# Clinical Cases: Hemodynamic Disorders

## Case 1: Pulmonary Embolism - Thromboembolism

### Patient Demographics
- **Age:** 52 years old
- **Sex:** Female
- **Occupation:** Accountant (sedentary work)

### Chief Complaint
"Sudden shortness of breath and sharp chest pain that started this morning"

### History of Present Illness
A 52-year-old woman presents to the emergency department with sudden-onset dyspnea and right-sided pleuritic chest pain that began 3 hours ago while she was at work. She describes the pain as sharp, worsening with deep inspiration, and rates it 7/10. She also noticed her heart racing and felt lightheaded. She returned from a 12-hour flight from Australia 5 days ago and has been relatively sedentary since due to jet lag. She takes oral contraceptive pills for menorrhagia. Her BMI is 32. She denies hemoptysis, leg pain, or swelling. Family history is notable for a sister who had a blood clot during pregnancy.

### Physical Examination
- **Vital Signs:** BP 100/70 mmHg, HR 118 bpm, RR 28/min, Temp 37.4°C (99.3°F), SpO2 88% on room air
- **General:** Anxious-appearing woman in moderate respiratory distress
- **Cardiovascular:** Tachycardic, regular rhythm, loud P2, no murmurs, JVP elevated
- **Lungs:** Clear to auscultation bilaterally (no infiltrates)
- **Extremities:** Right calf mildly swollen (2 cm difference), positive Homans sign (calf pain with dorsiflexion)

### Diagnostic Workup

**Laboratory Studies:**
| Test | Result | Reference Range |
|------|--------|-----------------|
| D-dimer | 4,850 ng/mL | <500 ng/mL |
| Troponin I | 0.18 ng/mL | <0.04 ng/mL |
| BNP | 380 pg/mL | <100 pg/mL |
| ABG (room air) | pH 7.48, pCO2 28, pO2 58 | pH 7.35-7.45, pCO2 35-45 |

**Imaging:**
- **CT Pulmonary Angiogram:** Large saddle embolus at main pulmonary artery bifurcation with extension into bilateral pulmonary arteries. Right ventricle dilated with RV/LV ratio >1.0 (right heart strain)
- **Doppler Ultrasound of Legs:** Non-compressible right popliteal and femoral veins consistent with deep vein thrombosis

**ECG:** Sinus tachycardia, S1Q3T3 pattern, right axis deviation

**Echocardiogram:** Dilated right ventricle with reduced RV function, interventricular septum bowing into left ventricle, McConnell's sign (RV free wall hypokinesis with apical sparing)

### Pathology Correlation
This case demonstrates **thromboembolism** and Virchow's triad:

1. **Virchow's Triad (Risk Factors Present):**
   - **Stasis:** Long-haul flight, sedentary lifestyle
   - **Endothelial injury:** Oral contraceptives, possible inherited thrombophilia
   - **Hypercoagulability:** Oral contraceptives, family history suggesting inherited condition

2. **Deep Vein Thrombosis Formation:**
   - Thrombus originated in deep leg veins
   - Venous thrombi are "red thrombi" (rich in RBCs, fibrin)
   - Propagated proximally in lower extremity veins

3. **Embolization:**
   - Thrombus dislodged and traveled through IVC to right heart
   - Lodged at pulmonary artery bifurcation (saddle embolus)
   - Mechanical obstruction of pulmonary blood flow

4. **Pathophysiology of Symptoms:**
   - Hypoxemia: V/Q mismatch from non-perfused lung segments
   - Right heart strain: Increased pulmonary vascular resistance
   - Elevated D-dimer: Fibrinolysis of thrombus
   - Elevated troponin/BNP: RV myocardial strain

### Clinical Image
![Saddle Pulmonary Embolism - CT Angiogram](case_01_image.jpg)

*CT pulmonary angiogram demonstrating a saddle pulmonary embolism. The thrombus (dark filling defect) straddles the bifurcation of the main pulmonary artery and extends into both right and left pulmonary arteries. This pattern of massive PE causes significant hemodynamic compromise due to obstruction of pulmonary blood flow.*

**Image Source:** Wikimedia Commons - "Saddle Pulmonary Embolism"
**License:** CC BY-SA 3.0
**URL:** https://commons.wikimedia.org/wiki/File:Saddle_pulmonary_embolism.png

### Diagnosis
**Massive Pulmonary Embolism** with hemodynamic compromise (intermediate-high risk) secondary to proximal DVT

