git patho v bare bones Flashcards
most common benign neoplasm of oropharynx
squamous cell papilloma
most common malignant neoplasm of oropharynx
SCC: squamous cell carcinoma
what is sialolithiasis?
calculi causing ductal obstruction (mostly in submandibular glands)
what are the causes of sialadenitis? (viral, bacterial, autoimmune)
viral: mumps (bilateral inflammed parotid glands)
bacterial: staph aureus, strep viridans
autoimmune: sjogren syndrome
most common benign neoplasms of salivary glands (2)
pleomorphic adenoma> warthin tumour
what is atresia?
a condition in which an orifice or passage in the body is (usually abnormally) closed or absent
what is achalasia?
swallowing disorder that affects the esophagus (esophagus muscles do not contract properly and do not help propel food down toward the stomach)
what is diaphragmatic hernia?
incomplete formation of diaphragm→ abdominal viscera herniates into thoracic cavity
what are varices?
an abnormally dilated vessel with a tortuous course
how are oesophageal varices formed?
liver cirrhosis→ portal HT→ formation of collateral channels to divert flow fr portal vein→ collateral veins get congested & dilated (varices)→ variceal rupture→ hematemesis, melena
what are mallory-weiss tears?
- longitudinal superficial mucosal tears near the GEJ (junction between distal esophagus and the proximal stomach (cardia))
- associated with severe retching/vomiting due to acute alcohol intoxication
- clinical: hematemesis
what is gerd?
reflux of gastric contents into lower esophagus, due to transient lower esophageal sphincter relaxation triggered by gastric distenstion
what is barrett esophagus?
- complication of chronic gerd
- intestinal metaplasia within esophageal squamous mucosa
- associated with increased risk of adenocarcinoma
common malignant neoplasms of oesophagus (2) + location
- SCC (upper 2/3 of oesophagus)
- adenocarcinoma (lower 1/3)
what are the causes of pyloric stenosis? (4)
- congenital: hyperplasia of pyloric muscularis propria→ obstruct gastric outflow
- benign, acquired: antral gastritis
- benign, acquired: peptic ulcers close to pylorus
- malignant, acquired: carcinomas of distal stomach/pancreas→ fibrose→ narrow pyloric channel
what is acute gastritis?
sudden onset of stomach mucosal injury/inflammation with NEUTROPHILS present
(damaging forces»protective mech)
gastritis vs gastropathy
gastritis: mucosal injury with NEUTROPHILS
gastropathy: mucosal injury with rare/absent inflamm cells
what is zollinger-ellison syndrome
- neuroendocrine tumours (GASTRINOMA) in small intestine or pancreas
- trophic effects on gastrin→ hypersecretes gastric acid
- present w duodenal ulcers or chronic diarrhoea
- treatment: PPIs
what is peptic ulcer disease?
- chronic mucosal ulceration in duodenum/stomach
- penetrates muscularis mucosa/deeper
what are the risk factors of peptic ulcer disease? (4)
- H. pylori infection
- NSAIDs
- cigarette use
- CVS disease
clinical presentations of peptic ulcer disease (4)
- epigastric burning/aching
- pain occurs 1-3hrs after food, worse at night, relieved by alkali/food
- penetrating ulcers can refer pain to back, left upper quadrant, chest
- n+v, bloating, belching, weight loss
what is the pathophysiology behind h.pylori gastritis?
- in almost all pts w duodenal ulcers, and most pts w gastric ulcers/chronic gastritis
- antral inflammation→ increased gastrin production→ increase HCl production→ gastric/duodenal peptic ulcer
- long standing infection→ involves body & fundus→ atrophic gastritis w reduced parietal cell mass & intestinal metaplasia→ decreased ulcers but increased risk of adenocarcinoma
what is the pathophysiology of autoimmune atrophic gastritis?
