#14 Getting to the Heart of Injection Drug Use Associated Infectious Endocarditis with Dr. Ayesha Appa

July 20, 2023 | By Shawn Cohen

Audio

Video

Bring some heart to the care of people with IDU-IE. Learn how to provide person-centered care addressing both the acute infection and SUD and when/how to advocate for surgical treatment. We’re joined by Dr. Ayesha Appa @AyeshaAppaMD, (UCSF)

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Show Segments

• Intro, disclaimer: 00:00 
• Guest Bio: 02:57
• Case from Kashlak: 04:30
• Differential and diagnosis: 05:52
• Epi of IDU-IE 10:17
• Taking a history: 14:02
• Harm Reduction Counseling: 19:22
• CT Surgery Evaluation: 22:22
• Hospital initiation of MOUD: 27:52
• IE Treatment Options: 31:52
• Cool New Antibiotics: 39:12
• Discharge Assessment and Planning: 46:12
• Guest one-liner, Lightning Round: 52:48
• Outro: 56:58

Injection Drug Use Associated Infectious Endocarditis Pearls

1. History about the specifics of how someone uses drugs can be helpful both for microbiological clues and for education for future prevention.
2. History taking can be iterative, it does not need to be completed in a single interaction and often shouldn’t be as we address urgent things (withdrawal, pain) to help make someone comfortable to have a longer discussion 
3. Have a low threshold to involve CT surgeons for their evaluation,  even if someone doesn’t meet strict surgical indications
4. General indications for surgery for endocarditis are the 3Ss – Structural problems cause by the infection, Size of vegetation, and Stickiness of the organism.
5. Multidisciplinary endocarditis teams can improve overall care by helping address the whole person (infection treatment, surgical considerations, addiction treatment, SDOH…)
6. Initiating MOUD for OUD is CRITICAL in patients who are interested, as it reduces mortality and is as important as antibiotics
7. Antibiotic courses are generally LONG (4-6 weeks) with IV being the gold standard
8. Discussions about the course of antibiotic treatment should balance providing the gold standard of treatment with patient preferences and feasibility
9. When daily infusions are infeasible or discordant with patient preferences, consider long-acting IV antibiotics (like dalbavancin) or certain oral antibiotics as evidence-based alternatives.
10. Injection drug use is not a contraindication for PICC placement and should be considered in select patients 

Getting to the Heart of Injection Drug Use Associated Infectious Endocarditis (IDU-IE) Notes 

Workup & Diagnosis

For a detailed discussion of diagnosis including an amazing infographic on Duke Criteria and a discussion of when to get a TEE check out OG Curbsiders #312 Infective Endocarditis.

Dr. Appa brings up a few key and critical points when working up a person who injects drugs (PWID) presenting with infectious symptoms

• Blood cultures before starting antibiotics improve the detection of a pathogen (Scheer 2018)
• The differential is broad and can be framed as to which anatomic compartments may be seeded by bacteremia: valves/endocardium, epidural space, pleural space, joints, etc. 
• The physical exam is important for assessing the location of the infection and should include an examination of the specific anatomic compartments above
• The interesting immunologic exam findings (Osler nodes, Roth spots) we were all taught in medical school generally imply subacute disease so may not be seen in most cases of acute bacterial endocarditis that is characteristic of IDU-IE (Baddour 2015)

Epidemiology

Much of the data around IDU-IE compares epidemiology and outcomes to a population of people with endocarditis who do not inject drugs. In general, people admitted with IDU-IE tend to be younger with fewer comorbidities (Pericàs 2021). Mortality in people with IE not related to IDU is a bit higher, but this is likely related to prior health status. The mortality of IDU-IE at 6 months is still shockingly high at 14%!!! (Pericàs 2021)

Admissions for IDU-IE are increasing and increasing fastest among younger people so it’s critical we learn to effectively address and prevent this! (Wurcel 2016, McCarthy 2020) 

Specific History

As Dr Appa says ID is all about the “microbiologic origin story” obtained via a thorough history. However, it’s important to get this history in a way that makes sense for the patient sitting in front of you. She emphasizes that getting this information should be iterative (can be completed over multiple visits) and management-focused (first questions should focus on things that will immediately change treatment). This means getting the meat of an infection risk-focused substance use history can be delayed while starting broad-spectrum antibiotics, addressing withdrawal, and managing pain 

When someone is feeling well enough to have the conversation, you can ask them to walk through how they use it in a step-by-step manner. 

