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Myastenia gravis 2 dengan thymoma pada penderita anak usia


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Myastenia gravis 2 dengan thymoma pada penderita anak usia

  1. 1. DISKUSI KASUSMYASTENIA GRAVIS DENGANTHYMOMA PADA PENDERITA ANAK USIA 5 THN Kemala Hayati Moderator : Dr. Maimun, ZA, M.Kes. SpPKPatologi Klinik Laboratorium Sentral RSSA MALANG Powerpoint Templates Page 1
  2. 2. DATA DASAR• An. MM, 4 thn, perempuan• Anamnesa :• Keluhan utama : mata seperti mengantuk• Mata seperti mengantuk sjk 3 minggu SMRS. Saat bangun tidur mata dpt membuka lebar,tp siang hari / setelah aktifitas mata kembali tampak spt mengantuk.• Riwayat keluarga dengan penyakit serupa disangkal Powerpoint Templates Page 2
  3. 3. PEMERIKSAAN FISIK• Pemeriksaan umum : Tampak sakit• KU : Cukup• Vital sign : Nadi : 88x/mnt, R : 28X/mnt, t : 36.5 C• Kepala :• Mata kiri : kelopak mata menutupi separuh mata Konjungtiva anemi : -/-, Sklera ikterik : -/-• Thorax : taa• Abdomen : taa• Antropometrik : PB : 105 cm,TB : 14,5 kg Powerpoint Templates Page 3
  4. 4. Darah Lengkap 3-1-2010 15-1-2010Hemoglobin (11.0-16.5 11.5 12.4mg/dl) 6.900 9.600Lekosit (3500-10.000 /µL)LED 34Trombosit (150.000 - 283.000 351.000200.000/µL) 35.3Hmt 7/-/-/49/38/5/6Hit.Jenis 81 86MCV (80-99 µm3) 26.6 27.7MCH (26.5-33.5 pq) 32.6 32.4MCHC (31.5-35.0 g/dl) 14.2 13.6RDW (10-15 µm3) Powerpoint Templates Page 4
  5. 5. LABORATORIUM 5-1-2010 ImunologiL Total T3 (0.79-1.49 ng/dl) 1.09A Free T4 (0.71-1.85 ng/dl) 0.91 TSH (0.49-4.67 µIU/ml) 2.517B0 ElektrolitR Natrium (136-145 mmol/l) 140 Kalium (3.5-5.0 mm0l/l) 4.54A 111 Chlorida (98-106 mmol/l)T Kalsium (7.6-11.0 mmol/l) 8.5O Fosfor (2.5-7-0 mmol/l) 4.84R Kimia DarahI GDS (60-110 mg/dl) 96U Ureum (10-50 mg/dl) 28.4 Kreatinin (0.7-1.5 mg/dl) 0.37M Powerpoint Templates Page 5
  6. 6. Kimia Darah 3/1 5/1 14/1 21/1GDS 96 EMG CT Scan(60-110 mg/dl) Kesimpulan : Kesimpulan : Menyokong Massa softUreum 28.4 suatu tissue pd(10-50 mg/dl) myastemia mediastinum gravis ant. SuspekKreatinin 0.37 Thymoma dg(0.7-1.5 mg/dl) DD retrosternal goiter dan limfoma Powerpoint Templates Page 6
  7. 7. JAWABAN• INTERPRETATIF & Pada pemeriksaan laboratorium klinik didapatkan hasil normal, dengan klinis Electromyography (EMG) serta CT Scan Thorax mengesankan suatu Myasthenia Gravis dan suspek Thymoma, DD: 1. retrosternal goiter, 2. limfoma• Saran : pemeriksaan Acetylcholine Receptor Antibodi ( AChR Ab) & Muscle Specipic kinase (Anti MuSk Ab) Powerpoint Templates Page 7
  8. 8. DISKUSI1. Penegakan diagnosa2. Laboratorium Myasthenia Gravis dan Thymoma Powerpoint Templates Page 8
  9. 9. 1. PENEGAKAN DIAGNOSA• Myasthenia Gravis (MG)• an acquired autoimmune disorder in which the postsynaptic AChRs are reduced in number or function, leading to muscle fatigue and weakness.• characterized by a fluctuating pathological weakness with remissions & exacerbations involving one or several skeletal muscle groups, mainly caused by antibodies to the acetylcholine receptor (AChR) at the post- synaptic site of the neuromuscular junction Powerpoint Templates Page 9
  10. 10. • Prevalence MG : 85–125 permillion,• The disease has 2 peaks: 1. 20 - 40 years ( ), 2. 60 - 80 years ( , )• the fetus acquire immune proteins (Ab) from a mother affected with MG.• Generally, cases of neonatal MG temporary & childs symptoms disappear 2-3 months after birth.• MG in juveniles is uncommon.• MG frequently associated with thymic abnormalities, called thymitis, 60% & thymoma 10% of patients. Powerpoint Templates Page 10
  11. 11. THYMOMA• Thymoma is an uncommon neoplasm from the epithelial cells of the thymus.• Well known for association with MG, histologic variability, & heterogeneity of malignant behavior.• Thymoma occurs in 10% patients MG• MG occurs in 33% of patients thymoma Powerpoint Templates Page 11
  12. 12. PATHOPHYSIOLOGY• Acetylcholine (ACh) synthesized in the motor nerve terminal & stored in vesicles• ACh from 150–200 vesicles released & combines with AChRs that densely packed at the peaks of postsynaptic folds.• Structure of the AChR fully elucidated; consists 5 subunits (2α, 1β, 1δ, & 1γ or ε ) arranged around a central pore. Powerpoint Templates Page 12
