Circulatory Shock/Hypotension II

Question 1

What is the guideline for hypovolaemic shock?

Answer 1

Loss of > 20% intravascular fluid (reduced preload) leading to reduced cardiac output (CO).

Question 2

What is the pathogenesis of hypovolaemic shock?

Answer 2

Fast volume loss results in poor ability to compensate, which can be haemorrhagic or non-haemorrhagic.

Question 3

What are the haemorrhagic causes of hypovolaemic shock?

Answer 3

Trauma-associated blood loss (~20% / 1L), internal haemorrhage (e.g., pelvis/long bones, spleen, liver abdominal vessel rupture, AAA), upper GI bleed (variceal), intra- and post-operative bleeding, and post-partum haemorrhage.

Question 4

What are the non-haemorrhagic causes of hypovolaemic shock?

Answer 4

Dehydration, GI fluid loss (diarrhoea, vomiting, surgical drainage), skin fluids (burns, heat stroke), and renal loss (adrenal insufficiency, salt-wasting nephropathies).

Question 5

What are the clinical features of hypovolaemic shock?

Answer 5

Tachycardia, tachypnoea, weak pulse, hypotension, narrow pulse pressure, cold/clammy skin, poor capillary refill, and symptoms of fluid loss (decreased turgor).

Question 6

What investigations are used for hypovolaemic shock?

Answer 6

RUSH or FAST scan bedside ultrasound (U/S), and full blood count (FBC) for haemoglobin/haematocrit levels.

Question 7

What is the management for hypovolaemic shock?

Answer 7

Fluid resuscitation and possibly blood/blood product transfusion.

Question 8

What is the guideline for cardiogenic and obstructive shock?

Answer 8

Blood pressure (BP) < 90mmHg with urine output < 20 ml/hr and normal or elevated left ventricular filling pressure.

Question 9

What is the pathogenesis of cardiogenic shock?

Answer 9

Failure of myocardial pump resulting from intrinsic myocardial damage (non-obstructive) or extrinsic pressure (obstructive).

Question 10

What are the non-obstructive causes of cardiogenic shock?

Answer 10

Myocardial infarction (MI), arrhythmias, and congestive heart failure.

Question 11

What are the obstructive causes of cardiogenic shock?

Answer 11

Compression of the inferior vena cava (IVC) via tension pneumothorax, pericardial tamponade, constrictive pericarditis, restrictive cardiomyopathy, and pulmonary embolism.

Question 12

What are the clinical features of cardiogenic shock?

Answer 12

Tachycardia, dyspnoea, weak pulse, hypotension, narrow pulse pressure, cold/clammy skin, poor capillary refill, and possibly increased jugular venous pressure (JVP).

Question 13

What investigations are used for cardiogenic shock?

Answer 13

Identification of the cause, cardiac markers of acute coronary syndrome (ACS), electrocardiogram (ECG), and pulmonary artery catheterisation.

Question 14

What is the management for cardiogenic shock?

Answer 14

Cardiopulmonary resuscitation (CPR) and managing the underlying cause, e.g., needle decompression for tension pneumothorax.

Question 15

What is the guideline for septic shock?

Answer 15

Shock caused by capillary leakage (redistribution of fluid from intravascular to extravascular compartment) and systemic vasodilation (peripheral pooling of blood).

Question 16

What is the pathogenesis of septic shock?

Answer 16

A dysregulated response to infection in the blood resulting in organ dysfunction, with a 40-50% mortality rate.

Question 17

What are the common infection sites for septic shock?

Answer 17

Respiratory tract, genitourinary tract, gastrointestinal tract (GIT), skin, and soft tissue.

Question 18

What are the common infective microbes causing septic shock?

Answer 18

Gram-positive: Pneumococcus, Staphylococcus, Streptococcus, Enterococci, Listeria; Gram-negative: Klebsiella, Pseudomonas, Escherichia, Haemophilus, Legionella, Neisseria.

Question 19

What are the clinical features of septic shock?

Answer 19

Tachycardia, tachypnoea, bounding pulse, hypotension, wide pulse pressure, flushed/warm skin, hyper or hypothermia, acute oliguria despite fluid resuscitation.

Question 20

What investigations are used for septic shock?

