TBL 4 - Autoimmune Diseases Flashcard Guide

A comprehensive collection of flashcards covering key concepts, definitions, and comparisons related to autoimmune diseases and their hypersensitivity mechanisms.

What is autoimmune disease?

Immune system attacks the body's own tissues, Loss of self-tolerance, Can be organ-specific or systemic, Caused by antibodies (Type II/III) or T cells (Type IV)

What's the difference between organ-specific and systemic autoimmune diseases?

Organ-specific targets one organ or tissue type; examples: Graves (thyroid), Type 1 diabetes (pancreas), Myasthenia gravis (neuromuscular junction). Systemic affects multiple organs; examples: SLE, Rheumatoid arthritis, Systemic sclerosis.

How do autoimmune diseases relate to hypersensitivity reactions?

Autoimmune diseases ARE hypersensitivity reactions against self.

What causes loss of self-tolerance in autoimmune disease?

Genetic factors (HLA associations, family history), Environmental triggers (infections, drugs, UV light), Hormonal factors (more common in women), Failure of regulatory T cells, Exposure of hidden antigens.

What lab test is used as a general screening for autoimmune disease?

ANA (Antinuclear Antibody), Positive in many autoimmune diseases especially SLE.

What hypersensitivity type is Graves disease? Mechanism?

Type II Hypersensitivity. Mechanism: Antibodies (TSI) bind and STIMULATE TSH receptor on thyroid. Result: Excess thyroid hormone production.

What hypersensitivity type is Hashimoto thyroiditis? Mechanism?

Type II Hypersensitivity (also has Type IV component). Mechanism: Antibodies against TPO and thyroglobulin, T cells destroy thyroid.

Compare Graves vs Hashimoto - both affect thyroid, what's different?

Graves: Antibodies STIMULATE TSH receptor, Hyperthyroidism, Low TSH. Hashimoto: Antibodies DESTROY thyroid tissue, Hypothyroidism, High TSH.

What hypersensitivity type is Myasthenia gravis? Mechanism?

Type II Hypersensitivity. Mechanism: Antibodies against acetylcholine receptors at neuromuscular junction, BLOCK receptors.

What is the edrophonium (Tensilon) test for Myasthenia gravis?

Gives edrophonium (acetylcholinesterase inhibitor). Increases ACh at neuromuscular junction. If Myasthenia gravis: Muscle strength temporarily IMPROVES.

What hypersensitivity type is Goodpasture syndrome? Mechanism?

Type II Hypersensitivity. Mechanism: Antibodies against type IV collagen in basement membranes of lungs and kidneys.

What hypersensitivity type is Autoimmune Hemolytic Anemia (AIHA)? Mechanism?

Type II Hypersensitivity. Mechanism: Antibodies against RBC surface antigens, RBCs destroyed by complement or phagocytes.

What is the Coombs test and what does it detect?

Direct Coombs (DAT): Detects antibodies attached to patient's RBCs. Indirect Coombs (IAT): Detects antibodies in patient's serum. Used for blood typing.

What hypersensitivity type is Immune Thrombocytopenia (ITP)? Mechanism?

Type II Hypersensitivity. Mechanism: Antibodies against platelet surface antigens (GPIIb/IIIa), platelets destroyed in spleen.

Compare ITP vs Wiskott-Aldrich - both have thrombocytopenia, what's different?

ITP: Type II autoimmune, antibodies destroy platelets, LARGE platelets. Wiskott-Aldrich: Immunodeficiency, genetic WAS mutation, SMALL platelets.

What hypersensitivity type is Pernicious Anemia? Mechanism?

Type II Hypersensitivity. Mechanism: Antibodies against intrinsic factor or parietal cells, can't absorb vitamin B12.

What is Type 1 Autoimmune Polyendocrine Syndrome (APS-1)?

Also called APECED syndrome. Genetic mutation in AIRE gene. Classic Triad: Chronic mucocutaneous candidiasis, Hypoparathyroidism, Adrenal insufficiency.

What is Type 2 Autoimmune Polyendocrine Syndrome (APS-2)?

More common than APS-1. Classic combination: Adrenal insufficiency, Autoimmune thyroid disease, and/or Type 1 diabetes.

What hypersensitivity type is Pemphigus Vulgaris? Mechanism?

Type II Hypersensitivity. Mechanism: Antibodies against desmoglein, leading to blistering of skin.

What is Nikolsky sign?

Skin separates/sloughs off with gentle lateral pressure. Indicates loss of cell-to-cell adhesion.

What hypersensitivity type is Systemic Lupus Erythematosus (SLE)? Mechanism?

Type III Hypersensitivity. Mechanism: Immune complexes deposit in tissues, leading to multi-organ damage.

What are the most specific antibodies for SLE diagnosis?

Anti-dsDNA antibodies are very specific for SLE. Anti-Smith antibodies are most specific but less sensitive.

Why is complement LOW in active SLE?

Immune complexes activate complement cascade, leading to consumption of complement.

What is the malar rash in SLE?

Butterfly-shaped rash across cheeks and nose bridge. Photosensitive, non-scarring, classic for SLE.

What hypersensitivity type are ANCA-Associated Vasculitides? Mechanism?

Type III Hypersensitivity. Mechanism: ANCA antibodies cause neutrophil activation and blood vessel inflammation.

Compare c-ANCA vs p-ANCA - what do they detect and in which diseases?

c-ANCA detects anti-PR3 for GPA/Wegener's; p-ANCA detects anti-MPO for MPA and EGPA.

What is Granulomatosis with Polyangiitis (GPA/Wegener's)? Classic triad?

ANCA-associated vasculitis, Classic triad: Upper respiratory, Lower respiratory, and Kidneys involvement.

What is Polyarteritis Nodosa (PAN)? What vessels does it affect?

Medium vessel vasculitis, associated with Hepatitis B infection. Affects medium-sized muscular arteries.

What hypersensitivity type is Type 1 Diabetes Mellitus? Mechanism?

Type IV Hypersensitivity. Mechanism: CD8+ T cells destroy pancreatic beta cells.

What autoantibodies are found in Type 1 Diabetes?

Anti-GAD65, Anti-insulin antibodies, Anti-IA2 antibodies, Anti-ZnT8.

What hypersensitivity type is Rheumatoid Arthritis (RA)? Mechanism?

Type IV Hypersensitivity. Mechanism: T cells activate in joints, leading to rheumatoid factor and chronic synovial inflammation.

What is anti-CCP and why is it important in RA?

Anti-CCP: Anti-Cyclic Citrullinated Peptide antibodies. More specific for RA than rheumatoid factor.

What are rheumatoid nodules?

Firm, subcutaneous nodules in RA patients, indicating more severe disease.

What hypersensitivity type is Multiple Sclerosis (MS)? Mechanism?

Type IV Hypersensitivity. Mechanism: T cells attack myelin sheath in CNS.

What does 'separated in time and space' mean for MS diagnosis?

Multiple lesions in different areas of CNS at different times.

What hypersensitivity type is Inflammatory Bowel Disease (IBD)? Mechanism?

Type IV Hypersensitivity. Mechanism: Inappropriate T cell response to intestinal bacteria.

Compare Crohn Disease vs Ulcerative Colitis

Crohn: Anywhere mouth to anus, skip lesions; Ulcerative Colitis: Colon only, continuous.

What hypersensitivity type is Celiac Disease? Mechanism?

Type IV Hypersensitivity. Mechanism: T cells react to gliadin, damaging small intestine villi.

What is dermatitis herpetiformis and its connection to Celiac?

Itchy skin rash due to IgA deposits in skin, a skin manifestation of Celiac disease.

What hypersensitivity type is Sjögren Syndrome? Mechanism?

Type IV Hypersensitivity. Mechanism: T cells and antibodies attack salivary and lacrimal glands.

What hypersensitivity type is Systemic Sclerosis (Scleroderma)? Mechanism?

Type IV Hypersensitivity. Mechanism: T cells stimulate fibroblasts, excessive collagen deposition.

What is CREST syndrome?

Limited cutaneous systemic sclerosis characterized by Calcinosis, Raynaud phenomenon, Esophageal dysmotility, Sclerodactyly, and Telangiectasias.

What is Raynaud phenomenon?

Episodic vasospasm of fingers/toes in response to cold or stress.

What hypersensitivity type is Polymyositis and Dermatomyositis? Mechanism?

Type IV Hypersensitivity. Mechanism: T cells and inflammation in muscles.

What are the characteristic rashes of Dermatomyositis?

Heliotrope rash, Gottron papules, Shawl sign, V-sign, all photosensitive.

What is Mixed Connective Tissue Disease (MCTD)?

Overlap syndrome with features of SLE, systemic sclerosis, and polymyositis.

What is Antiphospholipid Syndrome (APS)?

Autoantibodies against phospholipids cause hypercoagulable state, leading to thrombosis and pregnancy complications.

Why is lupus anticoagulant paradoxical?

Acts as a procoagulant in vivo but prolongs PTT in vitro, causing confusion.

What hypersensitivity type is Addison Disease? Mechanism?

Type II and Type IV Hypersensitivity. Mechanism: Autoimmune destruction of adrenal cortex.

Why does Addison disease cause hyperpigmentation?

Adrenal destruction leads to high ACTH, which increases MSH production, resulting in increased melanin.

What is Autoimmune Hepatitis? Types?

Type IV Hypersensitivity. Type 1: Anti-smooth muscle antibodies; Type 2: Anti-LKM1 antibodies.

What is Primary Biliary Cholangitis (PBC)?

Type IV Hypersensitivity. Autoimmune destruction of intrahepatic bile ducts.

What is Primary Sclerosing Cholangitis (PSC)?

Inflammation and fibrosis of bile ducts, mechanism unclear, associated with IBD.

Compare all Type II antibody-mediated diseases - what antibody and what effect?

Graves: Anti-TSH receptor, stimulates; Myasthenia Gravis: Anti-ACh receptor, blocks; Autoimmune Hemolytic Anemia: Anti-RBC, destroys.

