Case of the Week
Section Editors: Matylda Machnowska1 and Anvita Pauranik2
1University of Toronto, Toronto, Ontario, Canada
2BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
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December 21, 2017
Atypical PRES with Spinal Cord Involvement
- Background:
- PRES may have atypical imaging findings (33%-37%).
- Spinal cord involvement is very rare, with less than 20 cases reported in the literature.
- Clinical Presentation:
- Atypical PRES cases have similar clinical presentations, as typical cases with severe headache, seizure, vision loss, and altered mental status are common clinical presentations.
- The risk factors are also similar to typical cases: high or rapidly fluctuating blood pressure, renal failure, eclampsia, hemolytic uremic syndrome, SLE, organ transplantation, immunosuppressive agents, etc.
- Key Diagnostic Features:
- Atypical PRES imaging findings include enhancement, hemorrhages (subarachnoid or intraparenchymal), restricted diffusion, unilateral location, atypical locations, and permanent damages.
- Atypical locations may involve the temporal lobe, cerebellum, thalamus, brain stem, basal ganglia, corticospinal tracts, deep white matter, splenium of the corpus callosum, and spinal cord.
- Spinal cord PRES is very rare, and the gray matter is more involved than white matter.
- Our case shows involvement of both gray and white matter. Most reported cases were asymptomatic and resolved in a few weeks, similar to our case.
- The cervical cord is more commonly involved than the thoracic cord.
- The incidence and the extent of spinal cord PRES are difficult to assess because most patients are asymptomatic; therefore, dedicated spine MRI is not ordered at the time of presentation.
- The pathophysiology of spinal cord PRES is similar to that of typical PRES and thought to be due to blood-spinal cord barrier damages from the risk factors. The anterior spinal artery arises from the vertebral arteries (posterior circulation), explaining the possibility of spinal cord involvement given that posterior circulation has low sympathetic innervation.
- PRES remains the top differential diagnosis when the clinical presentations are classic even though the affected areas are unusual.
- When in doubt, follow-up with MRI in 1–2 weeks would be helpful to establish the diagnosis. PRES typically resolves after appropriate treatment.
- It is important to recognize and treat atypical PRES early to avoid unnecessary work-up and prevent complications.
- Differential Diagnoses:
- Spinal cord infarction: Patients typically have sudden onset of severe back pain, profound weakness, sensory loss, and bowel/ bladder incontinence. Spinal cord MRI may show a long cord lesion with T2/STIR hyperintensity and restricted diffusion. The lumbar and thoracic cord is more commonly involved than the cervical cord.
- ADEM: Patients may have monophasic encephalopathy similar to PRES but typically have recent viral infections with more profound neurologic deficits. A nonspecific long cord lesion could be seen.
- Neuromyelitis optica (NMO): Patients tend to be symptomatic with bilateral severe optic neuritis, obvious neurologic deficits from a longitudinally extensive cord lesion (contiguous lesion greater than 3 segments) or brain lesions (periventricular white matter lesions along the third ventricle, cerebral aqueduct, fourth ventricle), and positive serum aquaporin-4 antibodies (NMO-IgG).
- Infectious myelitis: Patients with viral and bacterial myelitis also tend to have obvious signs and symptoms of spinal cord involvement. The cord is expanded due to edema and enhanced due to loss of blood-spinal cord barriers. CSF profiles may show leukocytosis.
- Transverse myelitis (TM): TM is the diagnosis of exclusion and deemed to be idiopathic. Patients present with sensory and motor deficits according to the level of cord involvement. The involved cord is typically greater than 2 contiguous levels with edema and enhancement.
- Treatment:
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Control blood pressure and treat underlying risk factors.
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