Answer 20

Full blood count (FBC) with leucocytosis, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), hyperglycaemia without diabetes history, and positive blood cultures.

Question 21

What is the management for septic shock?

Answer 21

Fluid resuscitation, vasopressors (adrenaline), and intravenous broad-spectrum antibiotics (e.g., Tazocin and Vancomycin).

Question 22

What is the guideline for neurogenic shock?

Answer 22

Loss of sympathetic vascular tone and interruption of autonomic pathways leading to decreased vascular resistance.

Question 23

What is the pathogenesis of neurogenic shock?

Answer 23

Loss of sympathetic vascular tone and interruption of autonomic pathways, leading to decreased vascular resistance.

Question 24

What are the causes of neurogenic shock?

Answer 24

Spinal cord injury, spinal anaesthetic, traumatic brain injury, cerebral haemorrhage, and poisoning.

Question 25

What are the clinical features of neurogenic shock?

Answer 25

Bradycardia, tachypnoea, hypotension, normal pulse pressure, flushed/warm skin, and severe back or neck pain.

Question 26

What investigations are used for neurogenic shock?

Answer 26

None specific mentioned.

Question 27

What is the management for neurogenic shock?

Answer 27

Fluid resuscitation and atropine for bradycardia.

Question 28

What is the guideline for anaphylactic shock?

Answer 28

Type 1 (Ig-E mediated) hypersensitivity reaction leading to degranulation of mast cells and histamine release, lowering blood pressure.

Question 29

What is the pathogenesis of anaphylactic shock?

Answer 29

Type 1 (Ig-E mediated) hypersensitivity reaction causing mast cell degranulation and histamine release, which lowers blood pressure.

Question 30

What are the causes of anaphylactic shock?

Answer 30

Drug reactions, insect allergies, food allergies, and contrast medium allergies.

Question 31

What are the clinical features of anaphylactic shock?

Answer 31

Tachycardia, tachypnoea, hypotension, narrow pulse pressure, flushed/itchy skin, bronchospasm (wheeze, stridor, cyanosis), angioedema, vomiting, and diarrhoea.

Question 32

What investigations are used for anaphylactic shock?

Answer 32

Full blood count (FBC) with eosinophilia.

Question 33

What is the management for anaphylactic shock?

Answer 33

Adrenaline and airway support (e.g., intubation, nebulizers).

Question 34

What does RUSH stand for in the context of shock?

Answer 34

RUSH stands for Rapid Ultrasound for Shock and Hypotension.

Question 35

What is the primary purpose of the RUSH scan?

Answer 35

The primary purpose of the RUSH scan is to quickly identify the cause of shock and guide initial management.

Question 36

What are the key components assessed in the RUSH scan?

Answer 36

The key components are: 1. Heart: Assess for pericardial effusion, left ventricular function, right ventricular function. 2. IVC (Inferior Vena Cava): Evaluate for size and respiratory variation to estimate volume status. 3. Morrison’s pouch (right upper quadrant): Check for free fluid. 4. Aorta: Check for aneurysm or dissection. 5. Pulmonary: Assess for pneumothorax, pleural effusion, or interstitial syndrome (e.g., pulmonary oedema).

Question 37

What does FAST stand for in the context of trauma?

Answer 37

FAST stands for Focused Assessment with Sonography for Trauma.

Question 38

What is the primary purpose of the FAST scan?

Answer 38

The primary purpose of the FAST scan is to quickly identify free fluid (e.g., blood) in the peritoneal, pericardial, or pleural spaces, primarily in trauma settings.

Question 39

What are the key components assessed in the FAST scan?

Answer 39

The key components are: 1. Perihepatic and hepatorenal space (Morrison's pouch): Check for free fluid. 2. Perisplenic space: Check for free fluid. 3. Pelvis (pouch of Douglas in females, rectovesical pouch in males): Check for free fluid. 4. Pericardium: Check for pericardial effusion.

Question 40

How does the RUSH scan differ from the FAST scan?

Answer 40

1. The RUSH scan is more comprehensive and used in both trauma and medical patients to determine the cause of shock 2. The FAST scan is focused on trauma patients to quickly identify free fluid indicative of internal bleeding.