Pathology Flashcards
What is infection from animal to human called?
Zoonosis
What is the definition of an ulcer?
Full thickness loss of an epithelial surface
What is the definition of an erosion?
A shallow ulcer (some loss of an epithelial surface)
What enzyme test is used to test for H. Pylori?
Urease test
Why does H. Pylori contain a lot of urease?
So it can surround itself with ammonia (from the breakdown of urea) and raise the pH around it.
Complications of a duodenal ulcer, and their causes?
Perforation - extension of ulcer to peritoneal surface
Massive GI haemorrhage - Rupture of large vessel at ulcer base
Anaemia - Chronic blood loss from surface of ulcer causing iron deficiency
Gastric outlet obstruction - fibrosis around the ulcer causing scarring
Two types of cancer that an H.Pylori infection can lead to?
Adenocarcinoma
Lymphoma
Process of duodenal ulcer formation?
Gastric H. Pylori infection
Antral gastritis
More acid secretion
Increased duodenal acid load
Gastric metaplasia in duodenal bulb, leads to Infection
4 virulence factors of H. Pylori?
Urease
LPS
IL-8
Vacuolating cytotoxin
What are the two strains of H.Pylori which is worse?
Cag A+ and Cag A-
A+ is worse
A- is mostly asymptomatic
What are the two things that a Cag A+ strain does that lead to a duodenal ulcer?
Active duodenitis and bicarbonate suppressed
Treatment options for Barrett’s oesophagus?
Oesophagectomy
Photodynamic therapy
Laser ablation
Endoscopic mucosectomy
What is an inlet pouch?
Ectopic bit of gastric mucosa that rarely leads to carcinoma, it is congenital
Peptic ulcer risk factors?
H.Pylori infection Low Socio-economic status NSAIDS Heavy drinking Smoking
Complex and simple tests to diagnose H.Pylori?
Complex: endoscopy/culture/histology/urease test
Simple: Breath test/serology
Functional dyspepsia is what?
Dyspepsia with no evidence of structural disease at endoscopy in last 3 months
Dyspepsia alarm signals?
Weight loss
Persistent vomiting
Progressive dysphagia
Anaemia/GI bleed
Palpable mass
What is a hiatus hernia?
A hernia of the fundus of stomach pushed through the diaphragm
What is carnetts test and what does a positive and negative result suggest?
Patient lies flat and legs are lifted and then head is lifted
Positive if the pain increases or stays the same after legs are lifted
Negative if head is lifted and pain goes
Positive means likely in abdominal wall
Negative means intraabdominal
When should you endoscope a pt who comes in with dyspepsia?
True dypepsia with alarm symptoms
> 55yrs
Treatment for true dyspepsia?
Simple antacids/lifestyle changes/review medications
Full dose PPI for a month
Test and treat for H.Pylori
Signs of large gastric bleed?
Dizziness
Postural hypotension
Hypovolaemia
Weak pulse
HR >100
Where is calcium most likely to be deposited pathologically?
In necrotic tissue
What is steatosis?
abnormal deposition of lipid within cells
Where is the most common site for steatosis to occur?
The liver
What can cause hepatic fatty deposits to form?
Alcohol Type II diabetes Metabolic syndrome Hyperlipidaemia Obesity
What is haemosiderosis?
Abnormal deposition of haemosiderin
What is haemosiderin?
An iron pigment
What two conditions mainly result in haemosiderosis?
inflammation and systemic iron overload
How can inflammation lead to haemosiderosis?
Leads to a large leakage of RBCs into tissue which are degraded by macrophages, the iron from the haemoglobin may form haemosiderin
What is haemochromatosis?
A genetic condition where large amounts of iron is absorbed from the intestine
How does excess systemic iron overload lead to haemosiderosis?
What other impacts does this have?
Excess iron is deposited in tissues and forms haemosiderin
Excess iron can cause damage to cells it is deposited in, and large amounts are deposited in the liver and pancrease leading to liver disease and diabetes respectively.
Avg. loss of iron from the human body daily?
1mg
Common causes of liver damage?
Ingested substances e.g. ethanol, many prescribed drugs
Congenital accumulation of substances e.g. Iron, Copper, Alpha-1-antitrypsin
Immune mediated e.g. autoimmune
Infectious e.g. Hepatitis, EBV, CMV, bacteria e.t.c.
Effects of liver damage?
Liver failure
Cholestasis
Inflammation
Is acute liver injury likely to cause cirrhosis?
No, chronic will
What are stellate cells?
Liver cells that produce collagen and other matrix proteins, store Vit A and control vascular tone
What happens to blood flow in the liver during fibrosis?
What does this cause?
Thrombosis in sinusoids and small blood vessels
Capillarisation of sinusoids (loss of fenestrations and collagen in space of Disse)
Causes poor blood-hepatocyte change and increased vascular resistance
How does cirrhosis form from damaged cells in the liver
Nodules of regenerating hepatocytes form as hepatocytes divide to replace damaged cells. these are surrounded by bands of fibrous tissue and this is cirrhosis
Complications of liver cirrhosis?
