Module 9 Comprehensive Exam Review Notes

Anemias – General Framework

• Definition
  • Condition in which total number or quality of circulating RBCs and/or Hb is insufficient to transport O2 to tissues
  • Hall-mark lab signals → ↓ Hb, ↓ Hct, often ↓ RBC count
• Global compensatory themes
  • Tissue hypoxia → fatigue + pallor
  • ↓ O2 delivery → tachycardia/↑ CO, dyspnea
  • Renal sensing of hypoxia → ↑ erythropoietin (EPO) → marrow stimulation

Universal Signs/Symptoms (high-yield test triggers)

• Fatigue & exercise intolerance
• Tachycardia/palpitations; possible systolic flow murmur
• Pallor / cyanotic-tinged mucosa ("low pallor")
• Lab red flags: \text{Hb}<12\;\text{g/dL (F)};\; <13\;\text{g/dL (M)}, \text{Hct}<36\%

1. Iron-Deficiency Anemia (IDA)

• Epidemiology → most common world-wide
• Key labs
  • ↓ Hb / Hct
  • ↓ ferritin (storage form; think "ferric")
  • ↓ serum Fe, ↑ TIBC
• Etiologies / scenarios
  • Inadequate intake (vegans, malnutrition, developing nations)
  • Chronic blood loss → GI ulcer, heavy menses, chronic NSAID use (occult GI bleed)
  • Pregnancy → fetal iron siphoning
• Prototype vignette
  • Fatigued female, heavy periods, takes daily ibuprofen → low ferritin, microcytosis

2. Sickle Cell Anemia

• Genetics → autosomal recessive (carriers asymptomatic; FHx may appear “clean”)
• Pathophys
  • HbS polymerizes when deoxygenated → RBCs become rigid, sickle-shaped → vaso-occlusion
• High-yield manifestations
  • Severe pain crisis (ischemia)
  • Dactylitis in kids, stroke, acute chest, splenic sequestration
• Precipitants → infection, dehydration, hypoxia, acidosis, stress

3. Aplastic Anemia

• Core defect → pancytopenia from bone-marrow failure
• Triggers → radiation, chemo, autoimmune, methotrexate, viral hepatitis
• Clinical clues
  • Anemia (fatigue)
  • Leukopenia → recurrent infections
  • Thrombocytopenia → bleeding, petechiae

4. Vitamin B12 (Pernicious) Anemia

• Fundamental sign → neuropathy! (numbness, tingling, ataxia, confusion, dementia)
• Etiology → autoimmune destruction of parietal cells → ↓ intrinsic factor → malabsorption despite adequate diet
• Labs → macrocytosis, hypersegmented neutrophils, ↓ serum B12, ↑ MMA
• Test pearl → any anemia + neuropathy ⇒ circle B12 deficiency

Blood Product Reactions & DIC

Acute Hemolytic Transfusion Reaction (AHTR)

• Cause → ABO incompatible units (e.g.
  giving type A blood to type B pt)
• Triad → flank pain, hypotension, dark urine (hemoglobinuria)
• Pathophys → complement-mediated intravascular hemolysis → free Hb → acute renal failure; risk of DIC

Febrile Non-Hemolytic Reaction

• Donor leukocyte cytokines → fever/chills; not life-threatening, no hypotension/hemoglobinuria

Disseminated Intravascular Coagulation

• Run-away coagulation consumes platelets & factors → simultaneous micro-clotting & bleeding

Polycythemia Vera (PV)

• “Opposite of anemia” – neoplastic over-production of all myeloid lines (↑ RBC, WBC, PLT)
• Blood becomes hyper-viscous → sluggish flow, thrombosis
• Classic clues
  • Aquagenic pruritus (itching after warm shower)
  • Ruddy (flushed) face, splenomegaly, headache, blurred vision
• Danger → DVT, stroke, MI

Thalassemias

• Genetic defective globin chain synthesis (α or β) → malformed RBCs
• Inheritance → autosomal recessive (need two alleles)
• Populations → Mediterranean, Middle-East, South-Asian
• Key findings
  • Microcytic anemia + jaundice, dark urine (hemolysis)
  • Bone deformities / frontal bossing (marrow hyper-activity)
  • Splenomegaly

von Willebrand Disease (vWD)

• Autosomal dominant platelet function defect → ↓ vWF → platelets "less sticky"
• Platelet COUNT normal; bleeding time ↑
• Symptoms → nosebleeds, heavy menses, prolonged bleeding after dental work
• Distinguish from hemophilia (A/B) (X-linked) by genetics & lab panel

Systemic Compensations for Hypotension / Blood Loss

1. Sympathetic Nervous System (SNS)

• Catecholamines (epi / norepi) → ↑ HR (tachycardia), ↑ contractility, systemic vasoconstriction → ↑ BP, ↑ CO

2. Antidiuretic Hormone (ADH)

• Posterior pituitary release → kidneys reabsorb H₂O → ↑ plasma volume

3. Renin–Angiotensin–Aldosterone System (RAAS)

• $\text{Renin}\rightarrow \text{AngI}\xrightarrow{ACE} \text{AngII}$
  • Ang II → potent vasoconstrictor
  • Ang II → ↑ aldosterone → Na⁺ reabsorption → H₂O follows → ↑ preload/volume

Hemostasis Cascade ("Please Don’t Die")

1. Vascular injury
2. Platelet adhesion/aggregation → temporary platelet plug
3. Local vasoconstriction
4. Coagulation cascade → fibrin mesh (stable clot)
5. Reticulocyte count rises within days → marrow pumping out new immature RBCs to replace losses

