Trauma and nutrition Flashcards
What are the 4 main immediate possible features of physical trauma?
1) Intravascular fluid loss
2) Extravascular volume decrease
3) Tissue Destruction
4) Impaired Breathing
What are the 3 main later possible features of physical trauma (in addition to the 4 immediate effects)?
1) Starvation
2) Infection
3) Inflammation
As a consequence of a major accident a patient could suffer blood loss, impaired breathing and infection barrier penetration, what 7 effects would this cause which would lead to major organ dysfunction and sepsis?
1) Decreased circulating volume
2) Decreased red cells (Decreased O2)
3) Decreased white cells (reduced immune response)
4) Decreased cardiac output/BP
5) Decreased organ perfusion
6) Decreased energy substrate delivery to cells
What are the 2 main causes of mortality after major trauma within 5 days?
1) Head injury
2) Haematological shock
What are the 2 main causes of mortality after major trauma within 5-10 days?
1) Multi-organ failure
2) Acute respiratory distress syndrome
What is trauma?
An injury or wound to living tissue caused by an extrinsic agent
What 2 interruptions does shock cause?
Interruption to supply of substrates to the cell and interruption to the removal of metabolites from the cell
What are the 4 main kinds of trauma?
1) Injury
2) Surgery
3) Burns
4) Infection
What are the phases that a patient goes through following trauma?
Phase 1: Clinical shock
Phase 2: Hypercatabolic state (breakdown and use of substances)
Phase 3: Recovery (anabolic state) (storage of substances and growth)
What are the 2 possible outcomes of Phase 1: Clinical shock?
1) Spontaneous recovery - physiological adaptation
2) Resuscitation - intervention, taking the patient into phase 2
Within how many hours following trauma does phase 1: shock develop and how long does it last for?
2-6 hours following trauma
Lasts 24-48 hours
What are the 3 main hormones/substances secreted during Phase 1: shock?
1) Cytokines
2) Catecholamines
3) Cortisol
What are the 4 main effects of the substances secreted during Phase 1: shock?
1) Tachycardia
2) Increased respiratory rate
3) Peripheral vasoconstriction (selective peripheral shut down to preserve vital organs)
4) Hypovolaemia
What are the 2 primary aims within phase 1: shock?
1) Stop bleeding
2) Prevent infection
Phase 1: catabolic state develops how many days after trauma?
Approximately 2 days after trauma
Does the catabolic state have a useful role in recovery?
Its necessary for survival but if persists or is severe it leads to increased mortality
What are the 3 main hormones released during the catabolic phase?
1) Catecholamines
2) Glucagon
3) ACTH causing release of cortisol
What are the 5 main effects of the hormones released during the catabolic phase?
1) Increased oxygen consumption
2) Increased metabolic rate
3) Negative nitrogen balance (Skeletal muscle breakdown to release amino acids)
4) Increased glycolysis (skeletal energy reserve depleted)
5) Increased lipolysis (adipose tissue breakdown to release fatty acids)
What are the 2 primary aims during the catabolic state?
1) Avoid sepsis
2) Provide adequate nutrition
After how many days does the anabolic state occur following trauma?
3-8 days following uncomplicated surgery
May not occur for weeks after severe trauma and sepsis
(Coincides with the beginning of diuresis and request for oral intake)
The anabolic state involves gradual restoration of what 4 processes?
1) Body protein synthesis
2) Normal nitrogen balance
3) Fat stores
4) Muscle strength
What is meant by the obesity paradox in the anabolic state?
Obese people tend to recover more quickly - increased reserves
Adequate nutritional supply is critical during the anabolic phase but what is the major risk?
Refeeding syndrome risk
How long does the anabolic phase last?
May last a few weeks or a few months
What are the 6 steps in an inflammatory response at a trauma sight?
