Make sure the “punishment” fits the “crime.”
Comment: One of the fundamental principles of rheumatology is to make certain that the intensity of treatment matches the severity of the disease. Pleuritis, arthralgia, and low-grade fever with systemic lupus erythematosus (SLE) will respond to 60 mg of prednisone given daily. But these manifestations will also respond generally to far less prednisone, eg, 10–20 mg daily, doses associated with a much lower risk of infection or other complications. In contrast, severe hemolytic anemia and glomerulonephritis in SLE may not respond to low-dose prednisone and often must be treated not only with high doses of prednisone but also additional agents.
A normal cosyntropin stimulation test excludes adrenal insufficiency induced by glucocorticoid therapy.
Comment: The cosyntropin stimulation test determines the ability of the adrenal gland to produce cortisol in response to an exogenous corticotropin (adrenocorticotropic hormone, ACTH). However, the endogenous response to stress requires that all components of the hypothalamic-pituitary-adrenal axis be intact. Individuals treated currently with glucocorticoids and for many months after such therapy can have insufficiency of the central components of this axis (ie, normal adrenal response to exogenous ACTH but subnormal ability to produce ACTH endogenously).
Because tests of the central components of the axis are complex, most authorities recommend empiric hydrocortisone supplementation (100 mg three times daily) when these patients face major surgery or the stress of serious medical illness. Once the patient is beyond the perioperative period, the baseline prednisone dose can be resumed.
Rheumatoid arthritis rarely causes high-grade fever.
Comment: Although low-grade fevers in the range of 37.5°C often accompany active rheumatoid arthritis (RA), high-grade fevers are rare. Only 5% of cases manifest fever >38°C, and less than 1% have temperatures >38.3°C. Therefore, high-grade fever in a patient with well-established RA should prompt an investigation for an underlying cause (eg, infection) other than RA. In a patient with the new onset of inflammatory arthritis, the presence of high-grade fever is an argument against the diagnosis of RA or even a complication of RA, such as rheumatoid vasculitis (see Chapter 42). (See Chapter 4 for a discussion of the differential diagnosis of fever and arthritis).
Flare of a single joint in a patient with RA signals serious concern about septic arthritis.
Comment: Most flares of RA are polyarticular. When signs of new, increased inflammation affect only one joint, infection should be strongly considered. The most common cause of septic arthritis in RA is Staphylococcus aureus. Absence of fever does not exclude infection because only 50% of patients with septic arthritis present with fever. In the patient who has RA with only one “active” joint, arthrocentesis should be performed to exclude infection before intensifying anti-inflammantory therapy.