KIN 4605 Chapter : Diabetes Mellitus Discussion Spring 2012
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A 26-year-old woman presented with painful, stiff knees of 4 weeks duration. She had a 6-year history of Raynaud's phenomenon. On examination, she had bilateral effusions in both knee joints, but all other joints were normal. She had no skin lesions, muscle tenderness, proteinuria or fever. The results of relevant investigations are shown in Table C10.1. On the basis of these, a diagnosis of Systemic Lupus Erythematosus (SLE) was made and the patient treated with aspirin for her painful knees. She improved over 4 weeks and then remained symptom-free for 5 years. During this time, her antinuclear antibody remained positive at 1/80, her DNA-binding activity varied from 40 to 80%, and her C3 and C4 levels were occasionally low. Later, she developed a bilateral, butterfly rash across her cheeks, blotchy rash on her hands and thighs, consistent with active vasculitis and also presented with proteinuria, hematuria and glomerular nephritis. Her Raynaud's phenomenon concurrently became much worse. Following treatment with prednisolone, the skin manifestations gradually disappeared and the steroids were tailed off.
This patient presented with arthritis and Raynaud's phenomenon. She is unusual in that the arthritis of SLE usually involves small joints, but it is important to note that she remained perfectly well without treatment for 5 years, despite persistently abnormal serology.
Table C10.1 Investigations in Case 10.8.
| C-reactive protein | 8mg/l (normal) |
| Rheumatoid factor | Negative |
| Antinuclear antibody | Positive (titer 1/80; IgG class) |
| dsDNA-binding activity | 80% (NR 0-30% binding) |
| Antibodies to extractable nuclear antigens | Negative |
| Serum complement levels | |
| C3 | 0.35g/l (NR 0.65-1.30) |
| C4 | 0.05g/l (NR 0.20-0.50) |
| Serum immunoglobulins | |
| IgG | 22.0g/l (NR 7.2-19.0) |
| IgA | 3.8g/l (NR 2.0-5.0) |
| IgM | 1.2g/l (NR 0.5-2.0) |
| Biopsy of normal, sun-exposed skin (lupus band test) | Granular deposits of IgG and complement at dermo-epidermal junction |
1) Explain the immunological basis of her disease condition and the significance of her elevated levels of antinuclear antibodies (ANA).
2) Explain as to what caused her glomerular nephritis, vasculitis and bilateral skin rash.
3) How would you categorize the type of hypersensitivity reactions causing the above disease?
4) Explain how prednisolone helped to treat the symptoms.
5) Explain the biochemical mechanism of action of aspirin in its interaction with cyclooxygenase. Which class of macromolecules are affected by this interaction (inhibition) and state briefly a major side effect that may develop as a result of extensive aspirin therapy.
