Please enable JavaScript.

Coggle requires JavaScript to display documents.

Neuromuscular disease - Coggle Diagram

- - - - Sensory Division - detects changes in an internal/external environment and sends info to the brain
      - Motor division - motor nerve fibres conducts info from the CNS to the effectors (glands, skeletal muscles)
        
        Somatic NS - controls voluntary movements (skeletal muscles)
        
        Somatic motor impulses are generated in the primary motor cortex via upper motor neuron - transfer the message to lower motor neuron - then transfers to the peripheral nervous system (skeletal muscles)
        
        impulses are carried to the skeletal muscles via upper and lower motor neurons in the corticospinal pathway
        
        somatic motor commands generated in primary motor cortex
        - basal nuclei (in cerebral white matter, play role in starting/stopping of movement) & cerebellum (gets input sensory from the body from proprioceptors, therefore can the react and adjust the movements to ensure movement is smooth & coordinated
        
        Autonomic NS - involuntary motor control (cardiac muscle in heart/digestive system)
        
        Sympathetic division: - fight/flight
        
        Parasympathetic division - rest and digest
- - - - - Clinical disorders of the skeletal muscles
        
        abnormalities of myocyte structure & metabolism lead to various patterns of weakness & dysfunction
        
        can involve cardiac muscle fibres, resulting in a hypertrophic or dilated cardiomyopathy
        
        can be inherited or acquired
      - Muscular dystrophy (inherited)
        
        - breakdown of the dystrophin-glycoprotein complex, a network of fibrous proteins that stabilise the sarcolemma during contraction/relaxation
        
        progressive degeneration of the muscles with increasing weakness & disability
        
        - Duchenne Muscular dystrophy
        
        most common MD.
        
        1 in 3300 males
        
        Mutation in the dystophin gene on X chromosome
        
        Dystrophin protein is absent - sarcolemma weakens & tears easily leading to death of muscle fibres & replacement by scar & fatty tissue
        
        Symptoms appear between 1-5 years old
        
        late walking, toe walking, enlarged calf muscles, difficulty standing
        
        Gower's sign
        
        weakness gradually progresses to include all skeletal muscles, respiratory muscles, heart
        
        fatal - mid-20's
      - Inflammatory myopathy
        
        muscle inflammation: muscle weakness, fatigue, myalgia
        
        3 main types of chronic inflammatory myopathy:
        - polymyositis = progressive muscle weakness on both sides of the body = difficulty rising from seating position, climbing stairs, lifting, reaching overhead
        
        dermatomyositis = females, skin rash on face/eyelids, nails, elbow, knees, chest, back - accompanies the progressive muscle weakness
        
        inclusion body myositis = muscle weakness asymmetric, include abnormal inclusion bodies
        
        chronic inflammatory myopathies are idiopathic
        
        thought to be autoimmune disorders, in which the body's white blood cells, attack blood vessels, normal muscle fibres, & connective tissue in organs, bones & joints
      - Toxic myopathy:
        
        undesired manifestation of myopathic symptoms that can occur in pts when exposed to certain drugs
        
        muscle weakness
        
        myalgia
        
        myoglobinuria
        
        Elevated creatine kinase
        
        alcohol/certain snake venons cause toxi myopathies
        
        both can cause extensive injury of skeletal muscle called RHABDOMYOLYSIS = breakdown of damaged skeletal muscle causes myoglobin and other muscle proteins to be released in the bloodstream - toxic in the kidneys
        
        Glucocorticoid-induced myopathy
        
        most common type of drug-induced myopathy
        
        side affect of corticosteroid therapy
        
        glucocorticoids - catabolic effect on skeletal muscle
        
        myalgia/muscle weakness
        - Cushing's disease
        
        adrenal glands produce high levels of cortisol
        
        60% patients display muscle weakness
      - Juntionopathy
        
        caused by a defect in transmission at the neuromuscular junction
        
        destruction, malfunction or absence of 1 or more key proteins involved in neuromusclar transmission
        
        Myasthenia Gravis
        
        autoimmune disease
        
        Affects younger women and older men
        
        Abs against Acetylcholine receptor
        
        Blocks ACh binding to AChR
        
        Stops transmission of signal from motor neuron to muscle fibre
        
        Symptoms:
        
        muscle weakness
        
        fatigue
        
        visual disturbances
        
        Ptosis - droopy eyelids
        
        Swallowing/breathing difficulty
        
        Muscle weakness increases over the day or with repetitive movements
        
        Complication of disease = Myasthenic crisis
        
        respiratory muscle failure
        
        requires mechanical ventilation
        - Treatments:
        
        Acetylcholinesterase inhibitors (improve transmission of signal from neuron to muscle)
        
        Immunosuppressants - reduce number of autoanti-bodies
        
        Thymectom
        
        - Botulinum
        
        clostridum botulinum
        
        neurotoxic - Botulinum toxic (Botox)
        - Prevents ACH release at the axon terminals
        
        Increasing muscle weakness, paralysis, progressing to respiratory muscles
        
        Can cause death
        
        management of medical: headaches/migraines, spastic movement
        
        BT cleaves the SNARE proteins
        
        Blocks ACH release from the synamptic vesciles at the NMJ
        
        No transmission of signal
        
        Muscle paralysis
        
        Organophosphate poisoning
        
        chemicals used in domestic and industrial settings
        
        Pesticides
        
        Toxic nerve agents used in war/terroist activities
        
        Inhaled, ingested or absorbed via skin
        
        Severity & onset of symptoms dependant on exposure
        
        copious respiratory and oral secretions
        
        diarrhea/vomiting, sweating, altered mental status, autonomic instability, muscle weakness that can progress to paralysis & respiratory arrest