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📚 PATHOLOGY 1ST - Very Important Topics

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1. Cell Injury - Causes, Types, Reversible & Irreversible

• Hypoxia/Ischemia - no oxygen, no blood (most common!)
• Toxins - poisons, alcohol, cigarette smoke
• Infections - bacteria, virus, fungi
• Immune reactions - body attacks itself
• Genetics - born with defect
• Nutritional - vitamin deficiency
• Physical - trauma, heat, radiation

• Cell swells up (like a balloon filling with water)
• Nucleus normal
• Mitochondria swollen

• Nucleus shrinks and breaks (pyknosis → karyorrhexis → karyolysis)
• Cell membrane breaks
• Organelles destroyed

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2. Necrosis - Definition, Types, Differences from Apoptosis

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3. Apoptosis - Mechanism & Significance

1. Signal received (death signal)
2. Caspases (scissors of the cell) get activated
3. DNA gets cut into pieces
4. Cell breaks into "apoptotic bodies" (neat packages)
5. Macrophages eat the packages - NO inflammation

• Intrinsic (from inside cell) - via mitochondria, BCL-2 family
• Extrinsic (from outside) - via death receptors (TNF, FasL)

• Normal development (fingers form by removing webbing)
• Cancer suppression (kills mutated cells)
• When it goes wrong: too little = cancer, too much = neurodegenerative disease

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4. Acute Inflammation - Definition, Causes, Signs & Stages

1. Vascular stage - blood vessels dilate (get wider), more blood flows = redness + heat
2. Cellular stage - WBCs (neutrophils) leave blood and enter tissue
3. Resolution - either heals OR becomes chronic

• Histamine (first to arrive - causes swelling)
• Prostaglandins (cause pain and fever)
• Complement system (C3a, C5a)

• Aspirin (ASS-pirin) - blocks prostaglandins (anti-inflammatory)
• Ibuprofen (I-brew-fen) - same mechanism, NSAID
• Paracetamol (Para-set-all) - reduces fever/pain

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5. Chronic Inflammation - Causes & Differences from Acute

• Persistent infections (TB, leprosy)
• Autoimmune diseases (Rheumatoid Arthritis, Lupus)
• Foreign bodies (splinter, suture material)
• Prolonged toxic exposure (silica dust, asbestos)

• Macrophages (main cell - "big eaters")
• Lymphocytes (for memory/immunity)
• Plasma cells (make antibodies)
• Epithelioid cells + Giant cells (in granulomas)

• Prednisolone (Prednisone) - steroid, reduces chronic inflammation
• Methotrexate (Metro-X-ate) - for autoimmune/RA
• Hydroxychloroquine (Hydro-chloro-queen) - for lupus, RA

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6. Wound Healing - Stages & Factors Affecting Healing

• Primary intention - clean cut wound, edges close together (surgical wound) - heals fast
• Secondary intention - large wound, edges apart - heals slowly with scar tissue

1. Hemostasis (0-few hours) - bleeding stops, clot forms
2. Inflammation (1-3 days) - neutrophils clean the wound
3. Proliferation (3 days - 3 weeks) - new blood vessels grow (angiogenesis), fibroblasts lay collagen
4. Remodeling (weeks to years) - scar matures, collagen reorganizes

• Infection
• Diabetes
• Malnutrition (Vitamin C, Zinc deficiency)
• Old age
• Steroids (suppress inflammation)
• Poor blood supply

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7. Edema - Causes, Types & Pathogenesis

• Pitting edema - press finger = pit remains (heart, kidney, liver failure)
• Non-pitting edema - press = no pit (lymphedema, myxedema)
• Pulmonary edema - fluid in lungs (heart failure)
• Cerebral edema - fluid in brain (head injury)

• Furosemide (Furo-side = "Flushing out water") - strongest diuretic
• Spironolactone (Spy-rona-lactone) - potassium-sparing diuretic
• Hydrochlorothiazide (Hydro-Chloro-Thiazide = HCT) - mild diuretic

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8. Thrombosis - Causes, Fate & Complications

