# Clinical Cases: Oncology Principles

## Case 1: Febrile Neutropenia

### Patient Presentation
**Demographics:** 52-year-old female

**Chief Complaint:** Fever and chills after chemotherapy

**History of Present Illness:**
The patient received her third cycle of R-CHOP chemotherapy for diffuse large B-cell lymphoma 10 days ago. She developed fever (38.8C), chills, and mild cough this morning. She denies any specific localizing symptoms but feels generally unwell.

**Past Medical History:**
- DLBCL diagnosed 6 weeks ago
- No other significant medical history

**Medications:**
- R-CHOP chemotherapy (last dose 10 days ago)
- Ondansetron PRN
- No prophylactic antibiotics

**Physical Examination:**
- Temperature: 38.9C
- Blood pressure: 98/62 mmHg
- Heart rate: 108 bpm
- General: Ill-appearing, mild rigors
- HEENT: Oral mucosa intact, no thrush
- Lungs: Clear to auscultation
- Abdomen: Soft, non-tender
- Skin: No rashes, no cellulitis, no perianal tenderness

### Workup and Results

**Laboratory Studies:**
- WBC: 800/mcL
- **ANC: 120/mcL** (severely neutropenic)
- Hemoglobin: 10.2 g/dL
- Platelets: 92,000/mcL
- Creatinine: 1.0 mg/dL
- Lactate: 2.8 mmol/L

**Blood Cultures:** Pending (2 sets drawn)

**Chest X-ray:** No infiltrates

**Urinalysis:** Normal

### Clinical Image

![Febrile Neutropenia](case_01_image.jpg)

*Diagram illustrating the approach to febrile neutropenia, emphasizing the critical importance of rapid broad-spectrum antibiotic administration within 60 minutes of presentation.*

### Diagnosis
**Febrile Neutropenia - High Risk**

Criteria met:
- Fever: Temperature ≥38.3C single reading
- Neutropenia: ANC <500/mcL (severely neutropenic at 120)
- High-risk features: ANC <100, anticipated prolonged neutropenia

### Discussion
This case illustrates febrile neutropenia management:

- **Definition**: The lecture defines febrile neutropenia as ANC <500/mcL (or expected to decrease to <500) with temperature ≥38.3C single reading or ≥38.0C sustained over 1 hour.

- **Oncologic Emergency**: The lecture emphasizes that febrile neutropenia is an oncologic emergency requiring immediate broad-spectrum IV antibiotics. Mortality increases with each hour of delay.

- **Absent Localizing Signs**: The lecture explains that neutropenic patients cannot mount a normal inflammatory response, so classic infection signs may be absent. Pneumonia may show no infiltrate initially; cellulitis may lack erythema.

- **Anti-pseudomonal Coverage**: The lecture specifies that empiric therapy must cover Pseudomonas aeruginosa, a common and dangerous pathogen in neutropenic patients.

### Treatment Plan
1. **Immediate Broad-Spectrum IV Antibiotics (within 60 minutes):**
   - Cefepime 2g IV every 8 hours
   - OR Piperacillin-tazobactam
   - OR Carbapenem if high-risk resistant organisms

2. **Additional Coverage Considerations:**
   - Add vancomycin if: mucositis, skin/catheter infection, hemodynamic instability, known MRSA
   - Antifungal coverage if fever persists >4-7 days

3. **Supportive Care:**
   - IV fluids for hypotension
   - G-CSF consideration (filgrastim) if high-risk/prolonged neutropenia expected

4. **Monitoring:**
   - Daily CBC
   - Blood cultures if recurrent fever
   - Look for occult infection source

5. **Duration:**
   - Continue until ANC >500 and afebrile for 48 hours
   - Minimum 7 days typically

### Teaching Points
1. Febrile neutropenia = ANC <500 + fever ≥38.3C (or ≥38.0C sustained)
2. Immediate IV antibiotics within 60 minutes - oncologic emergency
3. Must cover Pseudomonas (cefepime, pip-tazo, carbapenem)
4. Neutropenic patients may lack inflammatory signs despite severe infection
5. Add vancomycin for mucositis, skin infection, hemodynamic instability

---

## Case 2: Tumor Lysis Syndrome

### Patient Presentation
**Demographics:** 24-year-old male

**Chief Complaint:** Muscle weakness and palpitations 24 hours after starting chemotherapy

**History of Present Illness:**
The patient was diagnosed with Burkitt lymphoma with high tumor burden (large abdominal mass, elevated LDH). He started chemotherapy yesterday with R-CHOP. Today he reports progressive muscle weakness, cramping, and palpitations. He has had decreased urine output despite IV fluids.

