Most are believed to be congenital in origin, and there is an increased incidence with coarctation of the aorta and polycystic kidney disease. Mycotic aneurysms are associated with bacterial endocarditis. The presentation is most often subarachnoid hemorrhage, which is similar to that seen in adults. The child develops headache, nuchal rigidity, photophobia, and perhaps focal neurologic signs. The diagnosis is confirmed by CT scan or spinal tap.
Treatment is surgical clipping.
The timing is similar to that in adults, and ideally the patient should undergo surgery as soon as angiography can be obtained and the patient regains consciousness. The surgical procedure is similar to that for adults, but pediatric aneurysms tend to arise as an enlargement of the parent vessel itself without a true neck, and may require a trapping procedure with sacrifice of the parent vessel. Mycotic aneurysms are treated surgically if they arise from distal vessels which can be sacrificed. Mycotic aneurysms arising from the primary arteries at the Circle of Willis carry an extremely poor prognosis regardless of treatment. These abnormalities have been noted with increased frequency with availability of MRI scanning.