General Medicine
Nutritional Deficiencies
Nutritional deficiencies for MBBS: assessment, vitamin deficiencies, enteral versus parenteral nutrition and refeeding syndrome, mapped to NMC codes IM23.1 to IM23.5.
MedNext Academy | 3 min read
Nutritional Deficiencies
Nutritional deficiencies for MBBS: assessment, vitamin deficiencies, enteral versus parenteral nutrition and refeeding syndrome, mapped to NMC codes IM23.1 to IM23.5.
This chapter covers nutritional assessment and the common vitamin and protein-energy deficiencies encountered in clinical practice. It emphasises requirements during illness, the recognition and urgent treatment of thiamine deficiency, the choice between enteral and parenteral nutrition, and the danger of refeeding syndrome.
High-yield: Nutritional Deficiencies
- Nutritional assessment combines dietary history, anthropometry and biochemical markers to identify malnutrition.
- Caloric and protein requirements rise during acute illness and catabolic stress.
- Protein-energy malnutrition in hospital worsens outcomes and delays recovery.
- Thiamine deficiency causes beriberi and Wernicke encephalopathy, the latter being a medical emergency.
- Wernicke encephalopathy presents with confusion, ophthalmoplegia and ataxia and needs urgent thiamine.
- Thiamine must be given before glucose in at-risk patients to avoid precipitating Wernicke encephalopathy.
- Vitamin B12 deficiency causes megaloblastic anaemia and neurological features including subacute combined degeneration.
- Vitamin D deficiency causes rickets in children and osteomalacia in adults.
- Vitamin A deficiency is a leading cause of preventable childhood blindness and causes night blindness first.
- Vitamin C deficiency causes scurvy with bleeding gums, perifollicular haemorrhage and poor wound healing.
- Enteral nutrition is preferred over parenteral nutrition when the gut is functional.
- Refeeding syndrome causes dangerous falls in phosphate, potassium and magnesium when feeding is restarted too quickly.
- Parenteral nutrition is reserved for a non-functioning gut and carries infective and metabolic risks.
- A balanced diet counselling addresses macronutrient and micronutrient adequacy during illness.
- Iron, folate and iodine deficiencies remain important public health nutritional problems in India.
Nutrition essentials
- **Assessment:** Dietary history, anthropometry and biochemistry; requirements rise in acute illness.
- **Thiamine:** Deficiency causes Wernicke encephalopathy; give thiamine before glucose in at-risk patients.
- **Route:** Enteral nutrition is preferred when the gut works; parenteral only for a non-functioning gut.
- **Refeeding:** Restarting feeding too fast drops phosphate, potassium and magnesium dangerously.
NMC competencies in this chapter
- **IM23.1:** Nutritional assessment and caloric requirements during illness
- **IM23.2:** Protein-calorie malnutrition in the hospital
- **IM23.3:** Common vitamin deficiencies
- **IM23.4:** Enteral and parenteral nutrition in critically ill patients
- **IM23.5:** Counselling patients on a balanced diet during illness
Frequently Asked Questions
Why is thiamine given before glucose in at-risk patients?
Giving glucose to a thiamine-deficient patient can precipitate Wernicke encephalopathy, so thiamine is administered first in those at risk, such as alcohol-dependent or malnourished patients.
When is parenteral nutrition preferred over enteral?
Enteral nutrition is preferred whenever the gut is functional; parenteral nutrition is reserved for a non-functioning gut and carries higher infective and metabolic risks.
What is refeeding syndrome?
Refeeding syndrome is a dangerous drop in phosphate, potassium and magnesium when nutrition is reintroduced too quickly in a severely malnourished patient, and it is prevented by cautious feeding and monitoring.
How does this chapter help for NEET-PG?
Vitamin deficiency syndromes, the thiamine before glucose rule and refeeding syndrome are common exam themes that map directly to questions.
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