Paraplegia

Question 1

What’s paraplegia and it’s causes

Answer 1

Definition:
Paraplegia refers to the impairment of motor and sensory functions in the lower extremities, leading to a complete inability to move the lower limbs. This condition results from damage to parts of the nervous system that control the lower body.

Causes:
Paraplegia can be caused by:
- Spinal Cord Injury or Disease: Damage to the spinal cord, spinal roots, or peripheral nerves. This could be due to traumatic injuries or diseases like tuberculosis of the spine (Pott’s disease).
- Intracranial Lesions: Certain lesions in the parasagittal area of the brain can also lead to paraplegia.
- Myopathies: These are diseases of the muscle that can impair movement.

Question 2

What are the types of paraplegia
& the common causes of paraplegia in Nigeria

Answer 2

Types:
Paraplegia is generally classified into two types:
- Spastic Paraplegia (Upper Motor Neuron, UMN): This type is characterized by increased muscle tone and reflexes.
- Flaccid Paraplegia (Lower Motor Neuron, LMN): This type is associated with decreased muscle tone and reflexes.

Common Causes in Nigeria:
- Tuberculosis of the Spine (Pott’s Disease): This is the most common infectious cause of paraplegia in Nigeria, typically affecting the lower thoracic and upper lumbar vertebrae.
- Traumatic Injuries: Spinal cord injuries from trauma are also common, with over 10,000 new cases reported annually in Nigeria. These injuries predominantly affect males under 30 years old.

Question 3

Give an overview of the spinal cord

Answer 3

The spinal cord is a crucial part of the nervous system, acting as a conduit for signals between the brain and the rest of the body.

• Length: Approximately 45 cm in adults.
• Location: The spinal cord begins at the foramen magnum at the base of the skull and extends to the upper junction of the L1/L2 vertebrae.
• Enlargements:
  
  • Cervical Enlargement: Corresponds to the brachial plexus, which innervates the upper limbs.
  • Lumbar Enlargement: Corresponds to the lumbosacral plexus, which innervates the lower limbs.
• Segments:
  
  • The spinal cord is divided into 31 segments, each giving rise to a pair of spinal nerves:
    
    • 8 cervical (C1-C8)
    • 12 thoracic (T1-T12)
    • 5 lumbar (L1-L5)
    • 5 sacral (S1-S5)
    • 1 coccygeal (Co1)
• Vertebrae: The vertebral column consists of 33 vertebrae:
  
  • 7 cervical
  • 12 thoracic
  • 5 lumbar
  • 5 sacral
  • 4 coccygeal

Question 4

• Spinal Cord vs. Vertebral Column: The spinal cord is shorter than the vertebral canal, ending at the L1/L2 level, while the vertebral column extends further down.
• Cauda Equina: The bundle of spinal nerves below the end of the spinal cord that resembles a horse’s tail.

Answer 4

• Spinal Cord vs. Vertebral Column: The spinal cord is shorter than the vertebral canal, ending at the L1/L2 level, while the vertebral column extends further down.
• Cauda Equina: The bundle of spinal nerves below the end of the spinal cord that resembles a horse’s tail.

Question 5

The spinal cord is composed of gray and white matter, which serve different functions: which are?

List the common tracts and Columns of the CNS

Answer 5

The spinal cord is composed of gray and white matter, which serve different functions:

• Gray Matter: Contains the nerve cell bodies and is involved in processing and relaying information.
• White Matter: Consists of myelinated nerve fibers (axons) that transmit signals up and down the spinal cord.

Columns and Fibers:
- Posterior Column:
- Contains the Gracile and Cuneate Fasciculi which carry sensory information from the body to the brain.
- Lateral Column:
- Contains the Lateral Spinothalamic Tract (LST) responsible for pain and temperature sensation.
- Anterior and Posterior Spinocerebellar Tracts (SCT) carry proprioceptive information to the cerebellum.
- Lateral Corticospinal Tract (LCST): This major motor pathway carries voluntary movement commands from the brain to the body.
- Anterior Column:
- Anterior Spinothalamic Tract (AST): Carries crude touch and pressure sensations.
- Anterior Corticospinal Tract (ACST): Involved in voluntary motor control, particularly for axial muscles.

Understanding these structures and pathways is crucial for diagnosing and managing paraplegia, as they reveal where damage may have occurred in the nervous system.

Question 6

Paraplegia can develop gradually or suddenly, and its causes are diverse, involving both cerebral and spinal origins. The pathological mechanisms can vary from non-compressive processes like neurodegenerative diseases to compressive lesions like tumors. Additionally, the causes can affect either the upper motor neurons (UMNs) or lower motor neurons (LMNs), leading to spastic or flaccid paralysis, respectively.

Question 7

What are the causes of Gradual Onset of Paraplegia

Answer 7

Cerebral causes
Spinal causes

Question 8

What are the examples of Cerebral causes

Answer 8

.

1. Cerebral Causes:
- Cerebral Diplegia: This condition, often a form of cerebral palsy, affects motor control, leading to symmetrical paralysis in both lower limbs.
- Parasagittal Meningioma: A tumor located in the parasagittal region of the brain, which can compress motor pathways that control the lower limbs, causing paraplegia.

