Acquired thrombotic thrombocytopenic purpura as the presenting symptom of systemic lupus erythematosus. Successful treatment with plasma exchange and immunosuppression--report of two cases

Thrombotic thrombocytopenic purpura (TTP) is a rare but life-threatening syndrome characterized by platelet aggregation causing occlusive microangiopathy. It has been described as a complication in systemic lupus erythematosus (SLE). Recent research indicated that genetic or autoantibody-induced deficiency of the metalloprotease ADAMTS13 plays a key role in the pathogenesis of TTP. Here we report two uncommon cases of TTP as the first presenting symptom of SLE. Both patients were treated with combined plasma exchange and immunosuppressive therapy, and recovered completely. Although TTP and SLE have several clinical findings in common, and both disorders may coexist more frequently than we currently assume, features of one disease should not mislead to reject the alternative disorder.

A multicentre, double-blind, randomized study to compare the safety and efficacy of once-daily ORG 10172 and twice-daily low-dose heparin in preventing deep-vein thrombosis in patients with acute ischaemic stroke

A multicentre, double-blind, randomized study was performed in 179 patients with acute ischaemic stroke resulting in limb paresis. The purpose was to compare the safety and efficacy of Org 10172 (1250 anti-Xa Units s.c. once daily) and heparin sodium (5000 IU s.c. twice daily) in preventing deep-vein thrombosis (DVT). Prophylaxis started within 72 hours of the onset of stroke and continued for at least 9 days. To detect DVT, patients underwent a daily 125I-fibrinogen leg scanning which, if found positive, was followed by venography. A first computed tomography scan of the brain was performed at screening to rule out cerebral haemorrhage and a second at cessation of treatment to detect any haemorrhagic transformations. At the 2-3-months' follow-up period the patients were examined for signs and symptoms of DVT or pulmonary embolism. On an intention-to-treat analysis, DVT occurred in 14.6% of patients receiving Org 10172 and in 19.8% of those receiving heparin during the treatment period (p = 0.392, NS). Pulmonary embolism was diagnosed in one patient in each group. Major conversion to a symptomatic haemorrhagic brain infarct was found in one patient in each group. Death occurred in 13.5% of patients treated with Org 10172 and in 6.7% of patients treated with heparin (p = 0.135, NS). Deaths were mainly related to pulmonary infection and cerebral oedema, thus considered to be due directly to the clinical status of the patients. 1250 anti-Xa Units of Org 10172 once daily is both safe and as effective as 5000 IU of heparin sodium twice daily given for DVT prophylaxis in patients with acute ischaemic stroke of recent onset.

Different inhibitory effect of etomidate and ketoconazole on the human adrenal steroid biosynthesis

The narcotic agent etomidate and the antimycotic drug ketoconazole are known to block steroid biosynthesis in man. To study the different effects of these imidazole derivatives on human adrenal steroid biosynthesis we incubated slices of human adrenal glands with 3H-labeled precursors and increasing concentrations of etomidate or ketoconazole (0-2000 microM). After extraction the labeled metabolites were separated by thin-layer chromatography and quantified by scintillation counting. Etomidate inhibited most potently 11 beta-hydroxylase activity by suppressing the formation of corticosterone from 11-deoxycorticosterone to 1% of control [50% inhibitory concentration (IC50) 0.03 microM] while ketoconazole suppressed 11 beta-hydroxylase to only 39% of control activity (IC50 15 microM). Ketoconazole however, most potently blocked the conversion of 17 alpha-hydroxy-progesterone to androstenedione by C17,20-desmolase to about 15% of control activity (IC50 1 microM) while etomidate showed a much weaker effect on this enzyme with a suppression to 50% of C17,20-desmolase control activity at a concentration of 380 microM. Both imidazole drugs showed a similar strong inhibitory effect on the activity of 17 alpha-hydroxylase (IC50 6-18 microM) and 16 alpha-hydroxylase (IC50 4-8 microM) and did not affect 21-hydroxylase. These in vitro data indicate a predominant inhibitory effect of etomidate on corticosteroid biosynthesis by relative selective inhibition of 11 beta-hydroxylase and of ketoconazole on the adrenal androgen biosynthesis by a predominant inhibition of C17,20-desmolase. This differential inhibitory effect of etomidate and ketoconazole on human steroid biosynthesis may be of clinical importance for a possible therapeutic use of these imidazole derivatives in endocrine disorders.

The influence of ketoconazole on human adrenal steroidogenesis: incubation studies with tissue slices

OBJECTIVE

The influence of ketoconazole on the various enzymes of human adrenal steroid biosynthesis was examined in vitro.

MEASUREMENTS

After incubation of human adrenal tissue slices with labelled precursors and ketoconazole (0-2000 microM), radioactive metabolites were separated by thin-layer chromatography and quantified by liquid scintillation counting. Enzyme activity was assessed by measuring conversion of tritium-labelled precursors to products.

RESULTS

In vitro, ketoconazole showed a significant inhibition on the following adrenal enzyme systems (with decreasing activity): C17,20-desmolase (IC50 2 microM), 16 alpha-hydroxylase (IC50 9 microM), 17 alpha-hydroxylase (IC50 18 microM), 18-hydroxylase (IC50 28 microM), and 11 beta-hydroxylase (IC50 35 microM). In the tested concentrations ketoconazole had no inhibitory effect on the 21-hydroxylase, the 3 beta-hydroxysteroid dehydrogenase and the 20-hydroxysteroid dehydrogenase component of the C17,20-desmolase enzyme system.

CONCLUSIONS

The data are in accordance with clinical findings where a strong suppression of serum androgen levels by relatively selective inhibition of C17, 20-desmolase has been assumed. The predominant blocking effect of ketoconazole on adrenal as well as on gonadal androgen biosynthesis might be of clinical benefit in the management of hyperandrogenic states.