Posterior reversible encephalopathy syndrome in a patient with a Chiari I malformation
A 25-year-old right handed female initially presented with complaints of left upper and lower extremity paresthesias and gait disturbance as well as nausea and vomiting. Her symptoms had progressed for a few months prior to admission. Her initial workup included an MRI of the brain and cervical spine, which showed a Chiari I malformation with tonsillar descent beyond the level of the C1 lamina and syringomyelia and syringobulbia with dilation throughout the cervical spinal cord and no evidence of hydrocephalus []. On physical exam she was noted to be weak in bilateral upper extremities with 4+/5 motor strength in the right upper extremity and 4-/5 motor strength in the left upper extremity. Bilateral lower extremities were 5/5 strength with the exception of bilateral extensor hallucis longus, which were 4/5. She had brisk patellar reflexes bilaterally and impaired tandem gait.\nShe underwent a suboccipital craniectomy, C1 laminectomy, cerebellar tonsillar cauterization using bipolar cautery, and duraplasty with Gore-Tex dural substitute. Intraoperative somatosensory evoked potentials (SSEP) and motor evoked potentials (MEP) monitoring demonstrated impaired amplitude in the right lower extremity, with no change following positioning or throughout the operation other than gradual improvement in the right lower extremity MEP during the surgery. Postoperatively she improved to full strength in the right upper extremity and 4+/5 throughout the left upper extremity. She was started on a dexamethasone taper postoperatively as prophylaxis against an inflammatory response given the cerebellar manipulation. Postoperative MRI revealed a suggestion of an acute infarct of the right inferior vermis and otherwise normal postoperative changes []. The MRI findings were attributed to the bipolar cautery of the cerebellar tonsils. She remained in the hospital for 4 days postoperatively for pain control and monitoring of slight postoperative dysphagia and was subsequently discharged to a rehabilitation facility.\nShe was readmitted to the hospital from rehab 6 days after discharge with complaints of worsening of her swallowing. She also noted left sided pain and worsening weakness. At this point her exam had declined from her postoperative exam and motor exam now revealed 3/5 strength in left dorsiflexion and extensor hallucis longus. At the time of readmission, she was normotensive with a blood pressure of 130/70. A swallow evaluation revealed significant aspiration. She underwent an MRI that showed bilateral acute infarcts of the cerebellar vermis []. We did not have a clear explanation for this increase from her postoperative scan. Given the evolution of the infarct she was started on pressors to increase her systolic parameters to 160-180 mmHg and optimize perfusion in the setting of ischemia. Two days after initiating pressors, the patient had a generalized tonic–clonic seizure. A CT of the head at that time demonstrated diffuse loss of sulci with effacement of the suprasellar and quadrigeminal cisterns. She was subsequently intubated for worsening mental status and lethargy. A follow-up MRI revealed diffuse bifrontal and parietal gray matter hyperintensity on FLAIR without changes on diffusion-weighted imaging consistent with PRES and suggestive of edema from hypoxic ischemic changes secondary to prior seizure []. An electroencephalography (EEG) showed no further seizure activity and CSF cultures were negative. She underwent an angiogram to evaluate for vasospasm as a possible etiology of her evolving infarcts, which showed no evidence of vasospasm or vasculitis. Following those results, the pressors were weaned off. A repeat CT of the head was obtained, which showed increasing cerebral edema. As a result of the increasing edema and her compromised neurologic exam, an intracranial pressure (ICP) monitor was placed and maintained for 2 days, which showed low opening pressure, and ICPs ranging from 1 to 7. Follow-up MRIs demonstrated progressive resolution of the cerebral edema and FLAIR signal [] with complete resolution at 2 years postoperative [].\nShe had progressive improvement in her mental status and was extubated. She continued to have swallowing difficulties and underwent serial swallow evaluations, ultimately requiring placement of a percutaneous endogastric tube (PEG). She ultimately improved and had only residual left hand weakness with motor strength 4/5. She was ultimately transferred to rehab. She continued to have significant left upper extremity dysesthesia. At 9-month follow-up, she was noted to have worsening of her syrinx and further descent of her cerebellar tonsils and so she underwent placement of a ventriculoperitoneal shunt.\nAt her latest follow up 4 years postoperatively, her motor exam was 5/5 throughout her right upper extremity, 5/5 in her left deltoid, biceps and triceps and 4/5 left opponens and 3/5 interossei. Both lower extremities were 5/5 strength throughout with a steady gait and impaired tandem gait, significantly improved from prior, though she has a stiff and wide-based spastic gait. She was no longer having any dysphagia, had no bulbar symptoms and her PEG had been removed. Her left upper extremity dysesthesia has significantly improved. Her 4 year follow-up MRI demonstrates resolution of her syringomyelia [].