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  15. 15. ….pathophysiology Normal • ACh combines with the binding sites on the subunits of the AChR • channel in the AChR opens, entry cations, chiefly sodium, produces depolarization at the end-plate region muscle fiber. • Depolarization triggering muscle contraction. • Process terminated by hydrolysis of ACh by acetylcholinesterase (AChE), present within the synaptic folds, & by diffusion of ACh away from the receptor. Powerpoint Templates Page 15
  16. 16. ….pathophysiology in the Myasthenia Gravis• the fundamental defect is a decrease number of available AChRs at the postsynaptic muscle membrane. • postsynaptic folds flattened, or simplified. • These changes result in decreased efficiency of neuromuscular transmission • although Ach released normally, it produces small end-plate potentials that may fail to trigger muscle action potentials • results in weakness of muscle contraction Powerpoint Templates Page 16
  17. 17. …pathophysiology Anti-AChR Ab reduce the number of AChRs by 3 mechanisms: (1) accelerated turnover of AChRs by a mechanism involving cross-linking & rapid endocytosis of the receptors; (2) blockade of the active site of the AChR, i.e., the site that normally binds ACh; (3) damage to the postsynaptic muscle membrane by the antibody in collaboration with complement. Powerpoint Templates Page 17
  18. 18. CLINICAL FEATURE• Presents between 15-50 years.• affected > in younger ages & reverse at older ages.• It has relapsing / remitting course, esp during the early years.• The cardinal symptom is abnormal fatigable weakness of the muscles; movement is initially strong but rapidly weakens.• Worsening towards the end of the day or following exercise is characteristic. Powerpoint Templates Page 18
  19. 19. ..clinical feature• No sensory signs or signs of CNS involvement, although weakness of the oculomotor muscles may mimic a central eye movement disorder.• The 1st symptoms usually intermittent ptosis or diplopia, weakness of chewing, swallowing, speaking or limb movement• Any limb muscle may be affected, most commonly those of the shoulder girdle; unable to undertake tasks above shoulder level, as combing the hair, without frequent Powerpoint Templates Page 19 rests.
  20. 20. ….clinical feature• Respiratory muscles may be involved & respiratory failure is a not uncommon cause of death & may be 1st presentation, in which case the dx is difficult if not thought of.• Aspiration may occur if the cough is ineffectual.• Sudden weakness from a cholinergic or myasthenic crisis may require ventilatory support. Powerpoint Templates Page 20
  21. 21. DIAGNOSIS & EVALUATIONHistory• Diplopia, ptosis, weakness• Weakness in characteristic distribution• Fluctuation & fatigue: worse with repeated activity, improved by rest• Effects of previous treatmentsPhysical examination• Ptosis, diplopia• quantitative testing of muscle strength• Forward arm abduction time (5 min)• Vital capacity Powerpoint Templates• Absence of other neurologic signs Page 21
  22. 22. …diagnosis & evaluation Laboratory testing• Anti-AChR radioimmunoassay: ~85% positive in generalized MG; 50% in ocular MG; negative result does not exclude MG. ~40% of AChR Ab negative patients with generalized MG have anti-MuSK Ab.• Repetitive nerve stimulation; decrement of >15% at 3 Hz: highly probable diagnosis if unequivocally positive Powerpoint Templates Page 22
  23. 23. …diagnosis & evaluation• Single-fiber electromyography: blocking & jitter, with normal fiber density; confirmatory, but not specific• Edrophonium chloride (Tensilon) 2 mg + 8 mg IV; highly probable diagnosis if unequivocally positive• For ocular or cranial MG: exclude intracranial lesions by CT or MRI Powerpoint Templates Page 23
  24. 24. 1 . PENEGAKAN PASIEN DIAGNOSATEORI• Ptosis (+) • Ptosis,diplopia,dysphagia• Gejala bertambah dgn • Dysharthria aktifitas • Myasthenic crisis (paralysis• CT Scan thorax : suspek of respiratory) thymoma • 75% have an abnormality of• EMG : menyokong suatu the thymus Myastenia Gravis • 10% have a thymoma • single fiber electromyography (SFEMG) • AChR Ab Myasthenia Gravis • Edrophonium test dgn thymoma Powerpoint Templates Page 24
