2008年11月29日 星期六

2008年11月26日 星期三

COPD+AE 是否一定要用抗生素?

Is it appropriate to start antibiotics for an acute COPD exacerbation?

Most exacerbations of COPD are caused by viral or bacterial infection. The clinical manifestations of exacerbations result from direct effects of viruses and bacteria from the host response. Antibiotics are not beneficial for a mild exacerbation but are beneficial in the treatment of moderate and severe COPD exacerbations, especially when purulent sputum is one of the presenting symptoms. Initial antibiotic choice (before any specific infectious agent is identified) should be based on the patient's age, risk factors, FEV1, number of exacerbations per year, recent antibiotic exposure, and presence of cardiac disease. Observational studies have identified advanced age, severe airflow obstruction, recurrent exacerbations, and coexisting cardiac disease as predictive factors for poor clinical outcomes after a COPD exacerbation.

Hint 1: The most prevalent bacterial pathogens in COPD are Haemophilus influenza and Pseudomonas aeruginosa. These pathogens enhance mucous secretion, disrupt normal ciliary activity, and cause airway epithelial injury, thereby further impairing mucociliary clearance.

Hint 2: Air pollution and other environmental conditions that increase airway inflammation or bronchomotor tone probably account for 15 to 20% of exacerbations. Increased respiratory symptoms resulting from coexisting conditions such as congestive heart failure and pulmonary emboli should be clinically ruled out in the evaluation of exacerbations.

NEJM - Vol. 359, No. 22, November 27, 2008

2008年11月19日 星期三

全球首例! 自身幹細胞 培植氣管移植







將壞損的氣管,換上移植氣管的西班牙「巴塞隆納臨床醫院」教授馬奇亞里尼說,因之前只做過豬的實驗,因此替卡斯提約動手術,令他提心吊膽。不過,看到從生物反應器取出的移植氣管十分完美,與正常人類的氣管看來無異後,心中放心不少。移植四天,馬奇里亞尼即宣稱手術大大成功,移植的氣管與原來氣管幾乎無法分辨。 聯合報╱編譯王麗娟/綜合報導/2008.11.20

Ginkgo Doesn't Prevent Dementia

Ginkgo extract "cannot be recommended" as a preventive for dementia, concludes a JAMA study.

Researchers randomized some 3000 patients to receive twice-daily doses of Ginkgo biloba extract or matching placebo. Participants averaged almost 80 years of age at entry, when they were either free of dementia or had only mild cognitive impairment; they underwent assessment every 6 months for a median 6 years' follow-up.

By the end of follow-up, there were no differences between the groups in overall incidence of dementia or Alzheimer disease.

An editorialist, calling this "the largest and longest randomized" trial to examine the effects of ginkgo extract, says it offers the "substantial bulk" of independently funded data on the substance. And writing in Journal Watch Psychiatry, Jonathan Silver comments that "in the present economy, people can put the [estimated annual $100 million expenditure for ginkgo] to better use."

JAMA article (Free)

2008年11月18日 星期二

AAA in women

An often overlooked danger of smoking is an increased risk of abdominal aortic aneurysm (AAA). There are particular risks for women. This study notes that
  • AAA is commoner in men but more likely to be fatal in women
  • Most research into AAA until now has been done in men
  • Age and smoking are the strongest risk factors for AAA in women
  • Women with diabetes are less likely to have AAA
The implication is that if we see an elderly woman who smokes and has a family history of AAA, we should probably arrange screening.

Source: BMJ 2008;337:a1724

Benign MS

The diagnosis of multiple sclerosis (MS) is distressing, and the prognosis is often very uncertain. It is encouraging to know that 5-40% of those diagnosed will have "benign MS" with only minimal disability 10 years after diagnosis.

In this cohort of 436 patients diagnosed with MS in 1985, 10% had the wrong diagnosis and just over 10% had benign MS. Benign MS is more likely if you are:
  • Female
  • Young
  • Free of motor symptoms at presentation
Source: Journal of Neurology, Neurosurgery, and Psychiatry 2008;79:1245-1248

2008年11月13日 星期四

Silent AMI

2008年11月12日 星期三



2008年11月8日 星期六

Blunt Aortic Injury

Blunt Aortic Injury and Anatomy
The descending aorta is fixed to the chest wall, whereas the heart and great vessels are relatively mobile. Traditional views have held that sudden deceleration causes a tear at the junction between the fixed and mobile portions of the aorta, usually near the isthmus. However, injury may also occur to the ascending aorta, the distal descending thoracic aorta, or the abdominal aorta. Many blunt aortic injuries probably involve a combination of forces, including stretching, shearing, torsion, and a “waterhammer” effect which involves simultaneous occlusion of the aorta and a sudden elevation in blood pressure. The aorta may also become entrapped between the anterior chest and the vertebral column, in a so-called “osseous pinch” effect to cause blunt injury.

