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Malabsorption - Coggle Diagram
Malabsorption
Coeliac
general
abnormal immune reaction to gluten
damage to surface enterocytes of s.i.
severely reduces their absorptive capacity
epidemiology
incidence of 1/70-300 in most countries
most freq.
early childhood
failure to thrive
irritability
abd. distension
diarrhoea
3rd/4th decades
presentation
classical malabsorption syndrome
diarrhoea/steatorrhoea
flatulence
weight loss
fatigue
most patients
milder
non-specific
bloating+indigestion
aymptomatic+IDA
easy to miss
aetiology
gluten
only partially digested in s.i
^proline
gluten peptides resistant to intestinal peptidases
antigenic
gliadin/glutenin
direct effects on int. permeability
disruption of tight junctions between enterocytes
gliadin
glutamine residues-react with transglutaminase
HLA-DQ2 class 2 MHC uncovered
potent t cell activators
host immune system
HLA-DQ2/8 heterodimer
but HLA-DQ2 present in unaffected
Host factors
perturbed t cell function
4q27 - disease related region
IL-2/21 genes
amplified immune response
IL2
secreted by antigen stimulated t cells
t cell activation/proliferation
IL21
t/b/nk cell proliferation
interferon gamma production
environmental triggers
breast feeding
age at first intro of gluten
intestinal viral inf.
epi vulnerable??
histopathology
villous atrophy
fully dev. coeliac
total malabsorption
sugars
fatty acids
monoglycerides
amino acids
water/electrolytes
loss of mature epi. cells
disaccharidase def.
intolerant to lactose/other sugars
crypt hyperplasia
^intraepithelial lymphocytes
gross appearance
visible submucosal vessels
mosaic/micronodular appearance
fissures
scalloping
most severe in proximal s.i.
duodenum
proximal jejunum
DX
circulating tTG/anti-endomysial antibodies
definitive
documentation of malabsorption
histology
improvement of symptoms and histology after withdrawal
clinical associations
skin blistering
dermatitis herpetiformis
igA against epidermal TG
splenic atrophy
atopy
autoimmune disease
complications
s.i. ulceration
non-specific chronic infl.
chronic ulcerative enteritis
small ^ in s.i and other gi adenocarcinomas
low ^ risk of lymphoma in s.i.
Enteropathy associated t cell lymphoma
presents with
haemorrhage
perforation
small bowel obstruction
systemic symptoms
proximal s.i.
young people (30-40)
often 10-20yr hx of symptomatic malabsorption
prognosis
usually poor
osteoporosis
muscle wasting
dental enamel hypoplasia
subfertility
impaired intestinal hormone prod. from s.i.
reduced pancreozymin,secretin, cholecystokinin
sec. reduction in pancreatic secretion/bile flow
gallstones
prognosis
adhere to gluten free diet
remain well
long term risk of malignancy
lymphoma
s.i. adenocarcinoma
oesophageal squamous cc.
Abetalipoproteinaemia
autosomal recessive
gene for apolipoprotein b normal
faulty mtp gene
impaired transepi. transport of lipids
steatorrhoea/diarrhoea
lipid vacuoles visible in enterocytes
failure to thrive
peripheral blood
burr cells-acanthocytes
Causes
Defective intraluminal digestion
pancreatic insufficiency
pancreatitis
CF
Zollinger Ellison syndrome
excess gastric acid secretion
inactivation of pancreatic enzymes
inadequate emulsification of fat
by bile salt
due to
disruptiion of bile
manufacture
hepatic dysfunction
flow
biliary obstruction
disrupt. of enterohepatic bile salt recycling
ileal disease/resection
Primary mucosal cell abnormalities
defective terminal digestion
disaccharidase deficiency
lactose intolerance
bacterial overgrowth
brush border damage
Defective epithelial transport
abetalipoproteinaemia
primary bile acid malabsorption
reduced small intestine SA
gluten sensitive enteropathy
coeliac
crohns disease
Lymphatic obstruction
lymphoma
TB/tuberculous lymphadenitis
Inf.
acute infectious enteritis
parasitic infestation
e.g tapeworm
absorbs vitb12
anaemia
tropical sprue
whipple disease
Iatrogenic
subtotal gastrectomy
extensive surgical resection
short gut syndrome
distal ileal resection/bypass
radiation enteropathy
tropical sprue
pathological changes
identical to coeliac but
less severe
more distal
malabsorption in tropics and subtropics
not africa
most freq. se asia/caribbean
characterised by
chronic diarrhoea
weight loss
lethargy
malaise
macrocytic anaemia
folate/vitb12 def.
