2. Spinal Cord Lesions.pdf

I’ve used batch 18 tafreegh and added some points on it Batch 20 ALJAZI ALMUTAIRI Spinal Cord Disorders SUHAIL ALSHAMMARI, MD 1 The Spinal Cord §Spinal cord roots ◦ Cervical (8) ◦ Thoracic (12) ◦ Lumbar (5) ◦ Sacral (5) segments • Although there are eight cervical nerves, there are only seven...

I’ve used batch 18 tafreegh and added some points on it Batch 20 ALJAZI ALMUTAIRI Spinal Cord Disorders SUHAIL ALSHAMMARI, MD 1 The Spinal Cord §Spinal cord roots ◦ Cervical (8) ◦ Thoracic (12) ◦ Lumbar (5) ◦ Sacral (5) segments • Although there are eight cervical nerves, there are only seven cervical vertebral bodies. Cervical nerves 1 through 7 exit above their named vertebral bodies, and cervical nerve 8 exits between C7 and T1 • All of the remaining segments have the same number of vertebral bodies and nerves, and the nerves exit below their named vertebral bodies • The spinal cord gray matter has the dorsal and ventral horns, and the anterior horn cells in the ventral gray horn represent the prototypical lower motor neuron (LMN) So if the disease affect the anterior gray matter, it will lead to a lower motor neuron syndrome • Motor deficits on the neurological examination are often interpreted as representing upper motor neuron (UMN) lesions versus LMN lesions, resulting in UMN and LMN syndromes Some diseases have both UMN & LMN syndromes, one example is ALS Amyotrophic lateral sclerosis, affects motor neuronsd This slide is to give you clinical & anatomical correlation Important to know where do bers cross in each tract, which information or sensation is carried in the tract will help you in understanding the syndromes En É TE o e Clinical Signs of Spinal Cord Lesions É Pyramidal signs = upper motor neuron signs Classical lower motor neuron syndrome Doctors usually grade re exes, clonus is the highest degree of hypere exia Lesion affecting half of the cord Spinal Cord Syndromes Terms you have to know Myelopathy = spinal cord injury Encephalopathy = brain injury Radiculopathy = injury to nerve roots Plexopathy = plexuses are affected Mononeuropathy = when a speci c nerve is affected for example median, femoral, ulnar…. Multiple mononeuropathy = many different nerves are affected 1) Hemisection/Brown-Sequard syndrome 2) Complete transection 3) Syringomyelia (central cavity) 4) Anterior spinal artery syndrome avascular syndrome In RTA The central canal widened Cavitation within the cord 5) the posterior cord, Tabetic syndrome (dorsal horn) Affect usually due to syphilis 6) Combined degeneration (posterior columns + lateral corticospinal tracts Happens in Vit B12 deficiency Very important do not forget it Usually 1 or 2 segments below (bc of the tract of lissauer) (Contralateral) (Half of the spinal is affected) (Ipsilateral) A “cape-like” sensory loss A lesion here will affect the crossing of the spinothalamic fibers from both sides that’s why you’ll have BILATERAL loss of pain & temp 1) Brown-Séquard syndrome Hemisection Lesions affecting one or other half of the of the spinal cord will cause UMN weakness and spasticity below Ipsilateral the lesion. • There is a deficit of spinothalamic loss (pain and temperature) below and contralateral to the lesion • Dorsal columnar loss (proprioception and vibration) below and ipsilateral to the lesion I Contralateral & below the lesion • Loss of pain & temp • Causes Ipsilateral & below the o Trauma lesion • Upper motor lesion o Compression from abscess, hematoma, or symptoms • Loss of neoplasm proprioception & vibration o Multiple sclerosis May happen with people who take anticoagulant 2) Complete Cord Transection • Corticospinal, spinothalamic, and dorsal column tracts are affected ( All modalities are affected) • Total loss of sensation below the level of the lesion • Loss of motor control below the level of the É lesion o Flaccid paralysis with atrophy at the lesion level due to destruction of anterior horn cells (LMN effect) • Bladder & bowel dysfuction • Urinary retention Complete Cord Transection • Spasticity below the level of the lesion due to interference with descending corticospinal tracts (UMN effect) • Decrease in voluntary bowel and bladder control • Decrease in respiration if lesion is above C5 (phrenic nerve to diaphragm is from 5 levels C3–C5) Bcz autonomic are affected bers Complete Cord Transection: Causes •Trauma • Usually due to a viral infection causing an autoimmune reaction • Or part of a demyelinating disease like MS •Transverse myelitis (usually postinfectious or demyelinative) •Tumor •Radiation injury 2 One of the commonest causes of transverse myelitis is neuromyelitis optica (NMO) Spinal Shock acute spinal lesion o – With any cord injury of significance, there is a 6-week to 8-week period of spinal shock – It is characterized by a