Systemic Infections Flashcards
How do systemic infections begin?
starts in one part of the body and then spreads to other sites using cardiovascular and lymphatic system
- often starts in one that are well-vascularized/intimately connected to cvs system
- e.g., lungs, kidneys
Inflammation of the Heart - what is it called?
there are 3
inflammation of:
- endocardium = endocarditis (most common bacteria, can hold/host colonization and create biofilm); affects valves
- pericardium = pericarditis (viral)
- myocardium = myocarditis (most often viral)
Lymphatic systems - what can be affected?
there are 3
lymphadenopathy = swelling of lymph nodes (can only feel, not see)
lymphadenitis = inflammation of lymph nodes (can see and feel pathogen)
lymphangitis = inflammation of lymph vessels
What are some systemic viral infections?
- infectious mononucleosis
- burkitt’s lymphoma
- cytomegalovirus infections
- dengue virus
what are the systemic bacterial infections?
-systemic inflammatory response syndrome (SIRS) = medical emergency characterized by rapid HR, RR, abnormal wbc + fever
* bacteremia = bacteria in bldstream
* sepsis = infection of bldstream
* septicemia = pathogen replicates to high #s, overcomes innate immune system
* septic shock = catastrophic drop in BP d/t severe sepsis (superantigens/ PAMPS)
- plague
- lyme disease
- rocky mountain spotted fever
What are the bacterial infections of the heart?
- subacute bacterial endocarditis
- infectious endocarditis
- acute bacterial endocarditis
- prosthetic valve endocarditis
What is the criteria for sepsis?
= suspected or documented infection and an acute increase in =/> 2 sepsis related organ failure assessment (SOFA) points
what is the criteria for septic shock?
suspected or documented infection plus vasopressor therapy needed to maintain mean arterial pressure @ >/= 65 mmHg and serum lactate > 2.0 mmol/L despite adequate fluid resuscitation
what is the definition of sepsis?
life-threatening organ dysfunction caused by dysregulated host response to infection
what is the definition of septic shock?
subset of sepsis in which underlying circulatory and cellular/metabolic abnormalities lead to substantially incr mortiality risk
how do you calculate mean arterial pressure (MAP)?
[2(diastolic) + systemic]/ 3
SIRS vs SOFA criteria
SIRS: more sensitive for diagnosing sepsis (quicker)
SOFA: more accurate for predicting hospital mortality among pts with sepsis
What is the Hour-1 bundle?
= system that promotes physicians to act as quickly as possible to obtain bld cultures, administer broad spectrum abx, start appropriate fluid resuscitation, measure lactate, and begin vasopressors if clinically indicated
- for sepsis / septic shock
Infectious Mononucleosis: EBV
what family? How does it infect and replicate? incubation period?
- herpes virus family, human herpesvirus 4 (HHV4)
- virus infects and replicates in oral cavity, is shed in saliva –> latent
- oropharyngeal epithelium, tonsils, and salivary glands
- B-cells affected –> atypical appearance –> systemic spread
incubation period = 5 weeks
What are the main viral agents causing systemic infections in Canada?
- west nile virus (WNV): in canada since 2001, have varying epidemic intensities linked to climatic factors
- epstein-barr virus: significant cause of systemic infections, including infectious mononucleosis and associated cancers
- cytomegalovirus (CMV): commonly found in immunocompromised individuals and can cause severe systemic disease
- dengue virus: incr encounters among travelers returning to canada
Infectious Mononucleosis, EBV: S/S + Dx
S/S: fever, sore throat, fatigue, generalized lymphadenopathy & enlarged spleen + liver
- look @ wb count
dx: monospot test (heterophile antibodies) + serology
Cytomegalovirus infections
family? where is it shed? general info?
- herpes virus family, HHV-5 (dsDNA virus) –> episomes = latency
- asymptomatic (primary) or CMV-mononucleosis-like syndrome
- shed virus in body fluids (saliva + urine)
- cell-mediated immunity
1.
what cancers are associated with EBV?
hodgkin lymphoma
non-hodgkin lymphoma
- B-cell lymphoma
- burkitt lymphoma
Who faces a higher risk of CMV reactivation?
immunocompromised individuals
- fever, pneumonia, hepatitis, encephalitis
what transmission can CMV have?
vertical transmission
- transplacental (75%), most asymptomatic
- congenital cytomegalovirus infection (microcephaly, seizurse, petechial rash, moderate hepatosplenomegaly with jaundice)
Dengue hemorrhagic fever: how many serotypes? how is it transmitted? incubation period?
