A rare cause of occipital headache.

Dear Sir,

A premorbidly normal, 13-year-old boy, presented with complaints of headache for last 1 month. The headache was intermittent, moderate to severe in intensity, located predominantly in the occipital region with occasional radiation to the neck and partial response to analgesics. There was no associated altered sensorium, speech abnormality, cranial nerve deficit, seizures, focal motor or sensory deficits, photophobia, diplopia, or vomiting. Detailed general physical and systemic examinations revealed normal fundus examination and blood pressure with generalized hyperreflexia.

Magnetic resonance imaging (MRI) brain and magnetic resonance angiography were normal. MRI spine revealed cervical cord arteriovenous malformation (AVM) at C3–C4 level with multiple collaterals [Figure 1a and b].

Figure 1

T1-weighted (a) and T2-weighted (b) sagittal magnetic resonance images of the cervical spine show multiple abnormal tortuous vascular flow voids (arrows) anterior to the spinal cord from medulla to C6 vertebral level consistent with spinal arteriovenous malformation. Note the indentation over the cord at C3–C4 level

Spinal vascular malformations account for only 5–10% of all spinal diseases.[1] The exact pediatric prevalence is unknown, but definitely it is less than in adults. They predominantly affect middle-aged men who present with lower extremity weakness and sensory disturbances. Very rarely, it presents as headache or visual disturbances.[12]

The cause of intermittent headache in this patient can be possibly due to two possible mechanisms; first being referred pain from cervical dermatomes to the occipital region and the second is episodic bleeding into the subarachnoid space causing obstruction of cerebrospinal fluid outflow.[2] These lesions can clinically mimic spinal stenosis which also presents with pain and compressive myelopathy symptoms. A relatively rare but significant complication is subarachnoid hemorrhage. The possibility of spinal AVM should be kept in the differential diagnosis of any patient with a subarachnoid hemorrhage who has a normal cerebral angiogram, although this entity is rarely reported in children.

Delay in diagnosis leads to the development of significant spastic paresis in the majority. In the largest series of pediatric spinal AVM comprising 38 cases, more than 90% patients presented with features of myelopathy.[3]

Spinal AVMs are hypothesized as developmental defects occurring between 4 and 8 weeks of embryonic development.[4] AVMs bypass capillary beds and behave as abnormal communications between arteries and veins. There are three biologically distinct types of spinal AVMs: Dural, intradural, and cavernous. Symptoms usually arise due to hemorrhage, compression, venous hypertension, and ischemia; however, AVMs are rarely symptomatic. Intradural AVMs are more likely to present with pain and acute neurological dysfunctions than spinal dural AVMs.[5]

Early diagnosis is of paramount importance in patients with spinal AVM because of the treatable and preventable potentially catastrophic complications. In terms of medical management, steroids can be used to tide over acute crisis situations, however there is no role of prolonged steroid therapy as it does not modify the underlying disease process and is also associated with significant side effects.

Surgical intervention is decided on symptomatology and topography of the lesion. The options include open microsurgical resection. Minimally invasive neurointervention technique is an upcoming modality, but its application is limited in view of lack of expertise.[6]

Thus, in children with focal occipital headache, a detailed neurological evaluation is warranted to look for features of mild quadriparesis, and imaging should be considered to rule out potentially hazardous entity such as spinal AVM, which is a treatable condition.