Inflammatory disorders Flashcards
How can ischaemia cause mucosal injury in the gut
- Systemic hypotension- affects intestinal mucosa
- Atherosclerotic disease
- Volvulus- colon twists on part of mesolcolon, obstructs veins
What drugs can cause mucosal injury of gut
NSAIDs,(Ibuprofen and diclofenac can cause ulceration, peptic ulcers) antibiotics, steroids
Chemotherapy e.g. 5-fluorouracil ⇒ Affects stem cells at bottom of pits
What classificiation system is used for gastritis and how is it classified
The Sydney System uses a combination of endoscopic features, histology and aetiology to classify gastritis
Main types of gastritis and their causes
Acute erosive / haemorrhagic gastritis ⇒ Ingestion of irritant chemicals causes damage to the surface of mucosa
Acute H. pylori infection usually no or minor symptoms, so seldom seen in biopsies
Chronic:
non atrophic like Hp
atrophic like autoimmune or chronic hp also
Special forms
What are the obvious hallmarks of non-atrophic gastritis ( chronic and active)
chronic -Lymphocytes and plasma cells in lamina propria
Active- neutrophils infiltrating epithelium of gastric pits
What is atrophic gastritis characterised by and what are the causes
characterised by loss of parietal (acid secreting) and peptic (pepsin secreting) cells in gastric body ( usually occurs in mucosa)
- Autoimmune gastritis ⇒ Need serology for anti parietal cell antibodies which affect fundus.
- Chronic H. pylori infection
Causes of Non-infectious granulomatous gastritis
e.g. Crohn’s disease, sarcoidosis
What is coeliac disease histology characterized by
- Chronic mucosal inflammation
- Variable Villous atrophy ⇒ flat surface
- Crypt hyperplasia ( as compensation) ⇒ longer crypts
May also have Increased CD8+ T- Lymphocytes in epithelium ⇒ Epithelial damage ⇒ Leads to malabsorption
Increase in lamina propria lymphocytes and plasma cells as well
Waht is coeliac disease diagnosed by
- Histology ( biopsy changes)
- Serology
- Response to gluten - free diet
How is coeliacs often picked up
routine haematology (iron deficiency anaemia) => presents as tiredness
What genes predispose for coeliac’s
HLA DQ2, DQ8
Pathophysiology of coeliacs
- Exposure to gluten (gliaden) in wheat, barley, rye or other glutamine- rich proteins (hordeins and secalins) results in:
- Gliaden-reactive T lymphocytes
- Tissue transglutaminase antibodies
What may be the presenting complain in some coeliac patients
Dermatitis herpetiformis ⇒ Blistering skin condition, CAN be presenting complain in some coeliac patients!!
Common presentations of coeliac
- Diarrhoea
- Abd pain, bloating, general sense of unease in stomach
- Anaemia ⇒ From iron or folate deficiency
- Dyspepsia
- Weight loss
- Recirring mouth ulcers may be common
- Fatigue
- Neuropsychiatric symptoms
Classical presentation of coeliacs
- Childhood
- FTT / Weight loss
- Short stature
- Malnutrition
- Steatorrhoea
- Delayed puberty
- Osteomalacia
- Myopathy
Investigations of coeliacs
what deficiencies are more common
- Anaemia (microcytic, macrocytic)
- Iron, folate deficiency
- Macrocytosis without anaemia
- Hyposplenic blood film due to splenic atrophy
- Low calcium, elevated Alk Phos due to met. bone disease
- Raised transaminases ⇒ liver enzymes, reasons not clear
- Hypoalbuminaemia
Testing for coeliacs
- Serological markers
- Anti-tissue transglutaminase antibody (IgA) (TTG) Sensitivity and specificity >95% ⇒ Usually can be used simply for diagnosis now in paeds w/o biopsy
- Anti-endomysial antibody (IgA)
- Anti-gliadin antibody (IgA, IgG)
- Anti-tissue transglutaminase antibody (IgA) (TTG) Sensitivity and specificity >95% ⇒ Usually can be used simply for diagnosis now in paeds w/o biopsy
- Small intestinal biopsy ⇒ Definitive test- show pathological features
- Scalloping, Loss of Kerking’s folds, mosaic pattern
What infection is common after broad spectrum antibiotics
C diff
What infection is more common in immune suppressed individuals, and what is the common histology
CMV -treatment of ulcerative in crohns
