Leprosy (Hansen's Disease) Overview
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Questions and Answers

What histological feature is NOT typically associated with Actinomyces infections?

  • Necrotic background
  • Multinucleated giant cells
  • Sulfur granules
  • Caseating granulomas (correct)

    • Which characteristic gross feature is indicative of Actinomycosis?

  • Firm masses with smooth surfaces
  • Painless swollen lymph nodes
  • Honeycomb abscesses (correct)
  • Clear fluid-filled cysts

    • In the context of Actinomyces infections, which immune cells are typically found intermixed with the organisms?

  • Mast cells and basophils
  • T helper cells and macrophages
  • Natural killer cells and dendritic cells
  • Neutrophils and plasma cells (correct)

    • In terms of tissue invasion, which statement about Actinomyces is accurate?

    <p>They invade tissues rarely and may produce infections only occasionally.</p> Signup and view all the answers

    What is the appearance of Actinomyces under microscopic examination?

    <p>Long, filamentous, fungal-like organisms</p> Signup and view all the answers

    What type of leprosy is characterized by a strong host defense leading to almost no bacilli being found?

    <p>Tuberculoid leprosy</p> Signup and view all the answers

    Which of the following correctly describes the morphology of lepromatous leprosy?

    <p>High bacilli counts with lipid-laden macrophages</p> Signup and view all the answers

    What is the primary factor that differentiates tuberculoid leprosy from lepromatous leprosy?

    <p>Presence of granulomatous response</p> Signup and view all the answers

    Leprosy is primarily caused by which of the following organisms?

    <p>Mycobacterium leprae</p> Signup and view all the answers

    What type of immune response is primarily involved in the lesions of leprosy?

    <p>Type IV hypersensitivity</p> Signup and view all the answers

    What is a significant clinical feature of lepromatous leprosy?

    <p>Symmetrical anesthetic nodules</p> Signup and view all the answers

    What is the incubation period for leprosy?

    <p>3 - 5 years</p> Signup and view all the answers

    Which clinical presentation is associated with high cell-mediated immunity in leprosy patients?

    <p>Pauci-bacillary lesions</p> Signup and view all the answers

    What is a characteristic feature of the chancre found in primary syphilis?

    <p>It has superficial ulceration and is solitary.</p> Signup and view all the answers

    Which of the following is typically seen in secondary syphilis?

    <p>Shallow oral ulcerations</p> Signup and view all the answers

    What does tertiary syphilis most commonly manifest as?

    <p>Aortitis and neurosyphilis</p> Signup and view all the answers

    What is the primary histological feature of syphilis across all stages?

    <p>Dense plasma cell inflammatory infiltrate</p> Signup and view all the answers

    In tertiary syphilis, gummas are most commonly found in which organs?

    <p>Bone, liver, and testes</p> Signup and view all the answers

    What type of bacteria causes Actinomycosis?

    <p>Anaerobic gram-positive filamentous bacteria</p> Signup and view all the answers

    The term 'endarteritis obliterans' in syphilis is associated with which condition?

    <p>Chronic inflammation of small vessels</p> Signup and view all the answers

    What is the timeline for the development of secondary syphilis after initial infection?

    <p>1-3 months after infection</p> Signup and view all the answers

    What histological feature is characteristic of tuberculoid leprosy?

    <p>Epithelioid histiocytes surrounding cutaneous nerves</p> Signup and view all the answers

    In lepromatous leprosy, what type of cells are primarily involved in the infection?

    <p>Macrophages (Virchow cells)</p> Signup and view all the answers

    How is syphilis primarily transmitted?

    <p>Sexually through contact with infected lesions</p> Signup and view all the answers

    What is a common characteristic of lepromatous leprosy?

    <p>High numbers of bacilli in the endothelium</p> Signup and view all the answers

    What unique characteristic identifies Treponema pallidum among other bacteria?

    <p>It is a unicellular, spiral-shaped, gram-negative spirochete</p> Signup and view all the answers

    What complication is frequently associated with syphilis?

    <p>Increased risk of HIV acquisition</p> Signup and view all the answers

    Which of the following statements about congenital syphilis is true?

    <p>It can be transmitted transplacentally or during birth</p> Signup and view all the answers

    What is one of the primary reasons for the rising incidence of syphilis in the United States?

    <p>Disproportionate effects on certain demographic groups</p> Signup and view all the answers

    Leprosy is caused by Mycobacterium leprae and Mycobacterium leprosidis.

    <p>False</p> Signup and view all the answers

    Tuberculoid leprosy is characterized by the presence of many bacilli due to a weak immune response.

    <p>False</p> Signup and view all the answers

    The lesions of lepromatous leprosy often lead to a symmetrical appearance in affected areas.

    <p>True</p> Signup and view all the answers

    The incubation period for leprosy can range from 1 to 2 years.

    <p>False</p> Signup and view all the answers

    The chancre in primary syphilis is characterized by being painful and multiple.

