This week in Morning Report on September 7th we discussed a case of a man presenting with three weeks of petechial rash on his lower extremities and intermittent fevers x 3 weeks. We reviewed an approach to petechial rash based on other clinical features of the patient’s presentation. As we gathered more information on history, physical examination and investigations, the patient was ultimately diagnosed with Viridans group streptococcus infective endocarditis of the tricuspid valve. The diagnosis and management of infective endocarditis was discussed as well as Duke’s criteria. See the highlights from our morning report below!

1. An Approach to Petechial/Purpuric Rash

Some definitions for your review: petechiae are red/purple dots that represent bleeding from leaking capillaries. Ecchymoses often occur in the deeper layers. Purpura are petechiae that have coalesced and become bigger

One note about the diagram below: Henoch-Schonlein Purpura (HSP) is a common vasculitis in children < 10 years old and often follows a URI – the pathophysiology is IgA deposition in the skin glomerulus and GI tract and kidneys. The diagnosis is clinical there is no thrombocytopenia or abnormal coagulation markers,a nd the skin biopsy shows leukocytoclastic vasculitis.

Hemolytic uremic syndrome can also present with anemia, AKI, and thrombocytopenia and therefore should also be considered in the differential diagnosis below. Most often the cases occur after infectious diarrhea usually related to E coli O157:H7. Other causes can be related to Shigella, Salmonella or medication-related.

2. Making a Diagnosis of Infective Endocarditis

The modified duke criteria are used for making a diagnosis of infective endocarditis.

• Definite endocarditis -2 major criteria, 1 major + 3 minor, or all 5 minor criteria
• Possible infective endocarditis -1 major criterion and 1 minor criterion, or 3 minor criterion
• Rejected – Firm alternative diagnosis explaining evidence of IE; or resolution of IE syndrome with antibiotic therapy for ≤4 d; or no pathological evidence of IE at surgery or autopsy with antibiotic therapy for ≤4 d; or does not meet criteria for possible IE as above

In our patient case he had 4/4 blood cultures positive for Viridans group streptococcus sensitive to penicillin, new 12 mm vegetation on the tricuspid valve with moderate tricuspid regurgitation on echocardiogram.

3. Systemic Manifestations of Infective Endocarditis

See below regarding systemic manifestations of infective endocarditis.

4. Management of Infective Endocarditis

Duration of antimicrobial therapy ranges from 4-6 weeks and is usually longer for increasing beta-lactam resistance, S. aureus, or prosthetic valve.

Acronyms defined:

• MSSA – methicillin-sensitive Staphylococcus aureus
• MRSA – methicillin-resistant Stayphylococcus aureus
• CNST – coagulase-negative Stayphylococci
• HACEK organisms – Haemophilus spp., Aggregatibacter spp., Cardiobacterium spp., Eikenella corrodens, Kingella spp.

Indications for early surgery in infective endocarditis include:

• Valve dysfunction with signs or symptoms of HF despite optimal therapy
• Left sided infective endocarditis with S. aureus, fungi or highly resistant organisms
• Heart block, annular/aortic root abscess, destructive penetrating lesions
• Persistent bacteremia or fever > 5 days after starting antibiotics
• Complete removal of implantable electronic cardiac device (PPM/CRT/ICD) systems in patients definite endocarditis
• Native left sided valvular endocarditis with mobile vegetation > 10 mm esp if anterior mitral leaflet involved
• Recurrent emboli and persistent vegetations despite antibiotics 

5. Prophylaxis for Infective Endocarditis

The best way to remember who should get prophylaxis for infective endocarditis to remember that there are specific PATIENT factors and then PROCEDURAL factors.

References:

1. A summary of Osler’s nodes, Janeway lesions, splinter hemorrhages – https://www.researchgate.net/publication/256470129_Osler’s_nodes_Janeway_lesions_and_splinter_haemorrhages/link/55575f2b08aeaaff3bf76f74/download
2. Baddour guidelines on management and investigations in the setting of infective endocarditis – https://www.ahajournals.org/doi/full/10.1161/CIR.0000000000000296
3. Prevention of Infective Endocarditis – https://www.ahajournals.org/doi/pdf/10.1161/circulationaha.106.183095

I hope this was helpful! Please email Sheliza at cmr@wchospital.ca if you have any questions or comments! 🙂