- chronic gastritis
- CD4+ T cells direct against parietal cell components→ loss of parietal cells→ defective acid & IF production
- defective HCl prod→ achlorhydria/hypochlorhydria→ stimulates gastrin release→ hypergastrinemia & G-cell hyperplasia→ neuroendocrine cell hyperplasia
- defective IF production→ defective ileal vit B12 absorption→ B12 deficiency & pernicious anemia
- atrophy & intestinal metaplasia→ increased adenocarcinoma risk
malignant neoplasm of stomach
adenocarcinoma
metastasis of gastric carcinoma/adenocarcinoma
- lymph node: invovles virchow node (left supraclavicular node0
- distant metastasis: liver, periumbilical region (sister mary joseph nodule), bilateral ovaries (krukenberg tumour)
what is duodenal atresia?
congenital failure of duodenum to canalise
what is the most common congenital GIT anomaly?
meckel diverticulum
what is meckel diverticulum?
congenital outpouching of all 3 layers of bowel wall (true diverticulum)
what is volvulus?
twisting of bowel along mesentery→ obstruction & disruption of blood supply→ infarction
what is the most common cause of intestinal obstruction in children?
intussusception
what is intussusception?
segment of bowel sliding forward into distal segment→ obstruction
pathophysiology of lactose intolerance
lactase deficiency→ lactose accumulates in intestine lumen→ osmotic diarrhoea
what is celiac disease?
congenital damage of small bowel villi due to gluten exposure (immune mediated)
what are the causes of acute appendicitis?
adults: luminal obstruction eg faecolith (stone made of feces in intestine)
children: lymphoid hyperplasia
increase intraluminal pressure→ compromise venous outflow→ bacterial proliferation→ acute inflammation
what are the clinical presentations of acute appendicitis?
early: periumbilical pain, fever, n/v
late: pain localises to RIF (right iliac fossa)/mcburney’s point
what is inflammatory bowel disease?
- autoimmune, chronic relapsing bowel inflammation (bloody diarrhoea, abdominal pain)
- associated w colonic adenocarcinoma
types of IBD (2)
- crohn’s disease
- ulcerative colitis
site of crohn disease vs UC
crohn disease: any GIT area
UC: only rectum (always) and colon
what is anorectal atresia?
congenital anorectal malformation→ absent anal opening at birth (failure of cloacal diaphragm to involute)
what is hirschsprung disease?
congenital failure of ganglion cells to descend into myenteric & submucosal plexus→ aganglionic segment cant relax→ no coordinated peristalsis→ functional obstruction!!→ massive dilatation of bowel proximal to obstruction (risk of rupture)
what is colonic diverticula?
wall stress e.g. vasa recta traverse muscularis propria→ outpouching of mucosa & submucosa
how does colonic diverticula lead to diverticulitis?
faecolith gets trapped in diverticula pouch→ infection→ diverticulitis
what are the causes of ischemic bowel disease?
- atherosclerosis of SMA
- arterial thromboembolism
- venous thrombosis
etc
what is pseudomembranous colitis?
antibiotic use→ disrupt normal colonic microbiome→ C. difficile overgrowth!!!→ severe inflammation of inner lining of colon
what are the causes of intestinal tuberculosis? (3)
- consumption of milk products containing mycobacterium bovis
- consumptiom of sputum fr person with active mycobacterium tuberculosis
- spread from distant TB sites
microscopic signs of intestinal tuberculosis (2)
- caseating granulomas (epithelioid histiocytes, langhan giant cells, central caseating necrosis)
- ziehl-neelson stain for acid-fast bacilli
what is amoebiasis?
colonic disease caused by entamoeba histolytica (protozoa)→ flask-shaped ulcers
what is familial adenomatous polyposis?
- autosomal dominant disorder w numerous adenomatous colonic polyps
- due to inherited APC mutation
what is cholestasis?
any condition that causes retention of bile: impaired bile formation or obstruction of bile flow
clinical presentations of cholestasis
tissue deposition of bilirubin (bile pigments)→ jaundice, icterus
others: pruritus, skin xanthomas (fat buildup under skin surface), intestinal malabsorption/vit ADEK deficiencies
what is extrahepatic biliary atresia?
