydralazine, can be used to control blood pressure, with a goal of normotension for the child’s age.
• Imaging: In a patient presenting with acute neurologic deficits, perform imaging immediately after stabilization of airway, breathing, and circulation. Imaging modality (CT, CTA, MRI/MRA) is based on patient acuity. Need for urgent imaging is based on the patient’s presentation.
• ICP control: An EVD can be placed if hydrocephalus is present (NB: avoid over-drainage of CSF to prevent re-rupture; we avoid draining more than 5 mL at a time). Elevate the HOB.
• Avoidance of seizures: Antiepileptic medication should be used if there is concern about seizures.

Preparation for definitive intervention, nonemergent

• Preparation for elective surgery: As previously discussed, nonemergent management varies greatly depending upon presentation. In elective cases, preoperative labs and imaging are needed.
• Admission to PICU if hemorrhage: For patients with a hemorrhage but minimal deficits, admit to the PICU for blood pressure control, seizure prevention, and preoperative imaging studies.

Preparation for definitive intervention, emergent

• Prepare operating room: In addition to the steps noted in Stabilization, the operating room should be notified to prepare for surgery. Equipment should include an emergent craniotomy set-up, as well as an operating microscope, multiple suctions, multiple bipolar electrocautery (if available), and an array of vascular clips.
• Consult with anesthesiologist: Consult with anesthesiologist and take appropriate measures to ensure that multiple large-bore IVs are present, patient is normotensive, and blood products sufficient to activate mass transfusion protocol are in the room. Some centers use antifibrinolytic therapy (e.g., tranexamic acid) to reduce intraoperative bleeding.
• Equipment ready for microsurgery: If possible, have the microscope draped and clips prepared prior to starting the case so quick access can be obtained should unexpected bleeding occur during opening.

Admission Orders

• Vital signs: Maintain continuous blood pressure, heart rate, and oxygenation monitoring; maintain strict monitoring of inputs and outputs.
• Activity: Bed rest, HOB at 30 degrees.
• Nursing: Maintain age-appropriate normotension and oxygenation. If present, we keep an external ventricular drain at 20 cm above external auditory meatus and monitor its output. Repeat neurological examination hourly and report changes.
• Diet: NPO
• Fluids: Isotonic IV fluids (usually normal saline) at maintenance levels
• Medications: These include antihypertensives (e.g., nicardipine, labetalol, and hydralazine), antiepileptics, stool softener, multivitamin, and pain management (usually short-acting narcotics such as fentanyl). Avoid aspirin, nonsteroidal anti-inflammatory drugs, and any long-acting sedating agents unless specific orders are indicated to the contrary.