A 52-year-old male, who had a heart-lung transplant 5 years earlier, is admitted to your ICU with suspected community-acquired pneumonia (CAP).
Outline the key clinical issues specific to this clinical situation that will need consideration in this patient's management.
Respiratory failure in a cardiopulmonary transplant patient is most commonly due to infection, rejection or a combination of the two and has a high mortality. A multi-disciplinary approach with quaternary level consultation is warranted including the transplant unit and infectious diseases.
Issues related to pneumonia
Causative organisms- Opportunistic infections e.g. PJP, CMV, Aspergillus, Scedosporium as well as other bacterial, viral or atypical causes of community-acquired pneumonia.
Early aggressive investigation – appropriate specimens/nasopharyngeal swabs and PCR testing, CXR, CT scan, bronchoscopy and consideration of lung biopsy
Early aggressive antimicrobial therapy – To cover standard CAP organisms and likely opportunistic organisms eg co-trimoxazole, ganciclovir, antifungal agents. Steroid therapy if severe PJP
Issues related to respiratory function
Need to rule out rejection (cellular or antibody mediated)- often treated empirically for both infection and rejection. Enhanced antibody response developed to combat infection may result in concurrent antibody mediated rejection (AMR).
Impaired cough and clearance of secretions.
Impaired lung function due to obliterative bronchiolitis (a manifestation of chronic rejection)- small airway disease
Bronchial or tracheal stenosis relating to the original anastomotic site may be present- large airway disease
Issues related to immunosuppression
On-going immunosuppression will need to be carefully managed in consultation with the transplant unit
Stress dose steroids if associated shock
Therapeutic drug monitoring of immunosuppression
Issues related to cardiac function
The transplanted heart is denervated. It is only responsive to directly acting drugs/hormones present in the circulation.
Normal compensatory cardiac autonomic reflexes are not present and therefore the heart is more sensitive to directly acting drugs and less able to rapidly respond to changes in intravascular volume.
Careful titration of fluid boluses needed- likely diastolic dysfunction.
Difficult to clinically assess response to and adequacy of therapy
Premature diffuse obliterative coronary atherosclerosis occurs resulting in impaired ventricular function
Issues related to other organ function
Renal – altered renal function secondary to calcineurin inhibitors
Altered adrenal function secondary to steroid use. Consider need for steroid cover
Glycaemic control with increased steroid dose
Other co-morbidities and issues related to reason for heart-lung transplant, e.g. vascular disease, diabetes
Early referral to transplant centre
Involvement of multi-disciplinary team – transplant unit, ID, respiratory, cardiology, physiotherapy Psychological support of patient and next of kin
Valid points not mentioned in the template were given credit
Additional Examiners' Comments:
Candidates who did not pass had knowledge gaps in this area.
This question is almost identical to Question 22 from the first paper of 2009. Therefore, the discussion section from this previous question can be safely reproduced here with virtually no modification. For a broader overview of complications following heart-lung transplantation, and specifically sepsis in the heart-lung transplant recipient, there are dedicated chapter in the Required Reading section:
Anyway: a systems-based approach to discussing the "key clinical issues":
Renal and electrolyte abnormalities:
Note how weirdly the range of bugs is arrayed. The community pathogens are fairly bog-standard, but the Stanford people found that gram-negatives dominated the hospital-acquired infectious lung flora.
Immunesuppression in the context of an acute infectious illness may have to be continued, because its cessation may result in catastrophic rejection.
Cisneros, J. M., et al. "Pneumonia after heart transplantation: a multiinstitutional study." Clinical infectious diseases 27.2 (1998): 324-331.
Reichenspurner, Hermann, et al. "Stanford experience with obliterative bronchiolitis after lung and heart-lung transplantation." The Annals of thoracic surgery 62.5 (1996): 1467-1473.
Gao, Shao-Zhou, et al. "Accelerated coronary vascular disease in the heart transplant patient: coronary arteriographic findings." Journal of the American College of Cardiology 12.2 (1988): 334-340.
Yusuf, S. A. L. I. M., et al. "Increased sensitivity of the denervated transplanted human heart to isoprenaline both before and after beta-adrenergic blockade."Circulation 75.4 (1987): 696-704