connective tissue diseases - Current Investigations . seminar

7/29/2019 connective tissue diseases - Current Investigations . seminar

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TUTORIALconnective tissue diseases: current

investigations

PRESENTED BY

DR.DAULAT RAM DHAKAD


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INTRODUCTION Are multifactorial conditions

Body tissues consisting of the cells and the matrix aredisrupted

A/w a complex genetic predisposition

Various, not well-understood, environmental triggers

Induce inflammatory and immune-mediatedresponses

Against components of the persons own body

As a result this group of diseases is also known as thesystemic autoimmune diseases


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Difficult to diagnose nonspecific symptoms

tend to overlap

Common histologic feature

inflammatory damage CT and blood vessels

fibrinoid material deposition


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Appropriate investigations are critical to making thecorrect diagnosis

Monitor disease activity and treatment To prevent death and the development of chronic

damage

Due to complications of the disease and the immuno

suppressive drugs used to treat it.


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investigative work-up: A full blood count.

A biochemical profile.

Assay of an acute phase reactant, usually the ESR orCRP.

Dipstick testing of urine, and microscopy of urine.

Immunology testing, including ANA.

A chest X-ray. Other tests as clinically indicated.


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Tests- Haematology Have a normochromic normocytic anaemia, a slightly raised platelet

count, and a raised ESR. Not true in patients with primary APS ,SLE and SSc, usually not

associated with a major inflammatory component.

High ESR in SSc, query about an overlap with another connectivetissue disease, or an additional pathology such as infection or

malignancy should be made

Active SLE may be associated with a fall in the haemoglobin, white cellcount, platelet count and/or autoimmune haemolytic anaemia

Thrombocytopenia occurs in APS.

Eosinophilia occurs in ChurgStrauss syndrome. In patients on immunosuppressive therapy monitoring of the full

blood count is essential

A fall in any of the components of the blood count should alert theclinician to the possibility of drug toxicity.


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Blood biochemistry SGOT/PT, S. bilirubin, B. Urea, S. creatinine:

Should always be checked to rule-out renal or (less frequently)hepatic involvement

CRP:1.Typically raised in active inflammation,2.Usually not elevated in SLE unless there is serositis, rule-out

underlying infection. Muscle enzymes:1. Creatine phosphokinase is most commonly used in diagnosisand monitoring of inf lammatory muscle disease

2. Blood levels may be very high on presentation with

polymyositis.3. Circulating levels of aldolase, transaminases, and lactatedehydrogenase may all be high in patients with muscleinflammation.

Globulins:Hypergammaglobulinaemia (polyclonal) may be seen especially

in patients with Sjgrens syndrome.


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Urine

Glomerulonephritis can occur in SLE or thevasculitides.

Abnormal dipstick test (show protein and/or blood)may be first clue of renal involvement.

Urine microscopy: can show an active sediment withwhite and red blood cells and casts.

Estimation of protein/creatinine ratio and creatinineclearance.


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Immunology

Connective tissue diseases are associated withcirculating autoantibodies and can be useful indiagnosis.

If a patient presents with what could be a connectivetissue disease (e.g. fever, rash, splinter haemorrhages,anaemia, and a raised ESR),

One or more of the following immunological tests areindicated, depending on the clinical context


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Antinuclear antibodies(ANA)

ANA is a nonspecific test Provides a rapid screening for SLE and related connective

tissue disorders.

Antinuclear antibodies (ANA) were first detected when theLE cell phenomenon was discovered. This test was superseded by the ANA indirect

immunofluorescence test (IIF). Human epithelial cell line (HEp2000) cells are used for

screening for ANA. This is a modification of the previous HEp2-based ANA

test so that SSA is also detected. Thus, with this test, a negative result excludes active SLE.


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Over 95% of patients with SLE and 50% of patients withscleroderma are ANA positive.

The higher the titre, the more likely the patient is to havean autoimmune disease

ANA titre of 1/1,600 is much more likely to be clinicallyrelevant than a titre of 1/100.

