Bact Inf of Circ, lymph, and res Flashcards
(24 cards)
Bacteremia definition=
bacteria in the blood
Septicemia definition=
a broader term that includes bacterial toxins or fungi in the blood
How does septic shock develop?
-generally induced by gram (-) bacteria in bloodstream:-Endotoxin (LPS) responsible for physiologic effects of septic shock-Lipid A core → most of the toxic properties
-Gram (+) bacteremia → septic shock via peptidoglycan or exotoxins (e.g. exotoxin A - P. aeruginosa (NOT GRAM+) and toxic shock syndrome toxin-1 - Staph.):
Polysaccharides of C. albicans, teichoic acid of Staph., capsule of S. pneumoniae also can initiate septic shock.
how is septic shock treated
- Hypotension: I.V. fluids (typically 1–2 L of normal saline over 1–2 h)
- Hypoxia: Ventilator therapy
- DIC: Transfusion of fresh-frozen plasma and platelets to stop bleeding OR heparin to prevent thrombi formation
- Bacterial infection: Administration of antibiotics
normal function of pericardium
- Exerts a restraining force to prevent sudden dilation of the cardiac chambers during exercise or hypervolemia ( fluid in the blood)
- Minimizes friction between the heart and surrounding structures
predisposing factors to bacterial pericarditis
- Pericardial effusion (i.e. fluid accumulation around the heart)
- Immunosuppression
- Chronic diseases (e.g. alcohol abuse and rheumatoid arthritis)
- Cardiac surgery
- Chest trauma
- Degenerative valve disease,
- prosthetic heart valves,
- I.V. drug abuse
- intracardiac devices
common causes of bacterial pericarditis
- Streptococci
- Staphylococci
- Gram-negative rods
- Anaerobic bacteria (esp. B. fragilis and Peptostreptococcus spp.)
- Haemophilus influenzae (in children)
- Early complication of Lyme disease (Borrelia burgdorferi)
which pathogens cause myocarditis
- Borrelia burgdorferi (Lyme disease)
- Orientia tsutsugamushi (Scrub typhus)
- Rickettsia rickettsii (Rocky Mountain spotted fever)
- Coxiella burnetii (Q fever)
- Mycoplasma pneumoniae
- Chlamydia pneumoniae
- Corynebacterium diphtheriae (through toxin production)
acute vs subacute bacterial endocarditis
-Acute bacterial endocarditis:
High fever (103°–104°F), acutely ill
Rapid damage to cardiac structures
Untreated progresses to death within weeks
Mycotic aneurysm may result - Inflammatory damage weakening of arterial wall. Rupture may produce death.
-Subacute bacterial endocarditis:
Low-grade fever
Night sweats
Weight loss
Vague constitutional complaints
Indolent course (progresses gradually) slow damage to the heart
Progression to death over weeks to months
bacterial pericarditis - diagnosis/treatment
DIAGNOSIS
- Fever
- Positive blood cultures
- Peripheral emboli
- Visualization of vegetative growth on echocardiography
TREATMENT
- Prior to blood culture results, empirical treatment with vancomycin (gram-positives) and gentamicin (gram-negative rods) to cover Staph., Strep. and Enterococci.
- Prolonged therapy is the norm and treatment periods in most patients may require more than 4 weeks.
- Surgical vegetectomy and valve replacement may be necessary.
sepsis definition
-systemic inflammatory response + suspicion or proof of an infectious cause
systemic inflammatory response syndrome definition
- two or more of following conditions:
- Temperature >38oC (or >100.4o F) (or hypothermia)
- Heart rate >90 beats/minute
- Respiratory rate >20 breaths/minute
- White blood cell count >12,000 cells/mm3 OR 10% immature neutrophils (“bands”)
- An absence of fever is most common in neonates and the elderly.
- Early signs of a septic response includes hyperventilation and confusion.
severe sepsis definition
-Sepsis associated with: Organ hypoperfusion (e.g. reduction in urine output, mental status changes, systemic acidosis and/or hypoxemia)
septic shock definition
-Sepsis + hypotension (systolic pressure < 90 mm Hg)
refractory septic shock and multiorgan failure definition
- hypotension not responsive to fluid and pharmacologic treatment
- Multiorgan failure = dysfunction of >1 organ (may include the kidneys, lungs and liver, as well as the development of DIC)=Associated with a high fatality rate
early signs of septic response:
-hyperventialation and confusion
mechanism of toxic shock (basic)
- Release of vasoactive substances (e.g. histamine) cause arterial hypotension directly
- Depression of cardiac muscle contractility by TNF (important cytokine, but one of many produced during severe sepsis and septic shock)
- Impairment of the protein C-mediated anti-coagulation pathway, resulting in disseminated intravascular coagulation (DIC)
late vs early DIC give patient
late: fresh frozen plasma
early: heparin
Unknown bacteriumcausing some shit what to give to treat?
Vancomycin and gentamicin to cover both Gram-positive and Gram-negative infections
Local sites of infections: Patient presentations:
- Straph. aureus or Strep. pyogenes: Generalized erythroderma in a septic patient suggests the toxic shock syndrome
- Neisseria meningitidis: Sepsis accompanying petechiae in skin
- Rocky Mountain spotted fever: Petechial skin lesions in person who has been bitten by a tick in an endemic area
- Vibrio vulnificus: Hemorrhagic skin lesions in a septic person who recently has eaten raw oysters
how is septic shock diagnosed
Blood cultures - if its a toxin then it pobably wont elp
Acute bacterial endocarditis (ABE) organisms
Staph. aureus (one of the most common causes)
Beta-hemolytic streptococci
Pneumococci
Subacute bacterial endocarditis (SBE): organisms
Viridans streptococci (most common cause)
Enterococci
Coagulase-negative Staph.
HACEK group (normal oropharyngeal flora)
[[Haemophilus (H. parainfluenzae, H. aphrophilus)
Actinobacillus (A. actinomycetemcomitans)
Cardiobacterium hominis
Eikenella corrodens
Kingella kingae]]
bacterial endocarditis major cause?
stapp aureus
