Infective Endocarditis

Today's case involved an 88-year-old man with a history of aortic valve replacement and multiple CABG surgeries who had a one-week history of fever.  His blood cultures were positive for Streptococcus gallolyticus and there was possible but not conclusive echocardiographic evidence of endocardial involvement.

There were multiple learning points:

-Organisms like S. gallolyticus (formerly S. bovis), S. viridans, S. aureus, HACEK organisms, and enterococci should spur suspicion in our minds regarding the possibility of infective endocarditis

-We discussed some of the symptoms of endocarditis including fever/constitutional symptoms, immune phenomena (Roth spots, Osler nodes, glomerulonephritis, positive rheumatoid factor), vascular phenomena (Janeway lesions, septic emboli, splinter hemorrhages), and symptoms of valvular dysfunction including congestive heart failure

-We discussed the Duke criteria for infective endocarditis

-We discussed the relationship between S. gallolyticus bacteremia and colon pathology (notably cancer)

-We discussed surgical indications for infective endocarditis which include persistent bacteremia/treatment failure, decompensated hemodynamics/heart failure, valvular abscess, vegetation greater than 1.0 cm, difficult to treat orgnanisms (e.g. Candida species), and refractory septic emboli

-Pacemaker lead removal should be considered if there is evidence of lead infection

-Cardiovascular surgeons will often be reluctant to operate on patients with septic neurologic consequences because of the risk of intracranial hemorrhage when they go on cardiovascular bypass with significant heparinization

-S. aureus has surpassed S. viridans as the most common cause of IE as a result of increasing use of vascular access devices/implants

Further Reading:

N Engl J Med. 2013 Apr 11;368(15):1425-33. doi: 10.1056/NEJMcp1206782.

HIV and Pneumococcal Pneumonia

Today's morning report highlighted the premise that a common presentation of a common problem can still generate a host of learning topics. 

Today’s case was of a 50-year-old man with HIV and AIDS (CD4 count of 8) presenting with fever and dyspnea.  He was adherent to Septra prophylaxis but was not on antiviral therapy.  His chest X-ray was consistent with a consolidative process, and blood cultures were positive for S. pneumoniae.

Learning points from today’s case:

- Pneumonia in an HIV positive patient with a low CD4 count is still more likely to be pneumococcal in etiology than any other

-We discussed the pathophysiology for why infection with encapsulated organisms is still more common in advanced HIV infection.  CD4 cells are helper T-cells which have a role both in cellular immunity (the more commonly implicated deficiency in AIDS) as well as humoral immunity by stimulating B-cells (less commonly mentioned in AIDS).  Encapsulated organisms are eliminated through antibody-mediated opsonization, which also explains why patients with multiple myeloma and functional asplenia are at increased risk.

-We discussed the opportunistic infections that can occur in AIDS.  More specifically, we discussed that Pneumocystis infection is nearly impossible in patients adherent to Septra prophylaxis.  We discussed CNS Toxoplasma infection and how seizures could lead to decreased level of consciousness and aspiration events.  Prophylactic regimens for opportunistic infections based on CD4 count were also discussed.

During your time on our wards (and in medicine as a whole) there are valuable pieces of information regarding any HIV patient that are helpful to collect.  These include mode of infection, duration of infection, current therapy, who follows the patient for his/her HIV, most recent CD4 count/viral load as available, history of opportunistic infections, and prophylaxis.

Further Reading:

Hirschtick, R. E., Glassroth, J., Jordan, M. C., Wilcosky, T. C., Wallace, J. M., Kvale, P. A., ... & Hopewell, P. C. (1995). Bacterial pneumonia in persons infected with the human immunodeficiency virus. New England Journal of Medicine, 333(13), 845-851.

Non-Resolving Pneumonia

Respirology Morning Report

The case discussed involved a person with non-resolving pneumonia, dermatomyositis and related pulmonary complications.  Here are some of the learning points:

-Non-resolving pneumonia was discussed with an acronym for a differential diagnosis:

A – Antibiotic – wrong choice of therapy

B – Bug – atypical or resistant organism (TB, fungus, MRSA)

C – Comorbidities (HIV, ESRD, DM, advanced age) that delay resolution

D – Diagnosis – not pneumonia – mimickers include malignancy, eosinophilic pneumonia, COP, connective tissue disease, drug reactions, exposures/hypersensitivity reactions

E – Empyema – complications of a pneumonia or abscess

Further Reading:

Finch, S., & Chalmers, J. D. BRIEF CLINICAL REVIEW: NON-RESPONDING PNEUMONIA.