    <p>False</p> Signup and view all the answers

    Tertiary syphilis can manifest as gummatous necrosis of the liver.

    <p>True</p> Signup and view all the answers

    Leprae bacilli produce both exotoxin and endotoxin.

    <p>False</p> Signup and view all the answers

    In tuberculoid leprosy, patients develop a granulomatous response due to a strong immune response.

    <p>True</p> Signup and view all the answers

    Endarteritis obliterans is a feature seen only in tertiary syphilis.

    <p>False</p> Signup and view all the answers

    Schwann cells are directly destroyed by leprosy due to the interference of leprae bacilli with their metabolism.

    <p>True</p> Signup and view all the answers

    Neurosyphilis is a common manifestation of secondary syphilis.

    <p>False</p> Signup and view all the answers

    Aortitis typically related to tertiary syphilis usually affects the thoracic portion of the aorta.

    <p>True</p> Signup and view all the answers

    Individuals with lepromatous leprosy show a strong cell-mediated immune response.

    <p>False</p> Signup and view all the answers

    The histological feature of plasma cell infiltration is not present in syphilis infections.

    <p>False</p> Signup and view all the answers

    Secondary syphilis lesions can include shallow oral ulcerations.

    <p>True</p> Signup and view all the answers

    The incubation period for tertiary syphilis ranges from 1 to 3 months after infection.

    <p>False</p> Signup and view all the answers

    Actinomyces are known to invade tissues and consistently produce infections.

    <p>False</p> Signup and view all the answers

    Honeycomb abscesses containing sulfur granules are a characteristic feature of actinomycosis.

    <p>True</p> Signup and view all the answers

    Actinomyces appears as large, round organisms under microscopic examination.

    <p>False</p> Signup and view all the answers

    Tuberculoid leprosy is characterized by abundant bacilli in cutaneous nerves.

    <p>False</p> Signup and view all the answers

    Noncaseating granulomas can be present in actinomycosis infections.

    <p>True</p> Signup and view all the answers

    Syphilis is a viral infection caused by Treponema pallidum.

    <p>False</p> Signup and view all the answers

    Macrophages in lepromatous leprosy are often found in well-circumscribed masses.

    <p>False</p> Signup and view all the answers

    Reactive changes can be observed in local lymph nodes during actinomycosis.

    <p>True</p> Signup and view all the answers

    The majority of syphilis cases are transmitted through skin-to-skin contact.

    <p>False</p> Signup and view all the answers

    Congenital syphilis can be transmitted at any stage of the disease.

    <p>True</p> Signup and view all the answers

    People with lepromatous leprosy generally exhibit a strong cell-mediated immune response.

    <p>False</p> Signup and view all the answers

    Men who have sex with men are disproportionately affected by syphilis.

    <p>True</p> Signup and view all the answers

    The World Health Organization estimated 7.1 million new adult cases of syphilis in the United States in 2020.

    <p>False</p> Signup and view all the answers

    What distinguishes tuberculoid leprosy from lepromatous leprosy in terms of immune response?

    <p>Tuberculoid leprosy occurs in individuals with good cell-mediated immunity, while lepromatous leprosy occurs in those with poor cell-mediated immunity.</p> Signup and view all the answers

    Describe the type of lesions seen in lepromatous leprosy.

    <p>Lepromatous leprosy presents with symmetrical anesthetic nodules and can cause deformities, notably leading to a leonine face.</p> Signup and view all the answers

    In the context of leprosy, what role do Schwann cells play in the pathogenesis of the disease?

    <p>Schwann cells are disrupted by leprae bacilli, which interfere with their metabolism and lead to nerve damage.</p> Signup and view all the answers

    How does the granulomatous response in tuberculoid leprosy manifest histologically?

    <p>The granulomatous response in tuberculoid leprosy is characterized by granulomas that closely resemble those found in tuberculosis.</p> Signup and view all the answers

    What are the primary morphological features of lepromatous leprosy lesions?

    <p>Lepromatous lesions contain large aggregates of lipid-laden macrophages known as lepra cells, often filled with masses of acid-fast bacilli.</p> Signup and view all the answers

    Identify the key clinical feature differentiating tuberculoid leprosy from lepromatous leprosy.

    <p>A key clinical feature is that tuberculoid leprosy has asymmetrical lesions, while lepromatous leprosy shows symmetrical lesions.</p> Signup and view all the answers

    What is the significance of the incubation period for leprosy, and how long does it typically last?

    <p>The incubation period for leprosy typically lasts 3 to 5 years, which is significant as it indicates the long-term development of the infection.</p> Signup and view all the answers

    Explain why leprosy is described as a 'chronic cutaneous infection.'

    <p>Leprosy is termed a chronic cutaneous infection due to its prolonged duration, impacting the skin and causing damage over time.</p> Signup and view all the answers

    What is the timeline for the development of tertiary syphilis after the initial infection?

    <p>Tertiary syphilis typically develops 5 to 30 years after the primary infection.</p> Signup and view all the answers

    What histological feature is characteristic of tertiary syphilis?