What is the diagnostic test of choice for blunt aortic injury?
Helical computed tomography (CT) is now the diagnostic test of choice for blunt aortic injury. Helical CT of the thorax is more sensitive for blunt aortic injury than angiography and is estimated to have a sensitivity of 100%, as compared with 92% for angiography. Other options for the diagnosis of blunt aortic injury include transesophageal echocardiography, intravascular ultrasonography, and magnetic resonance imaging.

Perioperative Management of Blunt Aortic Injury
Once the diagnosis of blunt aortic injury is made, treatment and surgical repair must be properly timed. Several studies have demonstrated the relative safety of a delayed approach, particularly if there are substantial coinjuries, using a regimen of beta-blockers and antihypertensive agents to decrease the shear force on the aortic wall. Fabian and colleagues performed a prospective study (Ann Surg, 1998) using beta blockers with and without vasodilators to maintain a systolic blood pressure of approximately 100 mm Hg (or 110 mm to 120 mm Hg in older patients) and a pulse rate of under 100 beats per minute in selected patients with blunt aortic injury and a coexisting head injury, pulmonary injury, or cardiac insufficiency. In this study, no patient had an aortic rupture while awaiting repair.

New England Journal of Medicine - Vol. 359, No. 16, October 16, 2008

PPI 之缺點

What are the risks of long-term use of proton-pump inhibitors?

Potential risks of long-term use of proton-pump inhibitors include secondary hypergastrinemia, malabsorption, and hypochlorhydria. These risks are mainly theoretical, but large, population-based, epidemiologic studies have suggested that long-term use of proton-pump inhibitors was associated with an increased risk of hip fracture by a factor of 1.4 in subjects over 50 years (presumably attributable to calcium malabsorption), an increase in the risk of infectious gastroenteritis by a factor of 1.5, and a doubling of the risk of Clostridium difficile colitis.


What are some lifestyle modifications that may be recommended to patients with gastroesophageal reflux disease?

Lifestyle modifications that may be beneficial to patients with gastrointestinal reflux disease include dietary changes, if there are obvious dietary precipitants, (coffee, chocolate, or fatty foods), reduction of obesity, smoking, and excessive alcohol use, avoidance of eating within 3 hours of bedtime, elevation of head of bed, and eating smaller more frequent meals. However, lifestyle changes are often insufficient to eliminate symptoms and recommendation for use of a proton-pump inhibitor is usually the first line of therapy.

2008年11月4日 星期二


Low Maternal Caffeine Intake Linked to Fetal Growth Restriction

Even small amounts of caffeine consumed during pregnancy may increase the risk for fetal growth restriction, according to a BMJ study.

Using questionnaires and saliva samples, researchers assessed the caffeine consumption of 2600 healthy pregnant women throughout pregnancy.

After adjustment for tobacco and alcohol use, women who consumed over 200 mg of caffeine daily (roughly 2 cups of brewed coffee) were at increased risk for fetal growth restriction (birth weight less than the 10th percentile), compared with women who consumed less than 100 mg. This finding was consistent for consumption across all trimesters. Women who reduced their caffeine intake had infants with a higher mean birth weight, relative to those who maintained their prepregnancy intake.

The authors suggest that women who are contemplating pregnancy should consume fewer caffeinated foods and beverages. "Once pregnancy is confirmed, they should make every effort to stop or markedly reduce caffeine consumption."


Maternal caffeine intake during pregnancy and risk of fetal growth restriction: a large prospective observational study
- BMJ 2008;337:a2332

To examine the association of maternal caffeine intake with fetal growth restriction.

Prospective longitudinal observational study.

Two large UK hospital maternity units.

2635 low risk pregnant women recruited between 8-12 weeks of pregnancy.

Quantification of total caffeine intake from 4 weeks before conception and throughout pregnancy was undertaken with a validated caffeine assessment tool. Caffeine half life (proxy for clearance) was determined by measuring caffeine in saliva after a caffeine challenge. Smoking and alcohol were assessed by self reported status and by measuring salivary cotinine concentrations.

Main outcome measures
Fetal growth restriction, as defined by customised birth weight centile, adjusted for alcohol intake and salivary cotinine concentrations.

Caffeine consumption throughout pregnancy was associated with an increased risk of fetal growth restriction (odds ratios 1.2 (95% CI 0.9 to 1.6) for 100-199 mg/day, 1.5 (1.1 to 2.1) for 200-299 mg/day, and 1.4 (1.0 to 2.0) for >300 mg/day compared with <100 mg/day; test for trend P<0.001). Mean caffeine consumption decreased in the first trimester and increased in the third. The association between caffeine and fetal growth restriction was stronger in women with a faster compared to a slower caffeine clearance (test for interaction, P=0.06).

Caffeine consumption during pregnancy was associated with an increased risk of fetal growth restriction and this association continued throughout pregnancy. Sensible advice would be to reduce caffeine intake before conception and throughout pregnancy.