### Treatment
1. High-flow oxygen therapy
2. IV heparin anticoagulation (unfractionated heparin given hemodynamic instability)
3. ICU admission for monitoring
4. Consider catheter-directed thrombolysis or systemic thrombolysis if deterioration
5. Transition to oral anticoagulation (DOAC) once stable
6. Minimum 3 months anticoagulation; consider extended therapy
7. Thrombophilia workup after acute treatment
8. IVC filter only if anticoagulation contraindicated

### Teaching Points
1. **Virchow's triad** (stasis, endothelial injury, hypercoagulability) describes conditions predisposing to thrombosis
2. **Venous thrombi** are red, RBC-rich, and arise in areas of stasis
3. **95% of pulmonary emboli** originate from deep leg veins
4. **D-dimer** has high sensitivity but low specificity; useful to rule out PE if low
5. **Right ventricular strain** (elevated troponin, dilated RV) indicates intermediate-high risk PE
6. **Saddle embolus** straddles the main pulmonary artery bifurcation and indicates massive PE
7. Oral contraceptives increase thrombotic risk 3-4 fold, especially in combination with other risk factors

---

## Case 2: Congestive Heart Failure - Chronic Passive Congestion

### Patient Demographics
- **Age:** 71 years old
- **Sex:** Male
- **Occupation:** Retired teacher

### Chief Complaint
"My legs are swelling and I can't breathe lying flat"

### History of Present Illness
A 71-year-old man with a history of coronary artery disease, prior myocardial infarction (5 years ago), hypertension, and type 2 diabetes presents with progressive bilateral lower extremity swelling and dyspnea over the past 3 weeks. He now sleeps propped up on 3 pillows (orthopnea) and wakes at night gasping for air (paroxysmal nocturnal dyspnea). He has gained 12 pounds over the past month despite poor appetite. He reports his abdomen feels distended and he feels full after eating small amounts. He has been less compliant with his medications and dietary sodium restriction recently due to financial difficulties.

### Physical Examination
- **Vital Signs:** BP 152/88 mmHg, HR 92 bpm irregular, RR 22/min, SpO2 91% on room air
- **General:** Elderly male in mild respiratory distress, sitting upright
- **HEENT:** JVP elevated to angle of jaw (>15 cm H2O)
- **Cardiovascular:** Irregularly irregular rhythm (atrial fibrillation), S3 gallop, laterally displaced PMI, 2/6 holosystolic murmur at apex
- **Lungs:** Bibasilar crackles to mid-lung fields
- **Abdomen:** Distended, positive fluid wave, tender hepatomegaly (liver edge 4 cm below costal margin), positive hepatojugular reflux
- **Extremities:** 3+ pitting edema to mid-thigh bilaterally

### Diagnostic Workup

**Laboratory Studies:**
| Test | Result | Reference Range |
|------|--------|-----------------|
| BNP | 1,850 pg/mL | <100 pg/mL |
| Creatinine | 1.8 mg/dL | 0.7-1.3 mg/dL |
| Sodium | 132 mEq/L | 136-145 mEq/L |
| AST | 68 U/L | 10-40 U/L |
| ALT | 52 U/L | 7-56 U/L |
| Total bilirubin | 2.4 mg/dL | 0.1-1.2 mg/dL |
| Albumin | 3.0 g/dL | 3.5-5.5 g/dL |

**Imaging:**
- **Chest X-ray:** Cardiomegaly, bilateral pleural effusions (larger on right), pulmonary vascular congestion, Kerley B lines
- **Echocardiogram:** Severely reduced LV ejection fraction (25%), dilated LV and LA, severe mitral regurgitation, elevated PA pressures (55 mmHg)

**Liver Biopsy (performed for elevated LFTs):**
- Centrilobular congestion with sinusoidal dilation
- Centrilobular hepatocyte atrophy
- Minimal fibrosis (early cardiac cirrhosis)
- Pattern consistent with chronic passive congestion

### Pathology Correlation
This case demonstrates **chronic passive congestion** from heart failure:

1. **Pathophysiology of Congestion:**
   - Left heart failure → elevated pulmonary venous pressure → pulmonary congestion
   - Right heart failure → elevated central venous pressure → hepatic and peripheral congestion
   - Congestion is passive (impaired venous outflow) vs hyperemia (active arterial dilation)

