2009年5月29日 星期五

Anticholinergic toxidrome

The symptoms of an anticholinergic toxidrome include blurred vision, choreoathetosis, coma, decreased bowel sounds, delirium, dry skin, fever, flushing, hallucinations, ileus, memory loss, mydriasis (dilated pupils), myoclonus, psychosis, seizures, and urinary retention. Complications include hypertension, hyperthermia, and tachycardia. Substances that may cause this toxidrome include antihistamines, atropine, benztropine, datura, tricyclic antidepressants, and scopolamine.

Due to the characteristic appearance and behavior of patients with this toxidrome, they are colloquially described as "Hot as a Hare, Dry as a Bone, Red as a Beet, Mad as a Hatter, Blind as a Bat".

Cholinergic toxidrome

The symptoms of a cholinergic toxidrome include bronchorrhea, confusion, defecation, diaphoresis, diarrhea, emesis, lacrimation, miosis, muscle fasciculations, salivation, seizures, urination, and weakness. Complications include bradycardia, hypothermia, and tachypnea. Substances that may cause this toxidrome include carbamates, mushrooms, and organophosphates.

Common mnemonics for organophosphate poisoning include the "killer B's" of bronchorrhea and bronchospasm because they are the leading cause of death, and "SLUDGE" - Salivation, Lacrimation, Urination, Diaphoresis or diarrhea, Gastrointestinal distress, and Emesis.

2009年5月27日 星期三

Hydrocortisone during Sepsis

On the basis of available evidence, current recommendations, and good clinical practice (and irrespective of the results of adrenal testing), the author, S.R. Bornstein, recommends that moderate doses of hydrocortisone (200 to 300 mg per day) should be given soon after the onset of septic shock in patients who remain hypotensive after adequate administration of fluids and vasopressor agents. Current evidence is insufficient to recommend the replacement of other steroids such as mineralocorticoids and adrenal androgens, which are also suppressed in patients with sepsis.

2009年5月26日 星期二

Kawasaki disease

Kawasaki disease-commonest cause of acquired heart disease in young children

Kawasaki disease may be rare, but it's now the commonest cause of acquired heart disease in children under 5. It's an acute, self limiting, multiorgan vasculitis of unknown cause. The problem is the vasculitis tends to affect coronary arteries and can cause sudden death if untreated. Immunoglobulins and aspirin reduce cardiac complications significantly.Diagnosis is essentially clinical-fever for five days and at least 4 of the following:Red eyes (bilateral conjunctivitis, no pus) Sore red mouth, red cracked lips, and classically a "strawberry" tongue with protuberant papillaePolymorphous maculopapular skin rashCervical lymphadenopathy, usually unilateral and >1.5 cm in diameterErythema and oedema of the hands and feet (with desquamation of the skin in the later stage of the illness).

Source: Heart 2009;95:787-792

2009年5月22日 星期五

Urine calcium oxalate crystals

What type of ingestion is accompanied by calcium oxalate crystals in the urine?
Ethylene glycol is metabolized to oxalic acid, which may combine with ionized calcium in plasma to form calcium oxalate crystals, which can be evident in the urine. Calcium oxalate can precipitate in the renal tubules and is considered to be involved in ethylene glycol-induced renal injury.

How do you calculate the osmolal gap?
A: Osmolal gap = measured serum osmolality – calculated serum osmolarity. To calculate serum osmolarity use the following formula: Serum osmolarity = ([2 × sodium] + [BUN ÷ 2.8] + [glucose ÷ 18.1]).


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New England Journal of Medicine - Vol. 360, No. 21, May 21, 2009

Ethylene Glycol Poisoning

Signs and Symptoms:
The principal clinical features of ethylene glycol poisoning are some degree of inebriation or alternation of consciousness, a profound metabolic acidosis, and acute renal failure. In severe cases, clinical hypocalcemia, multiorgan-system failure, and death occur. Methanol poisoning can cause metabolic acidosis, visual changes that may progress to blindness, and multiorgan-system failure and death. Untreated methanol poisoning is associated with a rate of death of 28% and a rate of visual deficits or blindness of 30% in survivors.


Antidotes for Methanol or Ethylene Glycol Ingestions:
Both ethylene glycol and methanol are primarily metabolized through the hepatic enzyme alcohol dehydrogenase. Either ethanol or fomepizole (4-methylpyrazole) can be used to inhibit alcohol dehydrogenase. Fomepizole was approved in the United States for the treatment of ethylene glycol poisoning in 1997; in 2000, an indication for methanol toxicity was added. Hemodialysis is an important adjunctive therapy for any ethanol-treated patient with a serum concentration of ethylene glycol or methanol of at least 50 mg per deciliter, significant academia, renal failure, or visuals signs or symptoms. Fomepizole has obviated the need for hemodialysis in many patients.

