Systemic Lupus Erythematosus ( SLE )
Chronic autoimmune disease which may affect every organ and tissue. Four main types of lupus are- SLE is a multisystem , autoimmune disease , involving complex pathogenetic mechanisms that can present at any age ( British Society of Rheumatology 2018 )
How common -a rare disease with an estimated incidence of 0.3 – 31.5 / 100,000 person per year worldwide differences in the incidence and prevalence of SLE -this varies with sex , age , ethnicity and time highest prevalence in N America incidence peaks in middle adulthood and occurs later for men women of child bearing age suffer the most with a female to male ratio of 9 : 1 SLE can develop at any age – tends to start later in men ( 5th to 7th decade ) risk of women acquiring SLE reduces after menopause men suffer less but more severely compared to women people of black ethnicity have highest incidence and prevalence of SLE ○ people of African heritage suffer with more severe disease and worse outcomes incidence has ↑↑ ed in the last 40 yrs Lupus affected nearly 1 in 1000 of the UK population in 2012.
Aetiology is poorly understood but genetic , hormonal , immunological and environmental factors are thought to be important.
interplay between genes , hormones and the environment SLE can be triggered in genetically- susceptible individual by exposure to certain environmental risk factors strong genetic contribution ( no obvious pattern of inheritance ) ○ 1st degree relatives are at significantly higher risk ( studies have shown that lupus inheritability is about 44 % ) ○ number of gene variants linked to SLE expression have been identified ○ more than 80 risk genes have been described female sex & hormonal influences ○ oestrogen containing contraceptives ○ use of hormone replacement therapy ○ elevated prolactin drugs can lupus like phenomenon by demethylation of DNA and alteration of self antigens ○ procainamide and hydralazine have the highest incidence ○ more than 100 drugs are known to be associated with drug induced lupus ○ some drugs can cause flare in patients with SLE as sulfa drugs UV rays , sun exposure , smoking viral infections ( for e.g antibodies against EBV are more prevalent in SLE sufferers compared to general population )
complex pathogenesis a breakdown of immune tolerance leading to antibody production & dysregulation of the inflammatory response abnormal immunological function and production of autoantibodies immune system is exposed to self antigens ( on exposure to environmental factors ) which causes activation of T and B cells which triggers a chronic self-aimed immune response ( induction & maintenance of the disease ) ie a persistent immune response against autologous nucleic acids autoantibodies production , immune complexes deposition , cytokine release , compliment activation – tissue inflammation lead to organ damage tissue damage due to antibodies or immune complex deposition can happen in kidneys , heart , vessels , CNS , skin , lungs , muscles and joints which causes significant morbidity and ↑↑ mortality.
multisystem disease with considerable heterogeneity in the early stages of disease limited number of features may be present many symptoms as fatigue , rash , joint pain are non-specific and overlap with those of more common conditions the time from symptom onset to diagnosis -reported to be about 2 yrs ( this is longer for patients with late onset SLE ie 50 or older ) the course of illness may differ in different individuals , it can be unpredictable within the same patient over a period of time considerable mortality due to flares of disease activity and accumulated damage ↑↑ ed risk of premature death -usually due to infection or cardiovascular disease Lupus patients die on an average 25 yrs earlier than the mean for women & men in UK
multi-system disease which can affect any organ in most patients constitutional symptoms as fatigue , cutaneous and MSK symptoms are the 1st manifestations of SLE can affect various organs with variable degree of severity chronic relapsing -remitting course and variable manifestations from mild mucocutaneous to devastating life-threatening illness can present with acute flares and period of remission in mild forms joints and skin are the main organs affected severe forms can involve the kidneys & heart which can be life threatening
Lupus – more than 100 antibodies are detectable for this condition ANA is used due to its high sensitivity ANA titer of 1 : 80 by direct is used as entry criteria in diagnostic criteria’s
Antinuclear antibody tests ( ANA ) is + ve in nearly all cases of SLE but is not specific for the disease ie ○ positive ANA test can also be found in numerous other autoimmune conditions as autoimmune thyroiditis , autoimmune liver disease & myasthenia among others Consider ANA testing in presentations as ○ unexplained multisystem inflammatory disease ○ symmetric joint pain with inflammatory features ○ young women with arthritis / arthralgias negative ANA does not r/o out the diagnosis as up to 20 % of the patients may be negative at various stages of the disease more than 20 % of the healthy normal population particularly females or relatives of patients with autoimmune diseases can have a + ve ANA consider discussing with rheumatology if ANA is negative or low titre but you have a high clinical index of suspicion ANA 1 : 160 or more – refer A positive ANA should trigger further antibody testing If ANA is negative – consider repeating at a subsequent time point only if there are new or worsening signs / symptoms indicating a SLE diagnosis
urinalysis is an important part of diagnostic workup ○ to check for nephropathy ○ urine protein to creatinine ratio Nephritis can be presenting symptom in SLE FBC ( anaemia in more than 50 % and cytopenia ) U&Es – renal impairment LFTS – SLE doesn’t affect the liver significantly ESR / CRP ( CRP can be normal or mildly elevated with high ESR ) serum protein electrophoresis – hypergammaglobulinemia indicating systemic inflammatory process
ENA panel ( Ro , La , Jo-1 , Sm , RNP , Scl-70 ) Anti-dsDNA antibodies ( 95 % sensitivity for SLE but they are only seen in about 60 % to 70 % of SLE patients ie a neg’ve test does not r/o SLE ) Compliment C3 and C4 antibodies Anti-phospholipid antibody.
