--- module: 050-02 language: en chapter: 50 title: "Malnutrition, Micronutrients, Enteral and Parenteral Support, and Obesity Care" module_title: "Nutritional diagnosis, refeeding physiology, artificial support, and metabolic treatment" source_sha256: 384bd31b3f248372880f20dddc6522125eb7050813698f467fa8b07114c6691b --- # Nutritional diagnosis, refeeding, artificial support, and metabolism ## Nutritional diagnosis ### Distinguish intake, absorption, catabolism, composition ### Weight mixes fat, muscle, bone, organs, water #### Oedema, ascites, obesity conceal muscle loss ### Combine weight rate, intake, disease, examination ### Examine muscle at temples, clavicles, interossei ### Grip, chair rise, gait, cough show function ## Fasting and critical illness ### Fasting: falling insulin mobilises stored fuel #### Ketone adaptation lowers amino-acid demand #### Red cells still need glucose ### Critical illness: stress hormones and cytokines #### Proteolysis and hepatic glucose despite feeding ### Treat disease, give protein, load muscle safely ## Energy and protein targets ### Requirement is estimated, not assumed ### Predictive equations fail in obesity, fever, burns ### Indirect calorimetry measures gas exchange ### Overfeeding: carbon dioxide, glucose, liver fat #### Adds ventilatory burden ### Underfeeding prolongs negative balance ### Protein target follows organs, losses, catabolism ### Measure actual delivery, not the prescription ## Biochemical markers ### Albumin is not a nutritional scoreboard #### Inflammation, leak, dilution, loss, liver failure #### Low value predicts severity, not intake #### Infused albumin does not rebuild muscle ### Nitrogen balance is only approximate ## Micronutrients ### Iron deficiency may precede microcytosis #### Ferritin rises with inflammation ### B twelve: nerve damage with or without anaemia #### Folate can mask progressing B twelve injury ### Thiamine deficiency #### Wernicke, neuropathy, lactic acidosis, heart failure #### Classic triad often incomplete #### Treat parenterally without waiting for results ### Fat malabsorption: vitamins A, D, E, K ### Zinc, copper, vitamin C, selenium by mechanism #### Excess zinc can cause copper deficiency ### Empirical replacement can itself be toxic ## Refeeding syndrome ### Intracellular redistribution emergency ### Total-body depletion despite normal serum values ### Carbohydrate raises insulin #### Electrolytes shift into cells #### Phosphorylation and ATP demand rise #### Sodium and water retained ### Arrhythmia, respiratory failure, seizure, death ### Identify risk before feeding ### Thiamine, electrolytes, cautious start, stepwise rise ### Do not stop feeding reflexively for every fall ## Oral and enteral support ### Oral preferred when swallowing is safe #### Treat symptoms, remove unnecessary fasting #### Texture change may reduce intake #### Mealtime assistance may beat a prescription ### Enteral when gut works but oral is insufficient #### Nasogastric short term, post-pyloric selected #### Confirm position, air auscultation unreliable ### Tube does not stop aspiration of saliva or reflux ### Residual volumes cause avoidable interruption ### Diarrhoea: antibiotics, infection, sorbitol, rate ## Parenteral nutrition ### When the gut cannot absorb enough safely ### Not automatically superior in critical illness ### Central access: infection, thrombosis, occlusion #### Dedicated aseptic lumen, daily necessity review ### Excess glucose: hyperglycaemia, lipogenesis, CO2 ### Long term: cholestasis, steatosis, trace elements ### Abrupt stop with insulin risks hypoglycaemia ### Transition while confirming oral delivery ## Obesity and metabolic treatment ### Chronic relapsing biological condition #### Stigma delays care, ask permission ### Sarcopenic obesity missed by body mass index #### Goal becomes function, not weight alone ### Weight loss triggers hunger and lower expenditure ### Drugs need long-term use and class-based review ### Metabolic surgery: durable loss, many benefits #### Leak, dumping, gallstones, deficiencies #### Vomiting or neurology may signal thiamine lack ## Goals, discharge, and follow-up ### Goals follow prognosis and values #### Feeding may not help irreversible disease ### Discharge states route, intake, line care, tests ### Follow delivery, strength, wounds, not weight alone ### Plan is updated as illness and life change