Clinical Briefs
By Louis Kuritzky, MD, Clinical Assistant Professor, University of Florida, Gainesville. Dr. Kuritzky is a consultant for GlaxoSmithKline and is on the speaker’s bureau of GlaxoSmithKline, 3M, Wyeth-Ayerst, Pfizer, Novartis, Bristol-Myers Squibb, AstraZeneca, Jones Pharma, and Boehringer Ingelheim.
Staphylococcal Toxins in Patients with Psoriasis, Atopic Dermatitis, Erythroderma, and in Healthy Control Subjects
The role that microbes play in some dermatoses is not always immediately evident. For instance, the yeast Pityrosporum orbiculare is etiologic in some cases of seborrheic dermatitis; hence, even though topical steroid treatment can control symptoms by reducing inflammation, antifungal treatment may also resolve seborrheic dermatitis.
Staphylococcus aureus (SA) is found on the skin or nares of up to 30% of healthy individuals. In skin lesions of atopic dermatitis (AD) or psoriasis (PSO), colonization with SA is found even more often (46-93%). Additionally, SA is cultured disproportionately more frequently in active skin lesions of AD and PSO than in uninvolved skin, giving credence to a potential etiologic role.
Patients (n = 75) with AD, PSO, and controls were evaluated for the presence of SA; additionally, SA subtyping was performed to determine the presence of Staphylococcal enterotoxin. More AD patients (88%) than PSO (60%) were lesion-positive for SA. In both disorders, there was a correlation between the presence of SA enterotoxin and dis-
ease severity. The authors posit that SA enterotoxin may induce or aggravate skin lesions of psoriasis and atopic dermatitis, and that methods to reduce SA colonization might be beneficial in both disorders.
Tomi NS, et al. J Am Acad Dermatol. 2005;53:67-72.
Insulin Resistance and Risk of Congestive Heart Failure
Heart failure (chf) is most com-monly caused by hypertension and coronary artery disease. Framingham data from as far back as 1974 have shown an association between diabetes and CHF. Only recently has a relationship between obesity and CHF been described. A variety of mechanisms by which diabetes or obesity might increase risk for CHF has been offered, but the insulin resistance (IR) shared by both maladies appears a likely culprit.
The Uppsala Longitudinal Study of Adult Men is a prospective observational study intended to investigate metabolic risk factors for cardiovascular disease in Uppsala, Sweden; between 1970-1974, all men age 50 were invited to participate (n = 2322), and the population was re-investigated in 1990-1995; these data provide the baseline information for this study. Baseline data included BP, smoking status, waist circumference, BMI, oral glucose tolerance test, insulin resistance (by euglycemic insulin clamp method), plasma insulin, plasma proinsulin, and lipids.
The population selected for study was free of CHF or valvular disease at baseline. During a mean follow-up of 8.9 years, 104 men developed CHF. The presence of IR was found to be a predictor of CHF, independent of diabetes, and other known CHF risk factors. The association between obesity and CHF, which held true whether waist circumference or BMI was used as the metric, was mitigated when IR was included in the multivariate analysis, suggesting that IR is, to some degree, causal in the relationship.
Ingelsson E, et al. JAMA. 2005;294:334-341.
Ciprofloxacin Interacts with Thyroid Replacement Therapy
A number of commonplace medications have been shown to interfere with absorption of orally administered thyroid hormone (levothyroxine), including aluminum-containing antacids, iron, cholestyramine, sucralfate, and calcium carbonate. Such interactions can be problematic on a large epidemiologic scale since, for instance, many of the middle-aged women who are taking thyroid hormone replacement (TH) are also taking calcium carbonate for bone health.
Two case reports highlight the potential of ciprofloxacin (CIP) to impede TH absorption. In Case 1, an 80-year-old woman who had been stable on 125 mg/d TH reported fatigue after 4 weeks treatment with CIP for osteomyelitis. Lab evaluation showed marked decreases in T4 and T3, with corresponding elevation in TSH (up to 44 mIU/L). Increasing the TH had no effect.
Case 2 was a 79-year-old woman treated with CIP (500 mg b.i.d. ´ 3 weeks) for a wound infection. Thyroid function tests and symptoms been previously stable on 150 mg/d of levothyroxine. Testing after 3 weeks of CIP indicated a decline in free T4 (from 22 to 13 picomoles/L) and an elevation in TSH (from 1.6 to 19 mIU/L). Providing an interval of 6 hours between CIP and TH produced normalization of thyroid function tests.
Other data have shown that providing a gap between calcium carbonate administration and TH resolves the medication competition. For patients who take TH, administration of CIP should be separated by at least several hours.
Cooper JG, et al. BMJ. 2005;330:1002.
Staphylococcal Toxins in Patients with Psoriasis, Atopic Dermatitis, Erythroderma, and in Healthy Control Subjects; Insulin Resistance and Risk of Congestive Heart Failure; Ciprofloxacin Interacts with Thyroid Replacement TherapyYou have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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