    <p>A prominent histological feature is the presence of a dense plasma cell inflammatory infiltrate.</p> Signup and view all the answers

    In addition to the common manifestations, what unique tissue changes occur in tertiary syphilis?

    <p>Gummas, which are firm to rubbery nodular masses, often appear in the liver, bones, and testes.</p> Signup and view all the answers

    What are the three main manifestations of tertiary syphilis?

    <p>The three main manifestations are cardiovascular syphilis, CNS neurosyphilis, and gummas.</p> Signup and view all the answers

    What is the clinical definition of a chancre in primary syphilis?

    <p>A chancre is a solitary, painless nodule that undergoes slow enlargement and superficial ulceration.</p> Signup and view all the answers

    Describe the lesions associated with secondary syphilis.

    <p>Secondary syphilis lesions include shallow oral ulcerations, generalized skin rash, and lymphadenopathy.</p> Signup and view all the answers

    What type of inflammatory response is apparent in the histology of syphilis?

    <p>The histology shows endarteritis obliterans characterized by plasma cell infiltration in small vessels.</p> Signup and view all the answers

    What is the causative agent of Actinomycosis?

    <p>Actinomycosis is caused by Actinomyces israelii, an anaerobic, gram-positive bacterium.</p> Signup and view all the answers

    Describe the appearance of the abscesses associated with actinomycosis.

    <p>The abscesses appear as firm masses with a honeycomb texture containing yellowish granules known as sulfur granules.</p> Signup and view all the answers

    What type of immune cells are commonly found intermixed with Actinomyces in tissue samples?

    <p>Neutrophils, plasma cells, eosinophils, and lymphocytes are commonly intermixed with Actinomyces.</p> Signup and view all the answers

    What are the histological features that may indicate an actinomycosis infection?

    <p>Histological features may include multinucleated giant cells, noncaseating granulomas, and reactive changes in local lymph nodes.</p> Signup and view all the answers

    What is the significance of sulfur granules in the diagnosis of actinomycosis?

    <p>Sulfur granules are indicative of Actinomyces infections, playing a crucial role in diagnosis.</p> Signup and view all the answers

    What generally occurs in tissues infected by Actinomyces that can lead to localized complications?

    <p>Infected tissues can develop firm masses with abscess formations, leading to the potential creation of sinuses and fistulae.</p> Signup and view all the answers

    What histological feature is typically absent in lepromatous leprosy compared to tuberculoid leprosy?

    <p>Lymphocytes are typically absent in lepromatous leprosy.</p> Signup and view all the answers

    What type of immune response is primarily involved in the pathogenesis of tuberculoid leprosy?

    <p>A strong cell-mediated immune response is primarily involved.</p> Signup and view all the answers

    In the context of syphilis, what does transplacental transmission refer to?

    <p>Transplacental transmission refers to the passage of the infection from mother to fetus through the placenta.</p> Signup and view all the answers

    What is a key characteristic of the syphilis infection in relation to HIV?

    <p>Syphilis increases the risk of acquiring HIV.</p> Signup and view all the answers

    What type of cells may be distended with leprosy bacilli in lepromatous leprosy?

    <p>Macrophages, specifically called Virchow cells, may be distended with leprosy bacilli.</p> Signup and view all the answers

    What is the primary cellular infiltrate observed in tuberculoid leprosy lesions?

    <p>Epithelioid histiocytes are the primary cellular infiltrate in tuberculoid leprosy.</p> Signup and view all the answers

    What is the main method of transmission for syphilis during its primary and secondary stages?

    <p>Syphilis is primarily transmitted through vaginal, anogenital, and orogenital contact.</p> Signup and view all the answers

    How are large numbers of leprosy bacilli typically found in lepromatous leprosy?

    <p>Large numbers of leprosy bacilli are found in poorly circumscribed masses in the dermis.</p> Signup and view all the answers

    Match the following features of actinomycosis with their descriptions:

    <p>Sulfur granules = Yellowish granules found in abscesses Honeycomb abscesses = Firm masses with numerous pus-filled cavities Microscopic appearance = Slender, filamentous, fungal-like organisms Granulomatous response = Presence of multinucleated giant cells</p> Signup and view all the answers

    Match the following locations with their association with actinomycosis:

    <p>GIT = Gastrointestinal tract as a common site of infection Mouth = Oral cavity where actinomycosis may initiate Female genital tract = Less frequent site for actinomycosis compared to GIT Skin = Often a site for secondary infections in actinomycosis</p> Signup and view all the answers

    Match the following histological features with their significance in actinomycosis:

    <p>Neutrophils = Initial immune response to infection Plasma cells = Associated with antibody production in chronic infections Eosinophils = Often involved in allergic reactions or parasitic infections Lymphocytes = Key players in the adaptive immune response against chronic infections</p> Signup and view all the answers

    Match the following types of cells with their role in actinomycosis infections:

