Infective Carditis Flashcards
What is a major distinction that can be made b/t Staphy A. & S. epi.?
S. Aureus is coagulase positive; S. Epidermidis is coagulase negative
But wait!!!! Streptococcus is also catalase negative.
Well, Strep is also hemolytic
What strain of Strep is alpha-hemolytic?
S. viridans
What Strep strain is beta-hemolytic?
S. pyogenes- Strep A
S. bovis should be implicated if pt. has what?
a GI neoplasm
S. mutans & S. mitis should be considered in pts. w a h/o what?
very poor dentition
What are the 2 most common enterococci assoc. w/ infective endocarditis?
E. faecalis, E. faecium
What labs would you order to rule out enterococcus-induced IEC?
bile-esculin test (if solution turns black then it is a + test); most enterococci are also gamma-hemolytic
Fungal IEC is incredibly rare, but what are the 2 most common assoc. w/ IEC?
Candida & Aspergillus
What are common atypical pathogens assoc. w/ IEC?
mycobacteria TB; Chlamydia
List out the HACEK acronym?
H: Haemophilus
A: actinobacillus
C: cardiobacterium
E: eikenella
K: kingella
Describe the morphology of HACEK bacteria
pleomorphic gram-neg. rods
You are a lab technician and you notice that the agar plate from an IEC pt. is corroded & emits a bleach-like odor; what pathogen is it?
Eikenella
What additional components must be added to the agar for haemophilus to grow?
factor X & V
you notice yellow granules on a trypticase soy broth agar; what pathogen is it?
actinobacillus
culture media must be supplemented with what for nutritionally variant strep. to grow?
pyridoxal
Corynebacteria would be moved to the top of your DDx if pt. had a history of what?
IV drug use; alcohol abusers; structural heart disease
what kind of medium is needed for corynebacteria?
loeffler’s medium
If pt. has symptoms of IEC and a recent h/o food poisoning, what would be the most suspected pathogen?
listeria monocytogenes
What kind of stain would you order if mycobacterium was suspected?
mycobacteria are acid-fast +
Your pt. works with rare exotic birds and is presenting w/ signs of IEC. What pathogen would you suspect and what stain would you order?
chlamydia; Giemsa/Wright stain
Dextran production causes what insults?
thrombotic & adhesive vegetation
what bacterial protein facilitates adherence?
Fim A.: increases binding capability to host fibronectin
infective endocarditis is assoc. w/ what systemic issues?
peripheral emboli & glomerulonephritis
onset of ARF typically occurs how long after URI?
3 weeks
Describe the pathophysiology of ARF.
Type II hypersensitivity; molecular mimicry of Abs targeting M protein also recognize human cardiac tissue; Cascade effects: Abs bind to endothelial cells to recruit lymphocytes that will lyse the cells; cell lysis release peptides that activate cross-reactive T-cells to amplify the damage
Infective Endocarditis will in most cases always reveal what for the cardio PE?
Mitral valve regurgitation
Infective Myocarditis can cause what conducting effect?
PR-interval prolongation
Infective Pericarditis is indicative of what PE findings?
friction rub, chest pain
What histological findings indicate infective myocarditis?
aschoff bodies & anitschkow cells
What would by your stereotypical drug regimen for ARF?
Bacteria: penicillin or amoxicillin; NSAIDs for arthralgias; inflammation: glucocorticoids; in server cases, carbamazepine or sodium valproate
What do you need to know about chronic RHD?
mechanism: repeated exposures to strep. A.; leads to valvular stenosis; usually presents 10-20 yrs. after initial infection
What is the most common culprit of bacterial vasculitis?
rickettsia rickettsii
What are the different characteristics of RMSF?
transmitted by dog ticks; small, gram - coccobacilli, stained w/ GIEMSA; bacteria replicates in vascular endothelial cells
How does the RMSF skin changes manifest?
macules first appear on wrists & ankles and then spread to remainder of the extremities
What is the standard drug for treatment of RMSF?
doxycycline
What is the most common protozoan assoc. w/ Infective vasculitis?