Five distinct patterns of nuclear staining (homogeneous,speckled, nucleolar, rim and centromere) may be seenindicating the origin of the antigen involved

Homogeneous and rim patterns are usually associatedwith anti-ds DNA and antihistone antibodies.

Speckled patterns may be associated with anti-RNP, anti-Sm, anti-SSA and anti-Scl-70.

Nucleolar antibodies may be associated with anti-Scl-70.


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Specificity of defined ANA in various disorders


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Causes of positive immunofluorescence for ANA

Connective tissue diseases Chronic liver diseases Organ-specific autoimmune diseases:

Pernicious anaemiaHashimotos thyroiditisMyasthenia gravisFibrosing alveolitis

Chronic tuberculosis and leprosy Lymphoma and other malignancies Old age (> 60 years) (low titre) Pregnancy (low titre)


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indirect immunofluorescence (serum) studies

Disease Indication for

diag.

Autoantibodies Expected results

DLE yes ANA +ve or -ve

Diss. DLE yes ANA +ve or -ve

SLE yes ANA +ve in >90%

Scleroderma yes ANA +ve

MCTD yes ANA +ve

Dermatomyositis yes ANA +ve

Vasculitis yes ANA -ve


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IIF pattern of nuclear fluorescence

a)homogenouspatternb) speckledpattern

a) nucleolarpattern and b)centromeric

pattern


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direct immunofluorescence microscopic findingsdisease Location of immune deposits Predominant

immunoreactantsensitivity

DLE BMZ- granular, and/or CBs and/or in vivo ANA IgM, IgG, IgA, C3 70-90%

SCLE BMZ- granular(LBT) IgM, IgG, IgA, C3 70%

SLE BMZ- granular(LBT) and/or in vivo ANAand/or CBs and/or SBV

IgM, IgG, IgA, C3 80%

Neonatal LE BMZ- granular IgM, IgG, IgA, C3 70-90%

Syst. Sclerosis BMZ- granular and/or in vivo ANA and/orSBV/-ve

IgM, IgG Not reported

Localized

sclero.(morphea)

Non specific Not reported

MCTD in vivo ANA (ENS) and/or BMZ- granularand/or SBV/-ve

C5b-9, IgG Not reported

Dermatomyositis BMZ- granular and/or in vivo ANA and/orSBV/-ve

C5b-9 Not reported

Cut. vasculitis Superficial dermal blood vessel walls C3, IgG, IgM 90%


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DIF of a case of SLE showing IgG reactivegranular (+++) deposits at the dermo-epidermal junction and superficial

dermal blood vessels

DIF of a case of SLE showing IgG reactive(+++) epidermal nuclear staining or in

vivo ANA


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antibodies to extractable nuclear antigens(anti-ENA)

Anti-ENA attempt to further identify these antibodies.

Seven anti-ENAs are routinely tested for by ELISA

Anti-RNP, antiSSA(Ro), anti-Ro52, anti-SSB(La), anti-Sm, antiScl-70, and anti-Jo-1.

A different method (Line immune-assay) is used toconfirm results and to detect anti-PM-Scl antibodies if

specifically requested.


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Autoantibody associations with connective tissue diseasesSLE

Anti-dsDNA antibodies: Assayed by radioimmunoassay (Farrassay)-Highly specific for SLE.-Titre can be a useful measure of disease activity.-Not sensitive, many patients with SLE do not demonstrate anti-

dsDNA antibodies Anti-Sm antibodies:

- Specific, not sensitive Anti-Ro and anti-La antibodies:

-Not sensitive.