no benefit from gluten free diet
tetracyclines may relieve
usually resolves on leaving area
diagnosis of exclusion
giardiasis
inf. with giardia dudodenalis
flagellated protozoan parasite
symptoms
generally mild malabsorption
non-specific gi symptoms
morphology
trophozoites
pear shaped
2 nuclei
contaminated water
in those with IgA def./gastric surgery
traveller's diarrhoea
childhood diarrhoea
less mature immune system
features
villous blunting
^IEL's
Whipple's
rare bacterial inf.
tropheryma whippelii
gram pos. actinomycete
non-acid-fast
older white men
multisystem
malabsorption
lymphadenopathy
arthralgia
CNS
mucosa
foamy macrophages
contain abundant PAS(d)+
stain
partially digested material
in lamina propria
lymphatic impairment
tx
respond to prolonged
cephalosporin or
co-trimoxazole
general
defective absorption of all/some
fats
proteins
carbohydrates
vitamins(Fat/water soluble)
electrolytes+minerals
water
generalised
absorption of several/all nutrient classes impaired
specific
identifiable molecular defect causing malabsorption of single nutrient
disturbance in at least 1 phase of nutrient absorption
intraluminal digestion
emulsification
terminal digestion
brush border
transepithelial transport
lymphatic transport of absorbed lipids
Clinical
chronic diarrhoea
^in stool mass/freq/fluidity
weight loss
anaemia
muscle wasting
neuropsychiatric problems
osteopaenia/porosis
failure to thrive
fertility problems
anorexia
bloating/abd. distension
borborygmi
bowel sounds
steatorrhea
hallmark
excessive fecal fat
stool
bulky
frothy
greasy
yellow/clay coloured
mucositis
bleeding - vit k def.
tetany
endocrine system
amenorrhea
erectile dysfunction
infertility
hyperparathyroidism
purpura/petechiae
oedema
dermatitis
diassacharidase def.(lactase def.)
congenital
rare
on milk feeding
explosive/frothy/watery stools
abd. distension
acquired
common
adults
often post enteric inf.
viral/bacterial
no mucosal cell abnormalities
features
fullness
flatulence
osmotic diarrhoea
unabsorbed sugars
bacterial fermentation
^hydrogen production
measured in exhaled air
gas chromatography
Bacterial overgrowth
normally proximal s.i.
scanty organisms
occasional oral commensals
work of gastric acid
motility
impaired motility
post surgery
Polya gastrectomy
^E.coli and bacteroides
deconjugate+dehydoxylate bile salts
diarrhoea+steatorrhoea
vit b12 def.
c14/hydrogen breath test
granulomatous enteritis
crohns enteritis
mucosal infl.
scarring
fistulas
post-surgery
short bowel
granulomas
mycobacterial ileitis
ulceration
malabsorption
S.I. tumours
uncommon site for primary neoplasms
despite
high cell turnover rate
vast surface area
adenomas/adenocarcinomas
distinctly rare in s.i.
ampulla of vater
other neoplasms
e.g. neuroendocrine tumours/lymphomas
more importance in s.i. than carcinoma
more common in s.i. than l.i
malignant tumours
1% of GI malignancies
most common
adenocarcinomas
presentation
majority in duodenum
40-70yr olds
napkin ring tumours/exophytic polypoidal lesions
duodenal tumours
can cause obstructive jaundice
esp. if ampulla of vater
obstruction
nausea&vomiting
occult blood loss
associations
major risk factor
chronic infl.
crohns
coeliac
FAP
HNPCC
Peutz Jeghers syndrome
but most sporadic
prognosis
most spread through wall at dx
invaded mesentery
metastasized to liver/LN's
resection
70% 5yr survival
carcinoids
from resident endocrine cells
2% colorectal malagnancies
more than 50% s.i. malignant tumours
more likely to metastasise if >2cm
common sites
appendix
rarely metastasise
ileum
rectum
rarely metastasise
stomach
colon
morphology
intramural/submucosal masses
less than 3cm
mucosa may be
intact
ulcerated
yellow/tan on transection
islands/strands
monotonous tumour cells
pink granular cytoplasm
granular nuclei
when invasive-obstruction
desmoplastic reaction
syndrome
tumour secretion of serotonin/bioactive amines
hepatic metastases/carcinoids outside gut
symptoms
flushing
cyanosis
wheeze
diarrhoea
cramps
n&v
right sided valvular heart disease
dx
excess 5HIAA in urine
after these 2 lymphomas and sarcomas
GI lymphoma
usually sporadic
more freq in
chronic gastritis
H.Pylori
chronic sprue-like syndromes
natives of mediterranean
immunodef. states
can be
b cell lymphoma
MALT
IPSID
heavy chain disease
1 more item...
similar to gastric MALToma but in s.i.
assoc. with campylobacter
1 more item...
mediterranean, middle east, pakistan, india, north america
young adults
3 more items...
Burkitts
t cell lymphoma
EATL
linked with coeliac