MMI 133 Part Five point Five

  1. The Cardiovascular system (in a nutshell...)
    • Circulated blood through tissues
    • Delivers important substances to cells
    • Removed waste from cells
  2. Blood
    • Mixture of formed elements and plasma
    • Plasma: liquid
    • -transported dissolved nutrients and waste products
    • -transports antibodies
    • Formed elements:
    • -red blood cells: carry O2 and CO2
    • -white blood cells (leukocytes): defend against infection
    • -platelets: involved in clotting
  3. Lymphatic System
    • Essential part of blood cirulation
    • -plasma filters out of capillaries into interstitial fluid
    • Lymph capillaries surround tissue cells
    • -larger, more permeable than blood capillaries
    • Interstitial fluid is picked up by lymph capillaries in the interstitial space
    • Once the plasma (interstitial fluid) enters the lymph capillaries it is called lymph
    • Lymph capillaries - very permeable
    • -easily pick up microorganisms or their products
    • Lymph nodes: contain macrophages, B cells and T cells
    • -help clear infectious organisms from lymph
    • -sometimes lymph nodes becomes infected and swollen: buboes = infected lymph nodes
  4. How the bacteria get into blood
    • Breach of skin
    • -trauma
    • Infection and inflammation of tissues
    • -perforation/penetration of intestine
    • -appendicitis
    • -invasion (eg. Salmonella)
    • -oral surgery, rift in gums
    • -kidney or lung infection
    • -catheters
  5. Bacterial Diseases
    • Septic shock
    • Puerperal sepsis
    • Endocarditis
    • -subacute
    • -acute
    • -pericarditis
    • Rheumatic fever
    • Plague
    • Lyme disease
    • Epidemic typhus
  6. Septic Shock
    • Blood is normally sterile
    • A few microorganisms are OK
    • -defensive phagocytic cells
    • -low in iron (iron in RBC): many microorganisms require iron for growth; lysis of RBC, acellerated microbial growth
    • Can be caused by Gram negative or Gram positive organisms
    • -most severe if Gram negatives are involved
  7. Septic shock diseases
    • septicemia or sepsis: toxic condition resulting from uncontrolled bacterial proliferation in blood due to failure of defenses
    • -clinical symptoms: chills, fever, accelerated breathing and heart rate
    • -cytokines are released
    • Lymphangitis: inflamed lymph vessels
    • Severe sepsis: when sepsis results in drop in blood pressure and dysfunction of at least one organ
    • -low blood pressure can still be controlled by addition of fluids
    • Septic Shock: final stage of sepsis
    • -blood pressure can no longer by controlled by addition of fluids
    • -multi-organ failure often occurs
    • -very high mortality rate
  8. Gram-negative septic shock
    • Gram-negative organisms = most common cause of sepsis
    • A.k.a. endotoxic shock
    • -due to release of endotoxins (LPS) from G- cell wall
    • -less than 1 nanogram is enough LPS to cause symptoms
    • ->200,000 fatal cases of septic shock per year in USA
    • No effective treatment exists
    • -early symptoms are non-specific, therefore may not be diagnosed in time
    • -administration of antibiotics at later stages may aggravate symptoms
    • -supportive therapy is key
  9. 3 pathogenesis of the Gram negative Septic shock
    • Endotoxin - Activation of macrophages
    • cytokin release
    • fever,
    • increased leakage from blood vessels, decreases in blood pressure, SHOCK or decrease OXYGEN EXCHANGE
    • or Increase in PMN adhesiveness, PMN traffic to lungs, release of lysosomal contents of PMN, increased capillary leakage, LUNG DAMAGE
    • Endotoxin - Complement activation
    • PMN traffic to lungs, release of lysosomal contents of PMN, increased capillary leakage, LUNG DAMAGE
    • or
    • increased leakage from blood vessels, decreases in blood pressure, SHOCK or decrease OXYGEN EXCHANGE
    • Endotoxin - Activation of clotting
    • DIC
    • or tissue damage from clots, then abnormal blood flow, then ORGAN SHUTDOWN
    • or decreases in available clotting proteins, HEMORRHAGE
  10. History - Peurperal Sepsis
    • Peurperal fever, childbirth fever
    • Nosocomial nfection
    • Infection of uterus (often S. pyogenes) -> infection of abdominal cavity (peritonitis) -> septicemia (often)
    • Transmitted by hands and instruments of physicians can be treated with penicillin
    • -disinfection/modern hygienic practices make this very uncommon
  11. Dr. Ignaz Semmelweiss
    • 1824-1848: peurperal sepsis was cause of death of avg 10% of women who gave birth in a particular clinic in a Vienna hospital
    • Compare with avg 4% in a separate clinic in the same hospital
    • First clinic: med students, second clinic: midwives
    • Alternate admission days; street births
    • 1847: death of Kolletschka
    • 1847: handwashing with chlorine introdruced
    • 1849: Semmelweiss dismissed
    • 1865: committed to mental institution, dies 14 days later of septicemia
  12. Rheumatic Fever
    • Follows Groups A streptococcal pharyngitis (S. pyogenes)
    • -antibodies against M-protein cross-react between strep antigens and host heart valves (autoimmune)
    • Age 4-18 most susceptible (not treated with beta-lactam)
    • Sore throat -> short period of arthritis, fever
    • -subcutaneous nodules at joints may be present at this stage
    • Inflammation of heart in ~50% of cases
    • -permanent valve damage
    • Glomerulonephritis (due to immune complex formation from anti-streptococcal antibodies)
    • Re-infection with Strep: can renew immune attack
    • Heart damage may be fatal
    • Treatment - monthly penicillin injection
    • Sydenham's chorea (Saint Vitus dance) in ~10% of cases
  13. Endocarditis
    • endocardium: epithelial tissue that lines heart muscle and covers valves
    • subacute bacterial endocarditis: slow development
    • -alpha-hemoplytic streptococci, staphylococci, enterococci
    • -fever, general weakness, heart murmur
    • -usually starts with focus of infection elsewhere in body: tooth extraction, tonsillectomies can release bacteria; abnormal heart valves increase risk- congenital, rheumatic fever, syphillis; bacteria lodge in blood clots (protected from immune system)
    • -fatal within a few months if untreated
  14. Endocarditis: acute bacterial endocarditis
    • Rapid progression
    • -Staphylococcus aureus
    • -bacteria migrate from focus of infection
    • -normal or abnormal valves are affected
    • -untreated: fatal within days
    • -prophylactic penicillin sometimes used during tonsillectomies and tooth extractions: limited effectiveness
    • Pericarditis: infection of sac around heart (pericardium)
    • -streptococci
Card Set
MMI 133 Part Five point Five
Lecture 12, last part... Ch 23 and 24