- complete/partial obstruction of extrahepatic biliary tree lumen
- within first 3 months of life
- jaundice, pale stools, tea coloured urine (obstructive jaundice)
- 1/3 of neonatal cholestasis cases
what is cholangitis?
inflammation of the bile duct system
what is primary biliary cholangitis (PBC)?
chronic, progressive condition that causes inflammation→ destruction of bile ducts
what is primary sclerosing cholangitis (PSC)?
chronic liver disease→ bile ducts inside & outside liver become inflammed & scarred→ become narrowed/blocked
what is choledochal cyst?
congenital anomaly of biliary tree (usually common bile duct)→ abnormal dilatation→ obstructs bile flow
where does gallbladder carcinoma spread to? (direct and metastasis)
usually adenocarcinoma
direct invasion: liver, stomach, duodenum
metastasis: liver, regional lymph nodes, lungs
what is cholelithiasis?
gallstones
what are the symptoms of cholelithiasis?
- RUQ/epigastric pain
- biliary colic (usually after fatty meal)
what is cholecystitis?
gallbladder inflammation
what is calculous acute cholecystitis?
obstruction of neck/cystic duct by a stone causing chemical irritation & inflammation
what is acalculous acute cholecystitis?
- cystic duct obstruction & cholecystitis in the absence of stones
- e.g. lack of gallbladder stimulation→ gallbladder stasis→ concentration of bile salts→ bile sludge→ build up of pressure→ ischemia
what is chronic cholecystitis?
- repeated acute cholecystitis, or without previous attacks
- commonly associated w cholelithiasis!!
why are most liver diseases chronic by the time of clinical presentation?
- liver has enormous functional reserve→ mild liver damage may not be clinically detected
- liver disease is usually an insidious process
what is the progression of acute hepatitis/mild liver injury?
acute hepatitis→ liver regeneration & repair
what is the progression of massive liver injury?
massive liver injury→ acute liver failure
what is the progression of chronic hepatitis/persistent liver injury?
chronic hepatitis→ fibrosis/cirrhosis→ chronic liver failure or acute-on-chronic liver failure
what is acute liver failure?
- occurs within 26 weeks of initial liver injury (no pre-existing liver disease)
- diffuse injury without obvious cell death
what are the causes of acute liver failure? (3)
- drugs/toxins
- acute hepatitis A/B/E
- autoimmune hepatitis
what is chronic liver failure?
progressive deterioration of liver functions for more than six months e.g. chronic hepatitis
what are the causes of chronic liver failure? (3)
- chronic hep B/C
- NAFLD
- ALD
what is cirrhosis?
scarred & permanently damaged liver (dense fibrous tissue formation)→ shrunken, firm, nodular liver
what is acute-on-chronic liver failure?
- unrelated ACUTE injury supervenes on CHRONIC disease
OR - CHRONIC disease itself has a flare of/ACUTE activity that directly leads to liver failure
what are the consequences of liver failure? (5)
- coagulopathy (impaired hepatic synthesis of coagulation factors)
- hepatic encephalopathy (liver dysfunction→ brain dysfunction)
- cholestasis (obstruction to bile flow)
- portal HT
- hyperestrogenemia (palmar erythema, spider angioma, hypogonadism, gynecomastia)
what is the causes of portal HT?
prehepatic:
- increased resistance: thrombosis/narrowing of portal vein
- increased flow: splenomegaly/arterial vasodilation→ increased splenic blood flow
intrahepatic: cirrhosis/non-cirrhotic
posthepatic:
- hepatic vein outflow obstruction
- heart problems eg RH failure
effects of portal HT (4)
- increased pressure in peritoneal capillaries→ ASCITES
- portosystemic shunting of blood→ devt collateral channels→ ANORECTAL & ESOPHAGEAL VARICES
- shunting of NH3 fr GIT into general circulation→ HEPATIC ENCEPHALOPATHY
- splenomegaly→ anemia, leukopenia, thrombocytopenia
which hepatitis viruses are transmitted fecal-orally?
- Hep A (SHELLFISH!)
- Hep E (water borne too)
which hepatitis viruses are transmitted parenterally?
