920 likes | 1.66k Views
Sistem Neuromuskular. Sistem Neuromuskular. Tiga komponen utama Neuromuskular Nerve Neuromuscular junction Muscle. Upper Motor Neuron.
E N D
Sistem Neuromuskular Tiga komponen utama Neuromuskular • Nerve • Neuromuscular junction • Muscle
Upper Motor Neuron • Semua neuron yang menyalurkan impuls motorik secara langsung ke LMN atau melalui interneuronnya, tergolong dalam kelompok UMN. Neuron-neuron tersebut banyak terdapat di girus presentralis dinamakan juga korteks motorik. Melalui aksonnya neuron korteks motorik menghubungi motoneuron di kornu anterior medulla spinalis.
Upper motorneuron Lower motorneuron
Lower Motor Neuron • Merupakan neuron-neuron yang menyelurkan impuls motorik pada bagian perjalanan terakhir (kornu anterior medula spinalis) ke sel-sel otot skeletal.
Motor end Plate • Pada ujungnya setiap akson akan bercabang-cabang dan setiap cabang menghubungi membrane serabut otot. Serabut-serabut otot setiap unit motorik berkisar antara 10-500 serabut otot. Tiap serabut otot memilki satu “motor end plate”.
Ujung-ujung terminal dari akson mengandung mitokondria dan ezim “cholin acertyltransferase”, yang diperlukan untuk sintesis “neurotransmitter” yang dinamakan “acetylcholine”.
Pelepasan Acetilkolin • Nerves releasing Achetylcholine at the neuromuscular junction (=end plate) cause the contraction of skeletal muscle. The functional unit of a muscle organ is the muscle fiber (=muscle cell).
The muscle fiber contracts in an "all-or-none" fashion when stimulated by an action potential. The action potential first causes intracellular Ca++ release from the sarcoplasmic reticulum and the Ca++ activates a cascade of events which results in the movement of actin over myosin (=sliding filament theory).
Tanda-tanda kelumpuhan UMN : Hiperrefleksia Terdapat refleks patologis Tonus otot meninggi atau hipertonia Terdapat Klonus Tidak terdapat atrofi otot yang lumpuh Refleks automatisme spinal (-) Tanda-tanda kelumpuhan LMN : Arefleksia (hilangnya refleks tendo) Tidak ada refleks patologis Hilangnya tonus otot (flacid) Tidak terdapat klonus Terdapat atrofi pada otot yang lumpuh
Gangguan yang menyebabkan kelemahan gerak (paralysis) Kelainan pada otot • Periodik Paralysis • Inflamatory miopathy • Miopati karena steroid • Rabdomyolisis Neuromuscular junction • Miastenia Gravis • Botulism • Tick paralysis • Lambert Eaton Myastenic Syndrome
Gangguan yang menyebabkan kelemahan gerak (paralysis) Neuropati akut • Paraneoplastik • Vaskulitis (lupus, poliarteritis) • Neuropati motorik multifokal Poliradikulopati akut • Guillain-Barre syndrome • Lime Disease • Sindrome Cauda Equina Penyakit Motor neuron • Poliomyelitis • Amyotropic Lateral Sclerosis (ALS)
Gangguan yang menyebabkan kelemahan gerak (paralysis) Medula Spinalis • Inflamasi (mielitis transversus) • Mielopati (spondilosis, hematom, infark) Otak (Cerebrum, cerebellum) • Lesi di Pons • Lesi fokal/multifokal (infark, hematom)
Jenis Gangguan Saraf • Polyneuropathy: motor, sensory, sensorimotor • Radiculopathy • Polyradiculopathy • Plexopathy • Mononeuropathy: isolated multiplex
Inherited HMSN and HLPP Amyloid Metabolic Diabetes Vitamins: B12, B1, E Dialysis, Liver failure Paraneoplastic sensory (anti-Hu) Toxic Drugs, alcohol, organophosphates Inflammatory/Immune GBS, CIDP Vasculitis Infective Leprosy, Lyme, HIV, Diphtheria Traumatic Klasifikasi kausa
Klasifikasi tipe kerusakan • Demyelinating • Axonal • Small fibre • Large fibre • Autonomic
Physical findings Nerve NMJ Muscle Reflexes Usually decr. NL or decr. NL or decr. Atrophy Can be severe Minimal Variable Fascic. Sometimes None None Sensory loss Sometimes None None
The Motor Unit Myopathies Motor Neurone Disorders Myasthenia etc Peripheral Neuropathy
Gangguan pada saraf: Variasi: • Cell body, axon & myelin • Fiber size: large, small • Motor, sensory, autonomic • Distribution: focal, multifocal, generalized • Course: acute, subacute, chronic, lifelong • Etiology: genetic, toxic, metabolic, autoimmune, traumatic, vascular, infectious
Gangguan pada Saraf: berdasarkan Lokasi • Radix radiculopathy • Plexus plexopathy • Single nerve mononeuropathy • Several nerves multiple mononeuropathy, mononeuritis multiplex • All nerves, polyneuropathylength-dependent • All nerves, polyradiculoneuropathynot length-dependent
Radix • Segmental loss of • motor • atrophy • weakness • reflexes • sensation • Signs usually minimal; symptoms can be severe (pain); • Usually only one limb.
