Block 15 key things to learn Flashcards
(24 cards)
What is the structure of the liver and what cells are in sinusoids?
Small hexagonal functions units called lobules- each lobule has a central vein surrounded by 6 hepatic portal veins and arteries.
Hepatic venule is connected to surrounding veins and arteries by sinusoids
Cells in sinusoids are-
kupffer cells- macrophages that break down RBC’s
Hepatocytes- line sinusoids and do most of liver functions
Stellate cells- quiescent and store vitamin A usually, but if liver damaged they become activated and secrete collagen scar tissue
What is hepatitis A?
Faecal-oral transmission
Incidence reducing, but increasing amongst MSM
Detected by- increased ALT increased bilirubin faecal HAV IgG anti-HAV IgM anti-HAV
Usually just an acute infection and recover
What is hepatitis B?
Transmission via body fluids
Sometimes becomes chronic- more likely to become chronic the younger you are when get it
See relationship between ALT and Hep B DNA
What is hepatitis C?
Transmitted by body fluids
HCV antibody blood test- takes 4-6 weeks to become positive or HCV PCR- take 10-14 days for result
10% mortality
Can treat with antivirals but often goes undetected until have cirrhosis
What is hepatitis E?
Most common cause of acute hepatitis
Passed on by contaminated pork
Low mortality unless pregnant or have chronic liver disease
What is crohns disease?
Macroscopic appearance-
serosal fat wrapping
cobblestone transverse ulcers
longitudinal serpiginous ulcers
Microscopic- crypt architecture preserved flat surface ulcer patch activity granulomas present fissuring ulcers transmural chronic inflammation
Complications- malabsorption, fistulas, anal lesions, perforation and haemorrhage and increased risk of bowel cancer
What is ulcerative colitis?
Macroscopic- length may be shortened normal serosa ulcers- flasked shaped inflammatory polyps
Microscopic- irregular surface diffuse crypt architectural distortion diffuse chronic inflammatory cell infiltrate rich in plasma cells
Crypt abscess is main histology
Symptoms- frequency and urgency, fever, cramping, abdominal pain, bleeding
Systemic implications of any IBD- arthritis, erythema nodosum, iritis, pyoderma gangrenous, sclerosing cholangitis, gallstones, renal stones and aphatous stomatitis
What is Addison’s disease, diagnosis and what is the treatment?
Insufficient production of cortisol mostly due to autoimmune disease.
Symptoms- hyperpiguentaion, weight loss, low blood pressure, nausea, vitiligo, constipation and abdominal pain
Diagnose by random cortisol level or 9am cortisol or by synacthen test.
Synachten test is when give synthetic ACTH which should stimulate cortisol release, then measure cortisol 30 mins later, if low level still then can diagnose Addison’s
Treat by giving hydrocortisone and fludrocortisone
What is cushings disease?
2 types- ACTH dependent or independent.
Dependent- most likely pituitary tumour
Independent- usually due to exogenous steroids
Symptoms- obesity, hypertension, muscle wasting, osteoporosis, moon face, increased diabetes and thrombosis risk
Diagnose by measuring cortisol levels or by overnight dexamethasone suppression test- should have low cotton levels but if high then can diagnose cushings
What is congenital adrenal hyperplasia
Glucocorticoids, mineralocorticoids and androgens all have same start point and if enzyme 21 hydroxyls which is needed for glucocorticoid and mineralocorticoid production is mutated then more androgens will be made instead.
2 forms- salt wasting- worse- less aldosterone and cortisol- many health problems
simple virilisation- more androgens so genital changes and early puberty
What are some antidiarrhoeal drugs?
Loperamide, codeine and co-phenotrope all act on mu opioid receptors to decrease peristalsis, increase transit time and increase water absorption
Octreotide reduces amount of water
Kaolin- helps thicken stool by acting as binding agent
What are some laxatives?
Bulk forming laxative- Isaphugula husk indigestible increases bulk of stool used if can't increase amount of fibre in diet
Osmotic laxative-
lactulose
synthetic sugar broken down by gut bacteria and releases osmotically active sugars to increase amount of water in stool
Stimulant laxative-
Senna and sennusoids
stimulates nerve endings in bowel and activates myenteric plexus to decrease time for water absorption and make sure there is more water in stool
Bisacodyl-
same but used to clear out for colonoscopy
What are IBD treatments?
Aminosalicylates- e.g. sulphasalazine Corticosteroids Immunosuppressants Biological therapies Helminth therapy Faecal microbiota transplant Small molecule drugs to modulate immune system Cytokine inhibitors
What are the layers of the adrenal gland and what comes from where?
Zona glomerulosa- outside- mineralocorticoids
Zona fasiculata- middle- glucocorticoid
Zona reticulata- inner- sex steroids
Medulla- catecholamines
What is shock and what are the different types?
Anaphylaxis Cardiogenic Hypovolaemic Neurogenic Septic
What is seen with hypovolaemic shock and how is it treated?
Issue is inadequate volume and a fall in clinical output
Then it is compensated by increased resistance, tachycardia and hypotension as a late sign
Clinical signs- cold clammy peripheries tachycardia prolonged capillary refill time empty veins
Cold clammy periphery
Weak pulse
Empty veins
Treats with-fluids to increase resistance and blood pressure
What is seen in pump failure shock?
Main problem is fall in cardiac output
compensated by increasing resistance and tachycardia
further problem- increase capacitance- failure of starlings law
Clinical signs- cold clammy peripheries tachycardia prolonged capillary refill time raised JVP
Have weak pulse
Full veins and raised JVP
Treat by giving inotropes- dilators and adrenaline to decrease resistance and help the heart pump
What is seen in vasodilatory shock like sepsis, neurogenic and anaphylaxis?
Main problem is vasodilation so fluid goes to wrong place
Compensated by tachycardia, auto regulation and raised cardiac output
Clinical sogns- warm, dry peripheries tachycardia short capillary refill time bounding pulse
What is seen in vasodilatory shock like sepsis, neurogenic and anaphylaxis?
Main problem is vasodilation so fluid goes to wrong place
Compensated by tachycardia, auto regulation and raised cardiac output
Clinical sogns- warm, dry peripheries tachycardia short capillary refill time bounding pulse
Treat with fluids and noradrenaline to cause vasoconstriction
What are some cytochrome P450 inducers?
Chronic ethanol use Barbituates Oral contraceptives Marujuana smoke Phenytoin Rifampicin Isoniazid
What are some cytochrome P450 inhibitors?
Acute ethanol use Cimetidine Ketoconazole Allopurinol Amiodarone
What is Conn’s syndrome?
Excess aldosterone production often caused by adenoma of adrenal gland.
Causes hypertension and hypokalaemia
What is a high extraction ratio for a drug and what is a low? And what does this mean in liver failure?
High extraction ratio- drug excretion heavily relies on the blood flow to the liver, so issue with blood flow in liver failure means drug will build up- verapamil, morphine, propanol
Low extraction ratio means excretion is independent of the blood flow and relies on intrinsic metabolising activity of the liver- e.g. phenytoin and warfarin
What are the stages of drug metabolism?
phase 1- reduction, hydrolysis of drug- makes drug more polar
Phase 2- detoxification by cytochrome p450, and make it more water soluble
Phase 3- biliary excretion of drug
