Upper Motor Neuron Disorders: Primary Lateral Sclerosis, Upper Motor Neuron Dominant Amyotrophic Lateral Sclerosis, and Hereditary Spastic Paraplegia

Following the exclusion of potentially reversible causes, the differential for those patients presenting with a predominant upper motor neuron syndrome includes primary lateral sclerosis (PLS), hereditary spastic paraplegia (HSP), or upper motor neuron dominant ALS (UMNdALS). Differentiation of these disorders in the early phases of disease remains challenging. While no single clinical or diagnostic tests is specific, there are several developing biomarkers and neuroimaging technologies which may help distinguish PLS from HSP and UMNdALS. Recent consensus diagnostic criteria and use of evolving technologies will allow more precise delineation of PLS from other upper motor neuron disorders and aid in the targeting of potentially disease-modifying therapeutics.

NCMP-21. REVERSIBLE MOTOR NEURON SYNDROME IN THE SETTING OF CANCER

60 year old female was admitted with difficulty swallowing, slurred speech and gait instability resulting in multiple falls worsening over 2-3 weeks. Her exam revealed subtle spastic dysarthric speech, spasticity in all four extremities (lower > upper and right > left), hyperreflexia, and bilateral Babinksi and Hoffman signs consistent with pure upper motor neuron syndrome. An MRI brain and total spine were without evidence of neurological pathology but revealed an incidental finding of lymphadenopathy concerning for neoplastic process. Her symptoms continued to worsen over the next few weeks and she developed severe, nearly continuous, extensor spasms of BLE (right > left) with stimulus sensitivity causing inability to walk. She was started on baclofen, tizanidine and diazepam for spasticity with only mild improvement. An MRI cervical spine was repeated (please see below) and revealed hyperintense T2 signal in lateral corticospinal tract (right > left) without enhancement and no cord compression. Given strong clinical concern for paraneoplastic process patient received 0.4 g/kg IVIG for 5 days and concurrent 1000 mg methylprednisolone for 3 days with dramatic improvement within days. Cervical lymph node biopsy lead to diagnosis of nodal marginal zone lymphoma. A CT abdomen revealed an ovarian mass concerning for teratoma vs dermoid cyst (pending resection and final pathology). She was treated with weekly boosters of IVIG and IV methylprednisolone and was started on Rituximab for her Lymphoma. When seen in clinic a month post discharge nearly all of her symptoms had resolved. Neurological exam showed subtle residual spasticity making this presentation most consistent with a reversible pure upper motor neuron syndrome.

Surgical treatment of spasticity: intrathecal baclofen pump implantation under subarachnoid block

Most patients with spasticity, rigidity, and other symptoms of the upper motor neuron syndrome respond effectively to surgical treatment with an intrathecal baclofen pump when their symptoms become intractable to nonsurgical measures. Baclofen administered into the lumbar subarachnoid space produces a locally high concentration at the spinal level and a low concentration supraspinally, avoiding most of the central side effects associated with a high oral dose, such as drowsiness and confusion.The aim of surgical treatment is to provide the appropriate volume and concentration of the drug in the subarachnoid space, avoiding the main surgical complications, that is, infections, skin erosion, and catheter displacement.The video can be found here: https://youtu.be/HetelPwwwak

Use of the Posterior Lumbar Approach for Psoas Major Injection in Hip Flexor Spasticity

ABSTRACT: Background: Hip flexor spasticity in patients with upper motor neuron syndrome of multiple etiologies has been managed with botulinum neurotoxin injections mainly targeting the “iliopsoas” muscle. A lumbar approach to target psoas major (PM) has been described; however, it has not been incorporated into clinical practice due to perceived risk of injury to surrounding structures. This study will investigate the feasibility and accuracy of ultrasound-guided (UG)-PM injection using a lumbar approach by assessing the intra/extramuscular injectate spread in cadaveric specimens. Methods: In eight lightly embalmed specimens, toluidine blue dye/saline was injected into PM using a UG-posterior lumbar approach. The posterior abdominal wall was exposed, and dye spread and surrounding structures digitized and modeled in 3D. The area and vertebral level of dye spread, distance of dye to the inferior vena cava (IVC), and abdominal aorta (AA) and dye spread to adjacent organs were quantified. Results: The models enabled visualization of the dye spread in 3D. Mean area of dye spread was 24.4 ± 2.8 cm2; most commonly between L2 and L4 vertebral levels. Mean distance of the dye to AA was 3.2 ± 1.2 cm and to IVC was 1.8 ± 0.4 cm. Dye spread remained intramuscular in all but one specimen. No dye spread occurred to any adjacent organs. Conclusions: The injection of PM using the UG-posterior lumbar approach was consistent and without spread to surrounding structures. This technique alone or in addition to the anterior approach is expected to have better clinical outcomes in the treatment of hip flexor spasticity. Further clinical studies are required.