4 serotypes = can make 8 antibodies (IgM & IgG for all 4 serotypes)
- transmitted by female mosquitoes (Aedes aegypti and Aedes albopictus) = endemic in tropics
- incubation period = 4-10 days after bite
Dengue: S/S?
- high fever
- retro-orbital headache
- intense joint and muscle pain
- rash (MP or petechial)
- skin more fragile - microhemorrhagia
- “white islands in a sea of red,” small healthy skin but rash is massive
- can have asymptomatic dengue but still have antibodies
What are the 3 types of Dengue?
- without warning signs
- with warning signs
- severe dengue
labratory tests for dengue
- serology (IgM, IgG)
- RT-PCR for detecting viral RNA
- CBC shows low platelet count and elevated hematocrit
What are the warning signs of dengue?
- clinical fluid accumulation, e.g., ascites, pleural effusion - d/t massive vasodilation
- liver enlargment > 2 cm
- severe abdominal pain
- persistent vomiting (min 3 vomiting episodes wihtin 24h)
- mucosal bleed
- lethargy or restlessness –> d/t hyporperfusion
Management/Treatment for Dengue?
- supportive care: hydration (oral or IV fluids)
- acetaminophen for fever + pain (avoid NSAIDs d/t bleeding risk)
- close monitoring for signs of hemorrhagic fever or shock
Systemic infections involving multiple organs: Lyme disease, etiology?
tell me about B. burgdorferi
most common vector-borne illness
B. burgdorferi
- spirochete
- transmitted by tick bite (ixodid tick)
- regurgitation to cause infection
- complex life cycle
Treatment for Lyme disease
abx treatment = most effective in earlier stages
- doxycyline
Lyme disease: Stage 1
- 3-30 days
- bull’s eye rash (erythema migrans), fever, muscle pain, joint pain, headache
Lyme disease: stage 2
- weeks to months
- spreads from blood to organs
- neurological + cardiac involvement
- inflammation causing joint pain thought to be autoimmune reaction
Lyme disease: stage 3
- months to years
- neuropathy and encephalopathy
- affects memory, mood, and sleep
How can bacteria be introduced into the bloodstream?
sharing needles or using a contaminated needle can introduce bacteria directly into the bloodstream
- SBE should be considered with any IV drug user who has a fever, even in absence of heart murmur
Diagnosis for definite endocarditis?
- 2 major criteria
- 1 major and 3 miner criteria
- 5 minor criteria
Bacterial infections of the heart
pericarditis: infection of sac surrounding the heart (complication from resp infection)
myocarditis: infection of heart (sepsis complication)
endocarditis: inflammation of inner layer of heart
- symptoms can be vague and intermittent
- will need valve replacement if not treated,
subacute bacterial endocarditis (SBE)
- s. mutans
acute bacterial endocarditis (ABE)
- s. aureus (most common cause)
Diagnosis for possible endocarditis?
- 1 major and 1 minor criteria
- 3 minor criteria
- positive blood cultures: 2+ cultures with typical microorganisms, or 1 positive culture for coxiella burneti (q-fever) or titre > 1:800
- echo: positive echo for oscillating cardiac mass, abcess, de novo prosthetic valuve dehiscence/ do novo valvular regurgitation
Minor criteria for endocarditis?
- predisposing risks factors
- vascular phenomenon: embolism, septic embolism, janeway lesion, mycotic aneurysm, conjunctival hemorrhage, intracranial bleed
- fever
- immunologic phenomenon: glomerulonephritis, Osler’s nodes, Roth spots, positive RF
- positive blood cultures not meeting major criteria
What is the most common cause of prosthetic valve endocarditis (PVE)?
- staphylococcus epidermis and S. aureus = most common cause of PVE
- many of these strains are methicillin resistant, extremely hard to treat