Liver failure
Portal hypertension
Hepatocellular carcinoma
Consequences of portal hypertension?
Oesophageal and Rectal varices
Caput medusae
Ascites
Splenomegaly
Toxins bypass liver, can reach the brain
How do ascites form in liver failure? all factors
Portal hypertension increases the hydrostatic pressure
Liver failure leads to less proteins produced and reduces the oncotic pressure
Both Lead to exudate in peritoneal cavity
The reduced plasma volume can then lead to activation of the RAAS pathway and retention of salt and water leading to further development of ascites
Symptoms of acute hepatitis?
Jaundice, pale stools
Weight loss
itching
Fatigue
What are the five Hepatitis viruses?
A, B, C, D and E
What are the differences in acute and chronic hepatitis? Which Hep viruses cause which?
Diffuse inflammation of the liver - A,B,C and E
Persistent, has lasted for more than 6 months - B, C and D
How is Hep A transmitted?
Faecal-oral route
How is Hep B transmitted?
Through contact with the blood
What hepatitis infection is self-limiting, and what percentages of cases do not resolve by themselves?
Hep B, 5-10% do not resolve
What Hep virus has lots of carriers?
Hep B
What is special about Hepatitis D?
Only associated with Hep b it is a delta agent (genome coated in hepatitis delta antigen)
How is Hep D transmitted?
Parenterally
Features of Hep C virus?
Has a variable incubation period 15-150 days
60-70% infected do not show symptoms
80% develop a chronic infection
Features of Hep E virus?
High mortality, 20% in pregnant women
Associated with middle age men and swine in UK
Route of transmission of Hep E virus?
Faecal-oral route
What hepatitis viruses have vaccines?
A and B
Pancreatitis causes?
Ethanol
Obstruction e.g. gallstone
Infections, Trauma, Autoimmune
Idiopathic
What happens in acute inflammation of the pancreas?
Activation of digestive enzymes
Damage to cells
Cell death
Acute and chronic complication of pancreatitis?
Acute:
- SIRS - multiorgan failure
- Necrotizing pancreatitis
Chronic:
- Destruction of pancreas (steatorrhoea)
- Diabetes
- Pancreatic pseudocyst
Whats more common ulcerative colitis or Crohns disease?
Ulcerative colitis
Clinical features of IBD?
Chronic and relapsing conditions
Diarrhoea, change in bowel habit/melaena
Abdominal pain
Fever
Where does ulcerative colitis affect?
Limited to the colon
More severe in the distal colon
Macroscopic features of ulcerative colitis?
Superficial mucosal ulceration
Normal serosa
Inflammation evenly distributed
Where does Crohns disease normally affect?
Can involve entire GI tract
Classically the terminal ileum
Macroscopic features of Crohns?
Deep ulceration
Bowel wall thickening and strictures
abnormal serosa (fat wrapping)
Microscopic features of UC?
Distortion of glands
Microscopic features of Crohns disease?
Transmural inflammation
Fissuring ulceration
Neuronal hyperplasia
Granulomas
Differential diagnoses for IBD?
Infective colitis
Diverticular disease
Ischaemic colitis
Pouchitis
TB
Ulcerative colitis complications?
Toxic megacolon
Dysplasia
Malignancy
Crohn’s disease complications?
Fistula formation
Abscess formation
Bowel obstruction
Malignancy
Aetiology of IBD
Mostly unknown
Infective agents e.g. mycobacteria, rotavirus, chlamydia
Genetic influences
Cigarette smoking: increases CD risk, decreased UC risk
IBD therapies?
Infliximab - TNF alpha antibody
Genetics of Crohns disease?
Quite a strong genetic link
NOD2 gene - recognises gram positive bacterial cell wall
IL23R gene
What cytokine is particularly increased in crohns disease?
TNF
How does blocking TNF-a work in crohns disease?
Inhibitor binds to TNF-a Preventing it from activating it’s receptors
Foxp3 expression is upregulated
This down-regulates inflammatory reactions associated with autoimmune diseases
Whats a T-reg cell?
A T cell that has been activated by a dendritic cell in a peyers patch, to produce an anti-inflammatory response to some antigens by secreting IL-10
What colour is collagen in an H&E stain?
Pink
How are tissues processed to produce slides?
Either:
- Embedded with paraffin wax
- Frozen
And then encapsulated in paraffin wax and cut
What type of lymphocyte dominates germinal centres in lymph nodes?
B cells
Common presentations of colorectal cancer?
Change in bowel habit
Anaemia
Bleeding
Obstruction
3 main ways colorectal carcinoma spreads?
Lymphatic vessels
Blood vessels (haematogenous spread)
Trans-coelomic
What is dukes staging and the four stages?
A B C and D, corresponds to TNM I to IV
A: Limited to wall, nodes clear
B: penetrated wall, nodes clear
C: nodes positive
D: distant metastases
