Gastroenterology Flashcards
How does gastroenteritis present and what can it be caused by?
D&V - caused by ingesting bacteria, viruses or toxins
No blood or mucus in the stool
Signs of dehydration - dry mucous membranes, reduced skin turgor
Which bacteria most commonly cause gastroenteritis?
1) Staph aureus - usually found in cooked meats and cream products
2) Bacillus cereus - mainly found in reheated rice
3) Clostridium perfringens - usually found in reheated meat dishes or cooked meats
4) Campylobacter
5) E coli incl. E coli O157 which can cause HUS
6) Salmonella
7) Shigella
What is the most common cause of infantile gastroenteritis?
Rotavirus
What is the most common cause of viral infectious gastroenteritis in all ages in England and Wales?
Norovirus
What is a common cause of respiratory infections that can also cause gastroenteritis esp. in children?
Adenoviruses
What are parasitic causes of gastroenteritis?
1) Cryptosporidium
2) Entamoeba histolytica
3) Giardia intestinalis
4) Schistosoma
How is gastroenteritis managed?
1) Conservatively with NG/IV fluid replacement or oral rehydration sachets
2) If severe, abx can be used
What are indications of antibiotics in gastroenteritis?
1) Systemically unwell
2) Immunosuppressed
3) Elderly
Which antibiotic can be used to treat salmonella and shigella?
Ciprofloxacin
What antibiotic can be used to treat campylobacter?
Macrolide e.g. erythromycin
What antibiotic can be used to treat cholera?
Tetracycline, to reduce transmission
Is food poisoning a notifiable disease in the UK?
Yes
How does norovirus present?
1) Abrupt onset, usually short lived GI upset 24-48h after inoculation
2) Typically self-limiting in healthy people but can cause pre-renal AKI in the frail
How do you prevent norovirus?
Strict handwashing with soap and warm water e.g. in hospitals, nursing homes and cruise ships
How does a peptic gastric ulcer present?
1) Iron deficiency anaemia - due to persistent blood loss
2) Abdominal pain made worse by eating
How does a peptic duodenal ulcer present?
1) Iron deficiency anaemia - due to persistent blood loss
2) Abdominal pain improved by eating
What are viral causes of gastroenteritis?
1) Rotavirus
2) Norovirus
3) Adenovirus
How does infective gastroenteritis present?
1) Sudden onset diarrhoea
2) Blood/mucus in stool
3) Faecal urgency
4) Nausea/sudden onset vomiting
5) Fever
6) General malaise
7) Abdominal pain/cramps
8) Associated headache
9) Myalgia
10) Bloating and flatulence
11) Weight loss
12) Malabsorption
How do you diagnose gastroenteritis?
1) Clinical - history + examination
2) Stool culture/sensitivity - not routinely needed for children/adults presenting with acute diarrhoea
3) Assess hydration status
What type of bacteria is clostridium difficile?
Gram positive
What are risk factors for developing clostridium difficile infection?
1) Use of broad-spectrum abx - clindamycin, ciprofloxacin, cephalosporins, penicillins
2) Healthcare setting
3) Age > 65
4) Co-morbidities - IBD, cancer, CKD
5) Immunosuppression - diabetes, HIV
6) PPI
How does C difficile present?
Asymptomatic OR
1) Watery/bloody diarrhoea
2) Painful abdo cramps
3) Nausea
4) Dehydration - dry mucous membranes, tachycardia, oliguria
5) Fever
6) Anorexia
7) Weight loss
8) Confusion
What are potential complications of C difficile?
1) Pseudomembranous colitis
2) Toxic megacolon
3) Sepsis
What is the definitive/gold standard diagnosis of C difficile?
Toxigenic C difficile in stool + colonic histopathology showing pseudomembranes
What two key investigations are done to diagnose C difficile?
Stool culture + colonic biopsy
What would you see on colonic biopsy in C difficile?
Pseudomembranes
How do you treat C difficile?
1) PO vancomycin ± IV metronidazole if severe
2) Second line = fidaxomicin
What is the key antibiotic used to treat C difficile?
Vancomycin
How do you treat recurrent C difficile infection?
Faecal transplant
How is C difficile managed?
1) PO vancomycin ± IV metronidazole
2) Avoid anti-diarrhoeal agents
3) Fluid replacement and supportive treatment
What does MALT stand for in MALT lymphoma?
Mucosa-associated lymphoid tissue
What is a MALT lymphoma?
Rare, low-grade non-Hodgkin’s lymphoma that usually presents in the stomach but can present elsewhere
What type of lymphoma is MALT lymphoma?
Non-Hodgkin’s (low-grade)
Where does MALT lymphoma typically present?
Stomach
What does MALT lymphoma develop from?
B lymphocytes in the marginal zone
What is MALT lymphoma strongly associated with?
H. pylori infection