• Do they clean their skin and wash their hands before injecting?
• Where do they source their water?
• What do they use for a cooker?
• What do they use for a filter?
• Do they share any supplies?
  • Needle, syringe, cooker, filter/cotton

For a great walkthrough of how to inject more safely check out Table 1 in this paper. (Chan 2022)

Subsequent education can be tailored to provide specific safer-use strategies (Harvey 2022). Whether or not the pathogen causing the infection clearly fits the risk (not cleaning skin and skin flora like staph aureus causing infection), this represents an important opportunity to facilitate safer use. 

Treatment of IDU-IE should have two equal focuses which we go into below- treatment of the infection (antibiotics +/- surgery) and treatment of substance use disorder

When to think about surgical evaluation

Surgical considerations are specific to the side of the valve infected (left vs right), whether the valve is native or prosthetic, and complications of the infection (Baddour 2015). Indications for surgery are identical for IDU-IE and non-IDU-IE (AATS Surgical Treatment of Infective Endocarditis Consensus Guidelines Writing Committee Chairs 2015)

Dr. Appa uses the 3S’s to help her remember indications for surgery – Structure, Size, and Stickiness

• Structural compromise of heart or tissue=new heart failure, heart block, abscess
• Size of the vegetation. R-sided>2.0cm, L-sided>1.0cm and particularly if on the anterior leaflet of the mitral valve or if increasing in size on appropriate therapy
• Stickiness of the infection or how difficult it is to treat. This refers to specific organisms (Candida, MDR GNRs) or cultures positive 1 week into treatment without an alternative source

In general, have a low threshold to involve CT surgeons for their perspective even if not meeting criteria exactly.

Multidisciplinary Care

Multidisciplinary teams dedicated to the evaluation and treatment of IDU-IE should be the standard of care. (Weimer 2021, Vyas 2022, Baddour 2022). These teams include perspectives from addiction medicine/psychiatry, infectious disease, cardiac surgery, nursing, social work, recovery coaches, peer support specialists, and others to discuss important points in immediate management (ie. surgical decisions) and to address the whole person’s needs including creation of a feasible follow-up plan.

It is worth noting that stigma against people who use drugs and people with substance use disorder(s) is pervasive, including among healthcare providers. Despite indications for surgery being identical for endocarditis whether or not it is related to drug use (AATS Surgical Treatment of Infective Endocarditis Consensus Guidelines Writing Committee Chairs 2015), one survey found that some cardiothoracic surgeons are less likely to offer repeat valve surgery to a person who uses drugs (Tiako 2021). Dr. Appa suggests that if you feel your patient is not receiving evidence-based evaluation and treatment, to consider transfer to a site where this care is more regularly offered.

Addressing their Substance Use Disorder

As Dr. Appa so eloquently puts it “we need to shift our perspective from one that is infection centric, and rather one that is use disorder and infection, whole person-centric”. A perspective that’s been echoed by others. (Serota 2017). For some context, one study (done by Dr. Appa!) showed that in 80 people with Staph Aureus IDU-IE who had a patient-directed discharge, there were no deaths related to infectious complications but nearly 10% died from an overdose. (Appa 2022). Clearly addressing the SUD should be the standard of care!!

For a person with OUD, addressing withdrawal and initiating MOUD (medications for opioid use disorder) in the hospital is critical and lifesaving. There is a wealth of data on the benefits of methadone and buprenorphine for OUD including reducing mortality by 50% (Pearce 2020, Sordo 2017) and hospitalization is a reachable moment to start treatment (Velez 2016). Some data specific to IDU-IE, receipt of MOUD after hospitalization was associated with reduced mortality in the month MOUD was received (Kimmel 2020). 

For a more detailed discussion see OG Curbsiders episode #224 Hospital Addiction Medicine and

OG Curbsiders episode #366 Opioid Use Disorder and Acute Pain in the Hospitalized Patient. In brief, if the person you’re seeing has an opioid use disorder/uses opioids regularly, they are going to go into withdrawal and will have an “opioid debt”. Opioids MUST be offered/provided to address pain and withdrawal with options including:

• Starting methadone with additional short-acting opioids for withdrawal and pain
• Using short-acting opioids alone to address both withdrawal and pain – an evidence-based practice associated with reduced premature discharges (Thakrar 2023)
• Starting buprenorphine with additional short-acting opioids for withdrawal and pain. As Dr. Appa notes this can be a little bit trickier as generally opioid withdrawal is required to start buprenorphine, but there are other methods to start it as well (see the upcoming episode on low-dose initiation of buprenorphine, Cohen 2021)

If someone is already on methadone or buprenorphine, they should be continued and doses can be adjusted to effectively treat OUD with additional short-acting opioids for pain and withdrawal.

