307 - Human Starvation (Dr Hoffer lecture)

  1. what is starvation?
    Starvation is the physiological condition created in the body by chronically insufficient food intake
  2. what are the 2 types of starvation?
    Physiological and Pathological
  3. what is pathological starvation?
    • Its a disease:
    • Protein energy malnutrition (PEM)
    • Starvation disease
    • Starvation- related malnutrition
  4. what is the reason that people don't survive starvation?
    Due to a lack of adaptation
  5. what are the clinical features of PEM?
    • Reduced body weight
    • Adipose tissue depletion
    • Muscle wasting and decreased strength
    • Reduced respiratory and cardiac muscular capacity
    • Skin thinning
    • Deceased metabolic rate
    • Hypothermia
    • Apathy
    • Edema
    • Immunodeficiency
  6. what are some adaptive mechanisms to inadequate protein and/or energy intake?
    • Reduced protein store
    • ↓↓ Skeletal muscle mass
    • ↓ Heart muscle mass
    • ↓ Respiratory muscle mass 
    • ↓ Protein reserve

    • Reduced metabolic rate
    • Hypotension
    • Bradycardia
    • Hypothermia
  7. what is a successful adaptation?
    • Protein and energy balance = 0
    • Normal serum albumin
  8. what is a failed adaptation?
    • Continuing protein and fat loss
    • Hypoalbuminemia
    • Immune deficiency
  9. how many patients suffer from moderate-to-severe PEM?
    • > 25%
    • The Canadian Malnutrition Task Force reports prevalence as 45%
  10. what are the 3 kinds of starvation disease?
    • 1. Starvation related malnutrition (SRM)
    • 2. Chronic disease-related malnutrition (CDRM)
    • 3. Acute disease related malnutrition (ADRM)
  11. what is starvation related malnutrition?
    • Simple, uncomplicated PEM
    • Muscle atrophy and fat depletion caused by solely by starvation
  12. what is chronic-disease related malnutrition?
    Cachexia: Muscle atrophy and fat depletion caused by a combination of starvation and chronic systemic inflammation
  13. what is acute disease-related malnutrition (ADRM)?
    • Not necessarily an existing disease per se
    • Rapid severe muscle catabolism induced by critical illness of severe trauma or sepsis
    • Likely mitigated by sufficient protein provision
    • Patient may or may not have existing PEM
  14. what is a successful adaptation?
    • PEM
    • Halts the loss of body mass despite continuing starvation
  15. what does a stable body composition imply?
    • Cessation of fat loss
    • Cessation of lean tissue
  16. what happens to the body when there is reduced ↓ resting energy expenditure?
    • Reduced ↓ mass of metabolically active tissue (muscle mass) (slow, and takes weeks)
    • Reduced ↓ energy expenditure per unit active tissue (fast, takes days)
  17. what happens to the body when there is reduced non-resting energy expenditure?
    • Reduced work of moving
    • Reduction of voluntary movements
  18. what happens when there is reduced energy expenditure  per kg active tissues?
    • Reduced heart rate and blood pressure
    • Reduced muscle tone
  19. what happens with reduced protein requirement in starvation?
    • Diminished ↘ lean tissue mass
    • More efficient retention of dietary protein
    • Lean tissue mass stabilizes despite continued low protein intake
  20. what happens in terms of mechanism in a successful adaptation?
    • Involves:
    • Reduced energy "requirement" for homeostasis
    • Reduced protein"requirement" for homestasis
  21. what are the benefits of a successful adaptation?
  22. what are the cost for a successful adaptation?
    • Lean tissue loss
    • Fatigue and inactivity
    • Immunodeficiency
    • Reduced tolerance to stress
  23. weight reduction is what kind of starvation?
    • Pathological starvation
    • Obese people benefit from reducing their excessive body store of adipose tissue to a desirable size
    • To accomplish this goal, they have to consumme less energy for a long time (aka they must starve)
  24. what are the consequences of adaptation to starvation (if obese people starve)?
    • Muscle atrophy
    • Lowered basal metabolic rate
    • Fatigue
    • Apathy
    • Hypothermia
  25. what is the cause of Starvation Related Malnutrition (SRM)?
    Common cause in the world is involuntary food deprivation
  26. what are the causes of Starvation Related Malnutrition in hospitals (SRM)?
    • Anorexia
    • Pain 
    • Nausea
    • Chewing and swallowing problems
    • Poverty
    • Gastrointestinal obstruction
    • Dysgeusia (when things taste bizarre)
  27. what is Chronic disease-related malnutrition (CDRM)?
    • starvation disease combined with chronic low grade systemic inflammation
  28. what is another name for CDRM?
  29. what are the characteristics of systemic inflammation?
    • Acute phase response (hypoalbuminemia and increased C-reactive protein concentration)
    • Increased muscle protein catabolism
    • Anorexia
    • Impaired adaptation to starvation
  30. what are the causes of starvation (CDRM) in hospitals?
    • Anorexia
    • Pain
    • Nausea
    • Chewing and swallowing problems
    • Poverty
    • Gastrointestinal obstruction
  31. what are the causes of systemic inflammation (CDRM) in hospitals?
    • Chronic infection
    • Autoimmune disease
    • Chronic kidney
    • Heart or lung disease
    • Certain Cancers
  32. Why are in-hospital starvation diseases so often ignored?
    • Cardinal features of starvation disease are generalized muscle atrophy and fat depletion but they are easy to detect
    • 2 reasons:
    • Patients with in-hospital starvation often have a normal BMI
    • Patients commonly have multiple reasons for muscle atrophy

  33. what is the cardinal feature of starvation disaese is?
    • Muscle atrophy
    • (Fat depletion)
  34. what are the 6 causes of muscle atrophy?
    • 1. Cachexia - systemic inflammation
    • 2. Hormone excess or deficiency
    • 3. Old age - sarcopenia 9 loss of muscle w/age)
    • 4. Protein energy malnutrition (PEM) - starvation disease
    • 5. Inactivity - disuse atrophy
    • 6. Neuromusclar disease
  35. Summary
    • Starvation can be Physiological and Pathological
    • Pathological starvation: Leads to the disease called PEM
    • PEM: common + difficult to treat disease in Montreal hospitals
    • SRM: simples, uncomplicated PEM (as in AN)
    • CDRM: PEM + chronic systemic inflammation that:
    •            ↑ muscle protein catabolism, induces anorexia and impairs the adaptation to starvation
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307 - Human Starvation (Dr Hoffer lecture)