Gut Flashcards
How do you classify imperforated anus?
Into High vs Low. Based on relation to puborectalis muscle.
What do you see in Alagille liver on biopsy?
fibrosis, absence of bile ductules, normal hepatic arterioles and central vein.
What neural aetiology has been proposed in pyloric stenosis?
Localised lack of NO synthase, reduction in neurofilaments, adhesion molecules.
What other conditions are associated with pyloric stenosis?
Aneuploidy - Turner's, trisomy 18 Cornelia de lange Oesophageal atresia Hirschprung's PKU Congenital rubella.
What percentage of Hischprung’s is long segment?
10%
What is the pathophysiology of Hirschprung’s disease?
- Failure of neural crest cells to migrate to correct location in bowel - absence of ganglion cells. Absence of inhibitory innervation - tonic contraction and colonic obstruction. (increase acetylcholinesterase staining)
- Abnormal nerve fibres (hypertrophic with thickened bundles
- Muscular neural cell adhesion molecule (abnormal expression prevents craniocaudal migration
- Lack of NO fibres
- Scarce interstitial cells of Cajal
What is genetics with Hirschprung’s?
Isolated in 70%
Associated chromosomal abnormality in 12% (90% Down’s)
Additional congenital anomaly in 18% (GI malfrmation, cleft palate, polydactyly, cardiac septal defects, craniofacial abnormality
Associated with neurocristopathies (NC) - gives rise to neuronal, endocrine, craniofacial, conotruncal heart and pigmentary tissues - MEN2, Waardenburg.
RET (proto oncogene) associated with LS
Endothelin B receptor associated with SS
What is the inheritance of Peutz-Jeghers? What are some complications?
AD
Intussusception, malignancy (GI and other)
- can get polyps in bronchi
What are some risk factors for achalasia?
Oesophageal atresia
CP patients
CF
What is the treatment for Achalasia?
- Medical - Nitrates, CCB, Botox
- Pneumatic dilatation (5% perforation risk)
- Heller’s myotomy - Reflux.
What is relaxation of lower oesophageal sphincter mediated by?
NO
What is abnormal oesophageal pH?
Lower than 4.
What is Sandifer’s syndrome?
GORD with spasmodic torticollis, dystonia.
What is a histological marker of aspiration pneumonia?
Lipid laden macrophages in BAL.
What is the failure rate of fundoplication?
5-20% (better with neurologically normal kids)
How do you diagnose H. Pylori?
Endoscopy - antral nodularity. Gram negative rods in surface mucosa 13C-urea breath test (children) Serology IgG (no use for 6 months post therapy) - does not confirm eradication.
How do you differentiate between osmotic and secretory diarrhoea?
- Stool sodium (70mEq/L in secretory)
- Stool osmolality (Increased in Osmotic - >(Na+K)x2.
- Stool pH (less than 5 in osmotic)
- Stool reducing substances (positive in osmotic)
- Volume (200mL/day in secretory)
- Changes when oral intake ceased (ceased with osmotic, persists with secretory)
What are the causes of secretory diarrhoea?
- Infection (cholera, E. Coli, Salmonella)
- Mucosa necrosis/atrophy
- Laxative use
- Bile acid malabsorption
- Congenital electrolyte transport defect
- Hormone secreting tumours (Phaeo)
- Mastocytosis.
What are the causes of osmotic diarrhoea?
- Osmotic laxatives
- CHO malabsorption (i.e. Glu-Gal transport defects, congenital lactase and sucrase deficiency)
- GI infections (enterovirus)
- Coeliac disease
- CMP/soy allergy
- Inflammatory diseases
- Auto-immune enteropathy
- Bacterial overgrowth.
What are some disorders associated with selective IgA deficiency?
- URTI
- Otitis media
- Sinusitis
- Bronchiectasis
- Allergic disorders
- IVIG allergy
- Giardiasis
- Strongyloidiasis
- Nodular lymphoid hyperplasia
Coeliac Achlorhydria HSP Inflammatory bowel disease GI lymphoma PBC Cholelithiasis Hep C.
What are risk factors for baterial overgrowth?
PPI, Blind loops, strictures, achlorhydria, dysmotility, inflammation, ileocaecal valve problems, PEM.
What are clinical features of bacterial overgrowth?
Steatorrhea (deconjugation of bile salts)
Megaloblastic anaemia (utilization of cobalamin)
Distention/flatulence (gas production)
Malabsorption (mucosal damage)
Hypoproteinemia
d-lactic acidosis. Normal histology but decreased disaccharidases.
Lactulose breath test +ve.
What is the incidence of coeliac disease in australia?
1%
What is the pathophysiology of coeliac disease?
Gliadin crosses gut epithelium, presented with HLA-DQ2 by APC to alpha/beta T cell receptor.
TTG deamidates, inducing stronger T cell response.
Cytokines induce damage (interferon gamma, IL-4, TNF-alpha)