Diagnosis is clinical on the basis of presence of a constellation of symptoms and signs + supportive serological studies / excluding other conditions No diagnostic criteria has been validated till now Patients may progress from ‘ preclinical-lupus’ through initial symptoms of the disease ( incomplete lupus erythematosus ) to full spectrum SLW Term ‘ undifferentiated connective tissue disease ‘ ( UCTD ) is used to describe presence of signs and symptoms which are consistent with SLE / other defined systemic autoimmune CTD but it does not fulfill the classification criteria yet.
Adult onset Still disease Behçet syndrome Chronic fatigue syndrome Endocarditis Fibromyalgia HIV infection Inflammatory bowel disease Lyme disease Mixed connective tissue disease Psoriatic arthritis Reactive arthritis Rheumatoid arthritis Sarcoidosis Systemic sclerosis Thyroid disease.
Conditions which have clinical and laboratory features that can mimic those which are present in SLE as rosacea ( butterfly rash ) viral infection ( particularly parvo virus can cause fever , rash , inflammatory arthritis and cytopenias ) ○ hepatitis B and C ○ CMV and EBV ○ infectious endocarditis Malignancies as lymphomas Type -2 interferonopathies Castleman’s disease Prolidase deficiency Angioimmunoblastic T cell lymphoma Evan’s syndrome Overlap syndromes – combine SLE characteristics with features from other diseases as Rh arthritis ( ‘ Rhupus ‘ ) Mixed connective tissue diseases – used to describe a combination of clinical manifestations of SLE , cutaneous systemic sclerosis and polymyositis / dermatomyositis in presence of anti-U1 – RNP antibodies
accelerated atherosclerosis – increased risk of CVD end stage renal disease blindness ( neuropsychiatric manifestations ) permanent skin damage and alopecia anxiety and depression complications related to treatment ( for e,g long term use of steroids as avascular necrosis , glaucome , cataract , weight gain , poor diabetes control ) greater all cause health care costs over time ( Sambaliev et al 2021 ).
Lupus -information from American College of Rheumatology https://www.rheumatology.org/I-Am-A/Patient-Caregiver/Diseases-Conditions/Lupus
Lupus Foundation of America on SLE- a valuable resource https://www.lupus.org/resources/what-is-systemic-lupus-erythematosus-sle
Versus arthritis on Lupus-simple and well organised section https://www.versusarthritis.org/about-arthritis/conditions/lupus-sle/
Lupus UK with useful videos an excellent resource https://www.lupusuk.org.uk/what-is-lupus/
Bath Institute of Rheumatic Diseases ( BIRD ) a charity working in the field of arthritis research – a valuable link for both patients and professionals https://www.birdbath.org.uk/
- Caroline Gordon, Maame-Boatemaa Amissah-Arthur, Mary Gayed, Sue Brown, Ian N. Bruce, David D’Cruz, Benjamin Empson, Bridget Griffiths, David Jayne, Munther Khamashta, Liz Lightstone, Peter Norton, Yvonne Norton, Karen Schreiber, David Isenberg, for the British Society for Rheumatology Standards, Audit and Guidelines Working Group, The British Society for Rheumatology guideline for the management of systemic lupus erythematosus in adults, Rheumatology, Volume 57, Issue 1, January 2018, Pages e1–e45, https://doi.org/10.1093/rheumatology/kex286
- Gergianaki, Irini, and George Bertsias. “Systemic Lupus Erythematosus in Primary Care: An Update and Practical Messages for the General Practitioner.” Frontiers in medicine vol. 5 161. 29 May. 2018, doi:10.3389/fmed.2018.00161
- Samnaliev, Mihail et al. “Health-care utilization and costs in adults with systemic lupus erythematosus in the United Kingdom: a real-world observational retrospective cohort analysis.” Rheumatology advances in practice vol. 5,3 rkab071. 16 Sep. 2021, doi:10.1093/rap/rkab071
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- Frances Rees, Michael Doherty, Matthew J Grainge, Peter Lanyon, Weiya Zhang, The worldwide incidence and prevalence of systemic lupus erythematosus: a systematic review of epidemiological studies, Rheumatology, Volume 56, Issue 11, November 2017, Pages 1945–1961, https://doi.org/10.1093/rheumatology/kex260
- Justiz Vaillant AA, Goyal A, Varacallo M. Systemic Lupus Erythematosus. [Updated 2022 Feb 12]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK535405