Haemodynamic disorders Flashcards
What are the aetiologies of oedema?
- Increased hydrostatic pressure (impaired venous return)
- Salt and water retiention
- activation of the renin-angiotensinaldosterone system which stimulates renal sodium retention.
- Reduced plasma oncotic pressure (reduced albumin in blood)
What are the causes of generalised oedema?
- Congestive heart failure: left heart failure causing right heart failure
- Inflammation
- Venous hypertension
- Lymphatic obstruction
- Hypoproteinaemia
What causes pulmonary odema?
- Left heart failure increases hydrostatic pressure in capillary bed
- Fluid accumulates in interstitial space then spills into alveolar spaces
What are the symptoms of pulmonary odeoma?
Breathlessness (dyspneoa)
- Worse lying flat (othopnea) need to lie on inclination to breathe better
- Alveolar space fluid predisposes to bacterial infection e.g penumonia
Define thrombosis:
Abnormal blood clot formation in circulatory system
What causes thrombosis?
- Endothelial injury (high BP)
- Stasis or turbulent blood flow
- Blood hypercoagulability (genetic or acquired)
What is arterial thrombosis?
- Almost always due to vessel wall injury causing atherosclerosis
- Stenosis of artery by thrombus causes ischaemia
Occlusion causes infarction to tissue supplied
What are the 4 fates of a thrombus?
- Propagation: get bigger
- Embolise: dislodge
- Dissolution
- Organisation and recanalization: usually in coronary arteries , where can see little lumen
Invaded by fibroblast and endothelial cells
Define emboli:
Abnormal material in circulatory system carried by blood to distant site
Define infarct:
Ischaemic necrosis caused by occlusion of arterial supply or venous drainage
What are the different types of infarct?
Red infarct: venous occlusion
- Tissues with double circulation
White infarct: arterial occlusion
- Solid organs
- Wedge shape
- Not much space in solid organ for blood to
accumulate
Define haemorrhage:
Blood extravation due to vessel rupture
What are the 4 types of shock?
- Hypovalaemic
- Fluid loss (more than 20%)
- Kidney, brain, skin most perfused
- May be cazsed by hypokalaemia
- Cardiogenic
- Heart can’t pump enough to meet demand
- Caused by acute MI
- Anaphylactic
- Neurogenic
What is systemic inflammatory response syndrome (SIRS)?
Must have two of:
- Temp greater than 38 or less than 36
- Tachycardia
- Respiratory rate more than 20 breaths/min
- WBC is large
What is sepsis?
SIKR with infection
What are the subtypes of sepsis?
Severe sepsis:
Sepsis with organ hypoperfusion
Septic shock:
Severe sepsis and hypoperfusion despite adequate fluid resuscitation or use of vasopressors/inotropes to maintain blood pressure
What are the consequences of sepsis?
In organ dysfunction and multi organ failure
Ischaemic tissue causes lactic acidosis
Acute tubular necrosis in kidney
What causes cerebral oedema?
breakdown of the normal capillary barrier
What is a consequence of cerebral haemorrhage
solid haematoma within the enclosed cranial cavity can cause a rise in intracranial pressure and tonsillar herniation.
What is shock?
A generalised failure of tissue perfusion.
