Podcast
Questions and Answers
Given the pathophysiology of tuberculosis, which of the following immune responses is most critical in controlling the infection in a previously exposed individual?
Given the pathophysiology of tuberculosis, which of the following immune responses is most critical in controlling the infection in a previously exposed individual?
- Neutralization of extracellular bacilli by IgG antibodies
- Type IV hypersensitivity reaction mediated by T lymphocytes (correct)
- Complement-mediated lysis of infected cells
- IgE-mediated mast cell degranulation
A patient presents with a chronic cough, night sweats, and weight loss. A chest X-ray reveals cavitary lesions in the upper lobes of the lungs. Based on the provided information, which of the following factors would most strongly suggest that the patient's condition is due to reactivation tuberculosis rather than a new primary infection?
A patient presents with a chronic cough, night sweats, and weight loss. A chest X-ray reveals cavitary lesions in the upper lobes of the lungs. Based on the provided information, which of the following factors would most strongly suggest that the patient's condition is due to reactivation tuberculosis rather than a new primary infection?
- The patient's current socioeconomic status is considered high.
- The patient has a history of living in an area with high environmental pollution.
- The patient reports having had a positive tuberculin skin test (TST) in the past. (correct)
- The patient's symptoms developed gradually over several months.
In a patient diagnosed with pulmonary tuberculosis, which of the following microscopic findings would be most indicative of a granuloma formed in response to the infection?
In a patient diagnosed with pulmonary tuberculosis, which of the following microscopic findings would be most indicative of a granuloma formed in response to the infection?
- Aggregates of epithelioid macrophages, Langhans giant cells, and a surrounding rim of lymphocytes (correct)
- Collection of lymphocytes and plasma cells surrounding a central area of liquefactive necrosis
- Diffuse infiltration of neutrophils with evidence of bacterial phagocytosis
- Focal areas of hemorrhage and edema with fibrin deposition
A researcher is studying the pathogenesis of tuberculosis. Which of the following mechanisms best explains how Mycobacterium tuberculosis establishes a persistent infection within macrophages?
A researcher is studying the pathogenesis of tuberculosis. Which of the following mechanisms best explains how Mycobacterium tuberculosis establishes a persistent infection within macrophages?
Considering the different types of tuberculosis, how would you differentiate between primary and secondary pulmonary tuberculosis based on the characteristics of the lesions?
Considering the different types of tuberculosis, how would you differentiate between primary and secondary pulmonary tuberculosis based on the characteristics of the lesions?
A patient is diagnosed with miliary tuberculosis. Based on the pathogenesis of this condition, which of the following statements is most accurate?
A patient is diagnosed with miliary tuberculosis. Based on the pathogenesis of this condition, which of the following statements is most accurate?
What is the most important factor that differentiates the fate of primary complex in tuberculosis between 'good fate' and 'bad fate'?
What is the most important factor that differentiates the fate of primary complex in tuberculosis between 'good fate' and 'bad fate'?
A pathologist is examining a lung biopsy from a patient with suspected tuberculosis. Which of the following features would be most characteristic of a tuberculous granuloma?
A pathologist is examining a lung biopsy from a patient with suspected tuberculosis. Which of the following features would be most characteristic of a tuberculous granuloma?
In the context of hydatid disease, what is the primary mechanism by which Echinococcus granulosus causes pathology in humans?
In the context of hydatid disease, what is the primary mechanism by which Echinococcus granulosus causes pathology in humans?
Considering the pathogenesis of hydatid cysts, why is it important to avoid spillage of cyst contents during surgical removal?
Considering the pathogenesis of hydatid cysts, why is it important to avoid spillage of cyst contents during surgical removal?
A patient presents with a large hydatid cyst in the liver. If the cyst ruptures spontaneously, which of the following complications is most likely to occur?
A patient presents with a large hydatid cyst in the liver. If the cyst ruptures spontaneously, which of the following complications is most likely to occur?
Which of the following best describes the microscopic composition of the wall of a mature hydatid cyst?