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New England Journal of Medicine - Vol. 360, No. 21, May 21, 2009

Elevated Troponin

What else can cause myocardial necrosis (and elevated serum markers) besides coronary artery disease?

Although elevated serum markers indicate myocardial necrosis, they provide no insight into its cause. In some patients, myocardial necrosis is caused by disorders other than coronary artery disease (e.g., pulmonary embolism, decompensated heart failure, severe hypertension or tachycardia, anemia, and sepsis). During evaluation of a patient with a possible acute coronary syndrome, the presence of elevated serum markers should be assessed in conjunction with other variables to provide insight into its most likely cause.

GRACE risk model

What is the GRACE risk model for patients with acute coronary syndrome?

The Global Registry of Acute Coronary Events (GRACE) risk model uses eight variables to predict whether a patient hospitalized with acute coronary syndrome will die or have a myocardial infarction in the hospital or in the next 6 months. These variables are age, Killip class (a classification of the severity of heart failure with myocardial infarction), systolic arterial pressure, ST-segment deviation, cardiac arrest during presentation, serum creatinine concentration, elevated serum markers for myocardial necrosis, and heart rate.

The application tool is available at www.outcomes-umassmed.org/grace

TIMI Risk Score

The Thrombolysis in Myocardial Infarction (TIMI) risk score uses seven variables to identify patients with acute coronary syndromes who are at risk for death, myocardial infarction, or recurrent ischemia within 14 days after hospitalization.

These include age greater than 65 years, three or more risk factors for atherosclerosis, known coronary artery disease, two or more episodes of anginal chest pain in the 24 hours before hospitalization, the use of aspirin in the 7 days before hospitalization, ST-segment deviation of 0.05 mV or more, and elevated serum markers for myocardial necrosis (troponin or creatine kinase MB).

Patients with three or more of the seven variables are considered to be at high risk, whereas those with no more than two of the variables are considered to be at low risk.

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New England Journal of Medicine - Vol. 360, No. 21, May 21, 2009

STEMI versus NSTEMI

In patients with myocardial infarction with ST-segment elevation (STEMI), in which the infarcted artery is usually occluded and there is ongoing transmural ischemia, it is well established that the earlier primary percutaneous coronary intervention (PCI) can be performed, the lower the mortality. By contrast, in patients with acute coronary syndromes without ST-segment elevation (NSTEMI) including unstable angina and myocardial infarction, the culprit artery is often patent, there is usually no ongoing transmural ischemia, and the patient often has a good response to initial medical treatment. The optimal timing of such intervention has been uncertain.

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New England Journal of Medicine - Vol. 360, No. 21, May 21, 2009

Influenza A H1N1 "Swine Flu"

Early Estimate of Pandemic Potential of Influenza A H1N1 "Swine Flu"
The current virus is transmitted efficiently but probably is less lethal than past pandemic viruses.

A team of epidemiologists has analyzed the influenza A (H1N1) epidemic in Mexico. Data related to the outbreak were collected primarily in April and early May 2009. The researchers presented several tentative conclusions:
  • Cases outside of Mexico occurred most commonly in countries that had the highest volume of travelers from Mexico.
  • Attack rates of clinical disease are higher in children younger than 15 years than in adults (relative risk for children, 1.52). This finding suggests that, although the virus is novel, adults might have some protection due to cross-immunity from exposure to strains that have circulated in the past.
  • The virus is transmitted more efficiently from person to person than are usual seasonal flu viruses.
  • The estimated fatality rate is 0.4% — this virus is considerably less lethal than the virus that caused the 1918–1919 pandemic but somewhat more lethal than usual seasonal flu viruses.
Comment:
These data indicate that the current H1N1 virus is more transmissible and possibly more lethal than regular seasonal flu viruses, but it is considerably less transmissible and lethal than the catastrophic 1918–1919 pandemic virus. However, influenza viruses mutate rapidly, and this virus could change considerably in the coming months. The 1918–1919 virus also was mild when it first appeared in the spring of 1918, but it killed about 3% of people that it infected when it returned the next winter.