Plexus • Pain • Weakness, atrophy, variable, but usually more severe than radiculopathy • Usually restricted to one limb • Etiology: • Brachial: trauma, neoplasm, idiopathic • Lumbosacral: diabetes, neoplasm
Single nerve (mononeuropathy) • Restricted distribution • Pain, numbness or tingling, atrophy, weakness • Etiology: • entrapment • trauma
Carpal tunnel syndrome • N.Medianus • Pain in hand, forearm, arm • Numbness in median distribution • Symptoms aggravated by wrist flexion
Ulnar neuropathy • Numbness • Atrophy of first dorsal interosseous • Weakness • Compression at elbow • Entrapment in cubital tunnel • Distal injury
Radial nerve: Saturday night palsy • Weakness of wrist & finger extensors, brachioradialis • Pressure palsy • Trauma (humerus fracture)
Peroneal palsy • Crossing legs • Weight loss • Hospitalization • Surgery
Several nerves (mononeuritis multiplex) • Often painful at onset • Often sudden • Deficits in the distribution of several peripheral nerves (one at a time) • Etiology: vasculitis
All nerves: Length-dependent (polyneuropathy) • Lower before upper extremity • Distal first (feet) • Atrophy of intrinsic foot muscles • Decreased ankle jerks • Stocking, then glove sensory loss • Distal motor and sensory findings always much more severe than proximal
Polyneuropathy (cont’d) • Most common kind of neuropathy • Etiology • metabolic (diabetes, renal failure) • nutritional (thiamine, B12 deficiency) • toxic (heavy metals, organic solvents, some drugs) • familial (Charcot-Marie-Tooth)
All nerves, not length-dependent(polyradiculoneuropathy) • Both proximal and distal weakness • Variable sensory symptoms • Autonomic symptoms (pulse, blood pressure, urination...) • Can affect respiration, swallowing • Autoimmune
Guillain-Barré Syndrome (GBS) Definisi GBS : • Penyakit demyelinasi akut, yang terutama mengenai susunan saraf tepi. Penyakit inflamasi pada sistim saraf tepi mempunyai karakteristik adanya infiltrasi limfosit dan makrofag dengan destruksi myelin • Derajad dan lokasi kerusakan tergantung saraf yang bermyelin: Motorik Merupakan penyakit Autoimmun
Guillain-Barre syndrome • Progresses over days to <4 weeks • Typically ascending weakness • Reflexes lost early • Motor symptoms predominate, but can affect sensation and autonomic function • Respiratory failure requires support
Guillain-Barre syndrome (cont’d) Penyebab : autoimmun • Target Antigen biasanya tidak diketahui • Pada beberapa kasus: Target serangan imun gangliosida (GM1, GQ1b) Faktor presipitasi: • Infeksi virus (HIV, CMV, varicella zoster) • Infeksi bakteri (campylobacter jenjuni, typhoid, paratyphoid) • Immunisasi • Sistemik (Hodgkins disease, leukemia, hipertiroidisme, sarkoidosis) • Transplantasi organ, operasi, kehamilan
Latar belakang GBS • Epidemiologi GBS • 1- 4 kasus/100.000 • Paling banyak pada pria • Meningkat sesuai usia • Insidennya bervariasi sesuai musim
Gambaran klinis GBS • Gangguan Motorik: paralisis yang progressif, simetris pada extremitas bawah dan atas, bersifat asendern dimulai dari distal ke proksimal • Gangguan sensibilitas: Stocking, dan glove sensory loss (dysesthesia) • Gangguan otonom: penyebab kematian
Clinical Picture of Polyneuropahty (Valenstein, 2000)
Gambaran klinis GBS • Atypical presentations • Miller-Fisher Syndrome • Areflexia • Ophthalmoplegia • Ataxia
diagnosis GBS • Riwayat penyakit sebelumnya atau vaksinasi • Dari pemeriksaan fisik (Physical Exam) • Laboratoratorium: • Peningkatan kadar protein pada pemeriksaan LCS dan rendahnya jumlah sel di LCS (disosiasi sitoalbumin) • Electromyography – adanya blok konduksi saraf
KRITERIA GBS MENURUT GILROY DAN MEYER (1979) • Paralisis flasid simetris, difus • Gejala sensoris subyektif • Penyembuhan sempurna dalam 6 bulan • Disosiasi citoalbumin • Tanpa atau sedikit demam saat muncul paralysis • AL normal atau lymphositosis dengan sedikit atau tanpa kenaikan KED. • Harus memenuhi 5 kriteria dari 6 kriteria