Idiopathic inflammatory muscle diseases. Dr. Paul Etau Ekwom MBChB, MMED Kenyatta National Hospital, Nairobi-Kenya
I.W, 28 YRS, FEMALE SHOP STEWARD Referred to KNH on 16/06/09 from Thika Nursing Home Weakness for 3/12 Difficulty swallowing for 3/52
Progressive weakness :neck muscles then limb girdle. Weakness had no diurnal pattern. No reported muscle pain. Progressive dysphagia, no odynophagia Associated fatigue. No diplopia, ptosis or sphincter involvement
h/o weight loss H/o arthralgia but no other no other historical features to suggest connective tissue disease No history of pregnancy losses or any clotting. No symptoms of thyroidal illness No h/o drug use reported, no alcohol use. No known exposure to any toxins or heavy metals. No vaginal bleeding, breast lump, altered bowel habits, cough reported
Seen initially by ENT team, came with barium meal that showed? Prox. Esophageal mass..panendoscopy and biopsy results were negative.
Examination Young female, ill looking with a nasogastric tube in place. Normal hair distribution and character, no oral ulcers, no malar rash, no cutaneous features of dermatomyositis or scleroderma noted. Limb girdle and neck weakness with decreased muscle power; power grade 2. normal deep tendon reflexes and tone. Distal muscle groups power grade 4-5
Laboratory tests TBC: Leucocytosis; WBC 15.1, Hb 14.7, plt 602 ESR 45 mm/hr. CPK: normal levels LDH: elevated 674 U/L, AST 60 u/l, ALT 45 u/l RBS: 4.6 mmol/l htsh: 0.48 uiu/ml (0.25-5) Urinalysis : normal
Creatinine 68 umol/l; egfr : 89.5 mls/min ANA: positive HIV 1 and 2 ELISA: Negative HBsAg: Negative. HCV serology: negative. Blood cultures: negative Anti-DSDNA: positive. RF: positive Tensilon test : negative
Plain radiograph chest: normal. ECG/echo: normal EMG: proximal upper and lower limb muscles showed myopathic potentials. Nerve conduction studies were normal. Histology: myositis; bundles of skeletal muscles with inflammation and degenerative changes. Heavy infiltration of lymphocytes with myolysis.
By Bohan Peter criteria (1975) fulfils diagnosis of polymyositis. Bohan and peter criteria Symmetric proximal muscle weakness Elevation of muscle enzymes: CK,LDH,AST, ALT Abnormal EMG with myopathic potentials, fibrillations Muscle biopsy with features of infiltration with lymphocytes, necrosis and regeneration. Typical skin rash for dermatomyositis ; for diagnosis of dermatomyositis. In view of young female, arthralgia and positive ANA, dsdna,? SLE Overlap syndrome
Differential diagnosis of I.I.M Viral myositis: Coxsackie virus, echo, influenza viruses, HIV, Hepatitis virus Bacterial and parasitic infections: Pyomyositis, Trichinella spiralis, Trypanosomiasis. Alcoholic myopathy Diabetes myopathy DRUGS :Statins, fibrates,zidovudine, HCQ, cimetidine,colchicine, glucocorticoids. Muscular dystrophies Thyroidal illness Vasculitis Myasthenia gravis. Neuropathies Granulomatous myositis: sarcoidosis
Treatment Prednisolone 60mg/day and taper. Methotrexate started at 7.5 mg/week Folate Omeprazole Calcium/vitamin D NGT feeding..currently removed, able to swallow. Physiotherapy: exercises.
I.I.M Rare disorders Combined incidence of 2-7 per million population. Three main subgroups, dermatomyositis (DM), polymyositis (PM) and inclusion body myositis (IBM) Polymyositis and dermatomyositis are commoner in Females than males; 3:1. Inclusion body myositis is commoner in men. Peak age 50-60 (Though PM,DM may start at any age) They each may present in isolation or with a connective tissue disorder ;SLE, RA, Sjögren's syndrome, polyarteritis nodosa (PAN), scleroderma and mixed connective tissue disease.
Causes PM/DM are autoimmune diseases with association with with genetic HLA class II alleles. IBM is thought to be a degenerative disorder due to presence of tau proteins and amyloid. Association with viral infections. Association with malignancy in DM; haematological, lung, ovary, breast, colon. In polymyositis, association with malignancy is uncertain.
Clinical features Muscle weakness and fatigue. Cutaneous features : Gottron s changes, heliotrope rash, periungal capillary changes, mechanic hands, ulcers, livedo reticularis, subcutaneous calcinosis. Raynauds phenomenon Dyspnoea. Arthralgia and non-erosive arthritis. Dysphagia, reflux. Cardiovascular: congestive heart failure, conduction abnormalities, coronary artery disease. Amyopathic dermatomyositis.
Diagnosis Muscle enzymes: CPK, LDH, AST,ALT, ALDOLASE. Myoglobin EMG Muscle biopsy. Imaging: MRI-T1,2 and STIR sequences. Autoantibodies: ANA- in 60-70%. Anti aminoacyl t RNA synthetase ( Anti Jo-1) Anti Mi-2, anti-signal recognition particle (anti-srp). Anti 155-140 in dermatomyositis associated with cancer Anti CADM 40 in amyopathic dermatomyositis. Anti-SUMO 1 antibodies in DM with ILD
Other tests ECG, ECHO Pulmonary function tests CT scan chest. Tests to r/o differentials: viral serologies, HIV tests, Blood sugar, thyroid profile
Screening for malignancies History and examination. DRE, breast and pelvic examination. Xray chest Mammogram. FOBT PNS examination Abdomen and pelvic imaging.
Treatment options Glucocorticoids Immunosuppressive therapy: Methotrexate Azathioprine MTX and AZA Cyclosporine Cyclophosphamide Mycophenolate mofetil Ivig ATG
Progress Muscle strength CPK ESR, CRP
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