Abstract surgical intervention, as medical therapy is unlikely

Abstract

Introduction: Infective
endocarditis (IE) is a serious complication of injection drug use. Right-sided
IE encompasses 5-10% of all IE cases, with the majority involving the tricuspid
valve (TV). The predominant causal organism is Staphylococcus aureus. Most cases of right-sided IE can be
successfully treated with antibiotics, but approximately 5-16% require eventual
surgical intervention.

Presentation of Case: We report the case of a 36-year-old female with active injection
drug use who developed methicillin-sensitive
Staphylococcus aureus IE of the tricuspid valve. Due to poor
adherence to medical therapy as a consequence of opioid addiction, she developed
septic emboli to the lungs and an abscess in the left main pulmonary artery.

Discussion: These
long-term potentially fatal, sequelae of incompletely treated IE require
surgical intervention, as medical therapy is unlikely to be sufficient. Surgical
management may involve TV replacement, pulmonary artery resection, and
pneumonectomy. Prevention of these complications may have been achieved by concurrent
opioid addiction therapy.

Conclusion: An
intravascular pulmonary artery abscess is a novel complication of advanced IE
that has not been previously reported. This complication likely arose due to
incomplete IE treatment as a consequence of opioid addiction, highlighting the
need for concurrent addiction management. Intravenous antibiotic therapy is
likely not adequate, and surgical intervention, including pulmonary artery
resection and pneumonectomy may be necessary. 

 

Introduction:

Tricuspid valve infective endocarditis (TVIE) is
a serious complication of injection drug use (IDU) with a mortality rate of
10-15% and potential for further deadly complications 1-3. Staphylococcus aureus accounts for
60-90% of cases of TVIE, with enterococci, streptococci, Pseudomonas, and HACEK organisms occurring less frequently 1,2,4.
Most cases of TVIE are treated medically, with only approximately 4% of all IE
surgeries in North America for TVIE 5. Surgical treatment is indicated in
cases of persistent and refractory infection with difficult to eradicate
organisms i.e. fungi 1,4. Additionally, large valve vegetations and septic
pulmonary emboli are indications for operative management 1. We report the
case of a patient with a history of active IDU who developed methicillin-sensitive Staphylococcus aureus
(MSSA) IE and Candida fungemia. After numerous unsuccessful attempts
to complete medical therapy, she subsequently developed septic pulmonary emboli,
proximal lung abscesses, and an abscess in the left main pulmonary artery. We
highlight the importance of concurrent treatment of opioid addiction with
intravenous antibiotic therapy in patients with IDU and deep-seated infections
to prevent long term complications, and review the literature to understand
potential surgical treatment of such sequelae.

 

Case Presentation:

A 36-year-old Caucasian female with a history of
active IV heroin use, anxiety, and depression presented to the emergency department
(ED) with one week of chest pain and shortness of breath. A trans-thoracic
echocardiogram revealed a 13 x 26 mm vegetation of the tricuspid valve (TV)
with moderate tricuspid regurgitation. She was treated with IV vancomycin and
cefepime, however left the hospital against medical advice (AMA) after one day,
feeling that her pain was poorly controlled. She presented to the ED again
within 24 hours with dyspnea and a productive cough. Chest x-ray revealed a
right middle lobe infiltrate. Blood cultures were drawn and grew MSSA (Fig. 1),
and she was admitted to the ICU on IV oxacillin. She completed one day of
therapy, once again leaving AMA.  She returned to the hospital one day
later with severe dyspnea.  Imaging revealed new septic emboli in the lung
fields (Fig. 2). The patient was admitted and completed an eight day course of
IV oxacillin. She was then discharged to a skilled nursing facility (SNF) with
a PICC line for continued medical treatment with oxacillin. She eloped from the
SNF after 12 days, returning to the ED for PICC removal. At that time she was
urged to stay for inpatient antibiotic therapy, but declined. Before leaving
the ED she was given one dose IM ceftriaxone and a ten-day course of oral
dicloxacillin.

 

Three weeks later, she presented to an
outpatient appointment with confusion and weakness. Blood cultures grew Candida
famata, and the patient was urged to report to the ED for treatment. She
was given one dose of caspofungin in the ED before leaving AMA. Blood cultures
drawn prior to administration of caspofungin subsequently grew Candida
parapsilosis, and the patient was again advised to return to the ED. She
was hospitalized on IV oxacillin and fluconazole and began to complain of
substernal chest pain. During this admission, she was found injecting heroin in
the hospital bathroom and required a 1:1 sitter with restricted visitation;
psychiatry was also consulted to evaluate capacity. Blood cultures remained
positive for MSSA throughout the hospital course, with no further growth of
Candida. Repeat chest x-ray during this admission showed multifocal airspace
opacities and continued cavitary lesions in the lung fields, improved from
previous imaging. She left AMA after seven days, deemed after formal
psychiatric evaluation to have decision-making capacity.