- Hep B
- Hep C (mainly blood, sexual & vertical are rare due to low circulating viral levels)
- Hep D
which hep virus’s genomes are RNA?
Hep A, C, D, E
which hep virus’s genomes are DNA?
hep B
which hep viruses have available vaccines?
hep A, B, D (HDV is protected by HBV vax)
which hep viruses DONT have available vaccines?
hep C, E
explain how there may be hep A epidemic in singapore?
low exposure to HepA→ youths have no antibodies→ are susceptible
introduction of infected material eg raw SHELLFISH→ epidemic
what is the pathophysiology of hep B virus?
enters blood→ infects hepatocytes→ viral DNA polymerase synthesizes missing DNA portions→ host RNA polymerase synthesizes mRNA→ produce more viral DNA→ progeny HBV releases by budding
some viral DNA may integrate into host cell genome→ carrier
what is the progression of disease of HBV carriers?
5-15% of infected become carriers (HBsAg detected in blood > 6mths)→ 10-30% develop chronic helpatitis→ cirrhosis→ liver cancer
1% carriers/year develop anti-HB (immune)→ recover :)
what is the epidemiology of HCV?
- hosts: infected humans & chimps
- 60-80% of infected become carriers→ chronic hepatitis
what is the epidemiology of HDV?
- mostly associated w IVDA
- infects HBV carriers (uses HBV coat to infect cells, aka HBV is a helper virus)
which virus has special effect on pregnancy?
Hep E!!
high mortality rate of 25% in pregnant women & fetus
rank the severity of symptoms of the different hepatitis viruses
HAV/HCV «_space;HBV «HDV
HEV is self limiting w no sequelae
what are the viruses that can cause hepatitis? (5)
- yellow fever virus
- EBV
- CMV
- rubella
- hantaviruses
what are the most common hepatitis virus causes of acute hepatitis?
- HBV (50%)
- HAV (20-30%)
- HCV (5%)
- HEV (<5%)
what are the most common hepatitis virus causes of chronic hepatitis?
- HBV (70%)
- HCV (20%)
which hepatitis viruses does NOT cause carriage and chronic hepatitis?
- Hep A
- Hep E
what are the most common hepatitis virus causes of liver cancer?
- HBV (70%)
- HCV (20%)
what are the mechanisms of drug & toxin induced liver injury?
- direct toxicity
- through hepatic conversion of xenobiotic→ active toxin
- through immune mediated mechanisms
what are the most common hepatotoxins causing liver failure? (acute + chronic)
acute: acetaminophen
chronic: alcohol…
what are the risk factors of alcoholic liver disease (ALD)? (4)
- severity depends on dose & duration
- gender: females
- ethnic & genetic differences e.g. in detoxifying enzymes
- comorbid conditions eg concomitant liver pathologies like viral hepatitis
what is the progression of ALD?
normal liver→ steatosis (fatty liver)→ steatohepatitis (hepatocellular inflammation and damage in response to the accumulated fat)→ cirrhosis→ hepatocellular carcinoma
steatosis & steatohepatitis can resolve/reverse w abstinence
what are non-alcoholic fatty liver diseases (NAFLD)
spectrum of disorders that present with hepatic steatosis/fatty liver in absence of/low alcohol consumption
what are the causes of NAFLD? (2)
associated w metabolic syndrome! buildup of fat in liver
1. insulin resistance→ dysfunctional lipid metabolism, increased production of inflamm cytokines
2. oxidative injury→ liver cell necrosis (fat laden cells are highly sensitive to lipid peroxidation pdts)
what is the progression of NAFLD?
