Muscle and Nerve Disease Flashcards
Common symptoms of muscle disorders
Weakness of skeletal muscles Dyspnoea (respiratory muscles affected) Cardiomyopathy Poor feeding/failure to thrive in newborns Cramping and pain Myoglobinuria
Common signs of muscle disorders
Wasting/hypertrophy
Normal/reduced tone and reflexes
Motor weakness
Classifications of muscle diseases
Muscular dystrophies Channelopathies Metabolic muscle disease Inflammatory muscle disease Congenital myopathies
Examples of muscular dystrophies
Duchenne's Becker's Facioscapulohumeral Myotonic dystrophy Limb-Girdle
Examples of channelopathies
Disorders of Ca, Na and Cl channels Familial hypokalaemic periodic paralysis Hyperkalaemic periodic paralysis Paramyotonia congenital Myotonia congenital
Examples of metabolic muscle diseases
Disorders of carbohydrate/lipid metabolism
Mitochondrial myopathies/cytopathies
Examples of inflammatory muscle diseases
Polymyositis
Dermatomyositis
Presentation of inflammatory muscle diseases
Acute or subacute presentation
Painful, weak muscles
Characteristic rash if dermatomyositis
Treatment of inflammatory muscle disease
Immunosuppression
Common investigations for muscle disease
History and examination Creatine-kinase EMG Muscle biopsy for structure, biochemistry and inflammation Genetic testing
Investigations of inflammatory muscle diseases
Creatine-kinase - would be elevated
EMG - inflammation and myopathic
Biopsy
Clinical presentation of myasthenia gravis
Fatiguable weakness of limbs and muscles of mastication Ptosis Speech affected Dyspnoea Diplopia
Investigations of myasthenia gravis
AChR antibody Anti-MuSK antibody Neurophysiology - EMG, repetitive stimulation Tensilon test CT chest
Symptomatic treatment of myasthenia gravis
Acetylcholinesterase inhibitor
Immunosuppressive treatment of myasthenia gravis
Prednisolone
Steroid-sparing agent
Conditions associated with myasthenia gravis
Thymic hyperplasia in young people
Malignant thymoma in older people
Under what circumstances might a thymectomy be done?
Malignant thymoma in females < 40
Peripheral nerves consist of
sensory and motor axons
Causes of peripheral nerve disease
Degenerative spine disease
Inflammation
Infiltration
Lesions
Examples of lesions of individual peripheral nerves
Compressive/entrapment neuropathy
Vasculitic
Causes of generalised peripheral neuropathy
Metabolic e.g. diabetes mellitus Toxic - drugs Hereditary Infectious e.g. Lyme disease Malignancy Inflammatory demyelinating conditions (acute or chronic) e.g. Guillain Barre syndrome
Symptoms of pathology at the nerve root
Myotomal wasting and weakness
Reflex change
Dermatomal sensory change
Symptoms of pathologies of an individual nerve
Wasting and weakness of the innervated muscle
Specific sensory change
Symptoms of generalised peripheral neuropathy
Sensory and motor symptoms starting distally and moving proximally
Investigation of nerve disease
Blood tests Genetic analysis Nerve conduction study Lumbar puncture - CSF analysis Nerve biopsy
Most common cause of Guillain-Barré syndrome
Acute inflammatory demyelinating polyradiculoneuropathy (AIDP)
Typical presentation of Guillain-Barré syndrome
2-4 weeks after relatively benign respiratory/GI illness
Complaints of finger dysesthesias and proximal muscle weakness of lower extremities
Weakness progressing to involve arms, trunk, cranial nerves and respiratory muscles
Typical pattern of weakness in Guillain-Barré syndrome
Ascending and symmetrical
Lower limbs affected before upper limbs
Symptoms of Guillain-Barré syndrome
Pain, tingling and numbness Progressive muscle weakness Co-ordination problems and unsteadiness Temporary paralysis of legs, arms, face or respiratory muscles Blurred vision/diplopia Difficulty speaking Dysphagia Difficulty with digestion/bladder control HR and BP fluctuations
Clinical features of an upper motor neurone lesion
Muscle weakness Decreased control of active movement Spasticity Clasp-knife response Babinski sign Increased deep tendon reflex Pronator drift
Clinical features of a lower motor neurone lesion
Muscle paresis/paralysis Fibrillations Fasciculations Hypotonia/atonia Hyporeflexia Weakness limited to segmental or focal pattern Muscle wasting in end-stage
What is myelopathy?
Disease of the spinal cord
What is radiculopathy?
Condition due to compression of a nerve in the spinal cord
Symptoms of radiculopathy
Pain
Numbness
Tingling
Weakness
Causes of non-compressive spinal cord lesions
Myelitis Vascular Metabolic Drugs and toxins Physical agents Degenerative
Clinical presentation of motor neurone disease
Limb onset
UMN and LMN signs
Lower motor neurone - muscle fasciculations, wasting, weakness
Upper motor neurone - increased tone, brisk reflexes
No sensory involvement
How is motor neurone disease diagnosed
Clinical presentation of combination of UMN and LMN signs, and EMG
Treatment of motor neurone disease
Supportive - PEG, NIV
Riluzole
