Thursday December 31, 2009


Case: Define chylothorax and describe different treatment modalities?

Answer: Chylothorax is defined as triglycerides more than 113 mg/dl (1.24 mmol/L) in pleural cavity.

A number of therapeutic interventions have been used to reduce chyle production and promote resolution of a chylothorax. Initial management typically includes restriction or temporary cessation of enteral feedings. Enteral feedings high in medium-chain triglycerides (MCT), or parenteral nutrition may be used. Total parenteral nutrition typically results in resolution in 75 to 80% of cases by that time. In resistant cases, pleurodesis, ligation of the thoracic duct, or placement of drains and pleuroperitoneal shunts may be considered.

Octreotide has become another option for management of patients with chylothorax. Although the exact mechanism by which the drug exerts its effects has not been defined, it is believed that the multiple effects of octreotide on the gastrointestinal tract and the reduction in splanchnic blood flow reduce thoracic duct flow and decrease the triglyceride content of chyle.

Wednesday December 30, 2009


Case: 38 year male presented to ER with severe chest pain. Patient informed you that he carries the diagnosis of Loeys-Dietz syndrome. What is your concern?

Answer: Aortic aneurysm rupture

Loeys-Dietz syndrome is an autosomal dominant genetic syndrome which has many features similar to Marfan syndrome, which is caused by mutations in the genes encoding transforming growth factor beta receptor 1 (TGFBR1) or 2 (TGFBR2). The disorder was first observed and described by Dr. Bart Loeys and Dr. Hal Dietz at the Johns Hopkins University School of Medicine in 2005.

Many of the physical findings typical in Loeys-Dietz syndrome are also found in Marfan syndrome cases, including increased risk of ascending aortic aneurysm and aortic dissection, abnormally long limbs and fingers, and dural ectasia (a gradual stretching and weakening of the dura mater that can cause abdominal and leg pain). However, it also has some additional traits not typical of Marfan patients, including widely spaced eyes, a split uvula in the back of the throat, and skin findings such as easy bruising or abnormal scars.

Bonus Pearl: Animal research has suggested that the angiotensin II receptor antagonist losartan, which appears to block TGF-beta activity, can slow or halt the formation of aortic aneurysms in Marfan syndrome 1. A large clinical trial sponsored by the National Institutes of Health is currently underway to explore the use of losartan to prevent aneurysms in Marfan syndrome patients. Both Marfan syndrome and Loeys-Dietz syndrome are associated with increased TGF-beta signaling in the vessel wall. Therefore, losartan also holds promise for the treatment of Loeys-Dietz syndrome.

References:

1. Losartan in Marfan's syndrome - Clinicaltrial. gov

Tuesday December 29, 2009
Association Between ICU Admission During Morning Rounds and Mortality

Background: No previous study has evaluated the association between admission to ICUs during round time and patient outcome. The objective of this study was to determine the association between round-time ICU admission and patient outcome.

Methods: This retrospective study included 49,844 patients admitted from October 1994 to December 2007 to four ICUs (two surgical, one medical, and one multispecialty) of an academic medical center. Of these patients, 3,580 were admitted to the ICU during round time (8:00 am to 10:59 am) and 46,264 were admitted during nonround time (from 1:00 pm to 6:00 am). The medical ICU had 24-h/7-day per week intensivist coverage during the last 2 years of the study. We compared the baseline characteristics and outcome of patients admitted to the ICU between the two groups. Data were abstracted from the acute physiology and chronic health evaluation (APACHE) III database.

Results: The round-time and non–round-groups were similar in gender, ethnicity, and age.

• The predicted hospital mortality rate of the round time group was higher (17.4% vs 12.3% predicted, respectively).
• The hospital length of stay was similar between the two groups.
• The round-time group had a higher hospital mortality rate (16.2% vs 8.8%, respectively).
• Most of the round-time ICU admissions and deaths occurred in the medical ICU.
• Round-time admission was an independent risk factor for hospital death (odds ratio, 1.321; 95% CI, 1.178 to 1.481). This independent association was present for the whole study period except for the last 2 years.

Conclusions: Patients admitted to the ICU during morning rounds have higher severity of illness and mortality rates.


Association Between ICU Admission During Morning Rounds and Mortality - CHEST December 2009 vol. 136 no. 6 1489-1495

Monday December 28, 2009
Tips on use of Atropine in AV conduction block

Atropine is useful in treating second-degree heart block Mobitz Type 1 (Wenckebach block), and also third-degree heart block with a high Purkinje or AV-nodal escape rhythm.

• It is usually not effective in second-degree heart block Mobitz type 2, and in third-degree heart block with a low Purkinje or ventricular escape rhythm.
• Atropine is contraindicated in ischemia-induced conduction block, because the drug increases oxygen demand of the AV nodal tissue, thereby aggravating ischemia and the resulting heart block.

Sunday December 27, 2009
About Dabigatran

Dabigatran is an anticoagulant from the class of the direct thrombin inhibitors. It is being studied for various clinical indications and may replace warfarin as the preferred anticoagulant in many cases. Unlike warfarin it works right away and does not require INR monitoring.

Phase 3 clinical trials are ongoing in treatment and prevention of secondary venous thromboembolism (VTE) in post-operative orthopedic patients; long-term prophylaxis in acute coronary syndrome and stroke patients with atrial fibrillation and symptomatic VTE because of various causes. Dabigatran at doses of 150 mg and 220 mg once daily when compared with the standard 40 mg dose of enoxaparin once daily, confirmed that dabigatran performed as well as enoxaparin in preventing thrombosis, with a similar risk profile.

Absorption is unrelated to food but may be decreased if taken with a proton pump inhibitor. Metabolism is slowed in people taking quinidine, verapamil, or amiodarone.

Approval from FDA is expected in 2010.

Saturday December 26, 2009
About Tolvaptan (Samsca)

Tolvaptan (Samsca) is the first oral dosage form in a class known as “selective vasopressin antagonists.” These drugs, also referred to as “vaptans,” cause renal elimination of water without increasing urinary excretion of sodium or potassium. An injectable vaptan, conivaptan (Vaprisol), has been available in the U.S. since 2006. Both conivaptan and tolvaptan are indicated for the treatment of hyponatremia. In addition, tolvaptan has been studied for treating heart failure.

Once-daily Samsca has been shown to significantly raise serum sodium concentrations in as early as 8 hours, and the change was maintained for 30 days. Exposure and response to Samsca are similar in patients with a creatinine clearance of 10-79 mL/min and in patients without renal impairment; thus no dosage adjustment is necessary.

The unique mechanism of action of Samsca selectively blocks the binding of vasopressin to the V2-receptors in the collecting duct of the kidney. If the V2-receptors are left unblocked, the binding of vasopressin with these receptors can cause water retention resulting in hyponatremia. By inhibiting the effects of vasopressin at the V2-receptor, Samsca increases the excretion of free water, while the excretion of sodium and other electrolytes is not directly affected (aquaresis).

Friday December 25, 2009


Merry Christmas