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Questions and Answers
What is granulomatous inflammation characterized by?
What is granulomatous inflammation characterized by?
Nodular collections of macrophages, lymphocytes, plasma cells, giant cells, and sometimes neutrophils.
Which of the following is NOT a type of granulomas according to etiology?
Which of the following is NOT a type of granulomas according to etiology?
Which of the following is an example of a bacterial infectious granuloma?
Which of the following is an example of a bacterial infectious granuloma?
What is the primary difference between necrotizing and non-necrotizing granulomas?
What is the primary difference between necrotizing and non-necrotizing granulomas?
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What are two types of giant cells that can be found in granulomas?
What are two types of giant cells that can be found in granulomas?
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What is a characteristic feature of Langhans’ giant cells?
What is a characteristic feature of Langhans’ giant cells?
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What is the causative organism for tuberculosis?
What is the causative organism for tuberculosis?
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Tuberculosis is a contagious disease that can be spread through the air.
Tuberculosis is a contagious disease that can be spread through the air.
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What is the name of the stain used to identify acid-fast bacilli in sputum?
What is the name of the stain used to identify acid-fast bacilli in sputum?
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What is the main component of the tuberculin test?
What is the main component of the tuberculin test?
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What factor is used to determine a positive result for the tuberculin test?
What factor is used to determine a positive result for the tuberculin test?
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What is the major mode of transmission for tuberculosis?
What is the major mode of transmission for tuberculosis?
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Inoculation through the skin is the most common way to contract tuberculosis.
Inoculation through the skin is the most common way to contract tuberculosis.
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What are some predisposing factors that can increase the risk of developing tuberculosis?
What are some predisposing factors that can increase the risk of developing tuberculosis?
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Which of the following is NOT a typical complication of tuberculosis?
Which of the following is NOT a typical complication of tuberculosis?
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Which of the following factors influence the course of tuberculosis (Select all that apply)?
Which of the following factors influence the course of tuberculosis (Select all that apply)?
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Secondary tuberculosis is more common in children than adults.
Secondary tuberculosis is more common in children than adults.
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What is a primary tubercular complex?
What is a primary tubercular complex?
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What is Ghon's focus?
What is Ghon's focus?
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What is the hallmark of healing in a tuberculous lesion?
What is the hallmark of healing in a tuberculous lesion?
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Miliary tuberculosis is a rapidly fatal condition.
Miliary tuberculosis is a rapidly fatal condition.
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Match the following routes of spread for tuberculosis with their definitions:
Match the following routes of spread for tuberculosis with their definitions:
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Study Notes
Chronic Granulomatous Disease
- A particular form of chronic inflammation, characterized by nodular collections
- Predominantly composed of macrophages with a variable mixture of:
- Lymphocytes
- Plasma cells
- Giant cells
- Neutrophils
- A key component is modified macrophages (epithelioid cells)
Types of Granuloma
-
Infectious granulomas: Mostly necrotizing granulomas
- Bacterial: tuberculosis, leprosy, syphilis
- Parasites: Schistosoma
- Fungi: cryptococcosis, histoplasmosis
-
Foreign body granulomas: Mostly non-necrotizing granulomas
- Form when the immune system can't digest foreign bodies (e.g., keratin, uric acid crystals, surgical suture)
