Disorder Of The Muscles

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NEUROLOGY Disorder of the Muscles Jose C. Navarro, MD, FPNA 2/13/06 Diagram: Problem with these areas: • Ant. Horn cell • From peripheral nerve ex. Brachial plexus • Myoneural Junction • Muscles Common Manifestation: WEAKNESS If patient comes with weakness of whole extremity, it’s a muscle disease. (generalized distribution) If it’s just one arm or one leg, it’s not a muscle disease. CHARACTERISTICS OF MUSCLE DISORDERS 1. Generalized 2. Distribution more proximal than distal • Ask for activities • Difficulty of raising hands over head; thus difficulty in combing hair and hanging clothes • In the lower extremities: difficulty of climbing up stairs and especially when going down stairs • In climbing, the distal muscles can help pull up. In going down, there is a problem with quads and extensor muscles, so its much harder • Difficulty in getting up from sitting a position ** to sit, start with NECK MUSCLES (kala nyo sa hips or sa legs no… nope! It’s the neck accdg. To doc)

If Distal Muscles Affected: 1. weakness at the fingers - difficulty in buttoning and strapping and unstrapping bras 2. Foot drop – foot snaps while walking 3. difficulty in walking on toes and heels *Peripheral Nerve (distal > proximal)

Disease

*Central – generalized

–

generalized

(proximal > distal)

ANTERIOR HORN CELL DISEASE • weakness of both proximal & distal muscles • segmental - manifestation correspond to area of spinal cord segment affected • sensory function is spared ex. Poliomyelitis –affects usually one extremity only PERIPHERAL NERVE DISEASE • weakness w/ numbness, paresthesia • most of the time mixed nerve = motor, sensory, autonomic MYONEURAL JUNCTION • distribution of weakness innervated muscles

are

cranially

head and neck muscles

Diagram: Myoneural Junction • no anatomical continuity • space between terminal boutton and pre and post- synaptic area lower motor neuron – alpha motor neuron, peripheral nerve, myoneural junction, muscle CLINICAL MANIFESTATION OF WEAKNESS 1. Inability to move 2. Gower’s Maneuver 3. Respiratory Embarrassment – failure • in severe disease • will necessitate intubation/respiratory support Gower’s Maneuver • In patient w/ generalized weakness; seen in both UMN and LMN lesion • Not exclusively in muscle disease, seen also in peripheral nerve disease • Ask the child to sit on the floor, then get up • If generalized weakness, develop diff techniques to get up • Turn; face floor; hands on the floor • Extend knees • Hands on the knees • Stand • As disase progresses: difficulty of getting up from a chair, then from a toilet bowl; later on difficulty of getting up from a stool • Protruding abdomen • Lordosis exaggerated • If with proximal weakness, thumb rotates inferiorly; (N) Thumb always pointing anteriorly • weakness makes are arm rotate internally • Weak shoulder, girdle muscles – arm rotates internally (like MONKEYS or APES!!) • To stand up, knees are buckled to maintain an erect position • all done to achieve the lowest point of gravity of the body • Walking • (N) arm swing opposite • W/ muscle disease, throw their bodies forward (Arms and legs go forward at the same time) (remember Doc’s sample walk) - “malikot” coz their trying to fix their point of gravity Extraocular movements – “Dilat na dilat”! •

Progressive • no longer able to walk • wheelchair-bound • can no longer move due to generalized weakness

DIAGNOSTIC TESTS • Creatine Kinase • Electromyography

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Pedigree/ Chromosomal Studies Muscle Biopsy – should be complementary to clinical diagnosis only Biochemical Exam

Muscle Biopsy • muscle located at periphery (N) • If migrate to center  pathological • Size of muscle fiber: 50 microns – same size as a hair strand *muscle biopsy is not done for diagnosis, it is only for confirmation *muscle cell nucleus is located in the subsarcolemma, in the periphery of the muscle fiber INFLAMMATORY MYOPATHY • progressive prox muscle weakness • Dysphagia • Myalgia • Elevated CK • Myopathic EMG • Muscle Biopsy – inflammatory *not caused by microorganisms *Dysphagia – because part of the esophagus is made up of skeletal muscle; thus cardiac and smooth muscles are not involved *since inflammation  pain *There is a certain amount of creatinine kinase in the blood, because CK can traverse the sarcolemma; normal value = 40IU/microliter *Elevated CK - muscle disease destroys sarcolemma, allowing CK to go out, thus increase CK Biopsy important characteristic of inflammation  infiltration of different cells – neutrophils, lymphocytes PATHOPHYSIOLOGY OF INFLAMMATORY DISEASE • autoimmune disease • patient starts to degenerate • antigen-antibody complex acts on muscle membrane DERMATO/POLYMYOSITIS • Dx: progressive proximal muscle weakness • Autoimmune disorder • 3F:1M • Skin lesions • 40 y/o and above • progressive proximal muscle weakness • Raynauds phenomenon • Dysphagia *Dermatomyositis – younger age group Polymyosistis –adults *Similar, only difference is dermatomyositis has rashes

Treatment: steroid & immunosuppressants Course and prognosis 20% that develop P or D in early life will develop malignancy sometime in their life *doc also said: 15% malignancy Picture of Polymyositis • inflammatory infiltrates • some beginning to degenerate

PROGRESSIVE MUSCULAR DYSTROPHY CLINICAL USUAL PATTERN INHERTITANCE *Duchenne X-linked dystrophy *Becker’s X-linked dystrophy *Limb-girdle Autosomal recessive Scapulohumeral Autosomal recessive Fasciohumeral Autosomal dominant Oculopharyngea Autosomal l dominant

Read: • • • • • •

Periodic paralysis Myasthenia Gravis Muscle dystrophy inheritance Duchenne Beckers Limb-girdle

- by Bee, Pauline n Liz HAPPY BIRTHDAY LUWI and PAULINE!