Anthony L. Komaroff, MDPublished in Journal Watch General Medicine May 21, 2009

Citation(s):Fraser C et al. Pandemic potential of a strain of influenza A (H1N1): Early findings. Science 2009 May 14; [e-pub ahead of print]. (http://dx.doi.org/10.1126/science.1176062)

2009年5月20日 星期三

The PERC score for PE

Differentiating Low-Risk and No-Risk PE Patients: The PERC Score
Christopher R. Carpenter, MD, MSC, FAAEM; Samuel M. Keim, MD, MS; Rawle A. Seupaul, MD; Jesse M. Pines, MD, MBA, MSCE; The Best Evidence in Emergency Medicine Investigator Group. Published: 05/14/2009

Abstract
Background: Pulmonary embolism (PE) remains one of the most challenging diagnoses in emergency medicine. The Pulmonary Embolism Rule-out Criteria (PERC) score, a decision aid to reliably distinguish low-risk from very low-risk PE patients, has been derived and validated.
Clinical Question: Can a subset of patients with sufficiently low risk for PE be identified who require no diagnostic testing?

Evidence Review: The PERC score derivation and validation trials were located using PubMed and Web of Science. A critical appraisal of this research is presented.
Results: One single-center and another multi-center validation trial both confirmed that the eight-item PERC score identified a very low-risk subset of patients in whom PE was clinically contemplated with a negative likelihood ratio 0.17 (95% confidence interval 0.11-0.25) in the larger trial. If applied, the rule would have identified 20% of potential PE patients as very low risk.

Conclusion: The PERC score provides clinicians with an easily remembered, validated clinical decision rule that allows physicians to forego diagnostic testing for pulmonary embolus in a very low-risk population.

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PERC Rule*
Age below 50 years
Pulse below 100 beats/min
Pulse ox above 94%
No unilateral leg swelling
No hemoptysis
No recent surgery
No prior DVT or PE
No oral hormone use
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PERC = pulmonary embolism rule-out criteria; min = minute; pulse ox = pulse oximeter reading; DVT = deep venous thrombosis; PE = pulmonary embolism.
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Reference:
http://www.medscape.com/viewarticle/702755_print

2009年5月19日 星期二

零感染破功 - 台東澳籍醫師確診


台灣出現首例新流感確定病例!這名男子是52歲的外籍醫師,4月前往美國紐約擔任郵輪船醫,5月17日從紐約到香港再到台灣,在飛機上就出現全身倦怠、流鼻涕、喉嚨痛的感冒症狀。入關篩檢體溫38.3度,直接送往署立桃園醫院隔離。根據了解,他是澳洲籍人士,不過已經在台東行醫20多年。

平地一聲雷,震壞了台灣新流感防疫網絡,因為嚴密防控,還是守不住第一起確認病例,境外移入台灣。疾管局發言人施文儀:「這個病例是一位外籍人士,52歲,他本身是一個醫生,平常在過去的這一些時間裡面,他是擔任遊輪的船醫。」

就是這一名52歲的男子,18日進入台灣之後,因為體溫達38.3度,又有美國旅遊史,被立即送往桃園署立醫院隔離觀察。

根據了解,他是在4月20號離開台灣抵達紐約,之後就上遊輪擔任船醫的工作,一直到5月17日一下船,就從紐約直接搭乘CX831先行到達香港,之後再由香港,轉乘CX468來到台灣。而疾管局推測,很有可能就是在遊輪上看病,被感染了H1N1新流感。

施文儀:「應該是在船上感染的,他是一個醫生,(在船上)也看了很多類流感的病人,那他所做的工作,其實他對這方面的專業,應該沒有問題,但是船上的旅客,在發生類流感的時候,或者是其他的疾病,肚子痛種種,也都是會找他看。」

這名澳洲男子表示,在從美國飛往香港之際,就發現自己有頭痛、倦怠、肌肉酸痛和一點咳嗽,原本以為只是長途飛行的不舒服,因此也沒戴上口罩。之後抵達台灣,沒有其他接觸史,就直接送往醫院。

施文儀:「檢體在(19日)下午3點左右,送到了實驗室,所以初步的結果,是在昨天晚間大概8點多9點,先做出了第一次RTPCR的陽性。」

謹慎起見,最後再做基因序列比對,到520凌晨4點,確認為新流感,疾管局承認,署桃送驗的動作的確還需要加快。而首例新流感的出現,也讓台灣防疫零病例,徹底被打破。

Nebulized 3% saline for acute bronchiolitis

Nebulized hypertonic saline solution for acute bronchiolitis in infants
Zhang L, Mendoza-Sassi RA, Wainwright C, Klassen TP

Acute viral bronchiolitis is the most common lower respiratory tract infection in infants, but the standard treatment remains supportive care. This review was conducted to assess the effects of nebulized hypertonic saline, which can increase clearance of mucus, in these patients. Four randomized trials involving 254 infants were included. Analysis of the pooled data suggests that nebulized 3% saline may significantly reduce the length of hospital stay and improve the clinical severity score in infants with acute viral bronchiolitis.There were no adverse effects noted with nebulized hypertonic saline when administered along with bronchodilators.

