CP11-7 GI Infections Flashcards
What sites in the GI tract are sterile?
Peritoneal space
Pancreas
Gall balder
Liver
What are some non-sterile sites of the GI tract?
Mouth
Oesophagus
Stomach
Small bowel
Large bowel
Does presence of all bacteria e.g. neisseria meningitides and strep pneumoniae, in the pharynx always mean there is infection?
No - a small amount of these bacteria can be present in normal pharyngeal flora
What are some GI infection signs seen on the mouth?
Angular cheilitis
Oral herpes simplex
Hairy leucoplakia
What are 3 examples of dental infections?
Caries
Pulpitis
Periapical abscesses
What are some examples of periodontal infection?
Gingivitis
Periodontitis
Periodental abscesses
Vincent’s angina aka acute necrotising ulcerative gingivitis
Oral facial space infections if spread.
What are the most common deep neck space infections?
Peritonsillar abscess aka a quinsy
Acute suppurative parotitis
What are some uncommon deep neck space infections?
Ludwig’s angina (submandibular space infections)
Parapharyngeal space infections - often have carotid sheath involvement
What is mucositis?
Inflammation of the mucous membranes if the GI tract
Who is most likely to get mucositis?
Chemotherapy patients - especially if have pre-existing periodontal disease.
What is another name for an effort rupture of the oesophagus?
Boerhaave syndrome
What happens as a consequence of intrathoracic oesophageal rupture?
Chemical mediastinitis, with mediastinal emphysema and inflammation which can lead to bacterial infection and mediastinal necrosis.
How does H. Pylori spread?
Faecal oral/ oral oral exposure
What percentage of h.pylori infections lead to ulcer disease?
10-15%
What are consequences of h.pylori infection?
Pain
Bleeding
Perforation of stomach
What allows h.pylori to penetrate the gastric mucus layer?
Formation of ammonia that neutralises gastric acid by bacterial ureases hydrolysing gastric luminal urea. Ammonia acts as a protective layer
What is the most common biliary tract infection?
Cholangitis
How do patients with cholangitis usually present?
Fever
Abdominal pain
Jaundice
Known as charcot’s triad
What bacteria most commonly cause infective cholangitis?
Enterobacteriaceae and enterococcus species
How do patients with cholecystitis present?
Abdominal pain
Fever
History of fatty food ingestion one hour prior to onset of pain
With gall stones usually
What LFTs are important to look at in cholangitis?
Conjugated bilirubin
Serum ALP
GGT
What commonly causes bacterial overgrowth in the small bowel?
Achlorhydria
Impaired bowel motility
Blind loops of bowel
Surgery
Radiation damage
How does bacterial overgrowth In the small bowel affect the body?
Bacteria may bind to vitamins e.g. vit B12, use nutrients and produce metabolites like fatty acids
What is associated with bacterial overgrowth of small bowel?
Malabsorption
Chronic diarrhoea
What is Whipple’s disease?
Infection of tropheryma whipplei affecting people with a rare immune defect causing joint symptoms, chronic diarrhoea, malabsorption and weight loss which develop over time. Usually only considered after other diagnoses are excluded.
What is the aetiology of liver abscesses?
Ascending biliary tract infection
Can occur in portal vein after peritonitis or colonic perforation
Haematogenous causes e.g. endocarditis
What is a GI disease we can get from un-wormed dogs?
Hydatid cyst
How does mycobacterium tuberculosis affect the GI tract?
Causes local symptoms like non healing oral ulcers, gastric ulcers and enterocutaneous fistulas
What site of the GI tract is most commonly affected by tuberculosis?
Ileo-caecal area
What are some infection complications of pancreatitis caused by enteric bacteria?
Necrotising pancreatitis
Peripancreatic fluid collection
Pancreatic pseudocyst
Acute necrotic collection
Walled off necrosis
How is a complicated intra-abdominal infection defined?
An infection that extends beyond the hollow viscus of origin into the peritoneal space and is associated with either abscess formation or peritonitis
What is the most common cause of complicated intra-abdominal infections
Perforation of an inflamed organ e.g. gallbladder, appendix, duodenum
How is complicated diverticulitis treated?
With antibiotics and surgery e.g. abscess drainage or resection of affected bowel
How does treatment of appendix differ if it is complicated vs uncomplicated?
Both treated with surgical management plus antibiotics in complicated but only a single dose of antibiotic prophylaxis in uncomplicated
What are some predisposing factors for intra abdominal abscesses?
Peptic ulcer perforation
Perforated appendix
Perforated diverticulum
Mesenteric ischemia/bowel infarction
Pancreatitis/pancreatic necrosis
Penetrating trauma
Postoperative anastamotic leak
How do patients with an intra-abdominal abscess present?
What is spontaneous bacterial peritonitis?
An ascitic fluid infection without an evident intra-abdominal surgically treatable source which occurs due to bacteria within the gut lumen crossing the intestinal wall into mesenteric lymph nodes which rupture due to portal hypertension.
Who is most likely to have spontaneous bacteria peritonitis?
Patients with advanced cirrhosis and ascites
How is spontaneous bacterial peritonitis diagnosed?
With ascitic fluid bacterial culture showing elevated ascitic fluid absolute polymorphonuclear leukocyte (PMN) count of >250 cells/mm3
What infection is common in patients with bowel cancer?
Bacteraemia caused by strep bovis aka s.gallolyticus which is associated with endocarditis
