---

What Was Answered (Summary)

Section A - Trauma & Emergency Surgery

1. Shock - Definition, classification (5 types), ATLS Classes I-IV, full management of hemorrhagic shock
2. Burns - Classification by depth, Wallace Rule of Nines, Parkland formula, airway management, surgical management
3. Tension Pneumothorax - Pathophysiology, clinical features, immediate needle decompression
4. Flail Chest - Paradoxical movement, management with analgesia + ventilation
5. Primary & Secondary Survey (ATLS ABCDE)
6. Damage Control Resuscitation - Permissive hypotension, 1:1:1 blood products, tranexamic acid

Section B - Wound & Soft Tissue

1. Wound Healing - 4 phases, factors affecting healing (local + systemic)
2. Chronic Ulcers - TIME framework, venous/arterial/diabetic/pressure ulcer management
3. Surgical Site Infections - Classification, organisms, prevention, treatment
4. Skin Grafts - SSG vs FTG comparison table, degloving injury
5. Keloid vs Hypertrophic Scar
6. Gas Gangrene - Clostridium, features, treatment (debridement + penicillin + HBO)

Section C - Elective Surgery

1. Hernia - Classification, direct vs indirect inguinal hernia, Lichtenstein mesh repair
2. Incisional Hernia - Risk factors, mesh repair
3. Abdominal Incisions - 9 types with uses, criteria for ideal incision
4. Uterine Prolapse - Degrees, features, pessary/surgical management (Manchester, vaginal hysterectomy)
5. Laparoscopic vs Robotic Surgery - Pros and cons

Section D - ENT & Ophthalmology (included in this paper)

1. Hearing Aids - 7 types (BTE, ITE, CIC, BAHA, Cochlear implant) with indications
2. Conjunctivitis - Bacterial, viral, allergic, gonococcal, trachoma
3. Refractive Errors - Myopia, hypermetropia, astigmatism, presbyopia
4. Blindness - Causes and prevention (SAFE strategy for trachoma)

Section E - Miscellaneous

1. Blood Transfusion Complications - Immediate + delayed + massive transfusion
2. SIRS & Sepsis - Definitions, Sepsis-3, Surviving Sepsis bundle
3. Anaesthesia - General, spinal, epidural, local with complications
4. GCS - Full scoring table
5. Intracranial Haemorrhages - Extradural (biconvex, lucid interval), subdural, SAH, intracerebral
6. Urinary Incontinence - 5 types, conservative/medical/surgical management
7. Haemolytic Disease of Newborn - Rh incompatibility, anti-D prophylaxis
8. Pregnancy Signs by Trimester

---

SHOCK - Detailed Explanation

---

1. Definition

"A manifestation of the rude unhinging of the machinery of life" - Gross, 1872 (Sabiston Textbook of Surgery)

---

2. Classification of Shock

---

3. Pathophysiology of Shock

A. Cellular Level

• Anaerobic respiration ceases
• Sodium-potassium ATPase pumps fail - cells swell with sodium and water
• Intracellular lysosomes rupture and release autodigestive enzymes
• Cell lysis occurs - intracellular potassium floods the bloodstream, causing hyperkalaemia
• This cellular injury is reversible early but becomes irreversible with prolonged shock

B. Microvascular Level

• Hypoxia and acidosis activate complement and prime leukocytes
• Generation of oxygen free radicals and cytokine release
• Injury to capillary endothelial cells - they become "leaky"
• Fluid escapes into tissues - tissue oedema forms, worsening cellular hypoxia
• Activation of the coagulation cascade can lead to DIC (Disseminated Intravascular Coagulation)

C. Systemic / Organ Level

• Reduced preload and afterload trigger baroreceptors
• Increased sympathetic activity → catecholamine release (adrenaline, noradrenaline)
• Results in: tachycardia, systemic vasoconstriction (except in septic/distributive shock where vasodilation occurs)

• Decreased renal perfusion → reduced glomerular filtration → oliguria
• Renin-angiotensin-aldosterone axis activated → further vasoconstriction + sodium/water retention

