Muscle weakness: signs of symptoms and causes

2021-01-26 12:00 AM

Grading, distribution and progression of muscle weakness and associated symptoms (e.g., markers of the upper motor neuron, lower motor neuron, localized in the cortex) are important in assessing the cause.

Description

Muscle weakness is characterized by weakness, anatomical distribution, and associated symptoms (eg, low motor neuron marker, high motor neuron marker, cortex localization markers).

Muscle weakness was assessed on a scale developed by the British Medical Research Council (MRC) during World War II.

Degree

Characteristics

0/5

There is no muscle contraction.

1/5

Muscle contraction.

2/5

Moves but can't beat gravity.

3/5

Movement overcomes gravity but not resistance.

4- / 5

Movement wins gravity, only weak resistance.

4/5

Movement wins resistance and gravity.

4 + / 5

The movement overcomes gravity and resistance with almost the strongest force.

5/5

Normal force.

Board. Gravity rating scale according to the British Medical Research Council.

Reason

Often met

Infarction in the middle cerebral artery.

Brain haemorrhage.

Deficient infarction, posterior inner capsule.

Bone marrow disease.

Single-nerve compression (eg carpal tunnel syndrome).

Nerve root disease.

Reduced blood potassium.

Less common

Scattered stiff fibres.

Peripheral neuropathy.

Infarction of the anterior cerebral artery.

Guillain – Barré syndrome.

Myasthenia gravis.

Myopathy.

Paralysis Todd.

Hypoglycemia.

Disabled

Figure. Anterior circulation and functional maps, cortical motor centre

Figure. Cerebral artery distribution regions. A, The region of the cortex; B, The central cortex.

Figure. Upper motor neuron anatomy

Figure. The mechanism of muscle weakness is based on the types of clinical signs of the arms and legs. Damage to the motor centre in the opposite side of the brain; lateral cervical spinal cord injury; damage to the posterior inner posterior cylinder; paralyzed Todd.

Figure. The mechanism of muscle weakness is based on clinical signs of muscle weakness. Guillain – Barré syndrome; tick list.

Figure. The mechanism of muscle weakness is based on the types of clinical signs that are weak and on the downward trend. Poisoning • Miller Fisher syndrome progresses to Guillain– Barré; polyneuropathy caused by diphtheria.

Figure. The mechanism of muscle weakness is based on clinical signs of bilateral legs and arms. Completely damaged neck marrow; anterior myelogenous syndrome.

Figure. The mechanism of muscle weakness is based on the types of bilateral clinical signs. Osteomyelitis of the neck; cervical root disease.

Figure. The mechanism of muscle weakness is based on clinical signs of the apical muscle groups. Peripheral neuropathy; Muscular dystrophy.

Figure. The mechanism of muscle weakness is based on the types of facial and hand clinical signs. Middle cerebral artery infarction.

Figure. The mechanism of muscle weakness is based on the types of clinical signs of the face, arms, and legs. Damage to the posterior inner wall; infarction in the anterior cerebral artery and the middle brain.

Figure. The mechanism of muscle weakness is based on clinical signs of unilateral and lateral extremities. Brain stem damage.

Figure. The mechanism of muscle weakness is based on the types of leg clinical signs. Lumbar root disease; anterior cerebral artery infarction; damage to the spinal cord below T1.

Figure. The mechanism of muscle weakness is based on the peripheral nerve root types of clinical signs. Nerve root disease.

Figure. The mechanism of muscle weakness is based on clinical signs of the apical muscle group. Muscle disease.

The mechanism of muscle weakness is based on clinical signs of the base of the limbs group. Length-dependent peripheral neuropathy.

Mechanism

The mechanism of muscle weakness is classified according to the anatomical distribution and associated symptoms (for example, signs of the upper motor neuron, the lower motor neuron, the localized signs in the cerebral cortex ...).

Symptoms of the upper motor neuron

Symptoms of lower motor neuron

Shrinkage.

Vibration.

Muscle weakness.

Increase reflexes.

Babinski sign.

Local muscle fibrillation.

Amyotrophic lateral sclerosis.

Reduced muscle tone.

Muscle weakness.

Reduce / lose reflexes.

Board. Symptoms of upper and lower motor neurons.

Mechanisms of muscle weakness include:

Motor centre damage in the cerebral cortex.

Damage to the back post, inner shell.

Central brain stem damage.

Spinal cord injury.

Nerve root disease.

Guillain – barré syndrome.

Peripheral neuropathy.

Disorders of neuromuscular connections.

Myopathy.

Metabolic diseases, poisoning, inflammation.

Motor centre damage in the cerebral cortex

Paralyzing the opposing hemiplegia according to the functional map distribution of the cortical motor centre (also known as the balanced dwarf). The accompanying upper motor neuron signs are characteristic. Immediately after acute cerebral motor centre, acute infarction occurs, loss of tone, soft paralysis, reduction or loss of reflexes appear. Spasticity and hyper reflex will appear after a few days to weeks.