Trypanosoma cruzi
Describe the etiology of Chagas Disease?
vector: reduviid bug (AKA kissing bug); trypomastigotes from the bug’s feces get introduced into a wound
Describe the clinical presentation of Chagas Disease?
Romana sign: unilateral painless periocular edema; Chagoma: focal lymphadenopathy at bite site; malise, fever, anorexia
Chronic Chagas disease can cause what clinical manafestations?
arrhythmias, RBBB, DCM, megaesophagus, megacolon
Chagas disease is most frequently found in which regions of the americas?
central & south america
What stain would you order for suspected chagas disease?
Giemsa stain
What are the drugs used to treat Chagas disease?
nifurtimox or benznidazole
What are the physical exam findings of myocarditis?
S3; mitral/tricuspid murmurs
Compare & contrast acute vs. fulminant myocarditis?
acute: 2-4 weeks after exposure, assoc. w/ DCM long-term complications; fulminant: usually within 2 weeks after exposure, assoc. w/ profound ventricular dysfunction, active inflammation & necrosis, sudden death syndrome or full recovery
Compare & contrast the differences b/t chronic active vs. chronic persistent.
active: symptoms 2 weeks after exposure, moderate ventricular dysfunction with ongoing inflammation & fibrosis; Persistent: characteristic of the absence of ventricular dysfunction w/ foci of myocyte necrosis
What long term complication is assoc. w/ chronic active myocarditis?
can develop into RCM 2-4 years after presentation
What is the most common cause of infective myocarditis?
Viral: coxsackie B
What are other viruses that can potentially cause infective myocarditis?
Parvovirus B-19; HIV, influenza, CMV, HHV-6; Hep. B.; enterovirus, rubella, polio
What type of bacterial myocarditis is assoc. w/ an AV block?
borrelia burgdorferi (AKA Lyme carditis)
What is the pathogenesis of diphtheriae induced myocarditis?
diphtheria toxin: subunit B binds to cells allowing subunit A to be released into the cytosol and inhibits EF2 (important for protein synthesis)
What is the clinical presentation of chronic chagas disease?
cardiomegaly, megaesophagus, & megacolon
composite a list of drugs that can cause Type 1 Hypersensitivity rxn. induced myocarditis?
ampicillin, thiazides, lithium
What would you expect to find w/ light microscopy for suspected immune mediated myocarditis?
eosinophils
Composite a list of direct cardiotoxins?
Anthracyclines (the “bicin”s); cocaine; alcohol; arsenic; cyclophosphamide; radiation; heavy metals
Serous pericarditis is typically caused by what?
Irritation from infection of contagious tissues such as a URI; but not a direct infection of the pericardium itself
What are common causes of serofibrinous pericarditis?
Acute MI; Dressler syndrome
What is the definition of purulent/suppurative pericarditis?
active infection in the pericardial space that has be extended from neighboring infections
What are the most common causes of hemorrhagic pericarditis?
TB; neoplasm
Adhesive mediastinopericarditis affects which layer of the pericardium?
parietal layer
What are the most common causes of mediatinopericarditis?
Post-infection, previous surgery, & radiation
Constrictive pericarditis, unlike mediatino, is not assoc. w/ HCM or DCM; Why?
heart is encased in a dense, fibrocalcific scar and cannot adapt to increased systemic demands
constrictive pericarditis mimics what other cardiopathy?
RCM
What is the most common primary malignancy of cardiac tissue?
