Food related disorders Flashcards
What is the pathophysiology of lactose intolerance ?
After weaning from breast milk, downregulation of expression of lactase gene causes reduction in the production of lactase enzyme except in Caucasians. This causes the lactose to pass to the large intestine intact, where it is consumed by the micro-flora and causes the production of gas and short chain fatty acids leading to blotting and osmotic diarrhoea.
what is Primary lactase deficiency?
It is caused by the absence of lactase persistence allele and is the classical form of lactate intolerance.
What is Secondary lactase deficiency?
Temporary lactose intolerance due to recent
infectious or inflammatory condition
what is Congenital lactase deficiency?
Autosomal recessive disorder resulting in inability to produce lactase from birth.
what is the clinical presentation of lactate intolerance ?
Abdominal bloating and/or
cramping, Flatulence, Diarrhoea, Borborygmi ± Nausea and Vomiting.
What is the symptomatological difference between milk allergy and lactate intolerance ?
Systemic symptoms such as Headache, Vertigo, fatigue, Memory impairment and Arrhythmias are only seen in milk allergy.
What is the Dx work up in lactate intolerance ?
It is a clinical diagnosis and testing is not usually required. Elimination of diet is diagnostic. Intestinal biopsy can be confirmatory, but is rarely done. If the hydrogen is > 20 PPM in Lactose hydrogen breath test lactose intolerance can be diagnosed. Rule out also Coeliac disease, crohn’s disease and infections
What are the ways to manage and prevent lactose intolerance ?
- Lactose restriction is the Most effective method and Up to 12 g lactose (1 cup milk) can be tolerated without significant symptoms.
Careful monitoring of food labels, patient education on high vs low-lactose containing foods can be helpful. - Supplemental Lactase can be Taken prior to meals and is Available over the counter.
What is the pathophysiology of Coeliac disease?
Tissue transglutaminase (tTG) deaminates gluten peptides which are subsequently phagocytosed by macrophages. In patients with coeliac disease, portions of deaminated gluten peptides are presented on the cell surface of the macrophage via unique versions of the MHC Class II molecules such as the DQ 2 and DQ 8. T-helper cells recognize the presented material and start local immune response and attract B-cells which release tTG antibodies causing systemic symptoms. Finally the Killer T cells recognize macrophage is in trouble and
start the process of destroying nearby enterocytes.
What is the Genetic aetiology of Coeliac disease?
Every patient with coeliac disease will have either the HLA-DQ2 and/or HLADQ8 alleles of the MCH Class II molecule gene. BUT not everyone who has one or both of these alleles will develop coeliac disease. If genetic testing DOES NOT reveal DQ2 or DQ8 alleles, you have eliminated coeliac disease and the patient may be diagnosed as having gluten intolerance.
What are the Gastrointestinal manifestations of Coeliac disease?
Diarrhoea, Steatorrhea, Bloating, Flatulence, Malabsorption, Weight loss and Vitamin deficiency.
What are the Extra-intestinal manifestations of Coeliac disease?
– Neurologic symptoms such as Ataxia and neuropathy. Dermatitis herpitiformis and Amenorrhea. Infertility,osteopenia and anaemia.
What are the diagnostic work-ups in Coeliac disease?
- IgA antibodies against tissue transglutaminase (tTG-IgA) and Total IgA.
*Upper endoscopy with small bowel biopsy
*Genetic testing for HLA-DQ2 and HLA-DQ8 but should only be used to rule out the disease.
What is the requirement for upper endoscopy for biopsy in Coeliac disease?
Patient undergoing diagnostic evaluation must be currently exposed to gluten (minimum
of last two weeks, preferably 8+ weeks) in order to have abnormal results detected on
serology and endoscopy.
What are the biopsy features of Coeliac disease?
Mucosal atrophy, blunting of intestinal villi and
increased intraepithelial lymphocytes.