    <p>Multinucleated giant cells = Indicator of a chronic immune response Neutrophils = First responders to bacterial infections Plasma cells = Produce antibodies as part of the immune defense Eosinophils = Participate in fighting parasitic infections, less typical in actinomycosis</p> Signup and view all the answers

    Match the following references with their relevance:

    <p>CDC: Mycobacterium lepromatosis = Contextual information about leprosy WHO: Syphilis = Global health guidelines on sexually transmitted infections N Engl J Med = Source of peer-reviewed medical information Middle East J Dig Dis = Regional studies on gastrointestinal diseases</p> Signup and view all the answers

    Match the type of leprosy with their respective microscopic features:

    <p>Tuberculoid leprosy = Scarcity of bacilli Lepromatous leprosy = Large groups of leprosy bacilli in macrophages</p> Signup and view all the answers

    Match the stage of syphilis with its characteristic feature:

    <p>Primary syphilis = Presence of a painless chancre Secondary syphilis = Systemic rash and mucous membrane lesions Tertiary syphilis = Gummas formation in various organs Congenital syphilis = Transmission through placenta to fetus</p> Signup and view all the answers

    Match the organism with its description:

    <p>Treponema pallidum = Spirochete shape and gram-negative Mycobacterium leprae = Involvement with skin and peripheral nerves</p> Signup and view all the answers

    Match the transmission route with the disease:

    <p>Syphilis = Transplacental transmission Tuberculoid leprosy = Contact with cutaneous nerves Lepromatous leprosy = Involvement with arrectores pilorum muscle</p> Signup and view all the answers

    Match the description with the correct epidemiological detail:

    <p>7.1 million new cases = Estimation by WHO in 2020 Dual diagnosis with HIV = Commonality among affected individuals Nonsexual contact transmission = Rare incidence for syphilis Rising incidence = Observed in the United States</p> Signup and view all the answers

    Match the lesion type with the condition:

    <p>Erythema nodosum leprorum = Associated with lepromatous leprosy Shallow oral ulcerations = Seen in secondary syphilis Gummas = Commonly found in tertiary syphilis Infiltrate in papillary dermis = Characteristic of tuberculoid leprosy</p> Signup and view all the answers

    Match the mode of diagnosis with the disease:

    <p>Syphilis diagnosis = Serological testing for Treponema pallidum Tuberculoid leprosy diagnosis = Histological examination of tissue Lepromatous leprosy diagnosis = Detection of bacilli in macrophages Congenital syphilis diagnosis = Assessment of transplacental exposure</p> Signup and view all the answers

    Match the immune response type with its corresponding leprosy:

    <p>Tuberculoid leprosy = Granulomatous response Lepromatous leprosy = Predominance of plasma cells</p> Signup and view all the answers

    Match the type of leprosy with its characteristics:

    <p>Tuberculoid leprosy = Lesions resemble those found in tuberculosis Lepromatous leprosy = Lesions contain large aggregates of lepra cells</p> Signup and view all the answers

    Match the term with its description related to leprosy:

    <p>Granulomatous response = Adaptive immune response in tuberculoid leprosy Destructive granuloma = Type IV hypersensitivity mechanism Macrophages = Cells that harbor lepra bacilli in lepromatous leprosy Schwann cells = Cells affected by leprosy leading to nerve damage</p> Signup and view all the answers

    Match the clinical presentation with the type of leprosy:

    <p>Tuberculoid leprosy = Almost no bacilli present in lesions Lepromatous leprosy = Presence of 'leonine face'</p> Signup and view all the answers

    Match the leprosy characteristic with the associated statement:

    <p>Pauci-bacillary = Refers to a small number of bacilli present Multibacillary = Indicates a large population of bacilli in lesions Interference with Schwann cells = Leads to nerve damage in leprosy Granulomatous lesions = Produced due to strong host response in tuberculoid leprosy</p> Signup and view all the answers

    Match the pathogen with its classification:

    <p>Mycobacterium leprae = Obligate intracellular gram-positive organism Mycobacterium lepromatosis = Associated with lepromatous leprosy Leprae bacilli = Weakly acid-fast organisms Lepra cells = Lipids-laden macrophages seen in lepromatous leprosy</p> Signup and view all the answers

    Match the immune system response with the appropriate leprosy type:

    <p>Cell-mediated immunity = Prominent in tuberculoid leprosy Poor host defense = Observed in lepromatous leprosy Type IV hypersensitivity = Leads to granuloma formation Absence of granulomatous response = Characteristic of lepromatous leprosy</p> Signup and view all the answers

    Match the incubation period with its key pathology:

    <p>3 - 5 years = Typical incubation for leprosy Short duration = Not applicable for leprosy Long duration = Associated with chronic infections 1 - 2 years = Not representative of leprosy's incubation period</p> Signup and view all the answers

    Match the description with the corresponding leprosy type or feature:

    <p>Asymmetrical lesions = Characteristic of tuberculoid leprosy Symmetrical nodules = Key feature of lepromatous leprosy Lipid-laden macrophages = Found in lepromatous leprosy lesions Granulomas with few bacilli = Typical for tuberculoid leprosy</p> Signup and view all the answers

