Embolism

EMBOLISM 
  • An embolus is any foreign body floating in blood. The process is called embolism.

Location of embolism

  • Artery / venous / capillaries / lymphatics
  • In domestic animals emboli always occurs in arteries
  • In human, venous embolism is common
  • Thrombus in leg vein may form emboli to reach large blood vessel, right side heart and pulmonary artery embolism

Types / Causes of emboli 

  • Thrombotic emboli : Thrombo embolism – arteries (Thrombi detach to form emboli)
    • Heart – vegetations
    • Parasitic; atherosclerotic; bacteria
  • Bacterial emboli  : Septicaemia
  • Parasitic emboli  : Dirofilaria immitis - Pulmonary artery – dog
    • Schistosomes – Portal; mesenteric; Nasal blood vessels
    • Trypanasomes – If tartar emetic is given rapidly, it kills large number of organism and forms emboli on coronary vessels which is fatal.
    • Filarial - Lymphatics emboli in brain
  • Neoplastic emboli : Clumps of tumour cells in circulation producing metastatic tumours.
  • Fibrin - In blood transfusion, when blood is improperly defibrinated / inadequate anticoagulants
  • Fat emboli - In fracture of long bones, fat in the marrow cavity gets dislodged and forms emboli. These are lodged in lungs and leads to death. 
    • “Fat embolism syndrome“ (Acute respiratory symptoms, tachycardia neurological symptoms)
  • Air or gas emboli
    • Incision of large neck veins (surgery / suicide)
    • Air sucked into veins Embolism
    • In criminal abortion Pumping air into uterus
    • Air in large uterine vein
    • Emboli
    • Enters circulation
    • Heart
    • Foamy blood
    • Acute heart failure – Sudden death
  • Caission's disease
    • Humans
    • Sudden change in atmospheric pressure
    • Under water construction workers
    • Deep sea / scuba divers
    • Unpressurised aircrafts ascends rapidly
    • Under water construction workers
    • Increase air pressure within under water compartment to compensate water pressure
    • Breathing
    • Increase air dissolve in blood, tissue fluid and fat
    • If the worker surfaces suddenly i.e decompresses
    • Dissolved gases come out as bubbles (O2, CO2, N2)
    • O2 and CO2 are soluble and cause no harm; N2 which is insoluble form emboli
    • AIR embolism (Brain, heart etc)
    • “Caission” means - water tight chamber used underwater
    • Also called “BENDS” – severe cramping pain
  • Clumps of normal of normal body cells
    • Occurs when tissue / organ is damaged
  • Amniotic fluid embolism
    • Complication of labour
    • Infusion of amniotic fluid (Epithelial cells, fat, mucin, meconium)
    • Maternal circulation
    • Due to tear in placental membrane or rupture of uterine veins
    • Maternal mortality (Respiratory distress; cyanosis, shock, convulsions, coma, death)
    • Rare in domestic animals - due to anatomical differences in placental / uterine structures

Pradoxical emboli

  • Emboli that pass directly from the right auricle into the left auricle through patent foramen ovale thereby emboli originating from vein will be lodged in systemic vessels instead of being in pulmonary vessels.

Significance / Result of embolism

  • Character of emboli
    • size - large emboli → large blood vessel blocked
    • septic / aseptic – new foci of infection
    • neoplasms – metastasis
  • Number of emboli
    • Increased sites of obstruction
  • Organs involved
    • Liver / Lung / muscle - Large blood supply
    • Very little effect
    • Heart / Kidney / Spleen - no collateral circulation - Infarction
Last modified: Wednesday, 7 December 2011, 9:04 AM