1. Endothelial injury - damage to vessel wall (atherosclerosis, smoking)
2. Stasis of blood flow - blood moving slowly (bed rest, heart failure)
3. Hypercoagulability - blood clots too easily (pregnancy, cancer)

• Arterial thrombus - in arteries (causes heart attack, stroke)
• Venous thrombus - in veins (DVT - Deep Vein Thrombosis)

1. Resolution - dissolves on its own
2. Organization - gets replaced by fibrous tissue
3. Recanalization - new channel forms through it
4. Embolization - breaks off and travels (dangerous!)
5. Calcification - becomes stony (phlebolith)

• Heparin (Hep-arin = "Help-arin") - fast-acting, given injection
• Warfarin (War-farin) - oral blood thinner
• Aspirin - prevents platelet clumping
• Alteplase/tPA - clot buster drug

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9. Embolism - Types & Complications

• Blood clot from leg DVT travels to lungs
• Symptoms: sudden breathlessness, chest pain, fast heartbeat

• Heparin - immediate treatment
• Warfarin or Rivaroxaban (River-oxaban) - oral, long-term
• Alteplase - if massive PE (clot buster)

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10. Shock - Definition, Types, Stages & Management

1. Compensated - body fights back, BP still normal
2. Progressive - body losing the fight, BP falls
3. Irreversible - organs dying, can't recover

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11. Hyperemia & Congestion - Difference

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12. Infarction - Causes, Types & Complications

• Myocardial infarction (MI) = Heart attack (white infarct)
• Cerebral infarction = Stroke
• Pulmonary infarction = Lung infarct (red)
• Splenic infarction = Spleen (white)

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📚 PATHOLOGY 2ND - Very Important Topics

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1. Anemia - Definition, Classification, Causes, Signs & Symptoms

• Men: >13 g/dL
• Women: >12 g/dL
• Children: >11 g/dL

• Pallor (pale skin, nails, conjunctiva)
• Palpitation (fast heartbeat)
• Paralysis - extreme fatigue, weakness
• Panting - breathlessness
• Tachycardia (fast heart rate)

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2. Iron Deficiency Anemia (IDA)

• Chronic bleeding (periods, peptic ulcer)
• High demand (pregnancy, growth)
• Inadequate intake (poor diet)
• Low absorption (stomach removed, celiac disease)
• Deficiency of iron stores

• Low Hb, Low MCV, Low serum iron
• HIGH TIBC (body asking for more iron)
• Low serum ferritin

• Koilonychia = spoon-shaped nails (concave nails)
• Atrophic glossitis = smooth, painful tongue
• Angular stomatitis = cracks at corner of mouth
• Pica = craving to eat mud/dirt/ice

• Ferrous Sulfate (Fer-rous Sul-fate = "Ferrous = Iron") - oral iron tablets
• Ferric Carboxymaltose (injection) - for severe cases
• Vitamin C taken with iron INCREASES absorption

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3. Megaloblastic Anemia

• B12 deficiency: Neurological problems (numbness, weakness, memory loss)
• Blood film: Hypersegmented neutrophils (neutrophil with 5+ lobes)

• Cyanocobalamin (Sigh-ano-CO-bal-amin = Vitamin B12 injection) - for B12 deficiency
• Folic Acid (Fo-lic acid = "Folate") tablets - for folate deficiency

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4. Aplastic Anemia

• Drugs - Chloramphenicol (anti-biotic), Chemotherapy
• Infections - Hepatitis, HIV, Parvovirus B19
• Radiation - X-ray exposure
• Toxins - Benzene, pesticides
• Autoimmune (most common - body attacks bone marrow)

• Pancytopenia = low RBC + low WBC + low platelets
• Bone marrow biopsy = empty/fatty marrow (key finding!)