    Match the stages of syphilis with their characteristics:

    <p>Primary syphilis = Lesion (chancre) develops few days to 3 weeks after infection Secondary syphilis = Generalized skin rash and oral ulcerations Tertiary syphilis = Diagnosed years after primary infection, includes aortitis Histology of syphilis = Dense plasma cell inflammatory infiltrate on histology</p> Signup and view all the answers

    Match the primary manifestations of tertiary syphilis with their descriptions:

    <p>CVS syphilis = Aortitis typically in the thoracic portion CNS neurosyphilis = Neurological complications arising from untreated syphilis Gumma = Firm to rubbery nodular masses found in various organs Gumma histology = Granuloma with central coagulative necrosis</p> Signup and view all the answers

    Match the length of time and corresponding syphilis stage:

    <p>Primary syphilis = Develops within 3 weeks of infection Secondary syphilis = Usually occurs 1-3 months after infection Tertiary syphilis = Appears 5 to 30 years after primary infection Histological features = Characteristic for all stages of syphilis</p> Signup and view all the answers

    Match the bacterial characteristics with Actinomyces:

    <p>Actinomyces israellii = Anaerobic, gram-positive, filamentous bacteria Commensal microbe = Normal flora in the human body Filamentous structure = Long, branching filaments Microbial habitat = Typically found in the oral cavity</p> Signup and view all the answers

    Match the lesions associated with secondary syphilis:

    <p>Shallow oral ulcerations = Common manifestation of secondary syphilis Generalized lymphadenopathy = Enlarged lymph nodes throughout the body Generalized skin rash = Varied presentation on the skin surface Healing process = May occur spontaneously or after treatment</p> Signup and view all the answers

    Match the histological features of syphilis with their descriptions:

    <p>Plasma cell infiltration = Most cases exhibit this feature Endarteritis obliterans = Affects small vessels in syphilis Lymphoplasmacytic infiltrate = Associated with secondary syphilis Gumma presence = Characteristic of tertiary syphilis</p> Signup and view all the answers

    Match the type of immune response with the bacteria involved:

    <p>Actinomyces = Involved in chronic infections Treponema pallidum = Causes syphilis via humoral immunity Neurosyphilis response = Often leads to a compromised immune state Chronic infection response = Involves lymphoplasmacytic infiltrate</p> Signup and view all the answers

    Match the complications associated with syphilis and Actinomyces:

    <p>Tertiary syphilis = Aortitis and neurological manifestations Actinomycosis = Characterized by honeycomb abscesses Neurosyphilis = CNS-related symptoms due to untreated syphilis Gummas = Granulomatous lesions affecting various organs</p> Signup and view all the answers

    Study Notes

    Leprosy (Hansen's Disease)

    • Caused by Mycobacterium leprae and Mycobacterium lepromatosis
    • Worldwide distribution, endemic in the tropics
    • Affects skin and peripheral nerves because the bacteria thrive in cooler areas of the body
    • Mycobacterium leprae is an obligate intracellular, gram-positive, weakly acid-fast bacteria
    • Incubation period: 3-5 years
    • Two types:

      Tuberculoid Leprosy (Paucibacillary)

      • Occurs in individuals with strong cell-mediated immunity
      • Granulomatous response
      • Bacilli are rarely found

      Lepromatous Leprosy (Multibacillary)

      • Occurs in individuals with weak cell-mediated immunity
      • Lack of granulomatous response
      • Macrophages filled with bacteria (lepra cells) form aggregates
    • Mycobacterium leprae does not produce exotoxins or endotoxins
    • Lesions form due to:
      • Destructive granulomas (type IV hypersensitivity)
      • Interference with Schwann cell metabolism
    • Morphology:
      • Tuberculoid leprosy:
        • Granulomatous lesions resemble tuberculosis
        • Epithelioid histiocytes surround small cutaneous nerves
        • Langhans giant cells may be present
        • Infiltrate can reach the epidermis
        • May destroy arrectores pilorum muscle
        • Bacilli are scarce
      • Lepromatous leprosy:
        • Macrophages (Virchow cells, lepra cells) form poorly circumscribed masses in the dermis
        • Few lymphocytes
        • Macrophages may contain large groups of leprosy bacilli (globi)
        • Bacteria are abundant in cutaneous nerves, endothelium, and media of vessels
        • May invade arrectores pilorum muscle
        • Subcutaneous nodules may form (erythema nodosum leprorum)

    Syphilis

    • Caused by Treponema pallidum, a gram-negative spirochete
    • Chronic venereal disease
    • Transmission:
      • Primarily sexually transmitted
      • Transplacental transmission (mother to fetus)
    • World Health Organization (WHO) estimated 7.1 million new cases in 2020
    • Increasing incidence in the United States
    • Men who have sex with men and non-Hispanic individuals are disproportionately affected
    • Often co-occurs with HIV
    • Syphilis increases the risk of HIV and other sexually transmitted infections
    • Stages:

