Clearing the fog around laboratory investigations in rheumatology

Dr Raju Khubchandani MD rajukhubchandani@yahoo.co.in

At the end of this interactive self assessment module you should be able to know when to order and how to interpret

• ANA• ENA (dsDNA and Sm, Ro and La, scl 70 and

centromere)• APLA• RF• ANCA

ANA +ve diseases in rheumatology are all except

• SLE

• JDM

• OJIA

• Scleroderma

• Sjogrens syndrome

• Polyarteritis nodosa √

The ANA test you asked for was reported by ELISA. Is that the correct technique?

• Y

• N √

• A 16 year old girl was vague body pains since 3 years. There are no systemic complaints and she reports a sleep disturbance. Her CBC ESR etc are all repeatedly normal. An enthusiastic orthopedic surgeon asks for an ANA which tests weakly positive (1:40-1 +)

• This child has lupus • This child has some connective tissue disease• This ANA should be ignored since 4-8% of the

normal population has weak positive titres

A 3 year old girl is seen by you for one swollen knee and one swollen ankle with a limp in the morning hours. Symptoms have been lasting for almost 8 weeks.Which of these tests are relevant

• ANA• RF • Anti DsDNA • None of the above

√

If the test you chose turns +ve how will this change your Management strategy? (select one)  

• Give only intraarticular injections

• Give intraarticular injections + NSAIDS

• Start Methotrexate

• Ask for 3 monthly instead of 6 monthly eye check.√

If the test you asked for is negative would you consider an alternate diagnosis? • Y • N √

A 11 year old girl is referred for low grade fever since 5 weeks. She feels very fatigued and has mouth sores.Pallor & petechiae are seen. Which of these actions are in order? 

• Ask for ANA as a screening test for SLE

• Ask for anti dsDNA as screening test for SLE

• Ask for anti Sm as screening test for SLE

• Ask for ANA,anti dsDNA, Sm all together

√

The ANA tests negative in this girl.You have almost certainly ruled out lupus • True

• False

√

The ANA tests +ve in this girl. Which of these statements is not appropriate? • She probably has Lupus

• She certainly has Lupus

• You wish to know the titre

• You wish to know the staining pattern before requesting autoantibodies.

√

The ANA by IF is 1: 640. All of these are now justified except • anti dsDNA

• anti Sm

• APLA

• ANCA √

• The ANA and dsDNA tests positive and you make a diagnosis of SLE. You start appropriate therapy. Will you repeat an ANA at every visit

• Y

• N √

The child is on regular follow up. After 1 year she has a florid hematuria with mild hypertension. Which of these autoantibodies will you repeat/request? • ANA

• Anti dsDNA

• Anti Sm

• Anti Ro

√

You transition this girl into adulthood and marriage. She becomes pregnant and aborts in her 4th month. This repeats twice and the obstetrician has requested TORCH titres. She calls you. You will:- • Ask for anti Ro/ La titres

• Ask for anti dsDNA

• Ask for Antiphospholipid profile

• Check whether ANA titres have risen?√

When asking for APL you will ask for  • ACLA IgG/IgM

• LA

• Anti B2GPA IgG / IgM

• Preferably all of the above√

You review her pregnancy records. She tested weakly positive for VDRL. Her husband is suspicious. Which of the below are true? • She certainly has a sexually transmitted disease

(std).

• This is a false +ve VDRL

• The std is the cause of recurrent abortions.

• The test is false +ve due to anticardiolipin antibodies. √

APLA syndrome can manifest as all of the below except.

• Recurrent second trimester abortions

• Isolated thrombocytosis

• Venous thrombosis

• Arterial thrombosis

√

APL antibodies testing is justified in a) A 6 yr old girl with acute infantile hemiplegia • Y• N

b) A 11 yr old with Budd Chiari syndrome • Y • N 

c) As a routine on diagnosis and annually in a child with SLE• Y • N

d) In a girl with Lupus who develops DVT after a flight from Zurich to Bombay • Y • N

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She finally conceives and on routine antenatal scans is found to have persistent fetal bradycardia. Which of the following antibodies will you order?

• anti dsDNA

• anti Ro

• anti La

• anti Sm√√

ORShe delivered normally but her newborn develops a facial rash at 5 weeks. A dermatologist called it atopic dermatitis. She called you because she still trusts only in you. The antibodies you will request are? • anti dsDNA

• anti Ro

• anti La

• anti Sm

√√

• A 16 year old girl has been having recurrent parotitis for about 2 years. She has generalized arthralgia and reports symptoms of dryness of eyes. The following autoantibodies are relevant

Ro and LadsDNASmScl 70 Anticentromere

√

• A 13 year old girl has been having Raynauds phenomenon for about 6 months. She has generalized arthralgia and reports symptoms of reflux and difficulty in deglutition. The following autoantibodies are relevant

Ro and LadsDNASmScl 70 Anticentromere

√√

An 11 year old girl has presented with arthritis of the large and small joints since about 3 months. She has pain on moving her jaw while eating breakfast and she wakes up with a stiff neck every morning. She has no other extraarticular features. Your most likely diagnosis is • PJIA• Extended OJIA• Systemic onset JIA• SLE

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The RF test is justified in this setting • Y

• N

√

You ask for the RF test. It returns negativeYou have ruled out JIA  • Y

• N √

You ask for the RF test. It returns strongly +ve Which of these is true:- • The test has suggested a diagnosis of RF +ve JIA

• The test is +ve in over half of children with JIA

• The test merely stratifies and prognosticates polyarticular JIA cases

• Ideally you should repeat the test once after 6 months.

• The test is useful in follow up of cases

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All of the below are false except • RA test and RF test are synonymous

• RF is the antibody to the Fab fragment of IgM

• In a 4 year old male with short duration arthritis this is a valuable test

• In the ped age group chronic fevers eg. Tb, malaria, endocarditis are very common causes for a false +ve weak RF√

The ANCA +ve diseases include all except

• Classic PAN

• Microscopic PAN

• Wegeners granulomatosis (WG)

• Churg Strauss syndrome

√

The following statements are true about ANCA except: • ANCA stands for Anti Neutrophil Cytoplasmic

Antibodies

• p & c stand for perinuclear & cytoplasmic staining patterns

• p. ANCA – antibody to MPO

• c ANCA – antibody to PR3

• ANCA titres may follow the course of the disease

• ANCA --- diseases are common in children√

A 15 year old girl presents with fever arthritis, hematuria, nodular skin rash, hypertension. Your tests may include the following except : • ANA

• ANCA

• RF

• Urine and renal biochemistry

• skin biopsy

√

Would your answers change if this girl developed hemoptysis? • Y

• N √

The lab reverts with a positive p ANCA. The most likely diagnosis is  • Classic PAN

• WG

• Microscopic PAN

• Churg Strauss syndrome√