Acute inflammation

Question 1

What is the defintion of acute inflammation?

What are the common causes of acute inflammation?

What are the consequences of acute inflammation?

Answer 1

Definition

• Immediate/early response to injury (minutes – days)

Common causes

• Infection (bacterial, viral, other)
• Physical agents e.g. burns
• Chemical agents
• Immune responses
• Tissue death from any cause

Consequences

• May be beneficial (e.g. bacterial killing, removal of dead tissue)
• Also potential harmful effects (e.g. lung damage in pneumonia, kidney damage in acute pyelonephritis)
• May precede chronic inflammation, healing and repair

Question 2

Acute Inflammation - Main Components

Answer 2

1. Vascular response – vasodilatation increased blood flow (redness, warmth) – increased permeability oedema (swelling)
2. Inflammatory cell infiltration – mainly neutrophils – macrophages (during later stages) – lymphocytes may also be involved

Question 3

what is this image showing?

Answer 3

Acute appendicitis

Question 4

What does this show?

Answer 4

A normal blood vessel

Question 5

What do these images show

Answer 5

vessels in acute inflammation

Question 6

This is a histology of someone with the following signs. what is the histology showing?

Nonspecific symptoms

Progressive fever

Anorexia (hamburger sign )

Nausea, vomiting, diarrhea , and/or constipation

Abdominal pain: classical presentation

Initially, dull migratory periumbilical pain (due to visceral peritoneum irritation)

After 4–24 hours, sharp RLQ pain (due to parietal peritoneum irritation by a distended and inflamed) with rebound tenderness

Signs

Blumberg’s sign: rebound tenderness caused upon suddenly ceasing deep palpation of the RLQ

McBurney point tenderness: an area one-third of the distance from the right anterior superior iliac spine to the umbilicus (in the RLQ)

Rovsing’s sign: deep palpation of the LLQ causes RLQ referred pain

Psoas sign: RLQ pain with extension of the right leg against resistance (secondary to inflammation)

Obturator sign: RLQ pain with flexion and internal rotation of the right leg

Answer 6

Question 7

What vascular changes are seen with acute inflammation?

Answer 7

1. Vasodilatation (arterioles)

– increased blood flow through capillary bed

2. Increased permeability (capillary bed, venules)

– protein-rich fluid escapes into extravascular space(exudates)

– increased concentration of erythrocytes (congestion)

– increased blood viscosity

– reduced blood flow (stasis)

3. Leukocyte margination

– loss of axial streaming

– first stage in process of leukocyte emigration

Question 8

Answer 8

Question 9

Answer 9

Question 10

What has happened to this appendix after inflammation?

Answer 10

Question 11

What are these

Answer 11

neutrophil polymorphs

Question 12

cute Inflammation - Chemotaxis

What is it?

What are chemotactic substances?

What are other effects of chemotactic molecules?

Answer 12

Chemotaxis

• migration along chemical gradients

Chemotactic substances

• bacterial products
• complement components (e.g. C5a)
• leukotrienes
• chemotactic cytokines (chemokines)

Other effects of chemotactic molecules

• leukocyte activation
• endothelial cell activation

Question 13

What hapens during phagocytosis

Answer 13

Question 14

Answer 14

Question 16

Acute Inflammation - Suppurative (Purulent) Inflammation

What is the differnece between pus and abscess?

Answer 16

Pus • Material composed neutrophils, necrotic cells and bacteria

• Complication of infection with pus-forming (pyogenic) bacteria Abscess • A localized collection of pus

Question 17

What can you see here

Answer 17

Purulent exudate on surface of brain stem - Left

Pus histology(full of neutrophils) - right

Question 18

what is wrong with this pons?

Answer 18

Cavity filled with green

Haematogenous spread - due to septicemia

Question 19

What happned to this temporal love?

Answer 19

Direct spread from middle ear infection causing an abscess

Question 20

Which of the hepatitis can be acute?

Answer 20

Hepatitis A - most common

B and C can also be acute but can become chronic

Question 21

What causes viral meningitis and viral myocarditis?

Answer 21

• Viral meningitis - Coxsackievirus, mumps
• Viral myocarditis - Coxsackievirus, echovirus

Question 22

What does this person have?

Answer 22

Viral Myocarditis

Inflammatory cells in myocardium are predominantly lymphocytes

Question 23

Acute Inflammation - Sequelae

Answer 23

Resolution

• limited / short-lived injury
• return of tissue to normal state

Scarring/ fibrosis

• more extensive tissue damage
• tissues with little capacity for regeneration
• abscess formation

Progression to chronic inflammation

Question 24

Acute Inflammation – Clinical Aspects

Classical clinical features

What specific type of cell will be raised?

Defects in leukocyte function can cause inflammtion - what is an example of a heriditary and acquired cause?

Answer 24

– heat (calor)

– redness (rubor)

– swelling (tumor)

– pain (dolor)

Raised white cell count in blood ( mainly neutrophils)

– particularly high in pyogenic bacterial infection

– also present in non-infective causes (e.g. myocardial infarction)

– neutrophil-rich leukocytosis in other body fluids

• e.g. Cerebrospinal fluid in bacterial meningitis

Hereditary (uncommon) e.g. chronic granulomatous disease

• Acquired e.g. leukaemia

 Predispose to bacterial infections, which may be life-threatening

Question 25

Anti-inflammatory therapy

Example of broad spectum and targeted treatment

Answer 25

Broad Spectrum

• Non-steroidal anti-inflammatory drugs (e.g. Ibuprofen) inhibit cyclooxygenase enzymes (COX-1, COX-2) involved with arachidonic acid metabolism to produce prostaglandins

Targeted Treatments

• Therapies blocking specific chemical mediators or receptor-ligand interactions (e.g. anti-TNF antibodies, anti-ICAM-1)