Antibiotics and where to get them

Antibiotic choice and the length of treatment are generally dependent on the pathogen and valve involved as well as on other infectious complications (Baddour 2015). In general, expect 4-6 weeks of antibiotics with the gold standard generally being IV therapy but this should be guided by an ID consultation.

Unfortunately, disposition options for these prolonged IV antibiotic courses are often limited by stigma and discrimination. Placement of a PICC and home infusion antibiotics are often not offered due to perceived risk despite studies showing this is a feasible option for some (Appa 2022, Suzuki 2018, D’Couto 2018). Discharges to skilled nursing facilities to complete antibiotics are often limited by outright discrimination (Kimmel 2021) which is both common and illegal (Cohen 2023). Staying in the hospital to complete therapy is often not desirable or possible.

Dr. Appa’s approach is imagining a matrix of routes of antibiotic (IV, long-acting, PO) on one axis and setting on the other (home, SNF/STR, hospital, co-located addiction medicine ID clinic or treatment program). The goal is to have the most evidence-based route in the least restrictive/limiting setting. If that’s not possible, then a discussion with the patient about matching options and their goals is important. Being in a facility for 4-6 weeks isn’t always possible for people, both from a comfort perspective and from a responsibilities perspective (work, childcare, pet care, etc.). An amazing resource to guide this discussion and antibiotic options is the recently published AHA scientific statement on IDU-IE. (Baddour 2022) Check out Figure 2 for a schematic guiding an approach to non-IV antibiotic options and Table 4 for alternative antibiotic choices in the setting of Staph Aureus Infection.

One key point Dr. Appa emphasizes is that a patient’s decision to not complete weeks of IV antibiotics in the hospital (or prematurely discharging for other reasons) does not mean they should be abandoned. Ideally, discussions about alternative treatment should happen in advance but even in the case of a sudden premature discharge, it remains our responsibility to offer alternative antibiotic options, connect them with addiction care and other necessary close follow up. Treatment is always better than no treatment!

Alternatives to prolonged IV antibiotics

When IV antibiotics can’t be completed for the recommended duration the two alternative options are long-acting lipoglycopeptides and oral antibiotics.

Long-acting lipoglycopeptides are weekly antibiotic infusions that have a similar spectrum of activity as vancomycin. The two currently available are dalbavancin and oritavancin. The data is generally positive and more robust for dalbavancin but remains predominantly observational, particularly in the setting of treating IDU-IE. (Cooper 2021)

It is clear that discharge on oral antibiotics, even if not the gold standard, can be an effective treatment particularly in the setting of premature discharge (Freling, 2023). One observational study found that among PWID with an invasive infection, there was no difference between readmission rates between the group who completed IV therapy and the group who left prematurely and were given oral antibiotics to complete the course. Those not given oral antibiotics on premature discharge had higher readmission rates than both other groups. (Marks 2020) This should be the nail in the coffin for the nonsense practice of not prescribing medications including antibiotics if a patient is prematurely discharged!

Dr. Appa frames it as: If you are stepping down to oral antibiotics, you want the right antibiotics (appropriate spectrum of activity, bioavailability, tissue penetration, clinical experience) for the right reasons (urgently leaving the hospital, shared decision making as above). Be proactive in working with ID consultants early to have a contingency plan in case this happens and have open communication with your patient including getting contact information to follow up. 

Links/Plugs

1. ID Addiction med partnerships (Serota 2020)
2. Contingency Management for Stimulant Use (check out Episode #5 Amp Up Your Treatment of Stimulant Use Disorder)
3. Chief Resident Immersion Training at BMC (CRIT)

Goal

Listeners will develop a mental model to provide person-centered and evidence-based care for people with injection drug use-associated infective endocarditis that addresses both the infection and underlying substance use disorder.

Learning objectives

After listening to this episode listeners will…  

1. Develop an approach to history taking specifically around infectious risks in a patient with IV substance use presenting with concern for infection 
2. Identify the indications for surgery in IDU-IE and describe how to partner with CT surgeons
3. Define the appropriate antibiotic course and options for antibiotic therapy

Disclosures

Dr. Appa reports no relevant financial disclosures. The Curbsiders report no relevant financial disclosures. 

Citation

Cohen SM, Appa A, Leyde S, Chan, CA. “#14 Getting to the Heart of Injection Drug Use Related Infectious Endocarditis”. The Curbsiders Addiction Medicine Podcast. https://thecurbsiders.com/addiction July 20th, 2023.