- Lead to accumulation of macrophages and histiocytes
- Exogenous (foreign): silicosis, surgical suture, trapped foreign body
- Endogenous (internal): keratin, uric acid crystals (gout)
-
Granulomas of unsettled etiology: Mostly non-necrotizing granulomas
- Sarcoidosis
- Crohn's disease
Giant Cells in Inflammation
-
Foreign body giant cells:
- Contain many (up to 100) nuclei
- Nuclei uniform in size and shape, resembling macrophage nuclei
- Scattered throughout the cytoplasm
-
Langhans' giant cells:
- Found in tuberculosis and sarcoidosis
- Nuclei resemble those of epithelioid cells
- Arranged around the periphery in a horseshoe or ring shape, or clustered at the poles of the giant cell
Tuberculosis
- A chronic infectious granulomatous disease caused by tubercle bacilli
- Common in communities with poor nutrition and housing
- Causative organisms:
- Mycobacterium tuberculosis (M.TB) (human)
- Mycobacterium bovis (bovine)
Clinical Identification of TB infection
- Gram-positive, acid-fast bacilli in sputum (best stained by Ziehl-Neelsen stain)
- Tuberculin test (Mantoux test)
Pathogenesis of Tuberculous Lesion
- Bacteria do not produce toxins
- Pathological changes depend on the chemical structure of bacteria
- Polysaccharide fraction: Chemotactic to neutrophils within a few hours, leading to an inflammatory response, but neutrophils are quickly destroyed by the bacteria (lack lipase)
- Lipid fraction: Chemotactic to macrophages within 24 hours, initiating a progressive infiltration with macrophages potentially for destruction of bacteria (contain lipase)
Tubercle Formation
- Macrophages phagocytose bacilli and change, becoming swollen and pink, called epithelioid cells
- Epithelioid cells fuse to form multinucleate giant cells
- Macrophages present bacterial antigens (tuberculoprotein) to T lymphocytes which become sensitized and accumulate around epithelioid cells, producing lymphokines related to delayed hypersensitivity (Type IV)
The Caseation
- Due to:
- Hypersensitivity (cytotoxic lymphokines)
- Ischemic necrosis (lack of blood supply)
- The tubercle formation is not accompanied by angiogenesis
- Endarteritis obliterans (inflammation of artery) starts in the center of the lesion
- Histologically, the necrosis is structureless and eosinophilic
Pathological Changes of Tubercle (Gross Picture)
- Microscopic in size, may fuse to form small yellowish-grayish nodules
- Appear soft and cheesy due to caseation
- Sharp borders, firm consistency
- Cut section: yellowish center, grayish periphery
Microscopic Picture of Tubercle
- Caseation necrosis: Begins in the center, structureless and eosinophilic
- Epithelioid cells: Large altered macrophages, abundant pale eosinophilic cytoplasm, large vesicular nuclei
- Langhans giant cells: Large cells with pink cytoplasm and multiple peripherally placed nuclei forming a circle or U-shaped arch
- Peripheral lymphocytes: (Mainly T cells)
Tuberculous Granuloma
- Epithelioid cells
- Giant cells
- Lymphocytes
Caseating Granuloma
- Caseous necrosis
- Epithelioid cells
- Giant cells
- Lymphocytes
Tissue Reaction in Tuberculosis
- Proliferative reaction: Tubercle formation, occurring in solid organs like liver and kidney
- Exudative reaction: Occurs in serous membranes, characterized by outpouring of inflammatory exudates rich in fibrin, numerous lymphocytes, possibly neutrophils, but scanty epithelioid and giant cells, and marked caseation
Fate of Tuberculous Lesion
- Localization (adequate immunity): Healing by proliferating fibroblasts at the periphery, resulting in fibrosis; small lesions are completely replaced by fibrosis, large lesions are encapsulated. Dormant bacilli may remain, reactivating if resistance weakens
- Reactivation of dormant bacilli in encapsulated or healed lesions
- Spread due to failure of localization
Spread of Tuberculosis
- Tubercle bacilli are non-motile, spread by macrophages, tissue fluids, lymph, or blood
- Routes of spread: local, lymphatic, blood
- Without effect: Isolated organ tuberculosis, miliary tuberculosis (involving many organs)
- Natural passages (e.g., through epithelial surfaces): Lung lesion to pleura (tuberculous pleurisy), transbronchial spread, tuberculous salpingitis to peritoneal cavity (tuberculous peritonitis), infected sputum into larynx (tuberculous laryngitis), swallowing of infected sputum (ileocaecal tuberculosis), renal lesions to ureter and bladder
Blood Spread of Tuberculosis
- Small doses may be destroyed by phagocytic cells
- Isolated organ tuberculosis: organism settles in one or few organs
- Miliary tuberculosis: large number of organisms reach bloodstream, affecting multiple organs (rapidly fatal).
