Presentation of Cerebral Arteriovenous Malformations in Children

Symptoms and Signs

Symptoms due to intraparenchymal hemorrhage

80–85% of all pediatric AVMs present with hemorrhage.  The rate of major bleeding is 4% per year, and the mortality rate is 1% per year (i.e., there is a 25% mortality rate associated with AVMs that hemorrhage). A nontraumatic intraparenchymal hemorrhage should raise concerns about the possible presence of an AVM or tumor. Rebleeding rates are approximately 6% for the first 6 months, then 3% per year afterward.

Symptoms resulting from hemorrhage due to AVM

• Seizures: Seizures are the most common symptom at presentation and are due to hemorrhage
• Headache
• Focal neurological deficits
• Decline in cognition
• Mass effect/ischemia
• AVM and steal: AVMs produce deficits through mass effect or from cerebral ischemia due to diversion of blood to the AVM from the normal cerebral circulation (“steal”).

Patterns of evolution

• Hemorrhage acute, steal chronic: The presentation of symptoms in AVM is generally acute if related to hemorrhage or seizure, often occurring within minutes to hours, or chronic, occurring over months, if related to steal phenomenon or headache.

Intervention

Initial therapeutic maneuvers are dependent on the presentation of the child.  For the healthy child or for the child who presents with chronic symptoms (seizure, developmental delay), there are often no immediate interventions necessary (with the exception of antiepileptic medication if seizures are present).  The following steps are warranted for the child who presents with an intracranial hemorrhage.  The severity of presentation can vary greatly, and treatment has to be individually tailored.

Stabilization

• Vascular access: Large bore IVs (at least 2) and an arterial line are placed initially. along with bladder catheterization. Airway intubation is done if the child is unable to protect his or her airway, and a nasogastric tube placed with the intubation.
• Blood pressure control: Antihypertensive agents such as labetolol or nipride can be used to control blood pressure with a goal of normotension for the child’s age.
• ICP control: An EVD can be placed if hydrocephalus is present (NB: avoid overdrainage of CSF to prevent re-rupture, often no more than 5 ml at a time), and the HOB is elevated.
• 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 on presentation.  In elective cases, preoperative labs and imaging are needed. 
• Admission to ICU if hemorrhage: For patients with a hemorrhage but minimal deficits, admission to the ICU for blood pressure control and preoperative imaging studies are the two important interventions.

Preparation for definitive intervention, emergent

• Prepare operating room: In addition to the steps noted in the Stabilization section, the operating room should be notified to prepare for surgery.  Equipment should include the operating microscope, multiple suctions, bipolar electrocautery, an array of AVM/aneurysm clips, a craniotome (drill), and a retraction system. 
• Consult with anesthesiologist: Anesthesia should be consulted and appropriate measures made to ensure that multiple large bore IV access is present and adequate blood products are in the room. 
• Equipment ready for microsurgery: It is helpful to have the microscope draped and clips prepared prior to starting the case if possible, so that quick access can be obtained should unexpected bleeding occur during opening. 

Admission Orders

• VS: Continuous blood pressure, heart rate, and oxygenation monitoring; strict monitoring of inputs and outputs.
• Activity: Bed rest, head of bed at 30 degrees.
• Nursing: Maintain age-appropriate normotension and oxygenation.  Keep external ventricular drain at 20 cm above external auditory meatus and monitor output per physician, repeat neurological examination hourly and report changes.
• Diet: NPO
• Fluids: Isotonic IV fluids at maintenance levels (usually normal saline)
• Medications: Antihypertensives (labetolol or nipride), antiepileptics, antibiotic (if EVD inserted), stool softener, multivitamin, pain management (usually short acting narcotics such as morphine) are the author’s preferred list.  Avoid aspirin and any long-acting sedating agents unless specific orders are indicated to the contrary.