case 2
Option D (Periarticular soft tissue swelling) is correct. This patient has a characteristic malar rash, arthralgias, fatigue, and weight loss with a positive antinuclear antibody. The diagnosis of SLE is strongly suggested. The radiographic findings of SLE are somewhat variable, but almost always reveal periarticular soft tissue swelling. There can also be periarticular osteopenia.
Option A (Erosions in the ulnar styloid) is incorrect. This can be an early radiologic feature that is characteristic of rheumatoid arthritis. Erosions are absent in systemic lupus erythematosus (SLE).
Option B (Expanded bony cortex) is incorrect. An expanded bony cortex is seen in Paget disease, which it most commonly asymptomatic. It is caused by increased bone turnover caused by osteoclasts.
Option C (Osteophytes) is incorrect. Osteophytes are a common radiographic finding of osteoarthritis.
Option E (Subchondral sclerosis) is incorrect. This is a characteristic feature of osteoarthritis, which does not present with constitutional findings.
High-yield Hit 1
Table 80-2. Autoantibodies in Patients with Systemic Lupus Erythematosus (SLE)*
Test Sensitivity (%) Specificity (%) Predictive Value (%)
ANA 99 80 15-35
dsDNA 70 95 95
ssDNA 80 50 50
Histone 30-80 Moderate Moderate
Nucleoprotein 58 Moderate Moderate
Sm 25 99 97
RNP (U1-RNP) 50 87-94 46-85
Ro (SS-A) 25-35
La (SS-B) 15
PCNA 5 95 95
From Cecil Essentials of Medicine 6E by Andreoli et al
High-yield Hit 2
Various autoantibodies are found in patients with SLE and are the hallmark laboratory features of the disease (Table 80-2). Virtually all patients with SLE (99%) test positive for antinuclear antibodies when a sensitive assay is used. Although many of the specific antigens to which these antinuclear antibodies are directed have been determined, and are useful both diagnostically and clinically in SLE, some antibodies are also seen in other autoimmune diseases. Antibodies to double-stranded DNA and the Smith (Sm) antigen are highly specific for lupus, whereas antibodies to Ro and La antigens are also commonly found in patients with rheumatoid arthritis and are especially common in patients with Sjögren's syndrome. Certain antibodies are associated with specific clinical manifestations of disease. For example, many patients with lupus nephritis have anti-double-stranded DNA antibodies. The relationship between antibodies to ribosomal P or neuronal antigens and lupus cerebritis is still under investigation. Autoantibodies alone are not diagnostic for any autoimmune disease but must be interpreted in the clinical context.
SLE is a clinical diagnosis; no one test or feature is fully diagnostic of the disease. Furthermore, many patients' clinical syndromes "evolve" over time, and only after several years are they recognized as having SLE. To classify patients with SLE more accurately and reproducibly for research purposes, an internationally accepted set of diagnostic criteria was developed (Table 80-3). By design, the diagnostic specificity of these criteria is high, to ensure that all subjects enrolled in research studies truly have SLE. However, although these criteria are valuable for practicing clinicians, patients may have clinical lupus without meeting the criteria. More than half of the manifestations listed in Table 80-1 are not part of the criteria.
From Cecil Essentials of Medicine 6E by Andreoli et al
High-yield Hit 3
Table 80-3. Criteria for Classification of Systemic Lupus Erythematosus*
Criterion Definition
1. Malar rash Fixed erythema, flat or raised, over the malar eminences, tending to spare the nasolabial folds
2. Discoid rash Erythematous raised patches with adherent keratotic scaling and follicular plugging; atrophic scarring may occur in older lesions
3. Photosensitivity Skin rash as a result of unusual reaction to sunlight by patient history or physician observation
4. Oral ulcers Oral or nasopharyngeal ulceration, usually painless, observed by a physician
5. Arthritis Nonerosive arthritis involving two or more peripheral joints, characterized by tenderness, swelling, or effusion
6. Serositis a. Pleuritis: convincing history of pleuritic pain or rub heard by a physician or evidence of pleural effusion
OR
b. Pericarditis: documented by electrocardiogram or rub or evidence of pericardial effusion
7. Renal disorder a. Persistent proteinuria >0.5 g/day or >3+if quantitation not performed
OR
b. Cellular casts: may be red cell, hemoglobin, granular, tubular, or mixed
8. Neurologic disorder a. Seizures: in the absence of offending drugs or known metabolic derangements (e.g., uremia, ketoacidosis, or electrolyte imbalance)
OR
b. Psychosis: in the absence of offending drugs or known metabolic derangements (e.g., uremia, ketoacidosis, or electrolyte imbalance)
9. Hematologic disorder a. Hemolytic anemia: with reticulocytosis
OR
b. Leukopenia: <4000/mm3 total on two or more occasions
OR
c. Lymphopenia: <1500/mm3 on two or more occasions
OR
d. Thrombocytopenia: <100,000/mm3 in the absence of offending drugs
10. Immunologic disorder a. Anti-DNA: antibody to native DNA in abnormal titer
OR
b. Anti-Sm: presence of antibody to Sm nuclear antigen
OR
c. Positive finding of antiphospholipid antibodies based on (1) an abnormal serum level of IgG or IgM anticardiolipin antibodies, (2) a positive test result for lupus anticoagulant using a standard method, or (3) a false-positive serologic test for syphilis known to be positive for at least 6 months and confirmed by Treponema pallidum immobilization or fluorescent treponemal antibody absorption test
11. Antinuclear antibody An abnormal titer of antinuclear antibody by immunofluorescence or an equivalent assay at any point in time and in the absence of drugs known to be associated with "drug-induced lupus" syndrome