COW Week 10

29yF presents with fever, sore throat, tonsillar exudate, anterior cervical LAD, no cough. Rapid strep negative. What is the next step? Pt has no allergies?

1) PCN V
2) Send Home
3) Send Throat Culture, start PCN
4) Augmentin

The correct answer is 2, Send Home. 

The IDSA just came out with new guidelines on September 9th 2012 for management of strep throat. GAS is the most common bacterial cause of acute pharyngitis, responsible for 5%–15% of sore throat visits in adults and 20%–30% in children. The main reason to treat strep throat is to decrease the chance of rheumatic fever and suppurative complications of strep throat. However, in adults, the chance of developing rheumatic fever is very small. We've all heard about the Centor criteria to diagnose strep throat. The 4 criteria are: Reported fever, anterior cervical LAD, lack of cough, tonsillar exudate. If the patient has 0 or 1 of these criteria this has pretty good negative predictive value and you can stop there. Generally, adults do not need to be tested for strep throat if they have a cough, runny nose, hoarseness and mouth sores, which are strong signs of a viral throat infection. However, strep and non strep symptoms have such overlap that even if a patient meets all 4 of the Centor criteria, there is a positive predictive value of only 35-55% leading to significant over treatment with abx that the IDSA says is unacceptable.  Because of this, treatment for strep throat should only be given with a positive diagnostic test, with rapid recommended over culture. If culture is chosen, you should wait until the culture is positive before giving abx even though it may delay treatment a couple days. Lastly, given the low frequency of strep complications in adults, a negative rapid strep test, even in the setting of 4 centor criteria, is enough to send the patient home without any further diagnostic studies. Cultures do not need to be sent to confirm the diagnosis.

The take home points are:
1) Rapid antigen/culture should be performed to diagnose and treat GAS pharygitis. Negative rapid should not be followed with a culture in adults.
2) Clinical Criteria has good negative predictive value, however, it is not specific enough to make a diagnosis alone.
3) PCN or Amoxicillin x 10 days is the treatment of choice for nonallergic patients
4) If PCN allergic, 10 day course of 1st generation cephalosporin, clindamycin, clarithromycin or 5 days of azithromycin can be used.

Click on the link below to see the new guidelines:
IDSA GAS Pharyngitis 2012 Guidelines

COW Week 9

37yo male complains of left leg painful swelling. Ultrasound confirms popliteal DVT. There was no antecedent trauma, surgery, hospitalizations, or trips. Family history is negative and thrombophilia workup is negative. After three months of warfarin therapy, what is the next step?

1. Continue Warfarin for 1 year
2. Stop Warfarin
3. Countinue Warfarin indefinitely
4. Stop Warfarin and start aspirin
5. Further diagnostic testing

After an idiopathic thrombotic event, the 10-year risk of recurrence is about 30 percent. The risk of major bleeding while on warfarin therapy is approximately 2 percent per year when warfarin is well managed. Therefore, it can be helpful to to further risk stratify patients which can be done with D-Dimer testing or lower extremity doppler ultrasound.

The Prolong Trial assessed using D-Dimer testing to determine the duration of anticoagulation. This was a prospective trial that evaluated 600 people with idiopathic DVT after 3 months of therapy with warfarin. Their D-Dimer was checked one month after stopping warfarin and if it was abnormal the patients were randomized to further anticoagulation or no therapy. The risk of venous thrombosis if you had a positive D-Dimer and you were left off of warfarin therapy was approximately 10 percent per year. A negative D-Dimer predicted a risk of recurrence of about 3 percent per year

The DACUS trial looked at 250 patients who had on warfarin for at least 3 months and then assessed residual thrombus by ultrasound. If there was residual thrombus, then they randomized patients either to resume warfarin or to stop warfarin; if there was no residual thrombus then they simply stopped warfarin therapy. Patient's without evidence of thrombosis had a low risk of DVT recurrence suggesting continued warfarin therapy was unnecessary in this group past the three month window.

The take-home points for unprovoked deep vein thrombosis are that the risk of recurrence is relatively high. The risk of major bleeding while on warfarin therapy is approximately 2 percent per year when warfarin is well managed. Using risk stratification tools such as D-Dimer and a duplex ultrasound for residual vein thrombosis can help guide your management.

Prolong Trial:
DACUS Trial: