Immunity and Autoimmune Disorders

Autoimmune Disorders

• Autoimmune disorders arise when antibodies develop against the body’s own cells or tissues.
• Autoantibodies indicate a loss of self-tolerance and can lead to localized or generalized organ involvement.
• Examples include Hashimoto thyroiditis, systemic lupus erythematosus (SLE), rheumatic fever, myasthenia gravis, scleroderma, and pernicious anemia.

Systemic Lupus Erythematosus (SLE)

• SLE is a chronic inflammatory disease that affects multiple organ systems.
• Characterized by a distinctive “butterfly rash” on the face.
• Common symptoms: arthralgia, fatigue, malaise, cardiovascular issues, and polyuria.
• Diagnosis involves serum antibodies, LE cells, and other blood analyses.
• Treated by rheumatologists with Prednisone (a glucocorticoid) and nonsteroidal anti-inflammatory drugs (NSAIDs).

Immunodeficiency

• Defined by a partial or total loss of one or more components of the immune system.
• Results in an increased susceptibility to infections and certain cancers.

Primary and Secondary Immunodeficiencies

• Primary immunodeficiencies arise from intrinsic developmental issues.
• Secondary (acquired) immunodeficiencies can occur at any age due to specific factors: infections, splenectomy, malnutrition, liver disease, immunosuppressive drugs, radiation, and chemotherapy.
• Increased risk of opportunistic infections from normally harmless flora.

Acquired Immunodeficiency Syndrome (AIDS)

• AIDS is chronic and arises from infection by the human immunodeficiency virus (HIV).
• HIV specifically targets and destroys helper T cells (CD4 lymphocytes), leading to a weakened immune response.
• Increases vulnerability to secondary infections and cancers, often with a long latent period.
• Antiviral therapies can suppress disease progression, especially when started early.

Microorganisms

• Microorganisms are small living entities, including bacteria, fungi, protozoa, and viruses.
• Nonpathogenic microorganisms are typically harmless and part of the normal flora, while pathogens cause disease.

Types of Microorganisms

• Bacteria: Prokaryotic organisms without a nucleus. Reproduce by binary fission and can survive without a host.
• Viruses: Obligate intracellular parasites that require host cells to replicate; treated with antiviral medications.
• Fungi: Eukaryotic organisms that cause mycotic infections; some are pathogenic, affecting skin or mucous membranes.
• Protozoa: Unicellular eukaryotes, often parasites; common diseases include trichomoniasis, malaria, and amebic dysentery.
• Helminths: Non-microorganism parasites with complex life cycles; examples include pinworms and tapeworms.
• Prions: Infectious proteins that cause neurodegenerative diseases such as Creutzfeldt-Jacob disease.

Basic Structure of Bacteria

• Bacteria have rigid cell walls that determine shape and protect against environmental factors.
• Two major types: gram-positive and gram-negative, crucial for determining treatment options.
• Structures include a selectively permeable cell membrane, external capsule, flagellae for mobility, and pili for attachment and DNA transfer.

Toxins and Spores

• Exotoxins: Primarily produced by gram-positive bacteria and can lead to significant tissue damage.
• Endotoxins: Found in the outer membrane of gram-negative bacteria; released upon cell death and can cause septic shock.
• Bacterial spores are dormant, resilient forms ensuring survival in harsh conditions; autoclaving is used for sterilization.

Signs and Symptoms of Infection

• Local inflammation signs: pain, redness, swelling, warmth; purulent (bacterial) vs. serous (viral) exudate.
• Systemic signs include fever, fatigue, headache, and nausea.

Principles of Infection

• Incubation Period: Time from organism entry to first signs of disease.
• Prodromal Period: Early signs often nonspecific, like fatigue and loss of appetite.
• Acute Period: Immune response intensifies, and specific infection symptoms manifest.

Infection Transmission Principles

• Strategies include isolating infectious reservoirs, restricting contaminated food access, and reducing contact between infected individuals.
• Importance of cleaning environments and sterilizing equipment to limit transmission.

Methods of Diagnosis

• Culture and staining techniques, drug sensitivity tests.
• Blood tests indicating leukocyte variations, such as leukocytosis for bacterial infections.
• Immunological tests for antigen and antibody identification.

Antimicrobial Classification

• Antibiotics derived from living organisms target bacteria, while antimicrobials cover broader categories including antiviral and antifungal agents.
• Bactericidal agents destroy organisms, whereas bacteriostatic agents slow their reproduction.

This quiz covers the development of autoimmune disorders, including the formation of autoantibodies and their impact on the body. It includes specific examples such as Hashimoto thyroiditis and systemic lupus erythematosus. Test your knowledge on how these conditions affect self-tolerance and organ systems.