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Pyomyositis and BiPAP/Diuretic Strategies in CHF - 8/22/2012

posted Aug 20, 2012, 3:13 PM by Rohit Das   [ updated Dec 27, 2012, 7:05 AM by Purnema Madahar ]

Hope everyone had a good weekend…let’s get back to it…

At resident report, Mary presented a patient with HIV/AIDS who presented with L thigh pain, and on imaging, had findings consistent with pyomyositis. Exam also showed isolated follicular skin lesions, and a significant TR murmur, with subsequent TEE showing a possible vegetation around the tricuspid valve. Cultures from CT guided drainage of the involved part of this patient’s left thigh grew MRSA. He denied any history of IVDA. A review article reviewing the epidemiology of pyomyositis (PM) is attached.

  • Very interestingly, PM was initially described as a disease of the tropics until AIDS hit the scene. Since the 1980s, pyomyositis has been increasing in frequency in temperate climates, and almost exclusively in AIDS patients.
  • In the attached series, among HIV patients, 95% were male, 36% had associated IV drug abuse, and presentations were generally in the lower extremity (68%, of which 43% were in the thigh). 70% of cases were due to Staph. There was a 3% mortality in this series, and a 19% recurrence rate.
  • True pyomyositis is always due to hematogenous spread from other sites of infection, and there are often (couldn’t find numbers) other sequelae of bacteremia (like endocarditis, as exemplified in this patient).

As mentioned, this patient had associated tricuspid regurgitation, of new onset. From TEE findings as well as the presence of other manifestations of hematogenous seeding, he most likely has right-sided endocarditis. Dr. LeFrancois went over some of the key exam findings for TR, and just to put some numbers to it:

  • Murmurs louder with inspiration are very characteristic of right sided murmurs, with a +LR of 8.
  • Systolic regurgitant wave in the jugular veins (i.e., CV-merger) has a +LR of around 7. Finally, a pulsatile liver on exam is also helpful, with a +LR of around 4.

Given the high likelihood of right-sided endocarditis, as described, Mary’s patient is going to receive 6 weeks of Vancomycin, which is the recommended regimen (some debate over whether Rifampin should be added…).

This patient also brought about a very interesting and extremely difficult to answer question – what’s the epidemiology around native valve endocarditis in non-IVDA patients with HIV? Yea – not much literature folks, as this is an extremely rare phenomenon. I pulled up one case series, quick summary:

  • In a 20 year period, the investigators reviewed HIV associated endocarditis diagnosed at their institution. Of almost 600 cases of HIV-associated endocarditis, ONLY EIGHT were not related to IVDA. They also reviewed the literature during the same time period, and only found 14 cases.
  • Of those 22 cases overall, only ONE was due to MRSA, with a coexisting documented “soft tissue” infection as the likely source. The most common pathogens were Non-typhi Salmonella and Strep. Pneumoniae, which in the setting of invasive infection, are AIDS-defining pathogens.
  • Bottom line – there isn’t much literature to go on and making any conclusions on this special cohort of patients is purely speculative. However, HIV itself is probably not a risk factor for IE, as HIV-associated IE is still rare in the absence of IVDA. Also, when it does occur, it may be due to AIDS-defining pathogens, as opposed to the typical organisms we usually think about (i.e., Staph and Strep).

We also had in promptu resident journal club today, and talked about some literature regarding management of CHF. Here’s a summary:

  • In 2007, investigators looked at noninvasive ventilation (CPAP or NIPPV) in the acute management of decompensated heart failure, versus standard of care (oxygen supplementation). There were three intervention arms, about 350 patients in each.
    • Analyzing for a primary outcome of death within 7 days, there was no difference between either standard therapy and noninvasive ventilation (Odds Ratio – 0.97, p = 0.87).
    • Analyzing for a composite primary outcome of death/intubation within 7 days , there was no difference between CPAP and NIPPV  (Odds Ratio – 0.94, p=0.81)
    • However, we did talk about several limitations of this study, including that it was a bit underpowered and didn’t account well for potential confounding coexisting illnesses.
  • We also looked at the “DOSE” trial from 2011, in which different modes of diuresis were compared in acute CHF management. Specifically, bolus vs continuous and low vs high dose (defined as 2.5 times patients’ home dose) were compared. The primary outcomes were CHF symptom assessment (quanitified by area under the curve analyses) and change in serum Creatinine.
    • Regarding bolus vs continuous, there was no difference in overall symptoms improvement in 72 hours, nor a significant different change in creatinine between the two groups.
    • Regarding low vs high dose, there was no difference in either outcome as well (though a nonsignificant trend towards improving symptom assessment scores was observed). High dose diuresis did lead to significantly decreased dyspnea scores, and increased change in weight and net fluid loss (these were all secondary outcomes).

Some really good stuff today. More tomorrow…Keep reading!!!

Bacterial Pyomyositis in the United States
Crum, Am J Med 2004, Volume 117: 420-428

Losa et. al., Clin Microbiol Infect 2003: 45-54

Gray et. al., NEJM 2008 Volume 359: 142-151

Felker et. al., NEJM 2011 Volume 364: 797-805
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