2. **Pulmonary Congestion (Left Heart Failure):**
   - Elevated left atrial pressure transmitted to pulmonary veins
   - Fluid transudation into alveoli (pulmonary edema)
   - Crackles on auscultation
   - "Heart failure cells" - hemosiderin-laden macrophages (chronic congestion)

3. **Hepatic Congestion (Right Heart Failure):**
   - "Nutmeg liver" - alternating red (congested centrilobular) and pale (periportal) zones
   - Centrilobular hepatocyte necrosis from hypoxia
   - Elevated AST/ALT and bilirubin
   - Progressive fibrosis can lead to cardiac cirrhosis

4. **Peripheral Edema:**
   - Elevated hydrostatic pressure from venous congestion
   - Decreased oncotic pressure from hypoalbuminemia
   - Sodium and water retention from neurohormonal activation
   - Dependent distribution (gravity-dependent)

### Clinical Image
![Nutmeg Liver - Chronic Passive Congestion](case_02_image.jpg)

*Cross-section of liver demonstrating the "nutmeg liver" pattern of chronic passive congestion. The alternating dark red areas (congested centrilobular zones) and lighter tan areas (relatively spared periportal zones) create a mottled appearance resembling a cut nutmeg. The centrilobular regions are most affected because they are farthest from the arterial blood supply and most susceptible to hypoxia.*

**Image Source:** Wikimedia Commons - "Chronic Passive Congestion of Liver"
**License:** CC BY-SA 3.0
**URL:** https://commons.wikimedia.org/wiki/File:Chronic_passive_congestion_of_liver_(2).jpg

### Diagnosis
**Acute on Chronic Systolic Heart Failure** (HFrEF) with biventricular failure
- New York Heart Association Class IV
- Stage D (advanced refractory)

### Treatment
1. IV furosemide for aggressive diuresis (goal net negative 2-3 L/day)
2. Sodium and fluid restriction
3. Daily weights and intake/output monitoring
4. Optimize guideline-directed medical therapy:
   - ACE inhibitor or ARB
   - Beta-blocker (when euvolemic)
   - Mineralocorticoid receptor antagonist
   - Consider SGLT2 inhibitor
5. Rate control for atrial fibrillation
6. Anticoagulation for atrial fibrillation
7. Consider cardiac resynchronization therapy (CRT) or ICD
8. Evaluate for advanced therapies (LVAD, transplant)

### Teaching Points
1. **Congestion** is passive blood accumulation from impaired venous outflow (vs. hyperemia which is active)
2. **"Nutmeg liver"** results from centrilobular congestion in right heart failure
3. **Centrilobular hepatocytes** are most vulnerable because they are farthest from arterial supply
4. **Transudative edema** results from increased hydrostatic pressure and/or decreased oncotic pressure
5. **BNP** is released from stretched ventricular myocytes and correlates with filling pressures
6. **Heart failure cells** (hemosiderin-laden alveolar macrophages) indicate chronic pulmonary congestion
7. The difference between **left and right heart failure** explains the different clinical presentations

---

## Case 3: Disseminated Intravascular Coagulation (DIC)

### Patient Demographics
- **Age:** 45 years old
- **Sex:** Female
- **Occupation:** Elementary school teacher

### Chief Complaint
"High fever, confusion, and bleeding from IV sites"

### History of Present Illness
A 45-year-old woman was admitted 2 days ago for community-acquired pneumonia. Despite initial improvement on antibiotics, she acutely deteriorated with spiking fevers to 40°C, altered mental status, and hypotension. The nursing staff notes she is bleeding from IV sites and has developed bruising. She has petechiae on her chest and arms. Her urine output has dropped significantly over the past 6 hours. She has no prior history of bleeding disorders.

### Physical Examination
- **Vital Signs:** BP 78/42 mmHg (on vasopressors), HR 128 bpm, RR 32/min, Temp 39.8°C (103.6°F), SpO2 89% on 100% FiO2
- **General:** Critically ill, intubated, sedated
- **Skin:** Diffuse petechiae, ecchymoses at IV sites and blood pressure cuff site, acral cyanosis of fingers and toes
- **Cardiovascular:** Tachycardic, weak peripheral pulses
- **Lungs:** Coarse breath sounds bilaterally, requiring mechanical ventilation
- **Abdomen:** Distended, decreased bowel sounds
- **Extremities:** Cool, mottled, cyanotic digits bilaterally

