Therapy for thrombotic occlusion of long-term intravenous alimentation catheters

Thrombosis and infection are closely related complications of implanted silastic catheters. A procedure, by which the thrombi are dispersed with urokinase while the catheter remains in situ, was uniformly successful in clearing the line in 20 patients, although in 5 the infusion had to be repeated 24 hr later. Catheter-associated infections are rendered susceptible to antibiotics as the infected thrombotic nidus is lysed and the organisms exposed. In 7 patients, 4 of whom were taking antibiotics, fever and blood cultures became negative. The procedure results in no detectable systemic fibrinolysis or other complications.     

Sciatic nerve palsy secondary to postoperative haematoma in primary total hip replacement

Sciatic nerve palsy is a recognised complication of primary total hip replacement. In our unit this complication was rare with an incidence of < 0.2% in the past ten years. We describe six cases of sciatic nerve palsy occurring in 355 consecutive primary total hip replacements (incidence 1.69%). Each of these palsies was caused by post-operative haematoma in the region of the sciatic nerve. Cases, which were recognised early and surgically-evacuated promptly, showed earlier and more complete recovery. Those patients for whom the diagnosis was delayed, and who were therefore managed expectantly, showed little or no recovery. Unexpected pain and significant swelling in the buttock, as well as signs of sciatic nerve irritation, suggest the presence of haematoma in the region of the sciatic nerve. It is, therefore, of prime importance to be vigilant for the features of a sciatic nerve palsy in the early post-operative period as, when recognised and treated early, the injury to the sciatic nerve may be reversed.     

Breast cancer incidence in women prenatally exposed to maternal cigarette smoke

BACKGROUND: Clinical studies show that maternal cigarette smoking reduces pregnancy estrogen levels. Women prenatally exposed to maternal cigarette smoke may, therefore, have a lower breast cancer risk because the fetal mammary gland's exposure to maternal estrogen is decreased. Associations between prenatal maternal cigarette smoke exposure and breast cancer, however, have not been observed in previous case-control studies that relied on exposure assessment after the onset of cancer. At the start of this study, cigarette smoking history was obtained directly from the mother. METHODS: The National Cooperative DES Adenosis project was a follow-up study of health outcomes in women prenatally exposed to diethylstilbestrol (DES). At the start of the study, women's mothers provided information about cigarette smoking habits during the time they were pregnant with the study participant. In the current study, the breast cancer rates are compared among 4031 women who were or were not prenatally exposed to maternal cigarette smoke. The resultant relative rate (RR) is adjusted for potential confounding by other breast cancer risk factors using Poisson regression modeling. RESULTS: Fetal exposure to maternal cigarette smoke appeared to be inversely associated with breast cancer incidence (RR = 0.49; 95% confidence interval [CI] = 0.24-1.03). The inverse association was more apparent among women whose mothers smoked 15 cigarettes or fewer per day than among daughters of heavier smokers. There were, however, too few cases to precisely estimate a possible dose-response relationship. CONCLUSION: These results support the hypothesis that in utero exposure to maternal cigarette smoke reduces breast cancer incidence.     

The cross-sectional cohort study: an underutilized design

Epidemiologists frequently study the experience of a population over time to estimate the association between exposure and outcome. These studies generally use case-control, prospective cohort, or retrospective cohort designs. The "cross-sectional cohort study," as it is termed here, represents an alternative to these standard methods. With this design, an investigator samples a source population cross-sectionally and then retrospectively assesses subjects' histories of exposures and outcomes over a specified time period. Certain threats to validity, such as nonignorable exiting and measurement error from retrospective assessments, must be considered carefully when using this design. However, in some situations, the cross-sectional cohort design may offer advantages over traditional designs-especially in studies in which there is a long interval between exposures and outcomes, in which exposures and outcomes can be accurately assessed retrospectively, and in which the outcome does not accelerate any exiting from the population. Such situations often arise when studying chronic or episodic conditions with low mortality, such as psychiatric disorders.