This version first published online: October 08. 2008 - Cochrane review abstract.

Background
Airway edema and mucus plugging are the predominant pathological features in infants with acute viral bronchiolitis. Nebulized hypertonic saline solution may reduce these pathological changes and decrease airway obstruction.

Objectives
To assess the effects of nebulized hypertonic saline solution in infants with acute viral bronchiolitis.

Search strategy
We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, issue 4), which contains the Cochrane Acute Respiratory Infections Group Specialized Register; OLDMEDLINE (1951 to 1965); MEDLINE (1966 to November 2007); EMBASE (1974 to November 2007); and LILACS (November 2007).

Selection criteria
Randomised controlled trials (RCTs) and quasi-RCTs using nebulized hypertonic saline alone or in conjunction with bronchodilators as an active intervention in infants up to 24 months of age with acute bronchiolitis.

Data collection and analysis
Two review authors (ZL, MRA) independently performed data extraction and study quality assessment. We pooled the data from individual trials using the Cochrane statistical package Review Manager (RevMan).

Main results
We included four trials involving 254 infants with acute viral bronchiolitis (189 inpatients and 65 outpatients) in this review. Patients treated with nebulized 3% saline had a significantly shorter mean length of hospital stay compared to those treated with nebulized 0.9% saline (mean difference (MD) -0.94 days, 95% CI -1.48 to -0.40, P = 0.0006). The 3% saline group also had a significantly lower post-inhalation clinical score than the 0.9% saline group in the first three days of treatment (day 1: MD -0.75, 95% CI -1.38 to -0.12, P = 0.02; day 2: MD -1.18, 95% CI -1.97 to -0.39, P = 0.003; day 3: MD -1.28, 95% CI -2.57 to 0.00, P = 0.05). The effect of nebulized hypertonic saline in improving clinical score was greater among outpatients than inpatients. No adverse events related to 3% saline inhalation were reported.

Authors' conclusions
Current evidence suggests nebulized 3% saline may significantly reduce the length of hospital stay and improve the clinical severity score in infants with acute viral bronchiolitis.

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This is a Cochrane review abstract and plain language summary, prepared and maintained by The Cochrane Collaboration, currently published in The Cochrane Database of Systematic Reviews 2009 Issue 2, Copyright © 2009 The Cochrane Collaboration. Published by John Wiley and Sons, Ltd.. The full text of the review is available in The Cochrane Library (ISSN 1464-780X).

This record should be cited as: Zhang L, Mendoza-Sassi RA, Wainwright C, Klassen TP. Nebulized hypertonic saline solution for acute bronchiolitis in infants. Cochrane Database of Systematic Reviews 2008, Issue 4. Art. No.: CD006458. DOI: 10.1002/14651858.CD006458.pub2.

2009年5月13日 星期三

Atrial Fibrillation and Stroke

Atrial fibrillation raises the risk of ischemic stroke by a factor of four to five, primarily as a result of cardioembolism of a fibrin-rich thrombus. (See figure below.) The annual rates of stroke among participants with atrial fibrillation in this study receiving clopidogrel plus aspirin was 2.4% and was 3.3% in patients receiving aspirin alone. These rates were both notably higher than those reported in previous studies among patients at high risk for stroke who received high-quality vitamin K–antagonist therapy (approximately 1.1 to 1.3%).

Oral Vitamin K Antagonists
Oral vitamin K antagonists are currently the most effective form of stroke-prevention therapy in patients with atrial fibrillation. However, vitamin K–antagonist therapy approximately doubles the risk of intracranial hemorrhage, is challenging to deliver in a high-quality fashion (i.e., maintaining an international normalized ratio of 2.0 to 3.0), and can diminish the quality of life because of frequent testing, dietary restrictions, and the possibility of drug–drug interactions.

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New England Journal of Medicine - Vol. 360, No. 20, May 14, 2009

2009年5月7日 星期四

Hypereosinophilic Syndrome

Hypereosinophilic Syndrome
The hypereosinophilic syndrome, defined as persistent eosinophilia (more than 1500 cells per cubic millimeter) of at least 6 months' duration leading to end-organ damage and without evidence of a clonal or reactive cause, is a diagnosis of exclusion. This syndrome is rare and accounts for less than 1% of eosinophilic diseases. It occurs predominantly in men and if, left untreated, usually has a progressive, fatal course. In hypereosinophilic syndrome almost any organ (including the bone marrow, heart, skin, and nervous system) can be affected either by eosinophilic infiltration or by thromboembolism.

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New England Journal of Medicine - Vol. 360, No. 19, May 7, 2009

2009年5月4日 星期一