Match the antibody to the disease: Anti-dsDNA, Anti-CCP, Anti-tTG, Anti-mitochondrial, c-ANCA

Anti-dsDNA: SLE; Anti-CCP: RA; Anti-tTG: Celiac; Anti-mitochondrial: PBC; c-ANCA: GPA.

Which autoimmune diseases are associated with HLA-B27?

Seronegative Spondyloarthropathies: Psoriatic arthritis, Ankylosing spondylitis, Inflammatory bowel disease, Reactive arthritis.

Which autoimmune diseases have increased risk in people with Selective IgA deficiency?

Increased risk for Celiac disease, SLE, Rheumatoid arthritis, and Type 1 diabetes.

Which autoimmune diseases are more common in WOMEN?

Autoimmune diseases with very high female predominance include SLE, Sjögren syndrome, and Hashimoto thyroiditis.

Compare the complement levels in SLE vs other conditions

SLE: LOW C3 and C4; other autoimmune diseases: usually normal complement.

Which autoimmune diseases can cause glomerulonephritis?

Goodpasture syndrome, SLE, ANCA vasculitis, IgA nephropathy.

Compare morning stiffness duration: RA vs Osteoarthritis

RA: Morning stiffness >1 hour. Osteoarthritis: Morning stiffness <30 minutes.

Which autoimmune diseases affect the thyroid? Compare them.

Graves disease: stimulate TSH receptor, hyperthyroidism. Hashimoto: destroy thyroid, hypothyroidism.

Compare the 'Big 3' systemic autoimmune diseases: SLE, RA, Systemic Sclerosis

SLE: multi-organ, low complement. RA: joints, anti-CCP. Systemic Sclerosis: fibrosis, sclerodactyly.

30-year-old woman with butterfly rash on face, joint pain, fatigue, and protein in urine. Most likely diagnosis and next steps?

Diagnosis: Systemic Lupus Erythematosus (SLE). Next steps: Check ANA, anti-dsDNA, complement levels.

65-year-old woman with progressive difficulty chewing, diplopia, and ptosis that worsens throughout the day. Diagnosis?

Diagnosis: Myasthenia Gravis.

45-year-old woman with dry eyes, dry mouth, and dental caries. Also has rheumatoid arthritis. Diagnosis?

Diagnosis: Sjögren Syndrome.

25-year-old man with chronic diarrhea, weight loss, abdominal pain. Colonoscopy shows skip lesions and cobblestone appearance. Diagnosis?

Diagnosis: Crohn Disease.

8-year-old child with polyuria, polydipsia, weight loss, and blood glucose 350. Diagnosis? What confirms it's autoimmune?

Diagnosis: Type 1 Diabetes Mellitus. Confirm: Anti-GAD antibodies.

50-year-old woman with proximal muscle weakness, difficulty standing from chair, and elevated CK. Also has purple rash on eyelids. Diagnosis?

Diagnosis: Dermatomyositis.

28-year-old woman with recurrent miscarriages, recent DVT, and prolonged PTT that doesn't correct with mixing study. Diagnosis?

Diagnosis: Antiphospholipid Syndrome.

What are the general treatment principles for autoimmune diseases?

Suppress immune system, reduce inflammation, prevent organ damage.

What is the role of Hydroxychloroquine in autoimmune disease?

Reduces inflammation, used primarily for SLE.

When do you use plasmapheresis in autoimmune disease?

Used for acute, severe cases like Goodpasture syndrome and severe SLE.

List all Type II hypersensitivity autoimmune diseases (antibody-mediated against cells/tissues)

Graves disease, Hashimoto thyroiditis, Myasthenia gravis, Pernicious anemia, Goodpasture syndrome, Autoimmune hemolytic anemia, Immune thrombocytopenia, Pemphigus vulgaris.

List all Type III hypersensitivity autoimmune diseases (immune complex-mediated)

Systemic lupus erythematosus, ANCA-associated vasculitides, Polyarteritis nodosa, Serum sickness, Post-streptococcal glomerulonephritis.

List all Type IV hypersensitivity autoimmune diseases (T cell-mediated)

Type 1 diabetes mellitus, Hashimoto thyroiditis, Celiac disease, Autoimmune hepatitis, Primary biliary cholangitis, Addison disease, Rheumatoid arthritis, Multiple sclerosis.

Match the buzzword to the disease: "Butterfly rash" "Exophthalmos" "Muscle weakness worse with use" "Saddle nose" "Bronze skin" "Sclerodactyly"

Butterfly rash: SLE; Exophthalmos: Graves disease; Muscle weakness worse with use: Myasthenia gravis; Saddle nose: Granulomatosis with polyangiitis; Bronze skin: Addison disease.

Match the antibody to the disease: Anti-dsDNA, Anti-CCP, Anti-Jo-1, Anti-centromere, Lupus anticoagulant

Anti-dsDNA: SLE; Anti-CCP: RA; Anti-Jo-1: Polymyositis; Anti-centromere: scleroderma; Lupus anticoagulant: APS.

What does LOW complement tell you in autoimmune disease?

Low C3 and C4 indicates active immune complex formation, specific for SLE.

What does positive ANA tell you?

ANA = screening test for autoimmune disease, positive in many conditions.