      Primary Syphilis:

      • Chancre develops 3 weeks after infection
      • Solitary, painless nodule with superficial ulceration
      • Healing occurs in 3-6 weeks

      Secondary Syphilis:

      • Develops 1-3 months after infection
      • Lesions include:
        • Shallow oral ulcerations
        • Generalized skin rash
        • Generalized lymphadenopathy
      • Spontaneous or treatment-induced healing

      Tertiary Syphilis:

      • Untreated infection
      • Manifests years after primary infection (5-30 years)
      • Three main manifestations:
        • Cardiovascular syphilis
        • Neurosyphilis
        • Gummatous necrosis (formation of firm, nodular masses, particularly in the liver, bones, and testes)
    • Histology:
      • Dense plasma cell inflammatory infiltrate
      • Proliferative endarteritis (endarteritis obliterans) affecting small vessels
      • In tertiary syphilis, gumma formation

    Actinomycosis

    • Caused by Actinomyces israellii, an anaerobic, gram-positive, filamentous bacteria
    • Commensal in the mouth, gastrointestinal tract, and female genital tract
    • Infection is rare, develops when the bacteria invade tissues
    • Gross appearance:
      • Firm masses with numerous abscesses (honeycomb abscesses)
      • Yellowish granules (sulfur granules)
      • Sinuses and fistulae
    • Microscopic appearance:
      • Slender, filamentous organisms aggregated into sulfur granules
      • Surrounded by neutrophils, plasma cells, eosinophils, and lymphocytes in a necrotic background
      • Multinucleated giant cells and noncaseating granulomas may be present
      • Reactive changes in local lymph nodes

    ### Leprosy

    • Leprosy, also called Hansen's disease, is a chronic cutaneous infection caused by Mycobacterium leprae and Mycobacterium lepromatosis.
    • It primarily affects the skin and peripheral nerves because these areas of the body have cooler temperatures, suitable for the bacteria's growth.
    • The incubation period can be long, typically 3-5 years.
    • Leprosy's pathology stems from the bacteria's lack of exotoxins or endotoxins.
    • Tuberculoid leprosy occurs in individuals with a strong cell-mediated immune response, leading to the formation of granulomas.
    • Lepromatous leprosy occurs in individuals with weak cell-mediated immunity, causing the formation of lepra cells, which are lipid-laden macrophages, often packed with masses of acid-fast bacilli.

    Syphilis

    • Syphilis is caused by the spirochete Treponema pallidum.
    • The spirochete is a gram-negative, coiled, unicellular spiral-shaped organism.
    • Transmission occurs primarily through sexual contact.
    • It can also be transmitted transplacentally from mother to fetus.

    Stages of Syphilis

    • Primary syphilis: Characterized by a chancre, a painless nodule with superficial ulceration, appearing on the external genitalia.
    • Secondary syphilis: Develops 1-3 months after infection with the initial lesion, manifesting as shallow oral ulcerations, generalized skin rash, and generalized lymphadenopathy.
    • Tertiary syphilis: Occurs years later, manifesting as aortitis, neurosyphilis, and gummatous necrosis of skin, soft tissue, bone, and joints.

    ### Actinomycosis

    • Caused by Actinomyces israellii, an anaerobic, gram-positive, long filamentous bacterium often found as a commensal organism in the mouth, gastrointestinal tract, and female genital tract.
    • Infection manifests as firm masses containing numerous abscesses with yellowish granules, often called "sulfur granules," and can lead to sinus formation and fistulae.
    • Microscopically, Actinomyces appear as slender filaments, usually aggregated into sulfur granules, intermixed with neutrophils, plasma cells, eosinophils, lymphocytes, and sometimes multinucleated giant cells and noncaseating granulomas.

    Leprosy (Hansen's Disease)

