Connective Tissue Disease and Vasculitis

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Blood tests to help in the investigations of these conditions are listed below and a guide to their use may be found in Test Profiles.

Connective Tissue Disease

This covers a wide range of relatively rare conditions including systemic lupus erythematosus (SLE), scleroderma, polymyositis and Sjorgren's syndrome.  Rheumatoid arthritis is common, and may present initially with similar features.  However, the early involvement of other organs (e.g. skin, kidneys, eyes, Raynaud's) may suggest an alternative diagnosis.

Vasculitis

Includes a heterogeneous group of diseases, characterised by inflammation and necrosis of blood vessel walls.  Presenting features may include fever, weight loss, fatigue, multi-system involvement (skin, nasal bleeding/crusting, arthralgia, myalgia, neuropathy), with raised inflammatory markers and abnormal urinalysis.  As with connective tissue disease, rapid diagnosis and treatment is essential to prevent organ damage and death. Serological markers such as ANCA may be helpful, but are not diagnositc and their absence does not exclude vasculitis.  Biopsy evidence of vasculitis is always preferable to confirm the clinical suspicion.

Clinical advice regarding the management of these conditions may be obtained from the department Medical Staff, or from the relevant clinical specialty (e.g. renal, medicine, rheumatology).  Patients may be referred to Immunology or to Rheumatology for assessment.

Advice for Medical Practitioners

Advice regarding the investigation, treatment or referral of all patients with possible connective tissue disease and vasculitis is available from the medical staff.  Advice out of normal working hours can be obtained from the on-call rheumatology, renal or medical teams (depending on the patient's particular problem).

Clinical Referrals (Immunology)

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All clinical queries may be directed to a member of the medical staff. We are happy to assess in-patients following telephone arrangement. Out-patient referrals may be made, in writing, to Dr Huissoon. Urgent referrals should be discussed by telephone.

Investigation Protocols

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Protocols can be downloaded from here

Pathology Phone Limits

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Phoning limits for biochemistry tests are as follows:

  Below Above Units
Sodium 120 150 mmol/L
Potassium 3 6.5 mmol/L
Urea   30 mmol/L
Creatinine   500 umol/L
Glucose 2.5 20 mmol/L
Calcium adjusted 1.8 3.5 mmol/L
Magnesium 0.4   mmol/L
Phosphate 0.3   mmol/L
AST   700 U/L
ALT   400 U/L
Total CK   500 U/L
Amylase   600 U/L
TBA   20 umol/L
Iron   70 umol/L
Total bilirubin   225 umol/L
Carbamazepine   25 ug /mL
Digoxin   2.5 ng/mL
Theophylline   45 mg/L
Phenytoin   20 mg/L
Phenobarbitone   70 mg/L
Lithium  <0.2 >1.5 mmol/L
Valproate   100 mg/L
Cyclosporin A   200 ug/L
CRP  

300

phoned with other abnormal results

mg/L
Salicylate   20 mg/L
Paracetamol   10 mg/L
Ammonia All phoned    
Lactate All phoned    
beta-HCG All phoned    
progesterone All phoned    
CSF glucose All phoned    
CSF protein All phoned    
NNU results All phoned    

 

PREDNISOLONE METABOLISM TEST

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PREDNISOLONE METABOLISM TEST

Aim: 

To assess prednisolone metabolism in steroid dependent asthmatics

Justification:

Small group of asthmatics remain symptomatic despite long term treatment with oral corticosteroids “prednisolone”, with major implication in terms of steroid induced side effects.  The cause of this lack of effect could be due to poor adherence, malabsorption, rapid metabolism or genetically mediated resistance to steroids.  The aim of this test is to assess the cause of the apparent lack of responsiveness to steroids in a patient.