 

One week later she presented to the ED again in
extreme pain, and was found to be in septic shock. She was started on IV
fluids, vancomycin, caspofungin, and ceftriaxone in the ED and admitted to the
hospital where she began to complain of pleuritic chest pain. Chest x-ray
depicted bilateral pleural effusions and a developing cavitary focus of the
right lung apex. CT chest with IV contrast demonstrated multiple new solid
cavitary lesions bilaterally, a left sided loculated effusion, and a 1.8 cm
fluid attenuation within the left perihilar lung surrounding a consolidation,
suspicious for a septic intravascular pulmonary embolism with abscess formation
in the left main pulmonary artery (Fig. 3). Trans-esophageal echocardiogram
revealed a 1.9 x 1.5 x 1.5 cm multi-lobulated, highly mobile vegetation on the
anterior leaflet of the TV with severe regurgitation and possible leaflet
perforation.

 

Cardiothoracic surgery was eventually consulted
for potential surgical intervention, but the patient was considered a poor
surgical candidate due to her continued hemodynamic instability and history of
non-compliance to therapy. A repeat chest CT was obtained which showed proximal
right-sided lung abscesses and findings suspicious for additional emboli in the
segmental and subsegmental arteries of the right lower lobe. She was discharged
to a subacute nursing facility with a PICC line for six weeks of continued
medical treatment on IV cefazolin. Blood cultures remained negative for two
weeks prior to discharge. The patient completed her antibiotic course with one
relapse. Repeat imaging after completion of antibiotic therapy demonstrated a
large highly mobile vegetation of the tricuspid valve, unchanged in size from
previous studies, with continued severe tricuspid regurgitation.

 

Discussion:

To our knowledge this
is the first reported case of an abscess in the left main pulmonary artery as a
complication of IE. The development of this abscess demonstrates the importance
of completion of intravenous antibiotic therapy and the necessity of addiction
management in promoting patient compliance. This patient repeatedly withdrew
from medical therapy due to her heroin addiction and thus developed serious and life threatening complications of IE including TV perforation,
septic emboli, and an arterial abscess.

 

TV repair/replacement is a well-studied
treatment option for IE with the patient meeting criteria for stage D tricuspid
regurgitation (symptomatic, severe TR) and published indications for TV surgery
6. Studies have shown better peri-operative and event free survival with TV
repair as compared to replacement 1,8. Indications for replacement include
significant leaflet tethering, distortion of the valve, ventricular
dysfunction, or severe pulmonary hypertension. This patient, with possible TV
leaflet perforation, was likely more suitable for TV replacement 1,7,8.
Additionally, practice guidelines state that patients with right sided IE are
indicated for surgical intervention in cases of lack of response to
antimicrobial therapy, sustained infection with difficult to treat organisms
including fungi and multidrug resistant bacteria, TV vegetations > 20 mm,
and recurrent pulmonary emboli despite antimicrobial therapy 1,9. However,
guidelines also suggest that it may be reasonable to avoid surgery in right
sided IE in patients with a history of IDU 9.

 

Septic emboli occur in approximately 13 to 44
percent of patients with IE 10. Treatment of septic emboli involves
underlying infection/source control in combination with antibiotic therapy 1,11.
Complications of septic emboli include mycotic pulmonary aneurysms treated with
coil embolization, vascular obstruction treated with thrombectomy, and
abscess/infarct of the lung lobes treated with surgical drainage and/or
resection of the infarcted area 10-13.

 

Intravascular abscesses have not been previously
reported as a complication of IE. At this point, medical therapy is unlikely to
be sufficient, and surgical treatment may be optimal. A related report studying
infiltrative, non-small cell lung cancer has shown that resection and repair of
the pulmonary artery followed by pneumonectomy using a temporary intra-arterial
conduit technique is both feasible and safe, with acceptable post-operative
morbidity rates (complication rates of 52.2% and 5-yr survival of 50%) 14.
This surgical technique has not been studied in patients with advanced IE, but
has potential for application to this case.

 

Although surgical treatment options were
available, they were not pursued in this case due to the patient’s history of
non-adherence to medical therapy. The patient’s disease course, complicated by
continued heroin use at home and even in the hospital on two occasions, underscores
the struggle of drug addiction. Appropriate opioid addiction treatment may
likely have facilitated adherence to and completion of a long-term intravenous
antibiotic regimen, preventing the development of catastrophic complications of
her disease. Research has shown that opioid use disorder can successfully be
managed during and after acute hospitalizations with methadone, and treatment can
help facilitate other inpatient care 15. An initial dose of 20-30 mg daily
can safely be started inpatient, and providers should encourage a long-term
treatment plan and arrange for transfer to a maintenance program after
discharge. If methadone cannot be initiated due to underlying disease or
concern for interaction with CYP-450 inducers such as antiretrovirals,
buprenorphine, a partial opioid agonist, can be used to manage acute withdrawal
symptoms, and can be continued outpatient 15. Initiation of methadone therapy
during our patient’s first hospital admission would likely have prevented her
prolonged disease course.

 

Conclusion:

The presented case demonstrates a novel and rare
complication of infective endocarditis. The development of the pulmonary artery
abscess was likely due to poor adherence to medical therapy, highlighting the
importance of completion of antibiotic treatment. The patient’s inability to
complete medical therapy, however, was a consequence of her heroin addiction,
emphasizing the necessity for concurrent addiction treatment. The current
opioid crisis in the United States was recently named a public health
emergency, and this case highlights the urgent need for effective and long term
addiction management strategies to ensure compliance to medical therapy –
including outpatient parenteral antibiotic therapy – and prevention of
potentially fatal long-term sequelae.