total loss of all spinal cord function below the lesion, as though every segment of the cord were injured directly – During this time period, the reflexes are lost E I More widening —> more effect, and the effect depends on the site of widening Commonly in lower cervical & upper thoracic spine 3) Syringomyelia O • Central Cord Lesions • Earliest motor effects of central cord lesions will involve anterior horn cells at the levels of the lesion, with a resultant LMN lesion pattern • Later, with further expansion, the corticospinal tracts can be involved and can cause caudal UMN signs • Central cord lesions which extend anteriorly may also affect second order spinothalamic fibers as they decussate in front of the anterior ventral commissure Syringomyelia: Causes In imaging we see sagging of the brain& cerebrum witch affects CSF circulation Herniation of cerebellar tonsils within the foramen magnum • Chiari I malformation (characterized by displaced cerebellar tonsils downward through the foramen magnum, usually a congenital malformation) • Tumor of spinal cord Decompression surgery is done for these patients • Hemorrhage • Trauma The anterior spinal artery originates from vertebral artery •The anterior spinal artery: 4) Anterior Spinal Artery Syndrome: Vascular review: o Supplies blood to the anterior 2/3 of the spinal cord o Receives blood from smaller medullary arteries at irregular intervals •Pressure in the anterior spinal artery is lower than normal arterial pressure Which makes it prone to closure easily •Blood supply to the anterior spinal artery is tenuous in two regions: F ◦ T1 to T4 ◦ T10 to L3: an area dependent on perfusion from one large artery that is a branch off the aorta, the artery of Adamkiewicz These are the sites of spinal cord infarction Anterior Spinal Artery Syndrome •Causes infarction of the anterior 2/3 of the spinal cord •Usually spares the posterior columns and posterior horns •Paralysis of voluntary and automatic respiration in cervical segments; it also results in bilateral Horner syndrome •Loss of voluntary bladder and bowel control, with What’s horner syndrome? preservation of reflex emptying Horner syndrome is a disorder of •Anhidrosis and loss of vasomotor tone the sympathetic , you’ll get • Ptosis • Anhidrosis • Miosis •Anterior horn destruction: complete flaccid paralysis and areflexia at the level of the lesion What’s the first thing to do if someone comes with spastic weakness & loss of pain & temp ? an MRI to see if there’s spinal cord compression Anterior Spinal Artery Syndrome: Causes •Dissecting aortic aneurysm may shear off origin of an important spinal artery •Hypotensive crisis •Cardiac surgery with prolonged cross-clamping of aorta •Atherosclerosis of aorta at origin of an important feeding artery •Emboli •AVM (arteriovenous malformation) of cord with shunting of blood from the cord Disease processes may specifically affect the larger posterior fibers of the dorsal (posterior) roots that are destined to become the posterior columns 5) Posterior Column (Tabetic Syndrome) Clinical features: ◦ Loss of vibratory and position sensations below the level of the lesion § Usually symmetrical § Predominantly involving the lower extremities § Leads to a sensory ataxia due to loss of position sense ◦ Areflexia—due to loss of the afferent limb of the reflex arc ◦ Hypotonia—loss of proprioceptors from muscle spindles, thus eliminating feedback to maintain proper tone Very important symptom in this ◦ Lightning pains syndrome Sensory ataxia there is loss of position sense when eyes are closed In contrast to cerebral ataxia, where people will be ataxic even when their eyes are open, and they walk with a wide-based gait Causes of Tabetic Syndrome •Tabes dorsalis—one form of tertiary neurosyphilis •Diabetes mellitus •Caused by disease processes that directly affect the posterior columns and lateral corticospinal tracts •May be difficult to distinguish from tabes dorsalis due to the common posterior column involvement • Vitamin B12 deficiency: 6) Combined Systems Degeneration Copper de ciency is common in bariatric surgery Zinc toxicity has the same effect because it inhibit copper absorption ◦ Diffuse involvement of dorsal columns and lateral corticospinal tracts ◦ Loss of position and vibratory sensations below the level of the lesion ◦ Loss of motor function below the level of the lesion ◦ Less common cause is copper deficiency: hypocupremic myelopathy ◦ B12 deficiency can also affect other areas of the nervous system: cerebral hemisphere, optic nerve, cerebellum, peripheral nerve Other causes: • HIV infection • Bariatric surgery • Veganism • Traumatic or surgical It’s an easy & treatable condition if you detect it early on You treat it by replenishing B12 Combined Systems Degeneration THANK YOU