Spongiform encephalopathy

Overview

Spongiform encephalopathy: A rare inherited prion disease which has a range of manifestations resulting primarily from degeneration of the nervous system.

Symptoms

* Impaired ability to control voluntary movements * Dementia * Speaking difficulty * Ocular dysmetria * Reduced reflexes in lower extremities * Absent reflexes in lower extremities * Positive Babinski sign * Spongiform cerebral degeneration * Dementia * Impaired brain function * Memory changes * Personality changes

Causes

* Orthopedic issues affecting the foot, ankle, leg, knee, or hip * Peripheral neuropathy (sensory and/or motor) –Slapping gait: Sensory neuropathies may result in a tendency to slap the feet firmly against the ground to improve proprioceptive input –Steppage gait: Seen in patients with foot drop –The classic tabetic gait combines both stepping and slapping gaits * Mononeuropathy/radiculopathy affecting the lower extremities may result in gait abnormalities (e.g., either a peroneal neuropathy or L5 radiculopathy can cause a unilateral steppage gait) o Myelopathy –Patients with bilateral lower extremity weakness and hypertonicity secondary to a spinal cord lesion may exhibit a spastic gait with stiffness of both legs and a tendency toward scissoring of the legs with walking o Brainstem or cortical lesions (e.g., multiple sclerosis, CVA) –Most commonly result in a hemiparetic gait with circumduction of the weak leg o Cerebellar lesions –Result in an ataxic gait, which tends to be wide-based, irregular, and staggering o Intoxications + Parkinsonism –Patients exhibit stooped posture, decreased arm swing, and shuffling (take many small steps) + Myopathies –Tend to produce a waddling gait because of weakness of the trunk, hip, and proximal lower extremity muscles + Spinocerebellar ataxia + Hereditary spastic paraparesis + Hysterical gaits + Inherited neuropathies (e.g., Charcot-Marie-Tooth disease) + GALOP syndrome (gait disorder, autoantibodies, late age onset, polyneuropathy) + Normal pressure hydrocephalus + Infection (e.g., neurosyphillis, meningitis) + Vitamin B12 or thiamine deficiency

Treatment

* In most cases, the treatment will be supportive * Exogenous toxins should be stopped and removed * Neoplasms, abscesses, hemorrhage require neurosurgical evaluation and intervention * Patients with Friedreich ataxia and mitochondrial disease need cardiac evaluation * Miller-Fisher variant of Guillain-Barré syndrome –Usually has a very good prognosis –IV immunoglobulin or plasmaphoresis may be used * Opsoclonus/myoclonus syndrome –Treated with steroids, ACTH, or IVIG –Neuroblastoma needs surgical evaluation * ADEM: Treat with high-dose intravenous steroids * AVED: Treat with vitamin E * Biotinidase deficiency: Treat with biotinidase * Hartnup disease: Treat with niacin * Refsum disease: Dietary restriction of phytanic acid * Epidosic ataxia: Treat with acetazolamide