Case 12
shock
,Physiological Causes of Shock
• Circulatory shock
Generalized inadequate blood flow to the extent that body tissues are damag
A state of tissue hypoxia due to reduced O2 delivery or increased O2
consumption.
• What are the two types of factors that reduce the cardiac output thus causi
shock?
1. Cardiac abnormalities that decreases the heart ability to pump blood, e.g.
VHD, arrhythmias, 70% of people who experience cardiogenic shock do not
survive.
2. factors that reduce venous return. E.g. diminished blood volume, blood flo
obstruction.
,Cont.
• Shock can also occur during normal CO, how?
1) Excessive metabolic rate
2) Abnormal tissue perfusion patterns
• The arterial pressure does not always correlates with the adequacy of circul
function.
• The shock itself leads to more shock, the inadequate blood flow causes
deterioration of heart function -- >> reducing the CO more.
• Stages of Shock
1) Non-progressive, Pre-shock: full recovery by the normal circulatory
compensatory mechanism
2) Progressive: without therapy, the shock becomes worse till death
3) irreversible: all know treatment are useless, but the person is still alive
,Classification of Shock
• Four types of shock:
Distributive, Cardiogenic, hypovolemic and obstructive.
• Distributive: characterized by sever peripheral vasodilation.
1. Septic shock
2. Systemic inflammatory syndrome: robust inflammatory respon
induced by major body insult that can be infectious or non- infectio
3. Neurogenic shock
4. Anaphylactic shock IgE mediated
5. Drug induced shock ( overdose, transfusion reaction)
6. Endocrine shock Addisonian crisis (adrenal failure due to
mineralocorticoid deficiency), myxedema.
,cont.
• Cardiogenic Shock: intracardiac causes of cardiac pump failure that
result in reduced CO.
1. Cardiomyopathy
2. Arrhythmias some arrhythmias ( VF) can present with cardiac arre
instead.
3. Mechanical ( sever aortic or mitral valve insufficiency, VSD, raptur
ventricular aneurysm). Aortic stenosis rarely causes shock.
• Hypovolemic : due to reduced intravascular volume.
1. Hemorrhagic – blood loss.
2. non-hemorrhagic – fluid loss other than blood.
- GIT losses, Skin losses, Renal losses, third space losses.
, Cont.
• Obstructive: extra-cardiac causes of pump failure, often associated
with poor right ventricle output.
- Pulmonary Vascular: RV failure from pulmonary embolism, or sev
pulmonary hypertension, obstruction of the pulmonary or tri valve
- Mechanical: primary physiologic disturbance is decreased preload
Tension pneumothorax, pericardial tamponade, constrictive
pericarditis, restrictive cardiomyopathy.
shock
,Physiological Causes of Shock
• Circulatory shock
Generalized inadequate blood flow to the extent that body tissues are damag
A state of tissue hypoxia due to reduced O2 delivery or increased O2
consumption.
• What are the two types of factors that reduce the cardiac output thus causi
shock?
1. Cardiac abnormalities that decreases the heart ability to pump blood, e.g.
VHD, arrhythmias, 70% of people who experience cardiogenic shock do not
survive.
2. factors that reduce venous return. E.g. diminished blood volume, blood flo
obstruction.
,Cont.
• Shock can also occur during normal CO, how?
1) Excessive metabolic rate
2) Abnormal tissue perfusion patterns
• The arterial pressure does not always correlates with the adequacy of circul
function.
• The shock itself leads to more shock, the inadequate blood flow causes
deterioration of heart function -- >> reducing the CO more.
• Stages of Shock
1) Non-progressive, Pre-shock: full recovery by the normal circulatory
compensatory mechanism
2) Progressive: without therapy, the shock becomes worse till death
3) irreversible: all know treatment are useless, but the person is still alive
,Classification of Shock
• Four types of shock:
Distributive, Cardiogenic, hypovolemic and obstructive.
• Distributive: characterized by sever peripheral vasodilation.
1. Septic shock
2. Systemic inflammatory syndrome: robust inflammatory respon
induced by major body insult that can be infectious or non- infectio
3. Neurogenic shock
4. Anaphylactic shock IgE mediated
5. Drug induced shock ( overdose, transfusion reaction)
6. Endocrine shock Addisonian crisis (adrenal failure due to
mineralocorticoid deficiency), myxedema.
,cont.
• Cardiogenic Shock: intracardiac causes of cardiac pump failure that
result in reduced CO.
1. Cardiomyopathy
2. Arrhythmias some arrhythmias ( VF) can present with cardiac arre
instead.
3. Mechanical ( sever aortic or mitral valve insufficiency, VSD, raptur
ventricular aneurysm). Aortic stenosis rarely causes shock.
• Hypovolemic : due to reduced intravascular volume.
1. Hemorrhagic – blood loss.
2. non-hemorrhagic – fluid loss other than blood.
- GIT losses, Skin losses, Renal losses, third space losses.
, Cont.
• Obstructive: extra-cardiac causes of pump failure, often associated
with poor right ventricle output.
- Pulmonary Vascular: RV failure from pulmonary embolism, or sev
pulmonary hypertension, obstruction of the pulmonary or tri valve
- Mechanical: primary physiologic disturbance is decreased preload
Tension pneumothorax, pericardial tamponade, constrictive
pericarditis, restrictive cardiomyopathy.
