Our immune system fights against bacteria, viruses, fungi, protozoa, and rogue cancer cells. When the “army-within” fails to recognize our own cells and starts attacking them, it results in autoimmunity. Medications needed to treat autoimmune diseases, sadly, also weaken our own “army,” increasing risk of infections and malignancies.
Mostly seropositive, e.g., antinuclear antibody (ANA), rheumatoid factor (RF)b antimitochondrial antibody, anti-SSA, anti-SSB
aPatients with one condition have increased risk of other conditions in the same group. For example, patients with RA have increased risk of Sjogren: patients with psoriasis have increased risk of ankylosing spondylitis.
bNote: ANA and RF are not only found in SLE and rheumatoid arthritis, but also in other autoimmune conditions and also in females and old patients with no connective tissue disease. Hence, presence of ANA and RF in serum is very nonspecific.
When asked about the most common cause (MCC) of death in a specific condition (e.g., what is the MCC of death in SLE, RA, ankylosing spondylitis, peripheral vascular disease?), the safest bet is to answer cardiovascular cause (it is the MCC of death in general population too). Also note that chronic inflammatory conditions such as SLE and RA are associated with accelerated atherogenesis.
or anticyclic citrullinated peptide.
2Rheumatoid factor is autoimmune antibody against our own Immunoglobulin G (IgG). Immunoglobulin M (IgM) rheumatoid factor is commonly tested and is specifically helpful in assessing the course and prognosis. But note that negative serum rheumatoid factor does not rule out rheumatoid arthritis.
Presentation: Recent-onset symmetrical polyarthralgia/arthritis with or without hx of classical rash (slapped cheek rash, or lacy rash that looks a like a fish net). It may be confused with RA due to symmetric inflammatory arthritis. Look for acute onset and history of contact with children.
Complication: Aplastic crisis or chronic pure red cell aplasia can occur in patients with hematologic disorder or who are immunosuppressed. Primary infection during pregnancy can lead to intrauterine fetal death and/or hydrops fetalis (due to severe fetal anemia).
Management: NSAIDs + DMARDs (except in patients with low-disease activity). All patients are recommended to have periodic slit lamp examination, as coexistent asymptomatic iridocyclitis can lead to blindness, if left untreated.
Systemic-Onset Juvenile Idiopathic Arthritis (Formerly Known as Systemic JRA or Juvenile-Onset Form of Still’s Disease
Results in difficulty in swallowing food (loss of salivary lubrication effect), dental caries (loss of protective effect of salivary secretions), and fissures in mucosa. Patients may have parotid gland enlargement.
Work-up: NSIDx is bedside Schirmer’s test (a filter paper is placed in the eye and the extent of wetness is measured). Check anti-Ro(SSA) and anti-La(SSB), which are specific serologic findings. Most specific test is salivary gland biopsy of lower lip, but may not be necessary.
Treatment: Maintain oral hygiene (avoid sugary drinks and drink water frequently to keep the mouth wet), and use artificial tears and/or saliva. Second-line agents are pilocarpine or cevimeline (these are procholinergic agents that promote glandular secretion).
Migratory, symmetrical arthritis that is nonerosive.a X-ray of joints is normal. (This is in contrast to RA, which is erosive, and X-ray is abnormal).
Work-up: If patient has any of the features of “SOAP BRAIN MD,” NSIDx is serum ANA (which is the screening test). If ANA is positive, NSIDx is anti-Smith and anti-dsDNA antibodies (these antibodies are specific to SLE, but not sensitive).
Pathophysiology: Immune complexes (anti-dsDNA antibody and antigen complex) are deposited in the glomerulus with subsequent activation of complement pathway, hence anti-dsDNA titers usually correlate with the severity of renal disease. Patients with high anti-dsDNA titer and low complement levels most likely have severe renal disease.
Work-up: In patients with SLE, always check urinalysis and serum creatinine to screen for renal involvement. UA may show RBC casts and/or proteinuria. If significant renal involvement is suspected, NSIM is renal biopsy.
High-dose IV steroids + mycophenolate or cyclophosphamidea
Etiology: It has been associated with the following drugs: Chlorpromazine (antipsychotic), Carbamazepine, Captopril, Hydralazine, Isoniazid, Methyldopa, Minocycline, Procainamide, Penicillamine, Phenytoin, Sulfasalazine, Sodium valproate, Quinidine, TNF inhibitors (e.g., infliximab, etanercept), Diltiazem, etc.
Diagnosis: Specific test for drug-induced lupus is antihistone antibody. Presence of anti-dsDNA can occur with minocycline or TNF-inhibitor-induced disease. Low complement levels and kidney or CNS involvement are rare.
Presentation: Joint pain (arthralgia) ± swelling and redness (arthritis) in different joints at different times. For example, CCS: patient presents with pain in the right knee joint. He also gives history of pain, swelling in the right wrist 3 days ago and left knee involvement 7 days ago.
Rx: Treatment is nonspecific and organ based. It also depends upon presence of ongoing inflammation. Commonly used drugs are immunosuppressants, such as methotrexate, steroids, hydroxychloroquine, etc.
• In CREST syndrome, skin involvement is localized to the face, hands, and forearm (i.e., acral distribution only). In systemic sclerosis, the skin involvement can involve the whole body including trunk and arms.
Any feature of CREST with additional involvement of any other organ, except isolated pulmonary HTN, is systemic sclerosis. Note: CREST can also be associated with pulmonary HTN (loud P2 sound on heart auscultation), but is usually not accompanied by pulmonary parenchymal fibrosis.
Gadolinium contrast (given with magnetic resonance imaging [MRI]) is almost exclusively excreted by kidney. If given to patients with advanced kidney disease, it can remain in tissues causing reactive fibrosis. Skin findings include patches, plaques, and peau d’orange appearance, along with sclerodactyly and other features similar to systemic scleroderma.
Could be paraneoplastic (associated with underlying malignancy)a
First step: Muscle creatine kinase (CK) and enolase (both will be high). Additionally, check myositis-specific antibodies (e.g., anti-Jo-1 antibodyMRS-1).