- Intranuclear and cytoplasmic inclusions are typical ⇒ accumulation of viral proteins in cytoplasm and nucleus
Intranuclear and cytoplasmic inclusions are typical ⇒ accumulation of viral proteins in cytoplasm and nucleus
In which part of the intestine is giardia infection more common
duodenum
where does ischaemic colitis often occur in
Mimics Crohn’s, most common in region of splenic flexure and descending colon
What is divericular disease and which group is it most common in . What is a complication
- In elderly, has chronic complications ⇒ stricture and fistulas
- Most common in sigmoid colon
Ulceration may eventually result in fistula
What drug is more likely to cause colitis and where does it affect most often
NSAIDs, TI
How does distribution of UC and CD differ
UC - inflammation is confined to mucosa, diffuse in distribution, while Crohn’s has skip lesions and is transmural
Typical microscopic features of UC and CD
UC has cryptitis, crypt abscesses, mucin depletion
vs patchy inflammation and transmural lymphoid aggregrates
How do ulceration patterns vary in UC and CD
UC has broad-based ulceration which may undermine mucosa while CD has apthous ulcers and deep fissuring ulcers leading to fistula formation
Are granulomas more common in UC or CD
Common in CD, may be transmural and in lymph nodes
Are polyps more common in UC or CD
More common in UC, fewer in numbers in CD but often larger
What is the greatest risk factor for IBD, does this vary in CD and UC
Having family member with IBD, but greater concordance in MZ twin studies for CD than UC
NOD2 gene in Crohn’s
How does smoking affect IBD risk
Aggravates CD but decreases UC risk
Main investigation for IBD
Biopsies- can distinguish between Crohn’s and UC, exclude other aetiologies. Should biopsy colon and TI
What is cryptiitis and crypt absecces
Refers to neutrophil infiltration, basically shows active disease
Hallmark of active disease in UC
What is the main presentation of ulcerative colitis
Rectal bleeding
Which part of colon is commonly involved in UC
Left colon
What is a pseudopolyps and what does it show. UC or CD
UC. Due to mucosa around it being destroyed and inflamed/ulcerated.
Very broad based ulceration, flat. NO inflammation going into muscularis propria . Ulceration mainly of mucosa
What is the main sign of chronic UC
Irregular, shortened crypts which won’t reach muscularis mucosae and increased inflammatory
What is a skip lesion in UC
Caecum and appendix may be involved- caecal patch lesion
Most common involvement of crohn’s
Anus
Are granulomas more common in right or left colon
left colon
What causes strictures in CD
Due to transmural thickening
is neoplasia risk higher in UC or CD
UC
Most common carcinoma from UC
colorectal
What does microscopic colitis usually present as and who in
Chronic watery diarrhoea and in middle aged, esp women
Appearance in endoscopy and histology of microscopic colitis
Normal appearance of mucosa at endoscopy but increase in chronic inflammatory cells identified in histology
Causes of mucroscopic colitis
Drugs like lansoprazole and NSAIDs
Steroids like budesonide
Two patterns of microscopic colitis
Collagenous colitis and lymphocytic colitis
What is lymphocytic colitis closely associated with
coeliacs
Causes of strictures
- Crohn’s disease
- Ischaemic colitis
- Diverticular disease
- Diaphragm disease ⇒ complication of NSAIDs, forms thin membrane- like structure
- Neoplasia
granulomas are mediated by which cells?
T cells
what macrophages are present in granulomas and what are they intermixed with
Histocytes with lymphoid follicles
clinicl\al manifestations of UC and CD
Rectal bleeding more common in UC, both likely to have diarrhoea ( more severe in UC). pain in both but more in CD, may have rashes and joint pain in both, weight loss in both (more in CD)
Is there stenosi/ dilatation of bowel in UC or CD
CD mainly
is malabsorption common in CD or UC
CD
Is neoplasia risk higher in UC or CD
UC
Which part of the GI tract is CD the most common
anus/ perianal region
Are these symptoms more common in UC or CD?
- MSK
- Hepatobillary
- CD
- UC
