Muscle Weakness ; Lecture Flashcards
Muscle weakness due to _________ disease is typically proximal, while weakness from _________ disease is distal.
muscle; nerve.
True/False: Bulbar involvement is characteristic of Myasthenia Gravis (MG).
True.
What are the key anatomical structures involved in motor function?
Motor cortex.
Medulla/spinal cord.
Anterior horn cell.
Motor neuron.
Neuromuscular junction (NMJ).
Muscle.
True/False: Stroke, multiple sclerosis (MS), and tumors can affect the motor cortex and spinal cord.
True.
What key aspects should be assessed in the history of a patient with muscle weakness?
Onset (sudden vs gradual).
Distribution (proximal vs distal, symmetrical vs asymmetrical).
Variability (fixed vs progressive).
Associated sensory features (e.g., tingling, numbness).
Symmetrical weakness suggests _________ causes, while asymmetrical weakness often indicates _________ or inflammatory causes.
genetic or metabolic; vasculitic.
Which toxins can cause peripheral neuropathy?
Alcohol, nitrous oxide, chemotherapy, amiodarone, and lead.
What are the most common causes of peripheral neuropathy?
Diabetes.
Alcohol.
Idiopathic causes (20%+).
Peripheral neuropathies can affect _________, _________, or both, and may involve _________, myelin, or both.
motor nerves; sensory nerves; axons.
What are the hallmark features of Myasthenia Gravis?
Fatigueable weakness.
Proximal limb involvement.
Ptosis and diplopia.
Bulbar symptoms (speech, swallowing).
Risk of respiratory failure.
True/False: Chronic peripheral neuropathies are usually length-dependent, starting in the legs.
True.
Myasthenia Gravis is associated with _________ dysfunction, including thymic hyperplasia and _________.
thymus; thymoma.
True/False: EMG with repetitive stimulation is more sensitive than antibody tests for diagnosing MG.
True.
How is MG treated?
Acetylcholine esterase inhibitors (e.g., pyridostigmine).
Immunosuppressants (steroids, azathioprine).
Thymectomy if thymoma is present.
Monitoring forced vital capacity (FVC).
_________ myopathy and _________ myopathy are common drug-induced muscle disorders.
Steroid; statin.
True/False: Mitochondrial disorders may involve eye movement abnormalities and are associated with muscle disorders.
True.
What tests are critical for evaluating neuropathy?
History and examination.
Nerve conduction studies (NCS).
EMG.
CSF study.
Neuropathy and vasculitic screens.
A neuropathy screen includes _________, _________, and _________.
FBC; glucose; B12/folate levels.
How is myopathy investigated?
Creatine kinase (CK).
EMG.
Muscle MRI.
Genetic testing.
Biopsy.
A 50-year-old landlady reports tingling in her fingers and feet with clumsiness and frequent falls. What is the likely diagnosis?
Diabetic peripheral neuropathy.
A 45-year-old reporter has numbness over the lateral two digits of the left hand. Phalen’s test is positive. What is the diagnosis?
Carpal tunnel syndrome
In a myasthenic crisis, _________ and _________ functions should be closely monitored.
respiratory; bulbar.
What are the key management strategies for neuromuscular diseases?
Multidisciplinary team (MDT) involvement.
Address breathing and swallowing issues.
Treat underlying causes.
Provide supportive care (e.g., physiotherapy, OT).
_________ and _________ are critical red flags in neuromuscular emergencies.
Sudden respiratory distress; progressive bulbar dysfunction.
True/False: Proximal muscle weakness typically involves difficulty with stairs, chairs, and hair grooming.
True
Muscle weakness can result from _________ motor neuron (UMN) lesions, _________ motor neuron (LMN) lesions, or both.
upper; lower.
True/False: Neurological muscle weakness typically affects proximal muscles first.
False (UMN lesions affect distal muscles, whereas muscle diseases often cause proximal weakness).
What is the difference between pyramidal and extrapyramidal tracts?
Pyramidal tracts: Voluntary control of body and face musculature (e.g., corticospinal and corticobulbar tracts).
Extrapyramidal tracts: Involuntary and automatic control (e.g., posture, muscle tone).
The lateral corticospinal tract decussates at the _________, while the anterior corticospinal tract remains _________ until it reaches the cervical and thoracic spinal levels.
medulla; ipsilateral.
Which cranial nerve is NOT part of the peripheral nervous system?
Cranial nerve II (optic nerve).
What are the key elements of a muscle weakness history?
Onset: Gradual or sudden.
Distribution: Proximal/distal, symmetrical/asymmetrical.
Variability: Fatigue, relapses, remissions.
Context: Recent illnesses, medications, alcohol use.
In UMN lesions, tone and reflexes are _________, while in LMN lesions, tone and reflexes are _________.
increased; decreased.
True/False: Fasciculations are commonly observed in LMN lesions.
True.
How are peripheral neuropathies classified?
Polyneuropathy: Diffuse involvement of peripheral nerves.
Mononeuropathy multiplex: Two or more isolated nerves.
Mononeuropathy: Single nerve involvement.
Guillain-Barré Syndrome (GBS) is an _________ neuropathy caused by _________ demyelination.
acute; autoimmune.
True/False: Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) is considered a chronic form of GBS.
True
What conditions commonly cause sensory-predominant neuropathy?
Diabetes.
B12/Folate deficiency.
Alcohol/toxins.
Uraemia.
What is the pathophysiology of Myasthenia Gravis?
Autoimmune attack on nicotinic acetylcholine receptors at the neuromuscular junction.
Common symptoms of MG include _________ weakness, _________ (speech, swallowing), and _________ (double vision).
fatigueable; bulbar; diplopia.
True/False: MG is commonly associated with thymoma or thymic hyperplasia.
True.
What are key investigations for MG?
ACh receptor antibody testing.
EMG for NMJ dysfunction.
CT thorax for thymoma.
A patient presents with ptosis, proximal muscle weakness, and symptoms that worsen with activity. What is the likely diagnosis?
Myasthenia Gravis.
What are the hallmark features of GBS?
Subacute ascending weakness.
Hyporeflexia or areflexia.
Post-infectious onset.
Elevated CSF protein with normal cell count.
Treatment for GBS includes _________ or _________, along with supportive care and FVC monitoring.
IVIG; plasmapheresis.
What are the clinical features of Motor Neuron Disease?
Mixed UMN and LMN signs.
Asymmetrical weakness.
Bulbar or limb onset.
No sensory involvement.
MND is a _________ diagnosis supported by EMG and _________ to exclude mimics.
clinical; MRI.
What are common causes of muscle weakness related to myopathies?
Steroid myopathy.
Statin-induced myopathy.
Myotonic dystrophy.
Polymyositis/Dermatomyositis.
Duchenne Muscular Dystrophy often presents with _________, _________, and scoliosis.
proximal weakness; contractures.
True/False: Eye movement disorders are rare in muscle diseases except for mitochondrial disorders.
True.
What investigations are key for muscle disorders?
CK levels.
EMG.
ESR/CRP.
Genetic testing.
Biopsy (if needed).
Supportive management for muscle disorders includes _________, _________, and _________.
physiotherapy; OT adaptations; dietary support.
True/False: Neuropathic pain in peripheral neuropathy is treated with gabapentin, pregabalin, or amitriptyline.
True.