1) Bacteria and pathogens enter the wound
2) Platelets release clotting factors
3) Mast cells secrete factors that mediate vasodilation to increase blood delivery to the injured area
4) Neutrophils and macrophages recruited to phagocytose pathogens
5) Macrophages secrete cytokines to attract immune cells and proliferate the inflammatory response
6) Inflammatory response is continued until wound is healed
Inflammatory mediator release after injury can cause systemic capillary leak, what 4 important substances escape from the capillaries?
1) H2O
2) NaCl
3) Albumin
4) Energy substrates
The cytokines IL-1, IL-6 and TNF can have what 8 effects?
1) Local effects (vasodilation, chemotaxis, cell adhesion proteins)
2) Metabolic effects (Catabolic)
3) Acute phase proteins
4) T cell activation and B cell proliferation
5) Anorexia
6) Endocrine effects (increased catabolic, inhibited anabolic)
7) Fever
8) Fibroblast proliferation (repair)
What are the 5 cardinal signs of inflammation?
1) Heat
2) Redness
3) Swelling
4) Pain
5) Loss of function
What are the 2 endocrine effects of cytokines?
1) Cytokine-mediated secretion of catabolic hormones (eg. IL-1 and TNF-alpha) - increased ACTH (->cortisol), glucagon and catecholamines
2) Cytokine-mediated inhibition of anabolic hormones (decreased growth hormone and insulin)
In health glycogen stores can maintain glucose for up to how many hours?
24 hours
What is the obligate substrate of the brain, what does it have to adapt to use as an alternative?
Obligate substrate = glucose (has no glycogen stores)
Adapts to using ketones as an energy substrate
What is the time limit of survival time for the brain in circulatory failure?
Won’t survive longer than 2 mins in circulatory failure
Why can the kidneys and liver survive for hours of interruption of blood supply?
Because the liver and kidneys are capable of gluconeogenesis
What are the main substrates of the liver and kidney?
Fatty acids and then amino acids
What are the main substrates of skeletal muscle?
Glycogen stores then fatty acids
1 kg of muscle produces how many grams of protein which produces how many grams of glucose?
1kg muscle = 200g protein = 120g glucose
What are the 3 stages in metabolic response to trauma?
1) Glycogenolysis - 24 hours max
2) Gluconeogenesis - skeletal and secreted protein breakdown
3) Lipolysis and ketogenesis
What 2 substances are amino acids broken down to form in gluconeogenesis?
Glucose and lactate
How many grams of nitrogen are lost per day during gluconeogenesis in the metabolic response to trauma?
60-70g per day
In lipolysis and ketogenesis in the metabolic response to trauma what 2 products are formed from FFAs?
FFA -> acetyl CoA -> acetoacetate and hydroxybutyrate
Which system particularly uses ketone metabolism in the metabolic response to trauma?
CNS
Ketones cause a loss of what 2 substances?
Cause diuresis (as they are acids) with a loss of H20 and electrolytes
Aerobic metabolism produces how many moles of ATP from 1 moles of glucose?
36
Anaerobic metabolism produces how many moles of ATP from 1 mole of glucose?
2
How does anaerobic metabolism lead to lysosomal enzyme release, what does this lead to?
1) Loss of ATP
2) Leads to loss of Na/K pump
3) Which leads to cellular swelling and loss of membrane integrity
4) Which leads to lysosomal enzyme release
5) Leads to cell death
In lactic acidosis what is the pH and [Lactate], what does this lead to?
pH 5.0 mmol/L
Cell death
How is muscle mass and [plasma protein] maintained in health?
By a balance between synthesis of new protein and skeletal muscle proteolysis
In trauma there is a unbalanced protein turnover, what 3 things does the unbalanced increase in skeletal muscle proteolysis lead to?
1) Increased [Free amino acids] - transported to the liver for gluconeogenesis and protein synthesis
2) Increased plasma [ammonia]
3) Increased N2 loss - via urinary excretion of urea
In trauma there is a decrease in the synthesis of new protein, the synthesis of which proteins increases and which decreases?
Increase in inflammatory modulators and scavengers (CRP, haptoglobin, clotting factors, modulators of clotting eg. protease inhibitors)
Decrease in albumin
What percentage of the bodies protein is readily available as a source of energy?