NAFLD→ isolated fatty liver (>80%) :))
NAFLD→ non-alcoholic steatohepatitis (NASH) :(→ NASH cirrhosis (11% over 15 yrs)→decompensation or HCC
what is metabolic associated fatty liver disease (MAFLD)?
basically same as NAFLD lol,,, just better criteria model
what are the diagnostic criterias of MAFLD?
detection of liver steatosis + at least one of:
- overweight/obesity
- T2DM
- clinical evidence of metabolic dysfunction
what are the manifestations of impaired blood inflow to the liver? (3)
e.g. portal vein obstruction, intra/extrahepatic thrombosis
- esophageal varices
- splenomegaly
- intestinal congestion
what are the manifestations of impaired INTRAHEPATIC blood flow? (4)
- ascites
- esophageal varices
- hepatomegaly
- elevated ALT/AST
what are the manifestations of impaired hepatic vein OUTFLOW? (5)
- ascites
- hepatomegaly
- elevated ALT/AST
- abdominal pain
- jaundice
what is a common non-neoplastic cause of liver mass?
focal nodular hyperplasia (FNH)
what is FNH?
non neoplastic!!
-due to focal alterations in hepatic blood supply
- well-demarcated but poorly encapsulated pale nodule typically with central fibrous scar
- background non-cirrhotic liver
what are 3 benign neoplastic cause of liver mass?
- hepatocellular adenoma (HCA)
- bile duct adenoma
- haemangioma
what are haemangiomas?
benign neoplasm of connective tissue
- hypervascular, venous malformations forming noncancerous mass (angioma)
- most common benign liver tumour
complication: rupture→ intraperitoneal leeding, thrombosis
what are hepatocellular adenomas?
benign neoplasm of hepatocytes
- pale, soft +/- hemorage in a non-cirrhotic background
what are the malignant neoplastic causes of liver mass? (3)
- hepatocellular carcinomas (HCC)(90%)
- cholangiocarcinoma (CC)(10%)
- hepatoblastoma
what is HCC?
malignant neoplasm of hepatocyte
- associated w HBV infections, younger pts in absence of cirrhosis
what is CC?
malignant neoplasm of bile duct (both within & outside liver)
- 2nd most common primary malignant tumour of liver)
- risk factors (eg HBV, HCV, PSC)→ chronic inflammation & cholestasis→ promotes somatic mutations or epigenetic alterations
what is hepatoblastoma?
malignant neoplasm
- rare but most common liver tumour of early childhood (<3yo)
- associated w FAP, Beckwith Wiedemann syndrome
what are the common primary sites of malignant neoplasms that metastasize to the liver? (4)
colon, breast, lung, pancreas
what is zollinger-ellison syndrome?
gastrin-secreting tumor of the pancreas→ stimulates H+ secretion by parietal cells (no negative feedback)
what is pancreas divisum?
congenital: foetal CBD and pancreatic duct fail to fuse→ enter duodenum separately
what is annular pancreas?
congenital: pancreas wraps around duodenum like a ring→ stenosis/obstruction
what is ectopic pancreas?
congenital: pancreatic tissue in non-pancreatic sites eg stomach, intestines
what is pancreatic agenesis?
congenital: missing parts of the pancreas
what is acute pancreatitis?
- reversible parenchymal injury
- inappropriate release & activation of pancreatic enzymes→ destroy pancreatic tissue→ breakdown of pancreatic protective mech→ autodigestion of pancreas→ acute inflammatory reaction
what is the pathogenesis of acute pancreatitis?
- duct obstruction → accumulation of enzyme rich fluid in pancreatic interstitium (raised intrapancreatic ductal pressure)→ edema→ impaired blood flow & → acinar cell injury (ischaemia)
- oxidative stress (eg alcohol) → release and activation of intracellular proenzymes → acinar cell injury
- defective intracellular transport (e.g. alcohol) → deliver proenzyme to lysosomal compartment→ intracellular activation → acinar cell injury
acinar cell injury→ activated enzymes→ acute pancreatitis
what is chronic pancreatitis?
- repeat episodes of acute pancreatitis, cause fibrosis (absent in acute)
- prolonged inflammation of pancrease
- irreversible destruction of EXOCRINE parenchyma, late stage destruction of ENDOCRINE parenchyma
what is the etiology of chronic pancreatitis?
- usually middle aged males
- most common cause is long term alcohol abuse
what are pancreatic pseudocysts?
non-neoplastic cysts presenting after acute pancreatitis or traumatic injury
what are the common solid pancreatic neoplasms?
- ductal adenocarcioma
- acinar cell carcinoma
