Dermatomyositis and Related Disorders MCQs

α-1antitrypsin deficiency is due to the insufficient plasma activity of the enzyme that degrades several proteins like neutrophil elastase, cathepsin G and proteinase 3. It is an AR disease and is characterized by emphysema and cirrhosis. The wild genotytpe is PiMM seen in > 90% of individuals. The clinically significant mutation is PiZZ, which is associated with The null phenotype (not in the list of options) is the least common but the most severe form of the disease where there is no detectable AAT in the serum. Reference: Harrison's Principles of Internal Medicine, 21 st ed, Ch: 341, Pg: 2615

15% improvement in FEV1 level of improvement would mean the presence of asthma. High dose inhaled steroids have been shown (ISOLDE) to improve quality of life and reduce hospitalisation rates by reducing the number of exacerbations, but it does not slow the rate of decline of FEV1 (hence does not affect prognosis). Breathless is common but subjective. Mild COPD (60 - 79% predicted FEV1) are often unknown to their GP. Those with moderate COPD (40 - 59% predicted) are seen intermittently seen by GP, whilst those with severe disease ( It is asthma which is associated with normal or increased transfer factor. COPD is associated with decreased transfer factor. Reference : Harrison's Principles of Internal Medicine, 21 st Ed, Ch: Ch:202, Pg: 2187

The patient has a restrictive lung disease with proximal muscle weakness and arthritis. Arthritis and ILD can be seen in diseases like RA and SLE, Sarcoidosis, Systemic Sclerosis etc. But here there is proximal muscle weakness and the patient is an elderly male with nail bed hemorrhages, which could indicate telangiectasia. So the diagnosis is Dermatomyositis. In polymyositis and dermatomyositis patients often develop proximal muscle weakness and of pain in the small joints of the fingers. They may have ragged cuticles and haemorrhages at the finger nail folds. Interstitial lung disease can occur. Underlying malignancy (lungs, ovaries, breasts and stomach) is present in 5% Reference : Harrison's Principles of Internal Medicine, 21 st Ed, Ch: 365, Pg: 2820

Proximal muscle weakness with high CPK suggests an inflammatory myopathy. Among the options Polymyositis is an Inflammatory myopathy. GBS does not cause elevated CPK. Hypothyroidism may cause weakness but here there are no clues to suggest a hypothyroidism. PMR causes girdle pain. Weakness is rare. Polymyositis classically presents with relatively painless progressive proximal muscle weakness. Dysphagia is common but the ocular muscles are very rarely involved unlike myasthenia gravis where this is a predominant feature. Diagnosis of polymyositis confirmed by elevated muscle enzymes (creatine kinase) and typical EMG and muscle biopsy findings. Reference: Harrison's Principles of Internal Medicine 21 st edition Ch:365 Pg:2819