PBL 11 - Crush Injury and Amputation

• What is major trauma?

  = any injury/combination of injuries which threatens life
• What is a crush injury?

  Injury resulting from subjection to severe pressure or force, often between 2 objects e.g. car accidents, industrial accidents, falling objects, and heavy machinery accidents, potentially resulting in damage to the tissues, muscles, nerves, and blood vessels in the affected area
• What does the severity of a crush injury depend on?

  Factors such as the force of the crush, the duration of compression, and the affected body part
• What are typically symptoms of crush injuries?

  Pain, swelling, bruising, deformity, difficulty moving the affected limb, and, in severe cases, shock due to blood loss internally or externally
• What is shock?


  = a medical emergency that occurs when the body's organs and tissues do not receive enough oxygen and nutrients to function properly due to various causes
• What are the typical signs of shock?

  Rapid, weak pulse - heart trying to compensate but not enough blood volumeLow blood pressure - due to dec blood volumeRapid and shallow breathing - organs not getting enough perfusion - build up in CO2 - triggers chemoreceptorsConfusion or unconsciousness - brain not getting enough perfusion
• What are the 4 main causes of shock?

  1. Hypovolemic2. Obstructive3. Distributive/vasodilatory4. Cardiogenic
• What is hypovolemic shock?

  Hypovolemia caused by significant loss of blood or fluids from the body due to severe bleeding, dehydration, or major burns etc --> reduced bv --> reduced preload --> reduced CO --> reduced tissue perfusion
• What is obstructive shock?

  Shock caused by the physical obstruction of blood flow, often due to conditions like a pulmonary embolism or cardiac tamponade --> reduced tissue perfusion
• What is cardiogenic shock?

  Shock caused by the heart being unable to pump enough blood to meet the body's needs due to heart failure etc --> reduced tissue perfusion
• What is distributive shock?

  Shock caused by widespread dilation of blood vessels --> reduced pre-load --> reduced CO --> inadequate blood supply to vital organs e.g. septic shock, anaphylactic shock etc
• How do we treat shock?

  Adress underlying cause e.g. infection if septic shockRestore blood volume using fluids or blood transfusion (if caused by severe hemorrhage)Provide O2
• What complications can arise from crush injuries?

  Multiple fractures

  Direct neurovascular damage —> ischaemia and/or numbness, tingling and sensory/motor deficits Compartment syndromeCrush syndrome AKI Infection
• How can we assess potential blood vessel damage?

  Using pulse points or doppler ultrasound
• How many pulse points are there?

  9
• What are the 9 pulse points?

  Radial Pulse (Wrist)Carotid Pulse (Neck)Brachial Pulse (Inside of elbow about two to three inches above the elbow crease)Temporal Pulse (Temple)Femoral Pulse (Groin - in femoral triangle)Popliteal Pulse (Back of Knee in the crease)Dorsalis Pedis Pulse (Top of Foot)
• Where is the dorsalis pedis pulse?

  Top of foot - place fingertips between great and first toes and slowly move them along groove between extensor tendons until pulse is palpable

  
• What is compartment syndrome?

  Increased pressure in a muscle compartment --> compression of bvs --> restriction of blood flow to muscles and nerves in that area --> ischaemia and permanent muscle and nerve damage
• How can a crush injury result in compartment syndrome?

  Significant force or compression can result in swelling and inflammation within the affected muscle compartment —> increased pressure...Worsened by damage to bvs caused by crush (worsens oedema and swelling) or fractures (results in local bleeding into compartment)
• How can we treat compartment syndrome?

  By relieving immediate pressure via a fasciotomy

  
• How does rhabdomyolysis result in an AKI?

  Released myoglobin is filtered by the kidneys glomeruli and usually excreted in the urine HOWEVER high levels of myoglobin accumilate in the renal DCT due to its acidic environment —> obstructionAdditionally, the renal tubular cells may take up myoglobin, leading to cellular injury= Acute kidney injury
• What is an AKI?

  = A sudden and rapid decline in kidney function, characterized by a sudden and often reversible decrease in the kidneys' ability to filter and excrete waste products and excess fluids from the blood —> buildup of waste products and electrolytes in the body, disrupting the balance of fluids and electrolytes
• What can cause an AKI?

  Decreased blood flow to the kidneys (prerenal causes) e.g. dec bp due to hypovolemia, heart failure etcDirect damage to the kidneys (intrinsic renal causes) e.g. inflammation, toxins etcObstruction of urine flow (postrenal causes) e.g. kidney stones —> obstructed flow and inc pressure in kidneys —> damage
• What is crush syndrome?

  The release of myoglobin and other cellular contents into the bloodstream from damaged muscles (rhabdomyolysis) --> acute kidney injury
• How can a crush injury result in crush syndrome?

  Crushing can damage muscles —> release of myoglobin and other cellular contents into the bloodstream (rhabdomyolysis)
• What are some consequences of an AKI?

  Dec kidney function (A WET BED):Metabolic acidosisFluid retention due to dec kidney function and reduced ability to form urineElectrolyte imbalances (sodium, potassium, and calcium) due to dec kidney function and reduced urine flowUremiaHypovolemia —> high bp
• How else can a crush injury result in an AKI?

  Shock (low bp —> reduced GFR —> reduced kidney function), dehydration etc
• Why are crush injuries at risk of infection?

  Open wounds or fractures associated with crush injuries can increase the risk of infection Inc by compromised blood supply to the affected area - may hinder the body's natural ability to fight infections
• What is a fracture?

  A broken bone accompanied by soft tissue injuryDifferent types of fracture can occur depending on the force applied to the bone
• What types of fractures are there?

  Greenstick Compression/buckle Transverse SpiralOblique Comminuted Segmental Avulsion
• What is a greenstick fracture?

  Where bone breaks incompletely due to bending - seen in children

  
• What is a transverse fracture?

  Where the break is in a straight line across the bone

  
• What is a spiral fracture?

  A ragged break which occurs when excessive twisting forces are applied to a bone e.g. in a football tackle

  
• What is an oblique fracture?

  Where the break is diagonal across the bone

  
• What is a compression/buckle fracture?

  Where the bone is crushed. This causes the broken bone to be wider or flatter in appearance - often seen in children

  
• What is a comminuted fracture?

  Where bone breaks into many fragments

  
• What is a segmental fracture?

  Comminuted fracture where fractured pieces are in segments

  
• What is an avulsion fracture?

  Where a tendon or ligament pulls off a piece of the bone

  
• What are the standard views used for a trauma x-ray?

  Lateral and AP view - allows us to assess displacement in all planes

  
• How do we describe a fracture?

  - Open or closed- Type of fracture- Location along bone- Displacement- AngulationDescribe distal part in relation to proximal using both lateral and AP view