T

Comprehensive Pathophysiology Review Notes

Endocrine System

  • Cushing’s Syndrome / Disease (↑Cortisol)

    • Patho: ↑ACTH ➜ ↑cortisol.
    • Mnemonic: “Cushion = Cushy” (patients look puffy).
    • Clinical picture:
    • Central obesity, moon-face, buffalo hump.
    • \text{Hyperglycemia}, \text{Hypertension}.
    • Protein & collagen breakdown ➜ thin skin, striae, poor wound healing.
    • Osteoporosis / bone pain.

  • Thyroid Disorders

    • Hypothyroidism (Hashimoto’s; autoimmune).
    • “Body slows”: weight ↑, cold intolerance, bradycardia, constipation, fatigue.
    • Hyperthyroidism (Graves’ disease).
    • “Body speeds”: weight ↓, heat intolerance, tachycardia/HTN, diarrhea, tremor, anxiety.

  • Diabetes Mellitus

    • Type 1: autoimmune destruction of pancreatic β-cells ➜ absolute insulin deficiency; insulin-dependent.
    • Type 2: gradual insulin resistance; risk ↑ with obesity, sedentary lifestyle, h/x gestational DM.
    • Acute crises:
    • DKA (Type 1): very high glucose, ketonuria, metabolic acidosis, Kussmaul respirations (rapid, deep).
    • HHS (Type 2): severe hyperglycemia, profound dehydration, minimal/no ketones.

Musculoskeletal System

  • Fracture Complications
    • Compartment Syndrome
    • Etiology: massive swelling (trauma, tight cast, circumferential burn).
    • 6 P’s: Pain (severe), Paresthesia, Pallor, Paralysis, Pulselessness, Poikilothermia (cold).
    • Fat Embolism (esp. femur): triad—dyspnea, petechiae, confusion.
    • Rhabdomyolysis: rapid muscle breakdown ➜ myoglobinuria, hyperkalemia, renal injury.

Skin & Burns

  • ABCDE of Dysplastic Moles: Asymmetry, Border irregular, Color varied, Diameter >6\,\text{mm}, Evolving/bleeding.
  • Pressure (Decubitus) Ulcers: unrelieved pressure + shear/friction/moisture ➜ ischemia & breakdown.
  • Major Burn Complications: infection → sepsis, hypovolemic shock, hypothermia, ↑metabolic demand, respiratory failure.
  • Cellulitis: bacterial infection of dermis/hypodermis; red, swollen, warm, tender.

Cardiovascular System

  • Uncontrolled Hypertension Damage

    • Brain: CVA/TIA, aneurysm.
    • Eyes: retinopathy ➜ blindness.
    • Kidneys: chronic kidney disease.
    • Peripheral: PAD.
    • Heart: CAD, left-ventricular hypertrophy (↓filling ➜ HF).

  • Acute Coronary Syndrome Spectrum

    • Stable angina (exertional, relieved rest; ischemia only).
    • Unstable angina (new/progressive pain; no infarction).
    • NSTEMI / STEMI myocardial infarction (tissue death) ➜ ↑troponin.

  • Atherosclerosis Risk Factors: smoking, DM, HTN, ↑LDL/↑TG, obesity.

  • Atrial Fibrillation: "irregularly irregular" ➜ stasis & clot risk ➜ embolic stroke.

  • Heart Failure Symptoms

    • Right-sided (systemic backup): peripheral edema, JVD, hepatosplenomegaly, ascites.
    • Left-sided (pulmonary backup): dyspnea, crackles, pulmonary edema, hypoxia.

  • Valvular / Pericardial Disorders

    • Rheumatic Heart Disease: post-strep immune attack ➜ valve damage.
    • Infective Endocarditis (tricuspid > others): bacteremia ➜ fever, chills, splinter hemorrhages.
    • Pericardial Tamponade
    • Fluid compresses heart (esp. right side).
    • Beck’s triad: muffled heart sounds, hypotension, JVD.

