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what is starvation?
Starvation is the physiological condition created in the body by chronically insufficient food intake
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what are the 2 types of starvation?
Physiological and Pathological
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what is pathological starvation?
- Its a disease:
- Protein energy malnutrition (PEM)
- Starvation disease
- Starvation- related malnutrition
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what is the reason that people don't survive starvation?
Due to a lack of adaptation
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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
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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
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what is a successful adaptation?
- Protein and energy balance = 0
- Normal serum albumin
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what is a failed adaptation?
- Continuing protein and fat loss
- Hypoalbuminemia
- Immune deficiency
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how many patients suffer from moderate-to-severe PEM?
- > 25%
- The Canadian Malnutrition Task Force reports prevalence as 45%
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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)
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what is starvation related malnutrition?
- Simple, uncomplicated PEM
- Muscle atrophy and fat depletion caused by solely by starvation
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what is chronic-disease related malnutrition?
Cachexia: Muscle atrophy and fat depletion caused by a combination of starvation and chronic systemic inflammation
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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
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what is a successful adaptation?
- PEM
- Halts the loss of body mass despite continuing starvation
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what does a stable body composition imply?
- Cessation of fat loss
- Cessation of lean tissue
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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)
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what happens to the body when there is reduced non-resting energy expenditure?
- Reduced work of moving
- Reduction of voluntary movements
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what happens when there is reduced energy expenditure per kg active tissues?
- Reduced heart rate and blood pressure
- Reduced muscle tone
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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
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what happens in terms of mechanism in a successful adaptation?
- Involves:
- Reduced energy "requirement" for homeostasis
- Reduced protein"requirement" for homestasis
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what are the benefits of a successful adaptation?
Survival
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what are the cost for a successful adaptation?
- Lean tissue loss
- Fatigue and inactivity
- Immunodeficiency
- Reduced tolerance to stress
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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)
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what are the consequences of adaptation to starvation (if obese people starve)?
- Muscle atrophy
- Lowered basal metabolic rate
- Fatigue
- Apathy
- Hypothermia
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what is the cause of Starvation Related Malnutrition (SRM)?
Common cause in the world is involuntary food deprivation
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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)
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what is Chronic disease-related malnutrition (CDRM)?
- starvation disease combined with chronic low grade systemic inflammation
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what is another name for CDRM?
Cachexia
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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
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what are the causes of starvation (CDRM) in hospitals?
- Anorexia
- Pain
- Nausea
- Chewing and swallowing problems
- Poverty
- Gastrointestinal obstruction
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what are the causes of systemic inflammation (CDRM) in hospitals?
- Chronic infection
- Autoimmune disease
- Chronic kidney
- Heart or lung disease
- Certain Cancers
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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 detect2 reasons:
- Patients with in-hospital starvation often have a normal BMI
- Patients commonly have multiple reasons for muscle atrophy
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what is the cardinal feature of starvation disaese is?
- Muscle atrophy
- (Fat depletion)
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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
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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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