Muscle and Nerve Diseases Flashcards
what are the components that allow muscle to convert chemical energy into mechanical?
Excitation-contraction coupling
The contractile mechanism
Structural components
The energy system
what are the symptoms of muscle disease?
Weakness of skeletal muscle Short of breath (respiratory muscles) Cardiomyopathy Poor suck/ feeding/FTT/floppy Cramp, pain Myoglobinuria
what are the signs of muscle disease?
Wasting/ hypertrophy
Normal or reduced tone and reflexes
Motor weakness…NOT sensory
what investigations are done to diagnose muscle disease?
CK EMG Muscle biopsy: -Sructure -Biochemistry -inflammation Genetic testing
name the different types of muscle disease
Muscular dystrophies Channelopathies Metabolic muscle disease Inflammatory muscle disease Congenital myopathies
what are the different types of muscular dystrophies?
Duchenne’s MD Becker’s MD Facioscapulohumeral MD Myotonic dystrophy Limb-Girdle MD
what is muscular dystrophy?
a hereditary condition marked by progressive weakening and wasting of the muscles
what are channelopathies?
Disorders of Ca, Na and Cl channels
name a few channelopathies
Familial hypokalemic periodic paralysis
Hyperkalemic periodic paralysis
Paramyotonia congenita
Myotonia congenita
what are different causes of metabolic muscle disease?
Disorders of carbohydrate metabolism
Disorders of lipid metabolism
Mitochondrial myopathies/ cytopathies
what are the 2 types of inflammatory muscle disease?
Polymyositis
Dermatomyositis
what are the characteristics of inflammatory muscle disease?
Acute or subacute Painful weak muscles Characteristic rash of DM Any age Other symptoms may be involved
what investigations are used to diagnose inflammatory muscle disease?
↑CK EMG, inflammation and myopathic Biopsy: -PM: CD8 cells -DM: humeral-mediated, B cells and CD4 cells
what is the treatment of inflammatory muscle disease?
Immunosuppression
what is Myasthenia Gravis?
Disorder of neuromuscular junction
autoimmune disease
what is the Clinical presentation of Myasthenia Gravis?
Fatiguable weakness: Limbs Eyelids (ptosis) Muscles of mastication (chewing) Talking SOB diplopia
what are the investigations for Myasthenia Gravis?
AChR ab Anti MuSK ab Neurophysiology: -Repetitive stimulation -EMG Tensilon test CT chest
what is the treatment for Myasthenia Gravis?
Symptomatic
Acetylcholinesterase inhibitor
Immunosuppression
Prednisolone
Steroid saving agent (azathioprine)
surgery
Thymectomy
what is Myasthenia Gravis associated with?
In young associated with thymic hyperplasia
In old may be associated with a malignant thymoma
what does the peripheral nerve consist of?
Sensory axons: Small fibres (pain + temperature) Large fibres (joint position sense + vibration)
Motor axons
what are different causes of nerve root disease?
Degenerative spine disease
Inflammation
Infiltration
what can cause a lesion of an individual peripheral nerve
Compressive/ entrapment neuropathy
Vasculitic (mononeuritis multiplex)
what nerves are affected in generalised peripheral neuropathy?
Motor/ sensory/ both
+/- autonomic features
what are causes of generalised peripheral neuropathy?
Metabolic: DM, alcohol, B12 Toxic: drugs Hereditary Infectious: Lyme, HIV, leprosy Malignancy: paraneoplastic Inflammatory demyelinating: -Acute = Guillain -Barre syndrome Chronic= CIDP
what are symptoms of nerve root disease?
Myotomal wasting and weakness
Reflex change
Dermatomal sensory change
what are symptoms of individual nerve disease?
Wasting and weakness of innervated muscle
Specific sensory change
what are symptoms of generalised peripheral neuropathy?
Sensory and motor symptoms starting distally and moving proximally
what are investigations of nerve disease?
Blood tests Genetic analysis NCS Lumbar puncture (CSF analysis) Nerve biopsy (nb sensory nerve)
what is amyotrophic lateral sclerosis?
rapidly progressive, invariably fatal neurological disease that attacks the motor neurones responsible for controlling voluntary muscles
describe the onset of amyotrophic lateral sclerosis?
Usually limb, later bulbar and respiratory involvement
why is there a combination of UMN and LMN signs in amyotrophic lateral sclerosis?
anterior horn cell is cell body of the lower motor neurone and part of the corticospinal tract
what are the combined signs of UMN and LMN in amyotrophic lateral sclerosis?
LMN= muscle fasciculations, wasting, weakness
UMN= increased tone, brisk reflexes
No sensory involvement
what is the prognosis of amyotrophic lateral sclerosis?
3-5 years from symptom onset
2-3 years from diagnosis
50% die within 14 months of diagnosis
how do you diagnose amyotrophic lateral sclerosis?
Unique combination of UMN and LMN signs
EMG
how do you treat amyotrophic lateral sclerosis?
Supportive only (PEG, NIV) riluzole
