Gastroenterology - Clinical Nutrition and Intestinal Failure Flashcards
What tool can be used to make a nutritional assessment of a patient?
MUST screening tool
Takes into account patients BMI, any weight loss and illness to assess overall risk of malnutrition.
How is malnutrition managed?
Food and encouragement.
Dietitian involvement is key for patients not meeting their nutritional requirements, and may prescribe nutrition supplements for patients.
NG tube can be given to provide nutritional and fluid requirements.
What is haemochromatosis?
An iron storage disorder in which excessive iron is deposited within issues.
Cause of haemochromatosis.
Autosomal recessive mutation of HFE gene on c’some 6.
Presentation of haemochromatosis.
- chronic tiredness
- joint pain
- pigmentation (bronze / slate grey)
- hair loss
- erectile dysfunction
- amenorrhoea
- cognitive symptoms
Note patients usually present after the age of 40 when iron overload becomes symptomatic; presents later in females due to menstruation acting to regularly eliminate iron from the body.
How is haemochromatosis diagnosed?
- serum ferritin elevated
- liver biopsy
- MRI can give detailed picture of hepatic and cardiac liver deposits
What are the complications of haemochromatosis?
- T1DM
- liver cirrhosis
- endocrine and sexual problems
- cardiomyopathy
- hepatocellular carcinoma
- hypothyroidism
- pseudogout
Management of haemochromatosis?
- venesection (weekly protocol of removing blood to decrease total iron)
- monitoring serum ferritin
- avoid alcohol
- genetic counselling
- monitoring and treating complications
What is Wilsons disease?
An excessive accumulation of copper in the body and tissues.
Aetiology of Wilsons disease?
Autosomal recessive mutation and Wilson disease protein on c’some 13.
Wilson disease protein normally responsible for removal of excess copper in the liver.
Features of Wilsons disease?
Hepatic problems (~40%):
- chronic hepatitis
Neurological problems (~50%):
- dysarthria
- dystonia
- Parkinsonism (copper deposition in basal ganglia)
Psychiatric problems (~10%):
- depression
- psychosis
Signs of Wilson’s disease?
Kayser-Fleischer rings in cornea.
Haemolytic anaemia.
Renal tubular acidosis.
Osteopenia.
Diagnosis of Wilsons disease?
GOLD STANDARD is liver biopsy for liver copper content.
Other investigations include:
- serum caeruloplasmin low
- 24-hour urine copper assay elevated
- low serum copper
- MRI brain showing non-specific changes
Management of Wilsons disease.
Copper chelation via:
- penicillamine
- trientene
Pathophysiology of alpha-1 antitrypsin deficiency?
Autosomal recessive defect of A1AT gene causes a deficiency of A1AT, which normally inhibits neutrophil elastase enzyme.
This causes cirrhosis of the liver, and causes bronchiectasis and emphysema in the lungs.
How is A1AT deficiency diagnosed?
- low serum-A1AT
- liver biopsy
- genetic testing for A1AT gene
- HRCT for bronchiectasis and emphysema
Management of A1AT deficiency.
- smoking cessation
- organ transplant for ESLD
- monitor for complications (e.g. hepatocellular carcinoma)
How much paracetamol must a patient take for serious and fatal adverse effects to take place?
In excess of 150mg/kg for adults.
Considerable inter-patient variability which depends on age, health and substances taken with paracetamol.
Pathophysiology of paracetamol poisoning.
Paracetamol is well absorbed from the stomach and small intestine, so reaches peak plasma concentration within 1 hour of ingestion.
It is conjugated by the liver, leading to two metabolites:
- glucuronide
- sulfate
When taken in overdose, the liver conjugation becomes inundated, causing paracetamol to be metabolised by an alternative pathway. This result in NAPQI formation, which is inactivated by glutathione to reduce any harm.
However, as glutathione levels deplete, NAPQI reacts with cells causing necrosis of the liver and kidney tubules.
Presentation of paracetamol overdose.
Asymptomatic for first 24 hours, or have general nonspecific abdominal symptoms (e.g. n+v).
After 24 hours hepatic necrosis begins, which can progress to acute liver failure:
- encephalopathy
- oliguria
- hypoglycaemia
- renal failure
- lactic acidosis
Clinical examination findings of paracetamol overdose.
Usually there is little to note, until acute liver failure develops.
If ALF develops:
- jaundice
- hepatic flap
- encephalopathy
- tender hepatomegaly
How should paracetamol overdose be investigated?
- U&Es (creatinine - renal failure?)
- LFTs (»ALT indicates hepatotoxicity)
- glucose (hypoglycaemia)
- clotting screen (prothrombin time)
- ABG (lactic acidosis)
- paracetamol level
How is paracetamol overdose managed?
- acetylcysteine
- activated charcoal
What is the mechanism of action of acetylcysteine?
Replenishes glutathione levels, allowing the liver to safely metabolise NAPQI and reducing the risk of ALF.