Which of the following best describes the microscopic composition of the wall of a mature hydatid cyst?
Given that TB bacilli are aerobic, where would the lesions typically be found in the lungs?
Given that TB bacilli are aerobic, where would the lesions typically be found in the lungs?
What is the role of macrophages in T.B. infection?
What is the role of macrophages in T.B. infection?
What is the significance of caseous necrosis in the context of tuberculosis?
What is the significance of caseous necrosis in the context of tuberculosis?
What is the difference in spread between primary and secondary tuberculosis?
What is the difference in spread between primary and secondary tuberculosis?
Which of the following characteristics of secondary tuberculosis contributes most to its increased tissue damage compared to primary tuberculosis?
Which of the following characteristics of secondary tuberculosis contributes most to its increased tissue damage compared to primary tuberculosis?
How is Bovine TB typically spread?
How is Bovine TB typically spread?
Of the following options, what is the best definition for 'Tuberculoma'?
Of the following options, what is the best definition for 'Tuberculoma'?
With regards to Hydatid disease, what is the role of dogs?
With regards to Hydatid disease, what is the role of dogs?
Flashcards
Tuberculosis (TB)
Tuberculosis (TB)
Chronic infective granuloma affecting body systems, mainly lungs, caused by TB bacilli; a leading cause of death worldwide after HIV.
Mode of TB Infection
Mode of TB Infection
Infection via droplet from active pulmonary disease, or oropharyngeal/intestinal lesions by consuming contaminated milk.
Tubercle
Tubercle
A small (1-3 mm) granuloma with central yellow caseation and a grey periphery, contains caseating material, epithelioid cells, and lymphocytes.
Primary Complex Constituents
Primary Complex Constituents
Signup and view all the flashcards
Secondary Tuberculosis
Secondary Tuberculosis
Signup and view all the flashcards
Secondary Pulmonary Tuberculosis
Secondary Pulmonary Tuberculosis
Signup and view all the flashcards
Tuberculoma
Tuberculoma
Signup and view all the flashcards
Miliary TB Definition
Miliary TB Definition
Signup and view all the flashcards
Hydatid Disease Definition
Hydatid Disease Definition
Signup and view all the flashcards
Hydatid Cyst Pathology
Hydatid Cyst Pathology
Signup and view all the flashcards
Study Notes
- Chronic specific inflammation includes pathology of tuberculosis and hydatid cysts as examples of granulomas.
Tuberculosis Definition
- It is a chronic infective granuloma that affects nearly all body systems
- It mainly affects the lungs
- It is caused by TB bacilli
- TB is the leading cause of death worldwide after HIV
Predisposing Factors for Tuberculosis
- Environmental factors include:
- Low socioeconomic standard
- Bad general hygiene
- Contact with tuberculous persons
- Overcrowding
- Environmental pollution
- Personal factors include:
- Being of African descent
- Malnutrition
- Debilitating diseases like diabetes mellitus
- Immune deficiency states
Characteristics of T.B. Bacilli
- Aerobic
- Acid-fast
- Non-motile
- Do not produce toxins
- Carried by macrophages
- Structure: comprised of carbohydrate, lipid, and protein (tuberculoprotein)
Types of TB Bacilli
- Human type
- Bovine type
- Other types
Mode of Infection
- Human type: droplet infection from an open, active pulmonary disease
- Bovine type: oropharyngeal and intestinal lesions acquired by drinking raw contaminated milk containing bacilli
Primary Tuberculosis
- Typically occurs in young, non-immunized individuals
- Methods of infection include inhalation, ingestion, and direct contact
- Sites of primary complex include lung, intestine, tonsils, skin, and rarely, the nose
Characteristics of a Tubercle
- N/E: appears as a small nodule, 1-3 mm, with central yellow caseation and a gray periphery
- M/E: central caseating material with structureless eosinophilic substance, epithelioid cells, macrophages, Langhan's giant cells, lymphocytes, and peripheral fibroblastic reaction
- Endpoint: Formation of epithelioid granulomas with giant cells and peripheral fibrosis