Angiosarcoma: Myxomas
Describe the pathogenesis of myxomas?
linked to germline mutation of PRKAR1A (alpha regulatory subunit of cAMP-dependent protein kinase type1) this is a tumor suppressor gene (carney complex); derived from multipotent mesenchymal stem cells in the endocardium
Describe the distinctive histological characteristics of myxomas?
stellated fusiform; polygonal cells immersed in amorphous myxoid matrix
What are cardiac fibromas composed of?
connective tissue & fibroblasts
cardiac fibroma is assoc. with what syndrome?
nevoid basal-cell carcinoma syndrome (NBCCS)
Describe the pathogenesis of NBCCS?
mutations in PTCH1 on ch.9 which is a tumor suppressor gene
What other presentations are assoc. w/ NBCCS?
skeletal abnormalities & odontogenic keratocysts, basal cell carcinomas
Papillary fibroelastoma is located where in the heart?
form on valves (sea anemone gross appearance)
What complications are assoc. w/ papillary fibroelastoma?
cores can embolize and occlude coronary arteries leading to myocardial ischemia
What is the most common primary cardiac tumor found in ped. pts.?
cardiac rhabdomyomas
Describe the distinctive histological characteristics of cardiac rhabdomyomas.
cells look like they have a spider inside with fibrillar processes containing sarcomeres protruding from the center to the margins of the cell
Cardiac rhabdomyomas can also be assoc. w/ hamartomas. Describe the pathogenesis of hamartomas.
assoc. w/ tuberous sclerosis caused by mutations in TSC1 &2
what primary cardiac tumor is assoc. w/ the highest incidence of sudden death?
cystic tumors of the AV node in the triangle of Koch
angiosarcomas are usually found in which regions of the heart?
right side
What cancer is most likely to metastasize to the heart?
malignant melanoma
What are the most commonly seen metastatic carcinomas of the heart?
lung, breast, GI, lymphomas/leukemias
Compare and contrast the differences b/t acute & subacute infective endocarditis?
Acute: short incubation (<6 wks.), Staph A., high risk of septicemia & septicemic shock; Subacute: long incubation (>6 wks.), Strep. viridans, vegetation w/ granulomatous tissue that can fibrose or calcify
Infective endocarditis caused by HACEK bacteria are most commonly seen in what group of pts.?
pediatric pts.
Define marantic endocarditis.
non-bacterial thrombotic endocarditis; commonly found on undamaged valves; vegetations are small & sterile
What are the most common causes of marantic endocarditis?
sepsis-induced DIC; pregnancy; venous catheters; carcinomas
What is one distinction that can be made b/t NBTE & LSE?
NBTE vegetation only forms on one side of the valve leaflets whereas LSE grows on both sides
What is typically seen on the results of a CBC for acute and subacute?
acute: leukocytosis; subacute: anemia
RF is found in which type of infective endocarditis?
subacute; also decreased complements: C3, C4, & CH50; nephritic syndrome
What can a CXR reveal for endocarditis?
Has an Embolus occured?
V/Q scanning is good for assessing what type of cardiopathies?
right-sided endocarditis
What can CT scans reveal about cardiopathies?
local abscesses, valvular abnormalities, & vegetations
What can a cardiac catheterization assess?
degree of valvular damage
If Cx come back negative, what would be the next best thing to order?
echocardiography
What is the clinical criteria for diagnosis of infective endocarditis?
2 major criteria or 1 major & 3 minors or 5 minors
What are the major criteria for infective endocarditis?
+ Cx (at least 2 that are drawn > 12 hrs. apart) or at least 3/4 + Cx with first and last Cx drawn 1 hr. apart; + ECG (defined as identifiable abscesses, a new dehiscence
List the minor criteria for infective endocarditis?
predisposition (IV drug use or h/o HD); fever; Vascular: janeway lesions, micro emboli, roth spots, mycotic aneurysm, septic pulmonary infarcts, ICH; microbiological evidence and + ECG findings
What serologic testing would you order if lyme carditis was suspected?
ELISA; if this is + then you would order a WB
acute lateral wall infarction is usually assoc. w/ what virus?
Parvovirus B19
TB pericarditis is assoc. w/ what?
elevated pericardial fluid adenosine deaminase; 50% of cases will develop constrictive pericarditis
