• Mixed Connective Tissue Diseases

    by  • 10/07/2013 • Rheumatology

    Overlapping group of disease – common pattern = they all affect many organs and are associated with fever, malaise, are chronic (relapsing/remitting), and respond to steroids. Difficult to diagnose – if unsure, refer to rheum.

    Systemic lupus erythematosus (SLE)

    1. p/c: Rare (1:3000), autoimmune, female, afro-carribean/asian, 15-40yo, multisystem involvement: joints (arthritis, myalgia…), skin (photosensitivity, butterfly rash, discoid lesions, urticarial…), lungs (pleural effusion, pneumonitis), kidneys (GN, HTN), heart (peri/endocarditis), CNS, blood (anaemia, thrombocytopaenia, splenomegaly), fatigue.
    2. Ix: autoimmune profile, ANA+ve (in 95%), increased double strained DNA, RhF+ve (in 40%), low C3/C4, low Hb, low WCC, raised ESR.
    3. Mx: NSAIDs, sunscreen, steroids in acute flares, hydroxychloroquine can improve skin/joint symptoms, cyclophosphamide, methotrexate, ciclosprorin (DMARDs) can also be used.


    Drug induced lupus:

    1. Caused by: isoniazid, hydralazine, procainamide, chlorpromazine, sulfasalazine, losartan, anticonvulsants.


    Discoid Lupus Erythematosus:

    1. >1 round/oval plaque on face, scalp, hands (well defined, red, atrophic, scaly, keratin plugs in dilated follicles)
    2. Scarring = alopecia = hypopigmentation
    3. No internal involvement
    4. Ix as you would for SLE
    5. Diagnose with lesion biopsy
    6. Tx: topical steroids, sunscreen.
    7. Remission in 40%, progress to SLE in 5%.

    Antiphospholipid syndrome

    1. May occur with SLE or alone
    2. Increased clotting tendency = thrombosis, stroke, migraine, miscarriage, myelitis, MI, multi-infarct dementia
    3. Tx: aspirin 150mg OD and refer to rheum (anticoagulate).


    Raynaud’s syndrome:

    1. Intermittent digital ischaemia precipitated by cold or emotion
    2. Change colour: palebluered. Ache.
    3. <25yo, prevalence 3-20%, female, abates at menopause, 5% develop scleroderma or SLE.
    4. Differentials: scleroderma -/+ CREST, SLE, RA, drug cause (=b-blockers), trauma, smoking, arteriosclerosis, use of vibrating tools (=’vibration white finger’), leukaemia, polycythaemia rubra vera (PRV), cold agglutins, thoracic outlet obstruction, thrombocytosis, monoclonal gammopathies…
    5. Mx: keep warm (gloves/socks), avoid b-blockers, smoking cessation, nifedipine 10-20mg tds or amlodipine 5mg od, fluoxetine, if severe symptoms (critical ischaemia/ulceration) – refer to rheum.



    1. Insidious, symmetrical, proximal muscle weakness due to inflammation, dysphagia, dystonia, respiratory muscle weakness, 25% have rash on cheeks/eyelids/other sun exposed areas (=dermatomyositis) and nail-fold erythema. Raised CK, 10% malignancy in pts >40yo.


    Systemic sclerosis:

    1. Rare spectrum of disorders causing fibrosis and skin tightening (=scleroderma).
    2. Raynaud’s is usually present. Also, HTN, lung fibrosis, GI symptoms, telangiectasias, polyarthritis, myopathy.
    3. Mx: tx Raynaud’s with nifedipine, amlodipine, or ARBs. Refer to rheum. CREST is a variant of systemic sclerosis and tends to have a better prognosis.


    CREST syndrome

    1. Calcinosis of subcutaneous tissues
    2. Raynaud’s
    3. oEsophageal motility problems
    4. Sclerodactyly
    5. Telagiectasia


    Sjogren’s syndrome:


    1. Primary Sjogrens syndrome: under-recognised cause of fatigue and dryness of skin/mucous membranes (=dyspareunia). Associated with autoimmune CTD and often presents with nodal OA. Long-term associated with lymphoma, autoimmune profile is characteristic.
    2. Secondary Sjogrens syndrome: associated with CTD (50% have RA) with keratoconjunctivitis sicca (reduced lacrimation=dry eyes) and/or xerostomia (reduced salivation=dry mouth) [sicca complex].
    3. Ix: Schirmer’s test = measure tear absorbance in filter paper placed at eye lid (<10mm in 5 mins = reduced lacrimation), collect saliva generated in 10mins (<0.5ml/min = xerostomia).
    4. Mx: refer to rheum, artificial tears, artificial saliva, skin rashes respond to anti-malarials, long-term monitoring for mucosal lymphomas in important.


    Polymyalgia rheumatic (PMR) and giant cell arteritis (GCA)

    2 separate conditions which are part of the same spectrum.

    1. Both affect elderly (>50yo), 50% of pts with GCA have PMR, 15% of pts with PMR have GCA, female preponderance, both respond to corticosteroids.
    2. p/c: general – malaise, anorexia, fever, night sweats, weight loss, depression
      1. o PMR: proximal symmetrical muscle pain and stiffness worst after rest (bilateral tenderness in upper arms/bilat shoulder pain).
      2. o GCA: unilateral throbbing headache, facial pain, scalp tenderness (combing hair), jaw claudication, visual symptoms (amaurosis fugax, diplopia) with 30-60% becoming blind before tx started.
    3. Ix: raised ESR (>30mm/hr) and normocytic anaemia, temporal artery biopsy for GCA (maybe –ve in a +ve pt, due to ‘skip lesions’), start steroids asap although may ender biopsy –ve. Exclude other diagnoses.
    4. Mx:
      1. o PMR: pred 15mg OD, review after 2-4/7
      2. o GCA: pred 1mg/kg/d (max 60mg OD), refer to rheum and ophthal.
    5. In all cases, v slowly reduced steroids down (by 2.5mg/month, then 1mg/month), monitor ESR, give OP prophylaxis to protect bones (bisphosphonates), give steroid advice.
    6. Prognosis: most require >2y of tx, prepare for relapse. 
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