Question 9

What are the examples of spinal causes
- Non-Compressive (Gradual Onset) Causes:
- Compressive Causes:

Answer 9

2. Spinal Causes:
- Non-Compressive (Gradual Onset) Causes:
- Motor Neurone Disease (MND): A neurodegenerative disorder that affects motor neurons, leading to progressive weakness and paralysis.
- Multiple Sclerosis (MS): An autoimmune disease that causes demyelination in the central nervous system, leading to a range of neurological symptoms, including paraplegia.
- Friedreich’s Ataxia: A hereditary disease that causes degeneration of nerve tissue in the spinal cord, leading to progressive weakness and loss of coordination.
- Subacute Combined Degeneration of the Cord (SACDC): This condition, often due to vitamin B12 deficiency, affects both the dorsal columns and corticospinal tracts, leading to weakness and sensory loss.

• Compressive Causes:
  
  • Intramedullary (5%): Tumors within the spinal cord itself, such as:
    
    • Glioma: A type of tumor arising from glial cells.
    • Ependymoma: A tumor originating from the ependymal cells lining the spinal cord.
    • Chordoma: A rare tumor that can occur anywhere along the spine.
  • Extramedullary:
    
    • Intradural (15%): Tumors or lesions located inside the dura mater but outside the spinal cord, such as:
      
      • Meningioma: A tumor arising from the meninges, the protective layers covering the brain and spinal cord.
      • Neurofibroma: A tumor of the nerve sheath.
      • Patchy Arachnoiditis (TB, Syphilis): Inflammation of the arachnoid layer of the meninges, often due to infections like tuberculosis or syphilis, which can lead to scarring and compression of the spinal cord.
    • Extradural (80%): Lesions outside the dura mater, most commonly leading to paraplegia, including:
      
      • Caries Spine: Tuberculosis of the spine, which can destroy vertebrae and compress the spinal cord.
      • Lymphoma/Myeloma/Metastatic Deposits in Vertebra: Cancerous growths in the vertebrae that compress the spinal cord.
      • Patchy Meningitis: Chronic inflammation of the meninges that can lead to scarring and compression.
      • Intervertebral Disc Prolapse: A herniated disc can compress the spinal cord or nerve roots, leading to paraplegia.

Question 10

What are the causes of sudden onset paraplegia

Answer 10

1. Cerebral Causes:
- Thrombosis of Unpaired Anterior Cerebral Artery: Occlusion of this artery can lead to ischemia in the brain regions controlling the lower limbs, resulting in sudden paraplegia.
- Superior Sagittal Sinus Thrombosis: A clot in this major brain venous sinus can cause increased intracranial pressure and affect motor control, leading to paraplegia.

2. Spinal Causes:
- Acute Transverse Myelitis: A sudden onset of inflammation across both sides of one level of the spinal cord, leading to paralysis below the level of the lesion.
- Spinal Cord Injury: Trauma to the spine can cause immediate and severe damage to the spinal cord, resulting in paraplegia.
- Anterior Spinal Artery Thrombosis: This artery supplies the anterior two-thirds of the spinal cord. Its occlusion can cause sudden loss of motor function and pain/temperature sensation below the level of the injury.
- Haematomyelia: Bleeding within the spinal cord, which can compress nerve tissue and cause paraplegia.
- Post-Vaccination: Rarely, certain vaccinations can trigger an autoimmune response leading to transverse myelitis or other conditions causing sudden paraplegia.
- Intervertebral Disc Prolapse: An acute herniation can suddenly compress the spinal cord or nerve roots, leading to paraplegia.

Question 11

What are the causes of flaccid paraplegia

Answer 11

Flaccid paraplegia involves a loss of muscle tone and reflexes, and it can result from lesions at different levels of the nervous system.

1. Upper Motor Neuron (UMN) Lesion in Shock Stage:
- Spinal Shock: A temporary condition following spinal cord injury where there is a sudden loss of reflexes below the level of the injury.
- Acute Transverse Myelitis: As described above, it can cause an initial flaccid paralysis.
- Spinal Injury: Traumatic injuries leading to spinal cord damage can initially cause flaccid paralysis before spasticity develops.

2. Lower Motor Neuron (LMN) Lesions:
- Involving Anterior Horn Cells and Peripheral Nerves:
- Acute Anterior Poliomyelitis: A viral infection that damages the anterior horn cells of the spinal cord, leading to flaccid paralysis.
- Acute Infective Polyneuropathy (Guillain-Barré Syndrome, GBS): An autoimmune condition where the immune system attacks the peripheral nerves, leading to flaccid paralysis.
- Progressive Muscular Atrophy: A subtype of motor neurone disease that primarily affects LMNs, leading to gradual muscle wasting and flaccid paralysis.

• Anterior Spinal Artery Thrombosis: As previously mentioned, occlusion of this artery can also lead to flaccid paralysis.
• Motor Neurone Disease (MND): Over time, MND can affect both UMNs and LMNs, leading to mixed features of spasticity and flaccidity.
• Diseases Affecting the Myoneuronal Junction:
  
  • Myasthenia Gravis (MG): An autoimmune disorder where antibodies block or destroy receptors at the neuromuscular junction, leading to muscle weakness and fatigue.
  • Hypokalemic Periodic Paralysis (HPP): A genetic disorder that causes episodes of flaccid paralysis due to low potassium levels.
• Diseases Affecting Muscles (Myopathies): Muscle diseases that impair muscle function, leading to flaccid paralysis.
• Hysterical Paralysis: Also known as conversion disorder, where psychological stress manifests as neurological symptoms, including paralysis.