Article, Neurology

Spinal cord arteriovenous malformation in a toddler presenting with altered mental status and fever

Case Report

Spinal cord arteriovenous malformation in a toddler presenting with altered mental status and fever

Abstract

Central nervous system arteriovenous malformations (AVMs) are a rare cause of subarachnoid hemorrhage and neurologic deficits. About 90% of these lesions are supratentorial, with a smaller percentage occurring in the posterior fossa and an even smaller number found through- out the spine. Although spinal AVMs are uncommon, these disorders represent a treatable cause of significant morbidity in a young age group. We report a case of a T11-T12 spinal AVM in a 14-month-old girl presenting with low-grade fever and lethargy who was found to have subarachnoid hemorrhage on evaluation and describe a reasonable stepwise approach to these patients in the emergency department utilizing computed tomography, lumbar punc- ture, magnetic resonance imaging, and angiography.

A 14-month-old female was brought into the emergency department (ED) for decreased energy and fever. The parents noted that 3 days previously she had begun with low-grade fevers (100.5?F), which they had been treating with Tylenol and Motrin. She had vomited on the first day of illness, but not since. One day after the initiation of her symptoms, she had been evaluated at an urgent care center and had been given a prescription for amoxicillin for an upper respiratory infection. When her energy level had not improved, the parents brought her in to the ED for further evaluation.

On examination, the patient’s vital signs included a temperature of 99.7, pulse of 114 beat/min, respirations of 20 per minute, and an oxygen saturation of 100% on room air. The patient’s examination was remarkable for decreased activity and inconsolable crying. She was moving all 4 extremities, had intact reflexes, and no evidence of Nuchal rigidity. Her examination was otherwise entirely normal.

A urine specimen, basic laboratory studies, and blood cultures were remarkable only for a white blood cell count of 14,700 with no left shift. The patient’s chest x-ray was normal. A noncontrasted computed tomography (CT) scan of the head was performed, which revealed subarachnoid and intraventricular blood, as well as hydrocephalus (Fig. 1). A lumbar puncture was performed to obtain cultures and

viral studies, which revealed 14,000 white blood cells per cubic centimeter and 38,000 red blood cells (RBC) per cubic centimeter in tube number 1, and 15,000 WBC per cubic centimeter and 40,000 RBC per cubic centimeter in tube number 4. Enterovirus and herpes simplex virus polymerase chain reaction studies were negative, as were cultures.

Neurosurgery was emergently consulted for placement of a ventriculostomy, and the patient was admitted to the pediatric intensive care unit (PICU). On inpatient day number 2, the patient was noted to have paralysis of her legs, decreased rectal tone, and a neurogenic bladder. A magnetic resonance imaging (MRI) was performed of her thoracic, lumbar, and sacral spine, revealing a T11-T12 arteriovenous malformation (AVM) (Fig. 2). She went emergently to the operating room for Decompressive laminectomy, dural augmentation, removal of subdural and subarachnoid blood, and AVM embolization. The patient went on to have a ventriculoperitoneal shunt placed for ongoing hydrocephalus. She was discharged on hospital day 20 with some residual weakness of the proximal and distal musculature of both legs. On follow-up over the next 2 months, she was found to have improved muscle tone, was able to walk, and only had minimal foot drop on the right.

Arteriovenous malformations are congenital malforma- tions of the vasculature, with abnormal arteriovenous plexi lacking intervening capillary beds. This creates tangles of vessels, gliotic neural tissue, and local calcification. The pathogenesis of AVMs has not been elucidated, but genetic variations are known to drive their development and clinical course [1,2]. Although epidemiology is not known, AVMs are known to account for 1% to 2% of strokes, 3% of strokes in young adults, and 9% of Subarachnoid hemorrhages (SAHs). Although they are often found incidentally through brain imaging, they may present in 10% of cases as an isolated, first-onset arterial aneurysm. Children are more prone to hemorrhage than adults [3].

Up to 90% of identified AVMs are supratentorial, but a small number are infratentorial. Spinal cord AVMs are rare entities, generally presenting in the adult population. In contrast to the presentation of supratentorial lesions, in spinal cord AVMs the presentation can be nonspecific. These patients often present with back pain, myelopathy, root

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dysfunction, and occasionally with increased intracranial pressure and altered mental status [4,5].

Not much is known about spinal AVMs in Pediatric populations, but they are thought to be very rare. Patients typically present with acute or progressive neurologic deficits, often due to SAH. One case series described 38 pediatric spinal cord AVMs dating back to 1962, 35 of which presented with increased intracranial pressure and neurologic symp- toms. The remaining 3 presented with SAH-like symptoms, namely, meningeal signs. Thirty-five of the total had evidence of SAH on evaluation [6]. Another case series presented 13 spinal AVMs presenting before age 2, 10 of which presented with neurologic symptoms [7]. There are only 2 published cases of pediatric spinal AVM presenting solely with meningeal signs and lethargy, as with our patient [8,9].

Historically, the diagnosis of spinal AVM has been made after the finding of SAH on LP and confirmed by surgery or autopsy [5]. As technology has improved, more diagnoses have been made using angiography [6]. There are no sensitivity and specificity data for head CT in the diagnosis of spinal AVM, as many reported cases predated the availability of CT. More recent reports show head CT to have limited utility, although it may be used to rule out other pathology. Pediatric patients with altered mental status but an otherwise normal neurologic examination mandate head CT followed by LP if the CT is normal. If the LP shows evidence of SAH, further emergent studies are necessary to rule out spinal AVM.

spinal angiography is the definitive evaluation for diagnosing these lesions, although multi-detector-row CT angiography of the spine shows promise in diagnosis, as well

Fig. 1 Head CT showing evidence of hydrocephalus and intraventricular blood.

Fig. 2 MRI showing spinal AVM at T11-T12. Note the patient’s neurogenic bladder.

[10]. As newer generation CT scanners become more widely available, this may offer an early diagnostic alternative at centers where angiography is not urgently available. If angiography is not available, the best initial diagnostic study for the ED provider is the MRI [11]. In patients with myelopathy, CT and LP offer no specific diagnostic advantage over MRI, and LP may cause progression of the patient’s neurologic deficit [12]. In addition, in a study of adult patients, 22 of 78 patients having MRI for unexplained myelopathy were found to have spinal AVMs [13]. There- fore, MRI or angiography should be done as soon as possible in patients suspected of having spinal AVMs, and in the absence of the need to rule out other pathology, LP should be avoided.

Although rare, spinal AVM is an important diagnostic consideration in the patient with unexplained back pain, progressive myelopathy, meningeal signs, or altered mental status. Not recognizing this disease can lead to tremendous disability in a young age group. Appropriate early therapy can result in arrest or reversal of neurologic deficits.

Yvonne Chow MD Noah White MD Luke Day BS

Rebecca Jeanmonod MD

Department of Emergency Medicine

Albany Medical College Albany, NY 12208

E-mail address: [email protected] doi:10.1016/j.ajem.2008.03.049

Case Report

References

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