    • Leprosy, also known as Hansen's disease, is a chronic cutaneous infection caused by Mycobacterium leprae and Mycobacterium lepromatosis.
    • It is a worldwide disease, especially prevalent in the tropics, due to travel and migration.
    • The disease affects the skin and peripheral nerves because M. leprae and M. lepromatosis thrive in cooler areas of the body.
    • Mycobacterium leprae is an obligate intracellular, gram-positive, weakly acid-fast organism.
    • The incubation period can be lengthy, ranging from 3 to 5 years.
    • Two main types of leprosy exist: Tuberculoid and Lepromatous.
    • Tuberculoid leprosy occurs in individuals with robust cell-mediated immunity.
    • Patients develop granulomatous responses with few bacilli.
    • Lepromatous leprosy occurs in individuals with poor cell-mediated immunity. They fail to develop a granulomatous response, resulting in increased bacterial load.
    • M. leprae does not produce exotoxins or endotoxins.
    • Leprosy lesions are characterized by:
      • Destructive granulomas (type IV hypersensitivity)
      • Interference with Schwann cell metabolism.
    • Tuberculoid leprosy (Paucibacillary), the less severe form, is characterized by:
      • Granulomatous lesions resembling those found in tuberculosis.
      • Strong host defense, leading to minimal bacilli, hence the name "Paucibacillary."
    • Lepromatous leprosy (Multibacillary), the more severe form, is characterized by:
      • Large aggregates of lipid-laden macrophages (lepra cells) filled with acid-fast bacilli.
      • High bacterial load within lesions.
    • Microscopic features of Tuberculoid leprosy:
      • Epithelioid histiocytes surrounding small cutaneous nerves.
      • Langhans giant cells may be present but without necrosis.
      • Infiltrates may reach the epidermis.
      • Possible destruction of arrectores pilorum muscle.
      • Bacilli are typically scarce.
    • Microscopic features of Lepromatous leprosy:
      • Macrophages (Virchow cells, lepra cells) scattered in poorly circumscribed masses in the dermis.
      • Few lymphocytes.
      • Macrophages are often distended with groups of leprosy bacilli (globi).
      • Bacteria are numerous in cutaneous nerves, endothelium, and media of small and large vessels.
      • May invade arrectores pilorum muscle.
      • Subcutaneous nodules (erythema nodosum leprorum) may develop.

    Syphilis

    • Syphilis is caused by the spirochete Treponema pallidum, a gram-negative, coiled, unicellular spiral-shaped bacterium.
    • It is a sexually transmitted chronic disease that can also be transmitted transplacentally.
    • Epidemiology:
      • Estimated 7.1 million new adult cases worldwide in 2020.
      • Increasing incidence in the United States.
      • Men who have sex with men and non-Hispanic persons are disproportionately affected.
      • Dual diagnosis with HIV is common, and syphilis amplifies the risk of acquiring HIV and other sexually transmitted infections.
      • Transmission mainly occurs through vaginal, anogenital, and orogenital contact with infectious lesions.
      • Rarely transmitted through nonsexual contact, including skin-to-skin and blood transfusions.
      • Congenital syphilis is acquired through transplacental transmission or contact with an infectious lesion at birth.
    • Stages of Syphilis:
      • Primary syphilis:
        • Lesion (chancre) develops within 3 weeks of infection on the external genitalia.
        • Chancre is a solitary, slowly enlarging, painless nodule with superficial ulceration.
        • Healing occurs spontaneously or after treatment.
      • Secondary syphilis:
        • Appears 1-3 months after infection.
        • Lesions include:
          • Shallow oral ulcerations.
          • Generalized skin rash.
          • Generalized lymphadenopathy.
        • Healing may occur spontaneously or after treatment.
      • Tertiary syphilis:
        • Develops several to many years (5-30) after primary infection in untreated individuals.
        • Characterized by:
          • Aortitis (typically in the thoracic portion).
          • Neurosyphilis.
          • Gummatous necrosis of skin, soft tissue, bone, and joint (Charcot joint).
        • Tertiary syphilis manifestations:
          • Cardiovascular: Aortitis.
          • Neurosyphilis: CNS involvement
          • Gumma: Firm to rubbery, multiple, nodular masses commonly found in the liver, bones, and testes. (Gumma is a granuloma with central coagulative necrosis).
    • Histology of syphilis:
      • Dense plasma cell inflammatory infiltrate present in most cases.
      • Proliferative endarteritis (endarteritis obliterans) affecting small vessels.
      • Endothelial hypertrophy and proliferation leading to intimal fibrosis, with a surrounding plasma cell infiltration, are characteristic of all stages of syphilis.
      • In tertiary syphilis, gummas are present along with other histological findings.

    Actinomycosis

    • Caused by Actinomyces israellii, an anaerobic, gram-positive, long filamentous bacteria.
    • It is a commensal organism found in the mouth, gastrointestinal tract, and female genital tract.
    • Infection typically occurs when the organism invades tissues.
    • Gross appearance:
      • Firm masses containing numerous abscesses (honeycomb abscesses).
      • Yellowish granules (sulfur granules) with sinuses and fistulae.
    • Microscopic appearance:
      • Slender, filamentous, fungal-like organisms (Actinomyces) typically aggregated into sulfur granules.
      • Mural organisms intermixed with neutrophils, plasma cells, eosinophils, and lymphocytes in a necrotic background.
      • Multinucleated giant cells and noncaseating granulomas may also be present.
      • Reactive changes may occur in local lymph nodes.