• Vasopressin (ADH) released → vasoconstriction + water reabsorption by collecting ducts
• Cortisol released from adrenal cortex → sensitises vessels to catecholamines, promotes sodium/water retention
• Respiratory compensation: Metabolic acidosis drives increased respiratory rate (tachypnoea) to blow off CO2 and produce compensatory respiratory alkalosis

---

4. ATLS Classification of Haemorrhagic Shock (Grades I-IV)

---

5. Clinical Stages of Shock

Compensated (Mild) Shock

• Tachycardia, tachypnoea
• Mild reduction in urine output
• Mild anxiety
• Blood pressure maintained (normal), but pulse pressure narrows
• Cool, sweaty peripheries, prolonged capillary refill time
• The body is still fighting - perfusion to skin, muscle, and gut is sacrificed to protect heart and brain

Uncompensated - Moderate Shock

• Compensatory mechanisms begin to fail
• Urine output drops below 0.5 mL/kg/hour
• Blood pressure starts to fall (mild hypotension)
• Increasing tachycardia
• Patient becomes drowsy and confused

Uncompensated - Severe Shock

• Profound hypotension
• Maximal tachycardia, then bradycardia as a preterminal sign
• Patient is comatose or unresponsive
• Anuric (no urine output)
• Labouring respiration
• Peripheries no longer respond to vasopressors
• Death is imminent without intervention

---

6. Specific Types - Additional Details

Hypovolaemic / Haemorrhagic Shock

Hypothermia + Coagulopathy + Acidosis Each factor worsens the others in a deadly spiral: bleeding → acidosis and hypothermia → impaired coagulation → more bleeding.

Cardiogenic Shock

• Heart fails as a pump
• Evidence of venous hypertension (JVP raised, pulmonary oedema) alongside signs of low output
• NOT hypovolaemic - the problem is pump failure, NOT volume depletion
• Treating with aggressive fluids can worsen pulmonary oedema

Obstructive Shock

• Mechanical obstruction reduces cardiac filling (preload)
• Tension pneumothorax, tamponade: the heart is compressed externally
• Beck's triad of tamponade: Hypotension + raised JVP + muffled heart sounds
• Treatment is removing the obstruction (needle decompression, pericardiocentesis)

Distributive / Septic Shock

• Peripheral vasodilation causes blood to "pool" in the periphery
• Cardiac output is actually high (hyperdynamic circulation) but tissue extraction is impaired
• Features: warm peripheries, bounding pulse, widened pulse pressure (opposite to hypovolaemic shock)
• Pathogenesis: Microbial substances (endotoxin, LPS) → activate TLRs → massive cytokine release (TNF, IL-1, IL-6) → vasodilation + endothelial damage + coagulation activation → DIC + multi-organ failure
• Mortality: 20-40% despite treatment (Robbins Pathology)

Neurogenic Shock

• Loss of sympathetic vasomotor tone following spinal cord injury (above T6)
• Bradycardia + hypotension (in contrast, hypovolaemic shock causes tachycardia)
• Warm, dry skin (vasodilated, not vasoconstricted)

Anaphylactic Shock

• IgE-mediated hypersensitivity reaction → massive histamine release
• Vasodilation + increased vascular permeability
• Trigger: Bee sting, drug (penicillin, NSAID), food (peanut)
• Adrenaline (epinephrine) is the first-line treatment

---

7. Ischaemia-Reperfusion Injury and SIRS

• The acid and potassium load that built up during hypoperfusion floods the circulation
• Causes direct myocardial depression and further vasodilation
• Molecules from dead cells (DAMPs - Damage-Associated Molecular Patterns) activate leukocytes
• Complement, neutrophils, and microvascular thrombi cause injury to distant organs (lungs, kidneys, brain)
• Leads to: ARDS (Acute Respiratory Distress Syndrome), Acute Kidney Injury, cerebral oedema
• This is the basis of Multiple Organ Failure (MOF)

---

8. Management of Shock

Universal Principles (All Types)