-Both these autoantibodies are associated with the neonatallupus syndrome-Women of childbearing age with either of these antibodies needto be advised accordingly-Ideally should have prepregnancy counselling


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Sjgrens syndromeAnti-Ro and anti-La antibodies

APS Anti-cardiolipin antibodies:

Low levels of anti-cardiolipin antibodies occur in a number ofother clinical situations (e.g. infection), so this finding is notspecific

SSc Anti-centromere antibodies (in limited cutaneous disease):

Specific, but not sensitive Anti-topoisomerase (anti-Scl-70) antibodies (in diffuse

cutaneous disease, with an association with pulmonary fibrosis):

Specific, but not sensitive Anti-RNA polymerase I and III antibodies (in diffuse cutaneous

disease, with an association with renal involvement):Specific, but not sensitive


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Inflammatory muscle disease Anti-Jo-1 antibodies (associated with lung fibrosis):

Specific, not sensitive Anti-PM-Scl antibodies (associated with SSc overlap)Vasculitis cANCA(associated with Wegeners granulomatosis):

Antibody is usually to proteinase 3. Specific, not sensitive Perinuclear ANCA (pANCA):

Less specific than cANCA for vasculitis. Antibody is usually tomyeloperoxidase

Overlap syndromes

U1 RNP antibodies:This antibody must, by definition, be present for the diagnosis ofmixed connective tissue disease


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Other investigations

Investigation of suspected muscle inflammation

Beside muscle enzymes Other tests are:

-Electromyography (EMG),Muscle biopsy,

-Magnetic resonance (MR) scanning

-Normal muscle biopsy does not exclude the diagnosis

of inflammatory muscle disease because the myositicprocess is patchy and may be missed on biopsy.


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MR images showing myositis.;

A: T1-weighted image shows the

replacement of the posteriormuscle groups with fat, fatatrophy

B: STIR image shows the muscle as

patchy high signal, indicating anincrease in the muscle watercontent (oedema).


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Investigation of suspected vasculitis

The gold standard investigation is biopsy, asappearances may be diagnostic.

Angiography

MR and

Computed tomographic (CT) angiography,


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Investigation of the patient with Raynaudsphenomenon

In the patient with primary (idiopathic) Raynaudsphenomenon,

There should be no symptoms or signs suggestive of an

underlying connective tissue disease ANA should be negative or present in low titre only

(


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Normal (A) and abnormal (B) capillaroscopy in a patient with SSc,

showing dilated loops and (left side of image)

giant capillaries and areas of haemorrhage.

AB


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Other investigations to identify presence and degree of

internal organ involvement

Investigation of breathlessness and dysphagia

The differential diagnosis is extensive,

Chest X-ray, Pulmonary function tests with transfer factor,

ECG: to include estimation of the pulmonary arterypressure

HRCT scan of the thorax.

Barium swallow


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Chest X-ray showing basalshadowing (pulmonary

fibrosis) in a patient withSLE.

Chest X-ray showing pericardialeffusion in a patient

with SSc. The patient was

breathless and the pericardialeffusion was drained.


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pathologyon BS

Decrease/absentparistalsis,dilation,hiatal

hernia


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Investigation of weight loss- Weight loss is often multifactorial and has severalpossible causes.

- Checking for bacterial overgrowth with hydrogen and

[ 14 C] labelled breath test. Investigation of lethargy

- Have an increased prevalence of thyroid disease overthe general population,

- Are often anaemic via a variety of possiblemechanisms.


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Conclusions Despite the lack of definitive tests for the diagnosis of connective tissue

diseases, there are many pointers to their diagnosis ANA remains a useful non-specific screening test for many connective tissue

diseases.

Elevated anti-ds DNA levels have a high association with SLE and its diseaseactivity.

Anti-ENAs are useful in identifying subsets of patients with connective tissuedisease.

In combination, the ANA, Anti-ds DNA and anti-ENA tests are extremelyhelpful in the diagnosis of many of the connective tissue diseases.

A negative ANA, anti-ds DNA and antiENA excludes the diagnosis of SLE.

Tests For Antihistone Antibodies Are useful in Excluding drug-induced SLE.

A detailed history and examination, backed up by relevant investigations, arekey factors in defining the problem at any one point in time so that anappropriate management strategy may be followed


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THANK YOU

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connective tissue diseases - Current Investigations . seminar