• Anemia symptoms (pale, tired)
• Infections (low WBC)
• Bleeding (low platelets)

• Antithymocyte Globulin (ATG) - immunosuppressant
• Cyclosporine (Sigh-clo-sporin) - suppresses immune attack
• Bone Marrow Transplant - best/curative treatment
• G-CSF (Filgrastim) - boosts WBC production

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5. Leukemia - Definition, Classification & Clinical Features

• Fever, fatigue, weight loss
• Bone pain
• Lymph node swelling
• Bleeding (low platelets)
• Frequent infections
• Hepatosplenomegaly (big liver and spleen)

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6. Lymphoma - Hodgkin's vs Non-Hodgkin's Lymphoma

• Nodular Sclerosis (most common, 70%)
• Mixed Cellularity
• Lymphocyte Rich
• Lymphocyte Depleted (worst prognosis)

• Fever > 38°C
• Night sweats
• Weight loss > 10%

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7. Hemophilia

• Prolonged bleeding after cuts/injury
• Hemarthrosis (bleeding into joints) - most common
• Muscle hematoma
• Spontaneous bleeding in severe cases

• Prolonged aPTT (activated partial thromboplastin time)
• Normal PT (prothrombin time)
• Normal platelet count

• Factor VIII concentrate - for Hemophilia A
• Factor IX concentrate - for Hemophilia B
• Desmopressin (DDAVP) - releases stored Factor VIII (mild Hemophilia A)
• Fresh Frozen Plasma (FFP) - emergency, contains all factors

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8. Disseminated Intravascular Coagulation (DIC)

• Sepsis (infection in blood) - most common
• Trauma (severe injury)
• Obstetric complications (placental abruption, amniotic fluid embolism)
• Pancreatic cancer, other malignancies

1. Trigger activates clotting everywhere
2. Tiny clots (microthrombi) form all over
3. Clotting factors and platelets get used up (consumed)
4. Body can no longer clot = uncontrolled bleeding

• Platelets - LOW
• PT and aPTT - PROLONGED (long)
• Fibrinogen - LOW (used up)
• D-dimer - HIGH (clot breakdown products)

• Treat underlying cause (antibiotics for sepsis)
• Fresh Frozen Plasma (FFP) - replaces clotting factors
• Platelet transfusion - if very low
• Heparin - controversial, used in certain cases

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9. Blood Transfusion - Indications, Complications & Reactions

• Severe anemia (Hb < 7 g/dL)
• Major blood loss (surgery, trauma)
• Aplastic anemia, thalassemia
• Hemophilia (FFP, factor concentrates)

1. STOP transfusion immediately
2. Give IV fluids
3. Adrenaline (if anaphylaxis)
4. Check blood group again

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10. Multiple Myeloma

• C - Calcium high (hypercalcemia) → constipation, confusion, kidney stones
• R - Renal failure (kidney damage)
• A - Anemia (bone marrow taken over by cancer)
• B - Bone pain/lytic lesions (punched-out holes in skull X-ray)

• Serum protein electrophoresis → M-spike (abnormal immunoglobulin peak)
• Bence-Jones protein in urine (light chains from myeloma cells)
• Skull X-ray → "punched out lesions" (looks like holes punched in skull)
• Bone marrow biopsy → >10% plasma cells

• Bortezomib (Bor-te-ZO-mib = "Borte-zoom") - proteasome inhibitor
• Lenalidomide (Le-nal-i-do-mide = "Len") - immunomodulator
• Dexamethasone (Dexa = steroid)
• Autologous stem cell transplant - for eligible patients

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🧠 MASTER MEMORY TRICKS SUMMARY

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Source: Robbins & Kumar Basic Pathology; Robbins Cotran & Kumar Pathologic Basis of Disease

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How to Study These Topics

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📌 PATHOLOGY 1ST — Topic 1 of 12

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🔴 Cell Injury — Causes, Types, Reversible & Irreversible

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🤔 What is Cell Injury?

• Recover (if damage is mild/short) → Reversible injury
• Die (if damage is too much) → Irreversible injury

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🔥 CAUSES of Cell Injury

💡 Most common cause = Hypoxia (lack of oxygen)

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🟡 REVERSIBLE Cell Injury

"Cell is hurt but ALIVE — if you remove the damage, it recovers."

• Cell swells up (like a balloon) — called cellular swelling
• Water enters cell (can't pump it out — pump needs energy/ATP)
• Fat droplets appear inside cell (fatty change)
• Nucleus looks normal
• Mitochondria swell

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🔴 IRREVERSIBLE Cell Injury (Cell Death)

"Cell is damaged beyond repair — it DIES."

