Infectious diseases Flashcards
H. Pylori gram stain and appearance
Gram negative, spiral
How does the urease enzyme facilitate colonisation of the stomach?
Urease neutralises stomach acid and enables penetration through gastric mucous. Patient produces more acid which allows it to further survive
What is VacA?
All pylori contain this gene which codes for a passive urea transporter and stimulates IL-8 –> inflammatory response causing the gastritis and inflammation
Disease associations for H. Pylori
- duodenal ulcer
- gastric ulcer
- gastric ulcer
- gastric lymphoma (MALT)
Ulcer pathogenesis from pH to Hp
- increased gastric secretion
- gastric metaplasia of duodenum
- stimulate immune response
- impairs mucosal defence
Therapy for H. Pylori eradication
- PPI
- Amoxicillin
- Clarithromycin
What would you give for H. pylori eradication if patient was allergic to penicillin or clarithromycin?
Metronidazole
Which antibiotics can be reused?
- Amoxicillin
- Bismuth
- Tetracycline
Which A/B should only be used once?
- Clarithromycin
- Metronidazole
- Quinolones
- Rifamycines
Most common cause of liver abscesses
Pyogenic - bacterial is most common (enteric bacteria)
Biliary tract is most common
Pathogenesis of pancreatitis
Typically inflammatory, from the blockage of pancreatic duct by a gall stone or chronic alcohol abuse. Pancreatic enzymes self digest organ - necrosis
Which of the viral hepatitis infections can cause chronic disease in humans?
B, C, D
Which hepatitis viruses are spread through blood and which through faecal-oral?
Blood - B, C, D
F-O - A, E
Markers of successful treatment of HBV
- HBeAg seroconversion to antiBeAb
- suppression of the HBV DNA
- Settling of the raised ALT
Nucleoside and nucleotide analogues
Nucleoside - lamivudine, entacavir
Nucleotide - tenofovir
Investigations for liver abscesses
- neutrophilia
- raised ALP
- Blood cultures positive 50%
What does hepatic bile contain?
– water, – bile acids, – bile salts (formed by the conjugation of bile acids with taurine or glycine), – bilirubin (end product of heme degradation), – cholesterol, – phospholipids, – excreted hormones and drugs
Epidemiology of cholethiasis
- what the stones consist of
• GS present in 10-20% adult population
• 20% will develop biliary colic or other
complications
Essentially consist of:
– Cholesterol
– Bilirubin
– Calcium salts
Classification of gall stones
Classification based on amount of cholesterol in stones
– Cholesterol (>50% crystalline cholesterol monohydrate)
– Pigment (black or brown) – bilirubin calcium salts
Factors commonly associated with cholesterol gall stones
*women, reproductive age, pregnancy, HRT, OCP, obesity, rapid weight loss, drugs Iprednisolone, cyclosporine, azathioprine…, ethnic groups
