1. CHRONIC INFLAMMATION
Dr. Saleem Shaikh

2. Introduction
Chronic inflammation is defined as prolonged process in which tissue destruction and inflammation occur at the same time.
Chronic inflammation can be caused in three ways
Following acute inflammation – the cause persists or survives for a long time
Recurrent attacks of acute inflammation – reccurent infection of the gall bladder may lead to chronic cholecystitis
Chronic inflammation starting de novo
General features of chronic inflammation -
Mononuclear cell infiltration: lymphocytes and monocytes
Tissue destruction and necrosis
Proliferative changes

3. Types of Chronic Inflammation
Based on etiology –
Non Specific – the irritant (causative) agent is non specific and results in formation of granulation tissue and fibrosis. Eg: osteomyelitis, chronic ulcer
Specific - the irritant agent causes a specific histologic response eg: tuberculosis
Based on histologic features
Chronic non-specific inflammation
Chronic granulomatous inflammation

4. Granulomatous Inflammation
Granuloma is defined as a circumscribed, tiny lesion composed of macrophages and lymphoid cells
The formation of granuloma is a protective defense reaction by the host but eventually causes tissue destruction because of persistence of the poorly digestible antigen.
Composition of a granuloma:
Epitheloid cells: resemble epithelial cells appearance; these are modified macrophages, which are a little elongated.
Multi nucleated giant cells: these are formed by fusion of epitheloid cells and may have more than 20 nuclei. Based on the arrangement of nuclei the giant cells can be grouped into various types
Lymphoid cells:
Necrosis: seen in some forms of granulomas
Fibrosis:

5. Types of Giant cells

6. Tuberculosis Mycobacterium tuberculosis causes tuberculosis.
Also known as Koch’s bacillus
This was once a very common and fatal disease but with advance in medicine and research the incidence and prevelance of tuberculosis had been reduced drastically. Resurgence of this disease is being seen because of AIDS.
Mode of transmission:
Inhalation
Ingestion
Inoculation
Transplacental routes

7. Spread of tuberculosis:
Local spread – macrophages carry the bacilli to surrounding tissues
Lymphatic spread –
Hematogenous spread –
Lung is the main organ to be affected by tuberculosis – pulmonary tuberculosis
Two main types
Primary
Secondary

8. Primary tuberculosis
The infection of a person who has not been previously infected or immunised is called as primary tuberculosis or Ghon’s complex.
the primary complex or ghon’s complexx in lung consists of three components-
Pulmonary component – ghon’s focus is a lesion in the lung. It is 1-2 cm in size and is seen usually in the periphery of upper part of the lower lobe.
The lesion is made up of granulomas with caseation necrosis
Lymphatic vessel component – the lymphatic vessels contain macrophages containing the bacilli
Lymph node component – the affected lymph nodes are matted and show casseation necrosis.

9. Fate of primary tuberculosis –
Heal by fibrosis and may undergo calcification
The caseous material may disseminate to other parts of the same lung. – progress primary tuberculosis
The bacillus may enter into blood vessels and spread to various tissues and organs - Primary milliary tuberculosis
The healed lesion may get reactivated due to decrease in immunity – progressive secondary tuberculosis.

10. Secondary tuberculosis
Infection in a person who has been previously infected or sensitized is called as secondary infection
Endogenous source
Exogenous source
The main lesion of secondary tuberculosis is seen in the apical region of the lung.
Microscopically it also has tuberculus granulomas with caseation necrosis.

11. Leprosy
Also known as Hansen’s disease is a chronic infectious disease, mainly affecting the cooler parts of the body such as skin, mouth, respiratory tract etc.
Caused by mycobacterium leprae
Two main types - Lepromatous leprosy & Tuberculoid leprosy
The patient has patches on the skin, which are hypopigmented and may have erythema. The lesions are hypoaesthtic or anaesthetic.

12. Syphilis
Syphilis is a sexually transmitted disease caused by spirocheates – Treponema pallidum.
Types of syphilis – Acquired & Congenital
Acuired –
Primary syphilis – typical lesion is known as Chancre, this appears 2-3 weeks after infection.
Secondary syphilis – mucocutaneous patches 2-3 months after infection
Tertiary syphilis – gumma appears 2-3 years later. These gummas are granulomas.
Congenital- develops in a foetus due to infection in mother. Many characteristic features seen like Hutchinsons triad and Hutchinsons teeth.