ANP & BNP – Natural Diuretics

• Released from over-stretched atria (ANP) or ventricles (BNP)
• Effects
  • Vasodilation
  • $\uparrow GFR$ → natriuresis + diuresis (Na⁺ & H₂O loss)
  • ↓ renin/AngII/aldosterone → ↓ preload & BP
• Clinical: BNP >500 pg/mL strongly suggests CHF

Atrial Fibrillation (AFib)

• "Irregularly irregular" rhythm; no P waves; atrial rate 300–350 bpm
• Ventricles pick random impulses → irregular pulses
• Risks → age, CAD, HF, post-cardiac surgery
• Major danger → embolic stroke (blood pools in quivering atria) → often anticoagulated

Core Hemodynamics

• Preload = ventricular stretch at end-diastole (↑ with fluids; ↓ with hemorrhage)
• Afterload = resistance LV must overcome (↑ with HTN, atherosclerosis)
• Contractility = intrinsic squeeze (measured by EF: $EF = \frac{SV}{EDV}\times100\%$)

Vascular Disorders

Peripheral Artery Disease (PAD)

• Same atherosclerotic mechanism as CAD
• Signature → intermittent claudication (leg pain w/ exertion, relieved by rest), ↓/absent distal pulses, cool pallid skin

Essential Hypertension

• “Silent killer” → long-term vessel & end-organ damage (CAD/MI, LVH, CKD, retinopathy, stroke)

Raynaud’s Phenomenon

• Paroxysmal arteriolar vasospasm → color sequence White → Blue → Red in fingers/toes, precipitated by cold/stress

Chronic Venous Insufficiency

• Damaged leg vein valves → pooling
• Manifestations → edema, stasis dermatitis (brown skin), venous ulcers, varicose veins, aching improved by elevation/compression

Ischemic Heart Spectrum

• Progression risk ladder → Stable < Unstable < NSTEMI < STEMI

Sudden Cardiac Death vs MI

• Cardiac arrest = electrical failure (VF/VT) → no pulse, treat w/ CPR + AED
• MI (NSTEMI/STEMI) = ischemic cell death; can secondarily precipitate arrest

Heart Failure Master Map

Left-Sided HF ("L for Lung")

• Causes → CAD/MI, HTN, valve disease
• Sx → pulmonary edema, crackles, orthopnea, PND, ↓ EF (systolic)

Right-Sided HF ("R for Rest of body")

• Causes → L-HF, COPD (cor pulmonale), pulmonic valve dz
• Sx → JVD, peripheral edema, ascites, hepatosplenomegaly, weight gain

Systolic vs Diastolic

• Systolic = weak pump (floppy) → ↓ EF (<40 %)
• Diastolic = stiff ventricle (hypertrophied) → normal/high EF but ↓ filling volume

Congenital Shunts

• Remember Left (oxygenated) → Right (deoxygenated) yields acyanotic
  • ASD, VSD, Patent Ductus Arteriosus (PDA)
• Right → Left yields cyanotic (blue) because deoxygenated blood enters systemic flow
  • Tetralogy of Fallot (TOF)

Tetralogy of Fallot – "PROVe"

1. Pulmonary stenosis
2. Right ventricular hypertrophy
3. Overriding aorta (straddles both ventricles)
4. Ventricular septal defect

• "Tet spells" – cyanosis during crying/feeding; child squats to ↑ SVR ↓ shunt

Valve & Endocardial Disorders

Rheumatic Heart Disease (post-GAS)

• Autoimmune (molecular mimicry) after strep pharyngitis/scarlet fever
• Antibodies attack valves (esp. mitral) → stenosis / regurg, murmurs, vegetations

Infective Endocarditis

• Bacterial colonization of valves (often tricuspid in IV-drug users)
• Sx → fever, night sweats, new murmur, splinter hemorrhages, Osler nodes (painful), Janeway lesions (painless), Roth spots
• Embolic phenomena → stroke, renal infarct, PE

Myocardial & Pericardial Inflammations

• Myocarditis – viral (Coxsackie B, COVID-19), arrhythmias, sudden death in young adults
• Pericarditis – sharp pleuritic pain, pericardial friction rub, relieved by leaning forward; may progress to …
  • Pericardial effusion – fluid accumulation
  • Cardiac tamponade – emergency; Beck’s triad: muffled heart sounds, JVD, hypotension (plus pulsus paradoxus)

Valvular Mechanics – Mitral Focus

• Quick test cue: "Obstruction DURING diastole?" ⇒ Mitral stenosis. "Back-flow DURING systole?" ⇒ Mitral regurg.

Rapid-Fire Clinical Case Triggers

• Fatigue + daily NSAIDs + ↓ ferritin ⇒ IDA
• 10-y/o severe abdominal pain + known sickle trait ⇒ vaso-occlusive crisis
• Anemia + neuropathy + vegan diet ⇒ B12 deficiency
• Blood transfusion → flank pain + dark urine + hypotension ⇒ Acute hemolytic reaction
• Mild fever during transfusion, vitals stable ⇒ Febrile non-hemolytic
• Flushed face; itching post-hot shower ⇒ Polycythemia Vera
• Finger blanch → blue → red in cold office ⇒ Raynaud
• Chest pain at rest, no troponin, ST depression ⇒ Unstable angina
• Crushing chest pain, ST elevation in II, III, aVF ⇒ STEMI (inferior wall)
• A‐fib on ECG, HR irregular 130, no P waves → start anticoag
• Post-strep teen with new murmur & arthritis ⇒ Rheumatic carditis
• IV drug user, fever, tricuspid murmur, Osler nodes ⇒ Infective endocarditis
• Trauma patient, distant heart sounds, BP 80/50, distended neck veins ⇒ Cardiac tamponade