(P4) Resp Patho: Silicosis of the lung

Question 1

Identify :

Answer 1

Silicosis of the lung

1. Chronic occupational lung disease caused by silica particles
2. Mesothelioma caused by asbestos
   * Note: Mesothelioma is a malignant tumor that is caused by inhaled asbestos fibers and forms in the lining of the lungs, abdomen or heart. Symptoms can include shortness of breath and chest pain. The life expectancy for most mesothelioma patients is approximately 12 months after diagnosis.*

Question 2

Identify:

What is the cause of this lesion and how is it formed?

Answer 2

Silicosis of the lung

• Caused by the inhalation of silicon dioxide:
  1. Silica particles are ingested by alveolar macrophages
  2. Macrophages are destroyed by silica particles
  3. Dead cells release free silica particles and fibro-genic factors*

4. Fibro-genic factors form nodules of collagen fibers

Question 3

Silicosis of the lung is usually described as?

Answer 3

Usually

slowly progressing, nodular, fibrosing pneumoconiosis

Question 4

Pneumoconiosis

Define:

Answer 4

Pneumoconiosis

is the general term for a class of interstitial lung diseases where inhalation of dust has caused interstitial fibrosis.

-Pneumoconiosis often causes restrictive impairment, although diagnosable pneumoconiosis can occur without measurable impairment of lung function.

Question 5

What are 3 types of pneumoconiosis?

Answer 5

primary pneumoconioses:

1. asbestosis
2. silicosis
3. coal workers’ pneumoconiosis (commonly referred to as CWP or black lung).

As their names imply, they are caused by inhalation of asbestos fibers, silica dust, and coal mine dust.

Question 6

This lesion is described as

and

composed of ?

Answer 6

Silicosis of the lung

• Silicotic nodule is composed of concentric whorls of dense, sparsely cellular collagen
• Infiltration composed of lymphocytes* and *macrophages

Question 7

What can be seen

at the

edge of the Nodule?

Answer 7

At the edge of the nodule – dust with carbon pigment and silica particles

NOTE: Silica particles are hard to see

Question 8

What can be seen on this Slide:

Microsopically?

Answer 8

Silicosis of the Lung

Micro: Nodule surrounded by chronic inflammatory cells (coal dust, macrophages, lymphocytes).

-Few cells in nodule (collagen fibers)

Accumulation of histocytes and proliferation of fibroblast

Question 9

NOTE:

What happens to the Silicon dixide?

Answer 9

Silicon dioxide is eaten by alveolar macrophage which die and release silicon particle & fibro-genic factor which turn into simple nodular silicosis.

-Macrophage (destroyed) contain silica particle → promotion of cytokine release → activation of fibroblast →more collagen fiber

Question 10

IDENTIFY:

Answer 10