  25. 25. 2. Laboratorium MG &• Thymoma Tensilon test: IV short-acting anticholinesterase, edrophonium bromide, is a valuable diagnostic aid; 2 mg initially, with a further 8 mg, half a minute later if no undesirable side- effects. Improvement in muscle power occurs within 30 sec & usually persists for 2-3 min.• Ice pack test: simple & less risky than tensilon test with improvement in ptosis in 2 mins.• EMG with repetitive stimulation show the characteristic decremental Powerpoint Templates response. Page 25
  26. 26. … laboratorium MG & Thymoma• Anti-acetylcholine receptor Ab (AChRA) is found in > 80%, < in purely ocular myasthenia (50%).• Anti-MuSK Ab found especially in AChRA-negative patients with prominent bulbar involvement.• Positive anti-skeletal muscle Ab suggest the presence of thymoma, but all patients should have a thoracic CT to exclude this condition, which may not be visible on plain X-ray.• Screening for other autoimmune disorders, particularly thyroid disease, is important. Powerpoint Templates Page 26
  27. 27. Anti-AChR Ab• Anti-AChR Ab detectable in serum of ~85% MG• 50% patients with weakness confined to the ocular muscles.• presence of anti-AChR Ab virtually diagnostic of MG, but a negative test does not exclude the disease.• The measured level of anti-AChR Ab does not correspond well with the severity of MG in different patients.• in an individual patient, a treatment-induced fall in the Ab level often correlates with clinical improvement. Powerpoint Templates Page 27
  28. 28. Anti-AChR antibodi• Acetylcholine receptor (ACHR) Ab not detected in healthy individuals or in patients with neurological disorders or AID other than MG• the specificity of these assays approaches 100 %• The most sensitive of the ACHR Ab assays is the ACHR binding Ab assay. Powerpoint Templates Page 28
  29. 29. AChR Ab Measurement • AChR Ab first measured by immunoprecipitation of 125I a-BuTx- labeled AChR in detergent extracts of human muscle, • most current assay employ AChRs extracted from muscle-like cell lines that express a mixture of fetal & adult AChRs • Enzyme-linked immunosorbent assay (ELISA) & other alternative assays not proved successful. Powerpoint Templates Page 29
  30. 30. AChR Ab• Measurement AChR Ab titers highly variable among MG patients, (0 to >1000 nm/L),• between individuals titers do not correlate well with clinical severity,• level of Ab within an individual correlates well with clinical scores after plasma exchange ,thymectomy,or immunosuppressive treatment. Powerpoint Templates Page 30
  31. 31. Interpretasi AChR Ab• Presence of ACHR Ab confirms a dx MG.• ACHR-binding Ab titer of ≥ 0.5 Nm considered positive.• ACHR-blocking Ab demonstrating ≥ 25% inhibition/blocking considered positive.• ACHR-modulating Ab demonstrating ≥ 26% modulation considered positive.• Absence of ACHR Ab does not rule out a dx of MG, as 10–15 % of MG patients lack detectible ACHR• Normally, there is no AChr Ab (< 0.05 nmol/L) in the bloodstream. Powerpoint Templates Page 31
  32. 32. MuSK Antibody• MuSK Ab found ~40% of AChR Ab negative patients with generalized MG• MuSK Ab rarely present in AChR Ab positive patients or in patients with MG limited to ocular muscles.• These Ab interfere with clustering of AChRs at neuromuscular junctions, as MuSK is known to do during early development.• There is also evidence MG patients without demonstrable Ab to either AChR or MuSK have other—as yet undefined—Ab that impair neuromuscular transmission. Powerpoint Templates Page 32
  33. 33. MuSK Antibody• About 10–15% of all MG patients with generalized symptoms do not have detectable anti-AChRs with AChR Ab―seropositive‖ generalized MG• never found, & no HLA association has been identified.• on clinical and pathologic grounds, the disease appears to have several unusual features. Powerpoint Templates Page 33
  34. 34. kemalaPowerpoint Templates Page 34