Exam 2 · Week 4 · BIO 280 Pathophysiology
M4 · Inflammation · Pain · Neurodegeneration
Inflammation when it helps, inflammation when it turns on the whole body, how wounds heal, and the diseases that take neurons away.
▸M4Inflammation · Pain · NeurodegenerationWeek 4
💡 The one idea
Inflammation is the repair crew. Sepsis is the repair crew burning the building down. Same mediators, same vasodilation, same leaky vessels — the difference is that it has stopped being local.
Local inflammation = healing. Systemic inflammation = shock.
🔥 The five signs, and why each one happens
- Redness and heat — vasodilation brings more blood in.
- Swelling — increased permeability lets fluid into the tissue.
- Pain — pressure from the swelling plus chemical mediators (bradykinin, prostaglandins).
- Loss of function — the consequence of the other four.
Acute inflammation lasts minutes to days, and neutrophils lead it. Chronic lasts weeks to years, is led by macrophages and lymphocytes, and it causes fibrosis and scarring — that is where the permanent damage comes from.
🚨 SIRS → sepsis → septic shock
Sepsis is a time-critical emergency. Every hour of delayed antibiotics measurably increases mortality.
| Stage | What it means |
|---|---|
| SIRS | A systemic inflammatory response — two or more of:
temp >38 or <36°C, HR >90,
RR >20, WBC >12,000 or <4,000.
Not necessarily infection — trauma, burns and pancreatitis do it too. |
| Sepsis | A dysregulated response to infection causing organ dysfunction. |
| Septic shock | Sepsis plus hypotension that persists after fluids, requiring vasopressors, with a rising lactate. |
Early (warm) sepsis is the trap: the vessels are dilated, so the skin is warm, flushed and dry, with a bounding pulse and a wide pulse pressure. They do not look like shock. Later it turns cold and clammy like every other shock — by then compensation has failed.
A rising lactate is the earliest honest sign that perfusion is failing.
🩹 How wounds heal
Four overlapping phases: hemostasis (clot, minutes) → inflammatory (days 1–4, neutrophils then macrophages) → proliferative (days 4–21, granulation tissue, collagen, new vessels) → maturation / remodeling (21 days to 2 years; the scar never exceeds about 80% of original strength).
| Intention | Wound | Scar |
|---|---|---|
| Primary | Clean, edges approximated — a surgical incision | Minimal |
| Secondary | Edges cannot be brought together — a pressure ulcer, a large burn. Heals from the base up by granulation. | Large; longer, higher infection risk |
| Tertiary | Deliberately left open (contamination), closed later | Moderate |
What stops healing: poor perfusion and oxygenation, diabetes, infection, low protein and vitamin C and zinc, steroids, smoking, age, and pressure that is never relieved.
Dehiscence (the wound opening) and evisceration (organs protruding) are emergencies: cover with sterile saline-soaked gauze, do not push anything back in, position low Fowler with knees bent, and call the surgeon.
🦵 Osteoarthritis vs rheumatoid arthritis
| Osteoarthritis | Rheumatoid arthritis | |
|---|---|---|
| Nature | Wear — cartilage degeneration | Autoimmune, systemic |
| Pattern | Asymmetric, weight-bearing joints | Symmetric, small joints of hands and feet first |
| Stiffness | <30 min, worse with use and at the end of the day | >60 min in the morning, better with use |
| Systemic | No | Yes — fever, fatigue, weight loss, nodules |
| Signs | Heberden and Bouchard nodes, crepitus | Ulnar deviation, swan-neck, boutonnière |
| Labs | Unremarkable | ↑ ESR/CRP, RF, anti-CCP |
⭐ Pain — the three kinds
| Type | Source | Feels like |
|---|---|---|
| Somatic | Skin, muscle, bone, joint | Sharp, well localized — you can point to it |
| Visceral | Organs | Deep, cramping, poorly localized, often referred elsewhere |
| Neuropathic | Nerve damage itself | Burning, shooting, electric, tingling. Responds poorly to opioids; needs anticonvulsants or antidepressants. |
Acute pain is protective, has an obvious cause, and resolves. Chronic pain lasts beyond healing (>3–6 months), serves no purpose, and shows as fatigue, depression and withdrawal rather than as tachycardia and grimacing.
Pain is what the patient says it is. A calm, sleeping or smiling patient may still be in severe pain — absence of visible distress is not evidence of absence of pain.
🧠 Neurodegenerative diseases
| Disease | What is lost | Hallmark |
|---|---|---|
| Alzheimer | Cortical neurons; amyloid plaques and neurofibrillary tangles; low acetylcholine | Short-term memory first. Then language, judgment, personality. |
| Parkinson | Dopamine neurons in the substantia nigra | TRAP — Tremor at rest, Rigidity (cogwheel), Akinesia / bradykinesia, Postural instability. Shuffling gait, mask face. |
| Multiple sclerosis | Myelin in the CNS — autoimmune, relapsing and remitting | Young adults, women more often. Optic neuritis, numbness, weakness, spasticity; heat makes it worse. |
| ALS | Upper and lower motor neurons | Progressive weakness with intact cognition and sensation. Death from respiratory failure. |
| Myasthenia gravis | Acetylcholine receptors (autoantibodies) | Weakness that worsens with use and improves with rest. Ptosis, diplopia, trouble swallowing. |
| Huntington | Basal ganglia neurons — autosomal dominant | Chorea, cognitive decline, psychiatric change; onset in the 30s–40s. |
Parkinson is too little dopamine; Huntington is the opposite movement problem. Parkinson patients cannot start moving; Huntington patients cannot stop.
🎯 Module quiz
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