Spinal Cord Disorder Lecture Notes (L15) PDF

SPINAL CORD DISORDERS ( MYELOPATHY ) Professor Ali Raheem Hashim Consultant physician and neurologist MBCHB. MD. CABM. FRCP. (UK)  Contents 1. Basic overview about spinal cord neuroanatomy 2. Spinal cord lesion localization 3. Causes / D...

SPINAL CORD DISORDERS ( MYELOPATHY ) Professor Ali Raheem Hashim Consultant physician and neurologist MBCHB. MD. CABM. FRCP. (UK)  Contents 1. Basic overview about spinal cord neuroanatomy 2. Spinal cord lesion localization 3. Causes / Differential Diagnosis of myelopathy 4. Clinical approach to commonly encountered neurological spinal cord disorders ( Syrinx , TM , SCD )  LECTURE ONE POINTS TO BE DISCUSSED 1. Applied neuroanatomy 2. Spinal cord lesion localization 3. Causes of myelopathy 4. Syringomyelia  BASIC OVERVIEW Applied Neuroanatomy ◦ The spinal cord is a thin, tubular extension of the central nervous system contained within the bony spinal canal. ◦ It originates at the medulla and continues caudally to the conus medullaris at the lumbar level (L1-L2) ◦ Enlarged in the cervical and lumbar regions, where neurons that innervate the upper (brachial plexus) and lower extremities (lumbosacral plexus), respectively, are located. ◦ The white matter tracts containing ascending sensory and descending motor pathways are located peripherally ◦ Whereas nerve cell bodies are clustered in an inner region shaped like a four-leaf clover that surrounds the central canal ◦ The membranes that cover the spinal cord—the pia, arachnoid, and dura—are continuous with those of the brain.  Grey Matter Tips to remember ◦ Dorsal Horn : Sensory Neurons ◦ Ventral Horn : Motor Neurons (Anterior Horn Cells) ◦ Lateral Horn : Sympathetic Neurons White Matter ◦ Dorsal Funiculus : Dorsal column – medial lemniscus Tract (Sensory : vibration, proprioception and fine touch )from the ipsilateral side of body ◦ Lateral Funiculus : Lateral Corticospinal tract - Motor movement of the limb ◦ Ventral Funiculus : Spinothalamic tract (Sensory : pain, temperature and crude touch) from the contralateral side of body Dorsal column Principial spinal cord tract  Dorsal column – medial lemniscus ◦ The fiber run in the spinal cord ipsilaterally ◦ Then decussate in the medulla at the dorsal column to the contralateral side ◦ Therefore, lesion at the cord is ipsilateral  Spinothalamic tract ◦ The fiber enter the spinal cord and decussate to the contralateral side immediately ◦ Run up till reaching the cortex ◦ Therefore, lesion at the cord is contralateral  Corticospinal tract ◦ The fiber from the motor cortex decussate at the level of pyramids in medulla to the contralateral side ◦ Then run down in the spinal cord as lateral corticospinal tract ◦ Therefore, lesion in the cord is ipsilateral Cord lesion is a triad of Sensory level  Spinal Cord Lesion Localization Level Limbs affected Lesion Above C5 Quadriparesis UMN (Higher Cervical) Upper limbs – LMN C5 – T1 Quadriparesis (Lower Cervical) Lower limbs – UMN T1 – L1 Paraparesis UMN (Dorsal) Below L1 Paraparesis LMN (Lumber)  Please always remember Signs UMN LMN Weakness affects groups of muscles affects single muscle fibers Atrophy Not atrophy or fasciculation Atrophy and Fasciculations Hypertonia (Spasticity); predominant in the antigravity musculature Tone Hypotonia 1. flexors in the upper extremities 2. extensors in the lower extremities Hyperreflexia Hyporeflexia or areflexia. Reflexes Extensor plantar responses Flexor plantar responses (Babinski’s sign positive). (Babinski’s sign negative).  What is sensory level ? A level below which, there is loss of all sensory modalities ( sensory level = spinal cord lesion ) - Louis Angle : T2 - Xiphisternum : T6 - Umbilicus : T10 - Inguinal ligaments : L1 Upper cervical lesion ( above C5 ) Lower cervical lesion ( C5 – T1 ) Thoracic / Dorsal lesion ( T1 – L1)  Spinal Shock ? ◦ Is a specific term that related to the loss of all neurological activities below the level of injury following acute serious and sever cord injury. ◦ May last up to 2-3 weeks ◦ Occurs due to lose of normal supraspinal excitation and increase spinal inhibition ◦ Patient has lower motor neuron signs ◦ What about planter response ? Up ? Down ? Equivocal ? Myelopathy is an injury to the spinal cord caused by severe compression that may be a result of spinal stenosis, disc degeneration, disc herniation, autoimmune disorders or other trauma Differential diagnosis of Myelopathy Neurosurgical 1.Trauma ( Fracture ) 2.Tumor Compressive 3.Abscess 4.Herniated Disc 5.Cervical Spondylosis 6.Syrinx cavity ( Developmental or acquired ) Differential diagnosis of Myelopathy Neurological 1.Inflammatory ( Transverse myelitis , MS , NMO ) 2. Infection ( HIV , TB ) NON 3.Metabolic ( B12 Deficiency - Subacute combined Compressive degeneration of the Cord ) 4. Vascular ( Stroke ) 5. Hereditary ( Spastic paraplegia , Spinocerebellar degeneration  Syringomyelia ◦ Syrinx is an intramedullary fluid-filled cavity typically found within the cervical to midthoracic spinal cord ◦ The cavity is most commonly filled with cerebrospinal fluid (CSF). ◦ Upward extension to the brainstem is called syringobulbia.  Primary Vs. Secondary Primary (Congenital or Developmental ) ◦ Congenital cases of isolated primary syringomyelia ◦ Syringomyelia more often arises associated with Chiari type 1 malformation, in which tonsil of cerebellum was displaced downwards Secondary ( Acquired ) ◦ Spinal cord tumours ◦ The chronic phase after trauma as an ex vacuo lesion that persists after absorption of an intramedullary hematoma  Clinical features / Central Cord Syndrome ◦ Cervicothoracic syringomyelia classically presents with insidious onset of a cape-like distribution of decreased pain and temperature sensation in the back, arms, and hands, which occurs due to disruption of the crossing spinothalamic tracts. ◦ There may be varying degrees of weakness in the arms (lower motor neuron type due to involvement of cervical anterior horn cells) and legs (upper motor neuron type due to involvement of lateral corticospinal fibers). ◦ A Horner syndrome may be present if a cervicothoracic syrinx affects the lateral columns (sympathetic chain). ◦ Bowel and bladder function are generally preserved unless the syrinx extends toward the sacral cord segments. ◦ Dorsal column is spared  WHY CAPE LIKE ? Because the distribution of spinothalamic and corticospinal tract fibers are from medial cervical to lateral lumber so central lesion involve the medial cervical fibers firstly which cause the cape distribution What is the best imaging modality for spinal cord disease ?  Diagnosis Magnetic resonance imaging (MRI) allows visualization not only of the syrinx but also of any associated abnormalities such as Chiari malformation or neoplasm The CSF is often normal  Treatment ◦ Conservative observation is warranted in cases with no or only minor symptoms 1. Nonoperative management includes medications to treat neuropathic pain. 2. Occasionally, trials of diuretics are attempted in the hope of reducing syrinx size. However, this is rarely successful. ◦ In cases of sever symptoms 1. Resection, if possible, 2. If not possible ◦ fenestration or marsupialization of the syrinx may be attempted. ◦ Shunting of the syrinx to the pleural or peritoneal cavities is also performed,