### Diagnostic Workup

**Laboratory Studies:**
| Test | Result | Reference Range |
|------|--------|-----------------|
| WBC | 2,100/μL | 4,500-11,000/μL |
| Hemoglobin | 8.2 g/dL | 12-16 g/dL |
| Platelets | 28,000/μL | 150,000-400,000/μL |
| PT | 28 seconds | 11-15 seconds |
| INR | 2.6 | 0.8-1.2 |
| PTT | 68 seconds | 25-35 seconds |
| Fibrinogen | 85 mg/dL | 200-400 mg/dL |
| D-dimer | >20,000 ng/mL | <500 ng/mL |
| Lactate | 8.2 mmol/L | 0.5-2.0 mmol/L |
| Creatinine | 3.4 mg/dL | 0.7-1.3 mg/dL |

**Peripheral Blood Smear:**
- Schistocytes (fragmented RBCs)
- Decreased platelets
- Left shift with toxic granulations in neutrophils

**Imaging:**
- **Chest X-ray:** Bilateral diffuse infiltrates consistent with ARDS

**Microbiology:**
- Blood cultures: Gram-negative rods (later identified as Streptococcus pneumoniae)

### Pathology Correlation
This case demonstrates **Disseminated Intravascular Coagulation (DIC)**:

1. **Pathophysiology:**
   - Massive tissue factor release from sepsis triggers coagulation cascade
   - Widespread fibrin deposition in microvasculature
   - Consumption of platelets and clotting factors
   - Secondary fibrinolysis generates D-dimer
   - Paradox of simultaneous thrombosis AND bleeding

2. **Laboratory Findings:**
   - **Thrombocytopenia:** Platelets consumed in microthrombi
   - **Prolonged PT/PTT:** Clotting factors consumed
   - **Low fibrinogen:** Converted to fibrin and degraded
   - **Elevated D-dimer:** Indicates fibrinolysis of clots
   - **Schistocytes:** RBCs sheared by fibrin strands

3. **Clinical Manifestations:**
   - **Bleeding:** Petechiae, oozing from puncture sites (consumption of factors)
   - **Thrombosis:** Acral cyanosis, organ ischemia (microvascular occlusion)
   - **Organ failure:** Kidney, lung, liver damage from microthrombi

4. **Underlying Causes:**
   - Sepsis (most common) - endotoxin/tissue factor
   - Obstetric complications - amniotic fluid, placental abruption
   - Malignancy - procoagulant factors
   - Massive trauma - tissue factor release

### Clinical Image
![DIC - Peripheral Blood Smear with Schistocytes](case_03_image.jpg)

*Peripheral blood smear from a patient with DIC demonstrating schistocytes (fragmented red blood cells, arrows). These helmet-shaped and triangular RBC fragments result from mechanical shearing as red cells pass through fibrin strands deposited in the microvasculature. The presence of schistocytes indicates microangiopathic hemolytic anemia.*

**Image Source:** Wikimedia Commons - "Schistocytes"
**License:** CC BY-SA 4.0
**URL:** https://commons.wikimedia.org/wiki/File:Schistocytes_in_DIC.jpg

### Diagnosis
**Septic Shock with Disseminated Intravascular Coagulation** secondary to Streptococcus pneumoniae bacteremia

### Treatment
1. **Treat underlying cause:** Broad-spectrum antibiotics, source control
2. **Hemodynamic support:** IV fluids, vasopressors (norepinephrine)
3. **Component replacement:**
   - Platelet transfusion (keep >50,000 if bleeding)
   - Fresh frozen plasma (replace clotting factors)
   - Cryoprecipitate (replace fibrinogen, target >100 mg/dL)
   - Packed RBCs for anemia
4. **Respiratory support:** Mechanical ventilation for ARDS
5. **Renal support:** Continuous renal replacement therapy if needed
6. **Do NOT give anticoagulation** in acute bleeding DIC

### Teaching Points
1. **DIC is always secondary** to an underlying condition - treat the cause
2. The **paradox of DIC** is simultaneous thrombosis and bleeding
3. **Schistocytes** on blood smear indicate microangiopathic hemolysis
4. **D-dimer** is markedly elevated due to fibrinolysis
5. **Fibrinogen** drops as it is converted to fibrin and degraded
6. **Sepsis** is the most common cause of DIC in hospitalized patients
7. The **coagulation cascade** is triggered by tissue factor released during sepsis
8. **Multi-organ failure** results from widespread microvascular thrombosis