Damage to the back post, inner shell

Causing complete motor paralysis of half of the body opposite side including the face, arms and legs. The symptoms of the accompanying upper motor neuron are characteristic. Due to the close proximity of nerve fibres to each other in the posterior medial region, even a small injury can cause signs of complete paralysis of the face, arms and legs. . The most common cause is a defect infarction.

Central brain stem damage

Damage to the central brain stem can affect the cranial nerve motor nucleus and/or downward bands of the motor fibres. Brain stem lesions are characterized by motor and/or sensory cues that cross the midline (eg, parietal cranial markers and signs of Para lateral bands). Causes include central cerebrovascular syndrome, hemorrhagic infarction, multiple sclerosis, and tumours).

Spinal cord injury

Unilateral damage to the spinal cord acts on the lateral strip of the pulp, causing muscle weakness on the same side. The upper motor nerve fibres cross at the pyramids in the brain. Upper motor neuron markers are quite characteristic.

Nerve root disease

Motor symptoms occur according to the distribution of the nerve roots. Nerve root damage typically causes sensory-positive disturbances (eg, pain), negative sensory disturbances (eg, hypersensitivity) according to the distribution of one or more nerve roots. Signs of the lower motor neuron are quite characteristic. Mechanical damage to the nerve roots is the cause of axonal degeneration and myelin sheaths located far from the site of damage (also known as Wallerian degeneration), leading to decreased sensation and movement according to the distribution of the nerve roots. trauma.

Common causes include spina bifida, intervertebral disc disease and tumours.

Guillain – Barré syndrome (GBS)

Guillain – Barré Syndrome (GBS), also known as acute myelin degenerative poly myeloid disease, is characterized by degenerative myelin condition with multiple axonal degenerative damage and lymphatic infiltrates and is associated with the previous infection (eg, Campylobacter jejuni, herpes viruses, Mycoplasma pneumonia). Guillain Barré syndrome typically causes soft paralysis in the apical muscle group, progressing to the base of the limb (also known as muscle weakness with an upward trend). Lower motor neuron symptoms are quite characteristic.

Peripheral neuropathy

Causes include mono-neuropathy and length-dependent peripheral neuropathy.

Single nerve compression

Mechanical damage causes degeneration of axons and myelin beyond the site of injury (also known as Wallerian degeneration), causing decreased movement and sensation in the distribution of the damaged peripheral nerve. Causes include carpal tunnel syndrome, general fibroids and rotational palsy (eg, "Saturday night" paralysis).

Length-dependent peripheral neuropathy

Length-dependent peripheral neuropathy can be caused by impaired nuclear membrane function in the enzyme, protein synthesis, axonal conduction dysfunction or a disturbance of energy metabolism. Metabolic disturbances at the peripheral nerve cause degeneration of nerve fibres at the far end and towards the centre. Causes include type 2 diabetes, alcohol use and hereditary neurological diseases.

Disorders of neuromuscular connections

Myasthenia gravis is caused by antibodies that directly resist acetylcholine receptors on the post-synaptic neuromuscular membrane. The typical myasthenia gravis affects the eye and facial muscles, by reducing the muscle tone, causing the patient to lose movement. Lambert-Eaton Syndrome is a paracellular syndrome associated with small cell lung cancer, caused by antibodies to the pre-synaptic calcium channel. Characterized by basal limb muscle weakness and transient type of weakness that increases with movement.

Muscle diseases

Muscle diseases typically cause root muscle weakness. One exception is dystrophy which tends to affect the cranial and apical muscle groups. The causes of muscle diseases include muscular dystrophy, metabolic disease and myositis. Metabolic-related muscle diseases, poisoning and inflammation Metabolic diseases and botulism can cause muscle weakness because of changes in the euphoria (in other words, with the resting voltage of the membrane) of the nerve fibres and/or muscle fibres, or because toxins work directly on nerves or muscles. Causes include hypokalemia, hypoglycemia, strychnine poisoning, tetani muscle and botulism.

Clostridium botulinum

Botulism is caused by the bacterium Clostridium botulinum, which produces a toxin that blocks the release of acetylcholine from the ends of the chrysanthemum.

Listed tick

Tick ​​paralysis is caused by a substance produced by a tick when sucking human blood, increasing sodium transport across the membrane without acting on the neuromuscular link. The function of the terminal chrysanthemum will rapidly improve after removing the tick. Characteristics of the disease include acute soft paralysis and ataxia, which can cause damage to the medulla oblongata and respiratory arrest.

Meaning

Grading, distribution and progression of muscle weakness and associated symptoms (e.g., markers of the upper motor neuron, lower motor neuron, localized in the cortex) are important in assessing the cause.