A few ID pearls

1. A few ID pearls

2. A 37-year-old man presents for the evaluation of localized swelling and tenderness of the left leg just below the knee. He suspects this lesion developed after a spider bite, although he did not see a spider. Examination of the leg reveals an area of erythema and warmth measuring approximately 5 by 7 cm. At the center of the lesion is a fluctuant area measuring approximately 2 by 2 cm, overlaid by a small area of necrotic skin. The man's temperature is 38.3°C. The pulse rate is 115 beats per minute. The blood pressure is 116/78 mm Hg. How should this patient be evaluated and treated?

3. Risk Factors for MRSA • Recent ABX use. • Recent hospitalization • HD • IVDU • DM • Previous MRSA infection/colonization

4. Initial treatment • Best initial treatment • I&D of “small” abscesses • Small = less than 5cm in length • Randomized trial of 166 patients with uncomplicated skin abscesses at risk for community-associated MRSA (CA-MRSA) who were managed with cephalexin or placebo following incision and drainage of skin and soft tissue abscesses. • The cure rates were similar in the two groups (84 and 90 percent, respectively).

5. MRSA Skin and Soft Tissue Infections • Patients with larger areas of infection and/or systemic signs of infection should be managed with antimicrobial therapy. • Empiric therapy • Beta-lactam antibiotics are no longer reliable empiric therapy for skin and soft tissue infections. • Local incidence rate = 56%

6. Options for therapy • Clindamycin • Use caution if local resistance rate is 10-15% • TMP/SMX • Use based on observational study only • Tetracyclines (Doxy or Mino) • Also from observational/retrospective data • Linezolid • Rifampin

7. MRSA Skin and Soft Tissue Infections • Bottom line • I&D is essential for abscesses • Pay attention to local resistance patterns • Beta-lactams are no longer viable first choices for empiric treatment of at-risk patients • TMP/SMX is good parenteral option but evidence is observational. • Linezolid second choice for those that cannot tolerate first choice meds.

8. A 37 year old man comes to the clinic with a 7-day history of coarse productive cough, fatigue/malaise, sore throat, nasal congestion and runny nose, and mild shortness of breath. His medical history is unremarkable. His vital signs include a temp of 99.1, RR of 18 and BP of 125/78. Examination reveals slightly erythematous oropharynx and very faint wheezes on chest exam but is otherwise unremarkable. What is the most likely diagnosis and treatment?

9. A 37 year old man comes to the clinic with a 7-day history of coarse productive cough, fatigue/malaise, sore throat, nasal congestion and runny nose, and mild shortness of breath. His medical history includes poorly controlled diabetes, HTN, CAD and childhood asthma. His vital signs include a temp of 99.1, RR of 18 and BP of 125/78. Examination reveals slightly erythematous oropharynx and very faint wheezes on chest exam. There are multiple small pustular skin lesions over his trunk and legs which he says were diagnosed as “staph” by a previous physician. What is the most likely diagnosis and treatment?

10. A 37 year old man comes to the clinic with a 7-day history of coarse productive cough, fatigue/malaise, sore throat, nasal congestion and runny nose, and mild shortness of breath. His medical history includes HIV/AIDS, chronic diarrhea, and medical noncompliance. His vital signs include a temp of 99.1, RR of 18 and BP of 125/78. Examination reveals slightly erythematous oropharynx and very faint wheezes on chest exam but is otherwise unremarkable. What is the most likely diagnosis and treatment?

11. Epidemiology • Usual causes of AB: • Influenza A/B • Parainfluenza • Coronavirus • Rhinovirus • RSV

12. Stats • How many patients diagnosed with acute bronchitis are given antibiotics? • 60-70%

13. S pneumo, H flu, S aureus, M cat • “There is no convincing evidence to support the concept of "acute bacterial bronchitis" caused by these pathogens in adults, with the exception of patients with airway violations such as tracheostomy or endotracheal intubation, or those with exacerbations of chronic bronchitis.”

14. Acute Bronchitis • “Routine antibiotic treatment of uncomplicated acute bronchitis is not recommended. If pertussis infection is suspected (an unusual circumstance), a diagnostic test should be performed and antimicrobial therapy initiated.”

15. Acute Bronchitis Diagnosis • Productive cough as the essential symptom • Concurrent URI symptoms • Rhinitis, sore throat, hoarseness • Fever is unusual sign and may suggest pneumonia or influenza

16. AB vs pneumonia • When to order a CXR? • Abnormal VS (HR>100, RR>24, Temp>38C) • Rales or signs of consolidation on exam • Advanced age (>75 years)

17. Duration of cough • What if cough is present for 2 weeks? • Selected studies have recovered pertussis in up to 10% to 20% of patients with cough lasting longer than 2 to 3 weeks. • Clinicians should limit suspicion and treatment of adult pertussis to adults with a high probability of exposure to pertussis—for example, during documented outbreaks. • Pertussis may be suspected regardless of immunization history.

18. Treatment of AB • NSAIDs, Tylenol, nasal decongestants • Strong patient-physician relationship and good communication • Reassurance

19. Evidence against ABX for AB • A meta-analysis of 9 studies: • 5 of 9 showed no benefit of either doxycycline or erythromycin • 2 showed slight clinical differences in patients treated with erythromycin or TMP/SMX • 2 showed superiority of albuterol to erythromycin • A second meta-analysis showed a 0.6 day reduction in cough duration. • Another study showed Azithromycin and Vitamin C were equivalent.

20. Patient information • Because the prevailing thought among many patients is that “antibiotics will treat my cough”, patient information/hand-outs are available to provide further reassurance that they are being treated appropriately and in line with current recommendations.

21. A 57 year old man with cirrhosis is ready to go home after an ICU admission and treatment of acute variceal hemorrhage. He has never had a GIB before. Besides the usual medications aimed at preventing recurrent GI bleeding, should he take any other preventative medications?

22. Prophylaxis for SBP • Risk factors have been identified • AF protein concentration < 1 • Variceal hemorrhage • Prior episode of SBP • Most flora originate in the gut • Theory: Intestinal decontamination can reduce SBP incidence in at risk patients.

23. Does prophylaxis work? • Meta-analysis of 13 RCTs (hospitalized patients with cirrhosis with risk factors for infection) • Significant mortality benefit • RR 0.70, CI 0.56-0.89 • Significant reduction in SBP development • RR 0.39, CI 0.32-0.48 • Antibiotic prophylaxis in cirrhotic patients with gastrointestinal bleeding was studied via systematic review. • Significantly reduced SBP development, bacteremia and death.

24. Regimens • Single weekly Cipro vs placebo • 3.6 versus 22 percent • Bactrim DS 1 tab daily 5 days/week • 3 versus 27 percent • Continuous oral Cipro (reduced mortality and incidence of SBP at 12 months) • Continous TMP/SMX 1 tab daily • Inpatient-only use of norfloxacin with discontinuation at time of discharge.

25. Recommendations • Those with gastrointestinal bleeding • Cefotaxime IV until taking PO then switch to Norfloxacin PO x 7 days total. • Continuous quinolone or TMP/SMX in those who have had one or more episodes of SBP • Switch antibiotics if develops SBP on this regimen • Short-term norfloxacin or TMP/SMX (in-patient only) in those with cirrhosis and AF protein <1g/dl hospitalized for another reason.