Miliary Tuberculosis
- Large number of organisms in the blood stream seed organs, producing millet-seed-sized follicles
- Rapidly fatal condition affecting lungs, spleen, liver, and kidneys
Spread by Natural Passages
- Spread from lung lesions to pleura (tuberculous pleurisy)
- Transbronchial spread to adjacent lung segments
- Tuberculous salpingitis to peritoneal cavity (tuberculous peritonitis)
- Infected sputum to larynx (tuberculous laryngitis)
- Swallowing infected sputum (ileocaecal tuberculosis)
- Renal lesions to ureter and trigone of bladder
Complications of Tuberculosis
- Spread
- Haemorrhage
- Destruction and severe fibrosis
- Amyloidosis in chronic cases
- Recurrence
Factors Influencing Course of Tuberculosis
- Dose and virulence of organism
- Immunity (natural innate immunity, general health, innate immunity, acquired immunity, delayed hypersensitivity)
- Hypersensitivity
Types (Patterns) of Tuberculosis
- Primary tuberculosis: Tuberculous infection for the first time, common in children, affects tonsils, lungs, intestine, and skin, tissue destruction less marked
- Secondary tuberculosis: Tuberculous infection of sensitized individuals, common in adults, any site may be affected, tissue destruction more marked due to hypersensitivity
Tuberculosis Affects Many Body Parts
- Middle ear
- CNS (brain and meninges)
- Tonsils
- Bones, spine, psoas muscle
- Intestine
- Liver, spleen, peritoneum
- Ureter
- Bladder
- Genitals (esp. epididymis)
- Adnexa
- Prostate, seminal vesicles
- Pericardium
Primary Tuberculosis
- In non-immunized individuals (children)
- Sites: lung, tonsils, intestines, skin
-
Primary tuberculous complex:
- TB bacilli in infected organ (primary focus)
- TB bacilli in draining lymphatics (tuberculous lymphangitis)
- TB bacilli in lymph nodes (tuberculous lymphadenitis)
Primary Pulmonary Tuberculosis
- Due to inhalation of tubercle bacilli affecting the lungs of children
- Takes the form of a primary pulmonary complex, comprising:
- Ghon's focus
- Tuberculous lymphangitis
- Tuberculous lymphadenitis
- Enlarged hilar lymph nodes draining the parenchymal focus
Ghon's Focus
- A peripheral subpleural yellowish lesion, usually in the lower aspect of the upper lobe or upper aspect of lower lobe (just above or below the interlobar fissure)
Fate of Primary Pulmonary Tuberculosis
- Localization and healing by fibrosis: Healing by fibrosis and calcification
- Reactivation of dormant bacilli: Reactivation in capsulated or healed lesions
-
Spread due to failure of localization:
- Direct spread (e.g., tuberculous pneumonia, pleurisy, pericarditis)
- Lymphatic spread
- Blood spread
- No effect, isolated organ tuberculosis or miliary tuberculosis
- Bronchial spread (e.g., tuberculous bronchopneumonia, tuberculosis of larynx)
Sequelae of Primary Complex
- Healing by fibrosis and calcification
- Progressive tuberculosis spreading to other areas of the same or opposite lung
- Miliary spread to lungs, liver, spleen, kidneys, and brain
- Reactivation of dormant primary complex
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Description
Explore the intricacies of Chronic Granulomatous Disease, characterized by specific forms of chronic inflammation and the types of granulomas associated with it. This quiz delves into the cellular compositions and classifications of infectious, foreign body, and unsettled etiology granulomas. Test your knowledge on the diverse factors involved in this condition.
