Congestion and oedema

Question 1

darcys law

Answer 1

flow = change in pressure over resistance

Question 2

congestion

Answer 2

relative excess of blood in vessels of tissue or organ. passive process, secondary phenomenon, can be acute or chronic

Question 3

examples of congestion

Answer 3

DVT, hepatic cirrhosis, congestive cardiac failure, hepatic central venous congestion

Question 4

hepatic cirrhosis

Answer 4

results from liver damage, regenerating liver forms nodules of hepatocytes with intervening fibrosis, loss of normal architecture portal blood flow blocked, collateral circulation, local chronic congestion- haemorrhage risk

Question 5

collateral circulation

Answer 5

shunts, various sites anastomose with the systemic circulation. main street blocked so use side streets and alleys

Question 6

congestive cardiac failure

Answer 6

heart unable to clear blood, right and left ventricles, decreased CO, decreased GFR which causes activation of renin angiotensin alderosterone system, increase sodium and water retention, increase fluid in body, increase fluid in veins. heart cannot clear blood, back pressure, blood damned back.

Question 7

normal microcirculation

Answer 7

driven by hydrostatic pressure, balanced by osmotic pressures and endothelial permeability, filtration from capillary beds to interstitium to capillaries and lymphatics

Question 8

oedema

Answer 8

accumulation of fluid in extravascular compartment, ECF and body cavities

Question 9

peripheral oedema

Answer 9

increased interstitial fluid in tissues

Question 10

effusions

Answer 10

fluid collection in body cavities eg pleural, pericardial, joint, abdominal cavity- ascites

Question 11

oedema transudate

Answer 11

not much protein or albumin, few cells, lots of water and elctrolytes, low specific gravity, alterations in haemodynamic forces that act across capillary wall

Question 12

oedema exudate

Answer 12

as a result of inflammatory due to increase vascular permeability, something else going on eg tumour inflammation allergy, higher protein content, water and electrolytes, high specific gravity

Question 13

pulmonary oedema due to left ventricular failure

Answer 13

increased left arterial pressure, increased pulmonary vascular pressure, increased pulmonary blood volume, increased pressure, increased filtration and pulmonary oedema

Question 14

pulmonary oedema in lungs

Answer 14

perivascular and interstitial transudate, progressive oedematous widening of alveolar septa, accumulation of oedema fluid in alveolar spaces

Question 15

peripheral oedema

Answer 15

right heart failure, cannot empty right ventricle in systole so blood retained in systemic veins which leads to increased pressure in capillaries increased filtration and then peripheral oedema,

Question 16

congestive cardiac failure and oedema

Answer 16

right and left ventricles both fail, pulmonary oedema and peripheral oedema at the same time, all about hydrostatic pressure

Question 17

lymphatic blockage

Answer 17

lymphatic obstruction leads to hydrostatic pressure upset, lymphatic drainage is required for normal flow, if blocked then lymphedema eg breast cancer may require radiotherapy to axilla which leads to fibrosis which leads to decreased outflow which leads to oedema of upper limb

Question 18

oedema in abnormal renal function

Answer 18

abnormal renal function results in sodium chloride and water retention. this is secondary in heart failure which reduces renal blood flow, and can be primary if acute tubular damage eg hypotension, decreased renal function is due to lack of salt and water, lack of intravascular fluid volume, leads to secondary increase in capillary pressure and then oedema

Question 19

low protein oedema occurs when (examples)

Answer 19

nephrotic syndrome, hepatic cirrhosis, malnutrition

Question 20

how does low protein cause oedema

Answer 20

low protein causes low capillary oncotic pressure, leads to increased filtration

Question 21

permeability oedema

Answer 21

damage to endothelial lining leads to increase pores in membrane which leads to osmotic force moving towards zero and proteins and larger molecules can leak out not just water

Question 22

permeability oedema examples

Answer 22

acute inflammation such as pneumonia, burns