• Cell membrane breaks
• Mitochondria destroyed
• Enzymes leak out (e.g., Troponin leaks in heart attack — used in blood tests!)

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⚖️ REVERSIBLE vs IRREVERSIBLE — Quick Table

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💊 Related Drugs (Easy Names)

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✅ EXAM POINTS to Remember

1. Most common cause of cell injury = Hypoxia
2. First sign of reversible injury = Cellular swelling
3. Point of no return = when cell membrane is damaged
4. Nuclear changes in order = Pyknosis → Karyorrhexis → Karyolysis
5. ATP loss = KEY mechanism of cell injury

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📌 PATHOLOGY 1ST — Topic 2 of 12

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🔴 Necrosis — Definition, Types & Differences from Apoptosis

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🤔 What is Necrosis?

Key point: Necrosis ALWAYS causes inflammation around it.

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📋 TYPES of Necrosis

🧠 "Can Lions Catch Gangster Fat Foxes?" (Coagulative, Liquefactive, Caseous, Gangrenous, Fat, Fibrinoid)

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1️⃣ Coagulative Necrosis

• Most common type
• Dead tissue becomes firm and pale like cooked egg white
• Cell shape is preserved (outline visible but inside dead)
• Where: Heart, kidney, spleen (organs with single blood supply)
• Cause: Ischemia (no blood)
• Example: Heart attack (Myocardial Infarction)

💡 Think: "Cooked egg white — firm, shape preserved"

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2️⃣ Liquefactive Necrosis

• Dead tissue turns into liquid/pus
• Cell shape completely destroyed
• Where: Brain (most common), bacterial abscesses anywhere
• Cause: Bacterial infections or brain infarct
• Example: Brain stroke, abscess (pus collection)

💡 Think: "Liquid = melts into soup" Brain is special — even ischemia causes liquefactive (not coagulative) necrosis!

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3️⃣ Caseous Necrosis

• Dead tissue looks like soft white cheese (like paneer/cottage cheese)
• Neither firm nor liquid — crumbly, cheesy
• Surrounded by granuloma (ball of macrophages)
• Where: Lymph nodes, lungs
• Cause: ALWAYS think Tuberculosis (TB)
• Example: TB lymph node

💡 Think: "Caseous = Cheese = TB always!"

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4️⃣ Gangrenous Necrosis

• Tissue rots/dies — especially in limbs
• Two subtypes:

💡 Think: "Gangrene = Rotten limb" Dry = no infection, Wet = with infection

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5️⃣ Fat Necrosis

• Fat cells are destroyed → release fatty acids → mix with calcium → form chalky white deposits
• Called saponification (soap-like material forms)
• Where: Pancreas, breast
• Cause:
  • Pancreatic fat necrosis → Acute pancreatitis
  • Breast fat necrosis → trauma to breast

💡 Think: "Fat + Calcium = Chalky soap = Pancreatitis"

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6️⃣ Fibrinoid Necrosis

• Blood vessel walls get fibrin deposits (look pink on microscope)
• Seen in walls of blood vessels
• Where: Autoimmune diseases, malignant hypertension
• Cause: Immune complex deposition, severe high BP
• Example: Rheumatoid arthritis, Lupus (SLE), malignant hypertension

💡 Think: "Fibrinoid = Fibrin in vessel walls = Autoimmune/High BP"

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📊 ALL TYPES — Quick Summary Table

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⚔️ NECROSIS vs APOPTOSIS — Differences

💡 Simple memory:

• Necrosis = Murder (messy, affects others, causes chaos)
• Apoptosis = Suicide (clean, planned, no mess)

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✅ TOP EXAM POINTS

1. Most common type of necrosis = Coagulative
2. Brain infarction = Liquefactive (exception to the rule!)
3. TB = always Caseous necrosis
4. Fat necrosis with pancreatitis = Saponification
5. Necrosis causes inflammation; Apoptosis does NOT
6. Fibrinoid = autoimmune diseases and malignant hypertension

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