Constituents of the Primary Complex
- Parenchymatous lesion known as Ghon's focus
- Tuberculous lymphangitis
- Tuberculous lymphadenitis
Fate of Primary Complex
- Good fate: Healing with a small fibrous scar, calcification, and encapsulation if large; organism may die or remain dormant
- Bad fate: Spread can be local, lymphatic, or hematogenous, with hematogenous spread being more common than in secondary tuberculosis, and natural passage less common than in secondary tuberculosis
Secondary Tuberculosis
- Typically occurs in adulthood
- Methods of infection:
- Endogenous reactivation of a dormant focus
- Exogenous infection through inhalation or ingestion
- Can affect any site, but mainly affects the lungs and intestines
Body's Reaction in Secondary Infection
- Hypersensitivity reaction leads to excessive tissue destruction and extensive caseation
- No nodal affection as the organism is destroyed in the necrotic tissue
- Commonly affected organs: kidney, suprarenal gland, fallopian tube, epididymis, brain, meninges, bones, and joints
Secondary Pulmonary Tuberculosis
- Characterized by an apical lesion (Assmann focus) as a small caseating tuberculous granuloma
- In most cases, destruction of the lung leads to cavitations
- M/E: Central area of caseation surrounded by granulomatous inflammatory reaction
Fate of Secondary Tuberculosis
- Good fate: Healing
- Bad fate: Extension and spread via local routes, natural passages (more common than in primary TB), blood (rarely, more common than in primary TB), or lymphatic routes
Primary TB vs. Secondary TB
| Characteristic | Primary TB | Secondary TB |
|---|---|---|
| Mode of infection | Exogenous | Endogenous or exogenous |
| Age | Childhood | Adults |
| Sites | Only organs exposed to exogenous infection | Any organ |
| Gross lesions | Primary complex, no cavity or ulcer | Fibrocaseous, cavity, ulcers, more extensive caseation |
| Criteria of proliferative reaction | Slowly occurring, less extensive, less caseation | Extensive, exaggerated, rapid, more caseation, liquefied caseation material |
| Spread | Lymphatic/blood, rare spread via natural passages | Spread via natural passages, rare lymphatic/blood spread |
Tuberculoma
- A localized mass of caseating tuberculous reaction surrounded by fibrous tissue
- Can reach a large size and may be mistaken for a tumor
- Can occur in any organ, including the lung, kidney, brain, and spinal cord
Miliary TB Lung
- Defined as acute hematogenous dissemination of a large dose of TB bacilli with widespread involvement of multiple organs
- Grossly, the affected organ shows numerous small, uniform, grayish-yellow dots near small blood vessels, not surrounded by hyperemia
- Pattern resembles millet seeds
- M/E: The affected organ shows large numbers of small, uniform epithelioid granulomas with giant cells, but minimal caseation and little or no surrounding fibrosis
Miliary TB
- Findings in the lungs include small, uniform granulomas with giant cells but minimal caseation and surrounding fibrosis
Complications of Secondary Tuberculosis
- Hemorrhage
- Obstruction of tubular organs due to adhesions
- Spread to the peritoneum and serous coverings
- Perforations are rare due to fibrosis and adhesion
- Amyloidosis
Hydatid Disease
- Definition: infective parasitic disease transmitted from animal (dog) to man
- Pathogenesis: caused by ingestion of eggs of Echinococcus granulosus, contaminates ingested food where eggs hatch in the intestine, pass through portal blood to the liver and mature into larval stage (hydatid cyst)
- The disease may pass to the systemic circulation reaching to different organs
Pathology of Hydatid Cysts
- A hydatid cyst may reach 20 cm in diameter and is composed of
- A lumen with straw-colored fluid
- An inner germinal layer that forms scolices
- An outer chitinous laminated layer
- A surrounding fibrous capsule
Complications of Hydatid Cysts
- Allergic manifestations, anaphylactic shock
- Abscess formation due to secondary bacterial infection
- Pressure atrophy onto surrounding tissue
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