Neurologic System

  • TIA: transient brain ischemia, symptoms resolve, warning for stroke.
  • Stroke Types
    • Ischemic (thrombus/embolus).
    • Hemorrhagic (vessel rupture).
  • ↑ICP Signs: headache, N/V, fixed & dilated pupils, posturing, Cushing’s triad = ↑BP + ↓HR + ↓RR.
  • Seizures & Status Epilepticus
    • Status = continuous >5\,\text{min} OR \ge 2 seizures within 5\,\text{min} without recovery.
  • Cranial Hemorrhages
    • Epidural (arterial): brief lucid interval ➜ rapid deterioration.
    • Subdural (venous): slower onset, elderly / anticoagulated.
  • Autonomic Dysreflexia
    • SCI above T6; irritant below lesion triggers massive sympathetic surge.
    • S/S: severe HTN, flushed face, headache, bradycardia; fix stimulus STAT.
  • Meningitis: meningeal inflammation ➜ fever, nuchal rigidity, headache, seizures, ↑ICP.
  • Pain Types
    • Somatic (skin, muscle, bone).
    • Visceral (organ; may be referred).
  • Neurodegenerative
    • Alzheimer’s: cerebral amyloid plaques ➜ memory ± personality loss.
    • Parkinson’s: loss of substantia-nigra dopamine ➜ tremor, rigidity, bradykinesia.
    • Multiple Sclerosis: CNS myelin destruction ➜ fatigue, optic neuritis, gait issues, incontinence.

Respiratory System

  • Atelectasis: alveolar collapse ➜ impaired gas exchange; tachypnea, shallow breaths.
  • Asthma: reversible bronchoconstriction + inflammation + mucus ➜ wheeze, dyspnea.
  • Cystic Fibrosis (autosomal recessive): thick mucus plugs lungs & GI; chronic infections.
  • COPD
    • Emphysema: alveolar wall destruction ➜ ↓surface area.
    • Chronic Bronchitis: mucus hypersecretion & airway inflammation.
    • Shared S/S: chronic cough, barrel chest, hypercapnia, hypoxemia.
  • Tension Pneumothorax
    • Collapsed lung + mediastinal shift ➜ pressure on right heart.
    • Findings: absent breath sounds affected side, tracheal deviation to opposite side, hypotension, tachycardia.
  • Tuberculosis: caseating granulomas; reactivates when immunosuppressed.
    • Symptoms: chronic cough, hemoptysis, night sweats, weight loss.
  • Influenza: viral URI/LRI: high fever, myalgias, sore throat.
  • Pneumonia: bacterial infection ➜ exudate in alveoli; productive cough, fevers, crackles.
  • Pulmonary Embolism (from DVT): clot obstructs pulmonary artery.
    • Risk factors: fractures, immobility, smoking, obesity, estrogen (OCP/HRT), pregnancy.

Fluid, Electrolyte & Acid–Base

  • Renin–Angiotensin–Aldosterone System (RAAS)

    • Trigger: \downarrow\text{BP}.
    • Effects: vasoconstriction, ↑HR, aldosterone-mediated \text{Na}^+ & \text{H}_2\text{O} reabsorption ➜ ↑BP/volume.

  • Capillary Forces

    • Hydrostatic pressure pushes fluid out.
    • Oncotic (osmotic) pressure from albumin pulls fluid in.
    • \downarrow\text{Albumin} ➜ \downarrow\pi_{oncotic} ➜ edema.

  • Key Electrolytes

    • Sodium: water balance & BP.
    • Hypernatremia: thirst, neuromuscular twitch.
    • Hyponatremia: hypotension, tachycardia, weakness.
    • Potassium (cardiac).
    • HyperK: weakness, confusion, peaked T waves.
    • HypoK: cramps, arrhythmias, ST depression / inverted T.
    • Calcium (muscle contraction; inverse with phosphate).
    • HyperCa: “stones, bones, groans, thrones” – kidney stones, bone pain, N/V, constipation; ↓phosphate.
    • HypoCa: numbness, tingling, tetany, ↑phosphate.

  • Acid–Base Disorders

    • Metabolic Acidosis: DKA, renal/liver failure (↓bicarb).
    • Respiratory Acidosis: hypoventilation (opioids, COPD, pneumonia).
    • Metabolic Alkalosis: severe vomiting, NG suction, excess antacid, some renal dz.
    • Respiratory Alkalosis: hyperventilation (panic attack, pain).