Diarrhoea Gastro Tutorial (2) Flashcards
Commenest cause of gastroenteritis in UK
Campylobacter - common cause of bloody diarrhoea
Origin of Campylobacter bacteria
- Chicken guts
- Spread
Abx for severe Campylobacter infection
Clarithromycin - only if very unwell, if not conservative management
Treatment and investigation for suspected UC
- Colonoscopy
- Corticosteroids in flare up - prednisolone
- 80% of people feel 80% better after 2 weeks of steroids
- If no improvement - complication can be toxic megacolon
Toxic megacolon management
- Fluids - 6L probably for 24hrs (3x saline and 3x dextrose, 20mmol of K+ added to each bag so 120 total due to high K+ losses)
- Biologics - Anti-TNF alpha eg Infliximab to try and save colon
- If no improvement in 24-48hrs –> colectomy
- But doing CRP and abdo x-ray regularly to see improvement
What is a Crohn’s mass and how to manage ?
- Inflamed loops of small bowel stick together + omentum = hard
- If perforates can cause abscess - assess this using CT scan
- If just Crohns - steroids
- If abscess - surgery needed
Differentials for mass felt in RIF with diarrhoea and abdo pain
- Crohns
- GI cancer
- Constipation - check if caecum is indentable?
- Chronic appendicitis?
Test to differentiate IBS and IBD
- Faecal calprotectin - if negative likely to not be IBD as VERY sensitive test
- BUT cannot tell between acute infection and chronic inflammation so careful as someone with IBS may just have gastroenteritis so test comes back +ve
Test to rule out coeliac disease
- Anti tissue transglutaminase antibody blood test
- Need to do total IgA alongside this - otherwise useless if low
Definitive test for coeliac disease and findings
- Endoscopy of 2nd part of duodenum
- Increased lymphocytes
- Flattened villi
How to assess whether diarrhoea is overflow diarrhoea or IBS?
- Take bloating history
- If bloating not present in morning but then worsens throughout day = IBS
- If bloating present overnight until morning = constipation overflow diarrhoea. Bloating will not subside until stool is passed
Causes of constipation
- Avoiding poo reflex too often - this then stops happening as often and feel need to go less and less –> constipation
- Diet - lack fibre
- Lack exercise
Cause of long term steatorrhoea and weight loss after visit to foreign country
- Giardia lamblia - parasite infection
- Causes malabsorption (hence steatorrhoea due to lipid in faeces) from presence of Giardia
- From contaminated water sources
Treatment for Giardia infection
Metronidazole
How to know when diarrhoea is caused by toxin
Effects are immediate - very fast
Usually contaminated by Staphylococcus on skin - produces toxins with are heat stable
Everytime reheat and cool food = multiplies, more and more toxin
Eg esp with kebabs
How to test for C.diff?
C difficile toxin A and B test on stool sample via PCR or enzyme immunoassay
C.difficile antigen (specifically glutamate dehydrogenase)
Treatment for C.diff
Oral vancomycin or metronidazole
2nd line -Fidaxomicin
Fluids for C.diff
- only large bowel affected
- Not too dehydrated
- 2-3L should be enough of half saline half dextrose with 40K+ added
Likelihood of second c.diff infection after treatment
High - spores are resistant to abx, they germinate a lot when gut is treated with antibiotics as no flora to compete with
Management of second C.diff infection
- Do nothing if mild - let GI tract regain flora
- If likely to be severe - treat with prophylactic vancomycin for 2 weeks following infection treatment
Other cause of diarrhoea post abx apart from C.diff
The antibiotics themselves - can cause diarrhoea
How can a low MCV be caused by GI issue?
Malabsorption - causes iron deficiency
= iron deficiency anaemia
Main causes of malabsorption in UK
- Crohns
- Coeliac disease
- Pacreatitis - eg from alcohol or gall stones
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Test for pancreatitis
Faecal elastase
Test for coealic disease
Coeliac serology - anti-TTG
Then gastroscopy with duodenal biopsy to see if flattened villi
Cause of triad of facial flushing, wheezy breathlessness and diarrhoea
Carcinoid syndrome - from neuroendocrine tumour in GI tract releasing serotonin hormones
Where do neuroendocrine tumours causing carcinoid syndrome often begin
- Start small/large bowel or appendix
- Spread to liver via portal vein = nodular, hard enlarged liver
At what point do neuroendocrine tumours cause carcinoid syndrome
- After spread to liver
- When just in GI tract, hormones go via portal vein and are broken down in liver so no effects
- When in liver, travel via hepatic vein systemically = carcinoid syndrome
Treatment for carcinoid syndrome
Somatostatin analogue - off switch for endocrine system eg Lanreotide (Somatuline) injection every 3 weeks
Causes of hepatomegaly in exams
- Carcinoid syndrome
- Polycystic liver - often have PCKD too
- Myelofibrosis - large liver and spleen
How to reassure someone they are experiencing overflow diarrhoea with proof?
Abdominal X-ray - will show bowel filled with faeces
First line laxatives for overflow diarrhoea
Example bisacodyl
Give at night to stimulate bowel to work in morning
Then glycerine suppositoreis into rectum in morning
How do glycerine suppositories work?
- Dissolve in rectum
- Draw water into rrectum
- Distends rectum
- Poo reflex initated
What is obstructive defaecation syndrome?
When someones anal sphincter does not relax or even contracts when they push out faeces
Often due to previous sexual abuse
Cause of bronw pigmentation if seen on colonoscopy
- Called melanosis coli
- Caused by excessive senna based laxative use
- Can do laxative screen on urine if suspect this
What happens following cholecystectomy sometimes to faeces?
- get diarrhoea
- Usually bile acids reabsorbed at terminal ileum
- For some reason they are not sometimes after this operation
- Large bowel secretes water into lumen in response to bile acids being there
- = diarrhoea
Treatment for bile acid malabsorption
Questran - Cholestyramine - bile acid sequestrants, bind them and make them inert
Dose of questran importance
Too much - do not absorb lipids properly = steatorrhoea
Too little - still get diarrhoea
Treatment options for UC flare up
- Oral steroids or mesalazine enemas
- If no better try a biologic
OR - If get better but then relapse try Azathioprine
- LAST option - colectomy
Do stool sample culture at presentation in case of infection