1. Treat the cause (haemorrhage control, drain pus, fix the heart)
2. Correct hypovolaemia first - give IV fluids before any vasopressor; giving vasopressors to an empty heart is dangerous and depletes myocardial oxygen rapidly
3. Airway and O2 - high-flow oxygen, intubate if GCS <8 or airway at risk
4. IV access - two large-bore (14-16G) peripheral cannulae; short, wide-bore cannulae allow rapid infusion (central lines have too high resistance for rapid resuscitation)

Management of Haemorrhagic Shock

• External: direct pressure, tourniquet, wound packing
• Internal: emergency surgery or angioembolisation
• Haemorrhage control is the single most important step - no amount of resuscitation corrects ongoing bleeding

1. Rapid haemorrhage control (surgical or interventional)
2. Permissive hypotension - allow SBP 80-90 mmHg (MAP ~50 mmHg) until bleeding is controlled; aggressive normalization of BP increases bleeding. Exception: Traumatic Brain Injury (maintain CPP, do not allow hypotension)
3. Avoid dilutional coagulopathy - minimize crystalloid; use blood products instead
4. Haemostatic resuscitation - blood products in a 1:1:1 ratio (packed red cells : fresh frozen plasma : platelets) to mimic whole blood

• Tranexamic acid (TXA): antifibrinolytic; 1g IV over 10 min, then 1g over 8 hours; must be given within 3 hours of injury (after 3 hours, it is harmful)
• Warm all fluids (prevent hypothermia)
• Calcium supplementation (citrate in blood products chelates calcium)
• Type O negative blood for immediate life-threatening haemorrhage while cross-match is awaited

• Urine output: target >0.5 mL/kg/hr (adults); >1 mL/kg/hr (children)
• Lactate clearance (normalize within 24 hours)
• Base deficit correction
• Heart rate and blood pressure normalization

Management of Septic Shock (Surviving Sepsis Bundle - 1-hour bundle)

1. Blood cultures (before antibiotics)
2. Broad-spectrum antibiotics within 1 hour of recognition
3. IV crystalloid 30 mL/kg for hypotension or lactate ≥4 mmol/L within 3 hours
4. Vasopressor (first choice: noradrenaline/norepinephrine) to achieve MAP ≥65 mmHg if fluids insufficient
5. Measure serum lactate; repeat if initial >2 mmol/L
6. Source control: identify and drain/remove focus of infection

Management of Cardiogenic Shock

• Treat underlying cause (reperfusion for MI - thrombolysis or primary PCI)
• Careful fluid challenge (do NOT flood the lungs)
• Inotropes (dobutamine - positive inotrope, reduces afterload)
• Mechanical support: Intra-Aortic Balloon Pump (IABP), LVAD in refractory cases

Management of Obstructive Shock

• Tension pneumothorax: Immediate needle decompression (14G, 2nd ICS, MCL) → chest drain
• Cardiac tamponade: Pericardiocentesis (needle drainage of pericardial fluid)
• Massive PE: Systemic thrombolysis or surgical embolectomy

Management of Anaphylactic Shock

• Adrenaline (epinephrine) 0.5 mg IM (1:1000 solution) immediately - repeated every 5 min
• IV fluids (large volumes)
• Antihistamines (chlorphenamine IV) + hydrocortisone IV (second line)
• Remove trigger
• Secure airway early (angioedema can close airway rapidly)

---

9. Type of Fluids in Shock

Colloids have no proven advantage over crystalloids in most studies; they are more expensive and have worse side-effect profiles - Bailey & Love's Surgery

---

10. Monitoring the Response to Shock Treatment

---

Summary Diagram of Shock

CAUSE (haemorrhage / sepsis / pump failure / obstruction)
        ↓
REDUCED TISSUE PERFUSION
        ↓
CELLULAR HYPOXIA
        ↓
Aerobic → Anaerobic metabolism → Lactic acidosis
        ↓
Na/K pump failure → Cell swelling → Lysosomal rupture → Cell death
        ↓
Endothelial damage → Capillary leak → Tissue oedema
        ↓
Coagulation activation → DIC
Immune activation → Cytokine storm
        ↓
ORGAN FAILURE (Lung-ARDS / Kidney-AKI / Liver / Brain)
        ↓
MULTIPLE ORGAN FAILURE → DEATH (60% mortality)

---