Nutrition + diet/ Nutrition in medicine Flashcards
What are the main causes of undernutrition?
- reduced nutritional intake:
- anorexia
- dysphagia
- physical disability
- nil by mouth
- pain
- side effect of treatment - increases nutritional losses:
- malabsorption
- wound exudate/burns - increased nutritional requirements:
- inflammation/infection
- pyrexia
- tissue healing
- metabolic effects
What is MUST?
Malnutrition Universal Screening Test
- Should be complete for all patients on admission to hospital
- There are 5 steps:
1. BMI: >20 = 0; 18.5-20 = 1; <18.5 = 2
2. Weight loss (past 3-6 months): <5kg = 0; 5-10kg = 1; >10kg = 2
3. Acutely ill and no nutritional intake >5 days (0-2)
4. Add scores from 1-3 (out of 6) - score 2+ = high risk
5. Action plan: - 0: routine care
- 1: observe
- 2: treat
*repeat this weekly
What are the different component of anthropometry?
- weight: dry, oedema, ascites
- height: ulna, knee length, full body
- BMI: actual or estimate
- weight history: recent weight loss/gain
- other: mid upper arm (muscle) circumference (MUAC/MUAMC)
- fat mass
- fat free mass (protein status)
- handgrip dynamometry
What can MUAC tell you about BMI?
- if MUAC <23.5, BMI likely to be <20 (normal –> underweight)
- if MUAC >32, BMI likely to be >30 (overweight)
How can you estimate weight from BMI?
Weight = BMI x Height
How can estimate dry weight if a patient has ascites?
Tense - adds 14kg
Moderate - adds 6kg
Minimal - adds 2.2kg
How can estimate dry weight if a patient has peripheral oedema?
Severe (up to sacrum) - adds 10kg
Moderate (up to knee) - adds 5kg
Mild (ankle) - adds 1 kg
What is the daily protein requirement for a healthy adult?
0.75g/kg
What is the normal albumin range?
35-50g/L
What is the main cause of hypoalbuminaemia, how does it occur?
Inflammation and sepsis
- capillaries have increased permeability and albumin drifts out
What is refeeding syndrome/how does refeeding syndrome arise?
- In starvation glucagon increases and insulin decreases
- glycogen is used up in first 24-72 hours
- metabolism shifts carbohydrates/glucose to fats and protein
- loss of fat, lean body mass, water and minerals
- intracellular stores of K+, Mg2+ and PO4- are depleted
- then in refeeding the metabolism shifts back from fats to glucose
- this increases insulin, increases utilisation of thiamine, energy production increases and therefore there is an increase in the uptake of K+, Mg 2+ and PO4-
- -> as the stores of these ions are already depleted there if hypokalaemia, hypomagnesia, hypophosphataemia, thiamine deficiency, and salt + water retention = oedema
What are the consequences of hypophosphataemia?
- seizures
- paraesthesia
- rhabdomyolysis
- weakness
- fluid and salt retention
- cardiac failure
- impaired respiratory muscle function
- osteomalacia
What are the consequences of hypokalaemia?
- tetany
- paraesthesia
- tremors
- ataxia
- seizures
- arrhythmias
- anorexia
- abdominal pain
What are the consequences of hypomagnesaemia?
- paralysis
- paraesthesia
- rhabdomyolysis
- respiratory depression
- paralytic ileus
- constipation
- cardiac arrest
- arrhythmias
What are the risk factors for refeeding syndrome?
- any pt with very little/no food intake >5 days
Any 1 of:
- BMI = 16
- Unintentional weight loss (>15% in 3-6 months)
- Little/no nutritional intake (>10 days)
- low levels of K+, PO4- or Mg2+ prior to feeding
Any 2 of:
- BMI <18.5
- unintentional weight loss of >10% in 3-6 months
- little/no nutritional intake (>5 days)
- history of alcohol/drug abuse (+ chemotherapy, antacids and diuretics)