    Leprosy (Hansen’s Disease)

    • Chronic cutaneous infection caused by Mycobacterium leprae and Mycobacterium lepromatosis
    • Found worldwide but endemic in tropical regions.
    • Affects skin and peripheral nerves because Mycobacteria grow in cool temperatures
    • Mycobacterium leprae is an obligate intracellular Gram-positive and weakly acid-fast organism

    Pathogenesis of Leprosy

    • Incubation period typically 3-5 years
    • Tuberculoid Leprosy: Occurs in individuals with good cell-mediated immunity, and patients develop a granulomatous response.
    • Lepromatous Leprosy: Occurs in individuals with poor cell-mediated immunity, patients do not develop a granulomatous response.
    • Mycobacterium leprae produces no exotoxin or endotoxin.
    • The lesion is produced by:
      • Destructive granuloma (type IV hypersensitivity)
      • Interference with metabolism of Schwann cells

    Morphology

    • Tuberculoid Leprosy (Paucibacillary)
      • Granulomatous lesions similar to those found in tuberculosis.
      • Bacilli are rarely seen due to strong host defense.
    • Lepromatous Leprosy (Multibacillary)
      • Lesions contain large aggregations of lipid-laden macrophages (lepra cells) often with masses ("globi") of acid-fast bacilli.

    Tuberculoid Leprosy

    • Characterized by epithelioid histiocytes surrounding small cutaneous nerves.
    • Langhans giant cells may be seen but without necrosis.
    • Infiltration may involve the papillary dermis up to the epidermis.
    • May destroy the arrectores pilorum muscle.
    • Bacilli are usually scarce.

    Lepromatous Leprosy

    • Macrophages (Virchow cells, lepra cells) are found in poorly circumscribed masses in the dermis, with few or no lymphocytes.
    • Macrophages may be distended with large groups of leprosy bacilli (globi).
    • Bacteria are present in large numbers in cutaneous nerves, endothelium, and media of small and large vessels.
    • May invade arrectores pilorum muscle.
    • May have subcutaneous nodules (erythema nodosum leprorum)

    Syphilis

    • Caused by Treponema pallidum, a spirochete.
    • Chronic venereal disease.
    • Transmitted through sexual contact.
    • Can be transmitted transplacentally to the fetus.
    • Treponema pallidum is gram-negative, coiled, unicellular, and spiral-shaped.

    Epidemiology

    • WHO estimated 7.1 million new cases of syphilis worldwide in 2020, with increasing incidence in the United States.
    • Men who have sex with men and non-Hispanic persons are disproportionately affected.
    • Dual diagnosis with HIV is common; syphilis increases the risk of acquiring HIV and other sexually transmitted infections.
    • Most cases are transmitted through vaginal, anogenital, and orogenital contact with an infectious lesion during the primary or secondary stages of the disease.
    • Rarely transmitted through nonsexual contact including skin-to-skin and blood transfusion.
    • Congenital syphilis can be acquired at any stage via transplacental transmission or contact with an infectious lesion during birth.

    Stages of Syphilis

    • Primary Syphilis:
      • Lesion (chancre) develops a few days to 3 weeks after infection on the external genital.
      • Chancre is a solitary, slowly enlarging, painless nodule with superficial ulceration.
      • Healing occurs in 3-6 weeks either spontaneously or after treatment.
    • Secondary Syphilis:
      • Usually develops 1-3 months after infection.
      • Lesions appear as:
        • Shallow oral ulcerations.
        • Generalized skin rash.
        • Generalized lymphadenopathy.
      • Healing may occur spontaneously or after treatment.
    • Tertiary Syphilis:
      • Untreated syphilis can lead to tertiary syphilis years later.
      • Most common manifestations include aortitis, neurosyphilis, and gummatous necrosis of skin, soft tissue, bone, and joint (Charcot joint).
      • It appears several to many years after primary infection (5-30 years).
      • Tertiary Syphilis:
        • Cardiovascular Syphilis
        • CNS Neurosyphilis
        • Gumma: Formation of firm to rubbery, multiple, nodular masses most commonly found in the liver, bones, and testes. - Gumma is a granuloma with central coagulative necrosis

    Histology

    • Most cases demonstrate a dense plasma cell inflammatory infiltrate on histology.
    • Proliferative endarteritis (endarteritis obliterans) affecting small vessels is characteristic of all stages of syphilis.
      • Endothelial hypertrophy and proliferation lead to intimal fibrosis.
    • Gumma in Tertiary syphilis.

    Actinomycosis

    • Caused by Actinomyces israellii, an anaerobic, Gram-positive, long filamentous bacteria.
    • A commensal organism in the mouth, GIT, and female genital tract.
    • Occasionally invades tissues and produces infection.

    Gross

    • Infection produces firm masses containing numerous abscesses (honeycomb abscesses) bearing colonies as yellowish granules (sulfur granules) with sinuses and fistulae.

    Microscopic (Histologic)

    • Actinomyces visible as slender, filamentous, fungal-like organisms usually aggregated into sulfur granules.
    • Mural organisms intermixed with neutrophils, plasma cells, eosinophils, and lymphocytes in a necrotic background.
    • Multinucleated giant cells and noncaseating granulomas may also be present.
    • Local lymph nodes may show reactive change.

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    Description

    Explore the key features of Leprosy, including its causes, symptoms, and types. Understand the differences between Tuberculoid and Lepromatous Leprosy, as well as the bacteria responsible for this disease. This quiz provides a comprehensive overview of the pathology and implications of Hansen's disease.

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