30%
Why will administration of adequate calories as carbohydrate/lipid not stop muscle wasting in trauma patients?
Because the primary stimulation for protein breakdown is cytokine secretion from activated macrophages
What will stop muscle wasting in starvation?
Administration of adequate calories as lipid/carbohydrate
How could protein turnover in trauma lead to pneumonia?
1) Extensive proteolysis leads to life-threatening damage to essential structural and secreted protein
2) Respiratory muscle weakness results in poor cough and retention of secretions
3) This can lead to pneumonia
Why is lactate produced in hypoxia?
Anaerobic respiration
Pyruvate doesn’t undergo oxidative phosphorylation via the TCA cycle but is reduced to lactate
What limits the length of time for which anaerobic metabolism can continues?
Can only continue until [Lactate] becomes toxic as H+ inhibits enzymes
How does lactate correspond with prognosis?
Blood lactate 5 = ~100% mortality
In a fracture of a long bone roughly how many grams of muscle protein are lost?
60-70g
In severe burns how many grams of muscle protein are lost?
300g
What is primary malnutrition?
Protein-calorie undernutrition (starvation)
Can be a dietary deficiency of specific nutrients
What is secondary malnutrition?
Nutrients present in equal amounts but appetite is suppressed or…
nutrients present in adequate amounts but absorption and utilization are inadequate or…
Increased demand for specific nutrients to meet physiological need
What are the 3 main consequences of malnutrition?
1) Negative nitrogen balance
2) Muscle wasting
3) Widespread cellular dysfunction
Malnutrition is associated with what 5 things in hospital?
1) Infection
2) poor wound healing
3) Changes in drug metabolism
4) Prolonged hospitalisation
5) Increased mortality
What are the 5 main features of refeeding syndrome?
1) Hypokalaemia
2) Hypomagnesaemia
3) Hypophosphataemia
4) Thiamine deficiency
5) Salt and water retention - oedema
How does refeeding syndrome occur?
Refeeding after starvation of malnutrition leads to sudden insulin secretion which leads to sudden increase in protein and glycogen synthesis which leads to increased glucose uptake, utilization of thiamine, uptake of K+, Mg 2+ and PO42- which leads to deficiencies of these substances in the blood
What is the main simple function of the CFTR protein?
facilitates production of thin, watery, free flowing mucous, which lubricates the airways and secretory ducts and protects the lining of the airways, digestive system and reproductive system so that macromolecules (eg. digestive enzymes) can be secreted smoothly out of secretory ducts
Why does CFTR dysfunction lead to malnutrition?
Via digestive enzyme deficiencies
Why does CFTR dysfunction lead to lung disease?
1) Increased bacterial colonisation
2) Causes neutrophil accumulation and elastase is secreted which digests lung proteins causing tissue damage
3) Dead neutrophils release DNA which increases the viscosity of CF sputum
What are the 6 main signs and symptoms relating to the GIT in CF?
1) Meconium ileus at birth
2) Severe hepatobiliary disease - hepatic metabolism of lipids, steroid hormones, drugs and toxins is compromised
3) Pancreatic cysts - exocrine insufficiency
4) Poor apetite
5) Failure to thrive
6) Low weight
Pancreatic cysts and the resultant exocrine insufficiency in CF has what 3 main affects?
1) Decreased insulin - diabetes
2) Decreased lipase - lipid malabsorption, steatorrhoea, fat soluble vitamin deficiency
3) Decreased protease - protein malnutrition
What are the 6 treatments for respiratory disease in CF?
1) Physio
2) Exercise
3) Bronchodilators
4) Abx
5) Steroids
6) Mucolytics (DNAse)
What are the 5 treatments for GI disease in CF?
1) Pancreatic enzyme replacement (creon)
2) Nutritional supplements
3) Fat soluble vitamins
4) High calorie diet
5) Ursodeoxycholic acid
Does trauma simply refer to injuries?
No, for example surgery is medically inflicted trauma