**Past Medical History:**
- Burkitt lymphoma (newly diagnosed)
- Previously healthy

**Pre-chemotherapy Labs:**
- Creatinine: 1.0 mg/dL
- Potassium: 4.2 mEq/L
- Uric acid: 9.8 mg/dL
- LDH: 2,450 U/L

### Workup and Results

**Current Laboratory Studies:**
- Creatinine: 3.2 mg/dL (was 1.0)
- **Potassium: 7.1 mEq/L** (severely elevated)
- **Phosphorus: 8.4 mg/dL** (elevated)
- **Calcium: 6.8 mg/dL** (low)
- **Uric acid: 14.2 mg/dL** (elevated)
- LDH: 4,200 U/L

**ECG:**
- Peaked T waves
- Widened QRS

**Urine Output:**
- 0.3 mL/kg/hour (oliguria)

### Clinical Image

![Tumor Lysis Syndrome](case_01_image.jpg)

*Diagram illustrating tumor lysis syndrome pathophysiology: rapid cell death releases intracellular contents (potassium, phosphate, nucleic acids converted to uric acid) leading to hyperkalemia, hyperphosphatemia, hypocalcemia, hyperuricemia, and acute kidney injury.*

### Diagnosis
**Tumor Lysis Syndrome (Laboratory and Clinical)**

Cairo-Bishop Criteria for Laboratory TLS (≥2 of the following within 3 days before or 7 days after chemotherapy):
- Uric acid ≥8 mg/dL or 25% increase ✓
- Potassium ≥6 mEq/L or 25% increase ✓
- Phosphorus ≥4.5 mg/dL or 25% increase ✓
- Calcium ≤7 mg/dL or 25% decrease ✓

Clinical TLS: Laboratory TLS + AKI, seizures, arrhythmia, or death

### Discussion
This case illustrates tumor lysis syndrome:

- **Mechanism**: The lecture describes TLS as occurring when rapid tumor cell death releases intracellular contents. Potassium and phosphate are released directly; nucleic acids are metabolized to uric acid.

- **High-Risk Tumors**: The lecture identifies Burkitt lymphoma, ALL, and rapidly proliferating tumors with high tumor burden as highest risk. High LDH reflects rapid cell turnover.

- **Hypocalcemia Mechanism**: The lecture explains that hypocalcemia results from calcium phosphate precipitation as phosphorus rises dramatically.

- **Uric Acid Nephropathy**: The lecture describes how uric acid crystals precipitate in renal tubules, causing acute kidney injury. Maintaining high urine output is critical for prevention.

### Treatment Plan
1. **Emergent Hyperkalemia Management:**
   - IV calcium gluconate (cardiac protection)
   - IV insulin + glucose (shift potassium)
   - Sodium bicarbonate if acidotic
   - Kayexalate or patiromer
   - Emergent hemodialysis if refractory

2. **Rasburicase (Recombinant Uricase):**
   - Rapidly converts uric acid to allantoin
   - Contraindicated in G6PD deficiency

3. **Aggressive IV Hydration:**
   - Target urine output 80-100 mL/m2/hour
   - Monitor for fluid overload

4. **Phosphate Management:**
   - Phosphate binders
   - Avoid calcium-containing binders if hypercalcemic

5. **Dialysis:**
   - If refractory hyperkalemia, severe AKI, or fluid overload

6. **Prevention for Future Cycles:**
   - Pre-hydration
   - Allopurinol or rasburicase prophylaxis
   - Monitor labs every 6-8 hours during high-risk period

### Teaching Points
1. TLS: Hyperuricemia, hyperkalemia, hyperphosphatemia, hypocalcemia
2. High-risk: Burkitt, ALL, high tumor burden, high LDH
3. Prevention: Aggressive hydration + allopurinol/rasburicase
4. Rasburicase contraindicated in G6PD deficiency
5. Dialysis for refractory hyperkalemia or severe AKI

---

## Case 3: Malignant Spinal Cord Compression

### Patient Presentation
**Demographics:** 65-year-old female

**Chief Complaint:** Progressive back pain with leg weakness

**History of Present Illness:**
The patient has metastatic breast cancer with known bone metastases. She developed new mid-back pain 2 weeks ago, initially attributed to muscle strain. The pain has progressively worsened and is now severe, worse at night, and radiates around her chest "like a band." Over the past 3 days, she has developed progressive leg weakness and difficulty walking. Today she noticed she cannot feel when she needs to urinate.

**Past Medical History:**
- Metastatic breast cancer (ER+, HER2-)
- Bone metastases (spine, pelvis)
- On hormonal therapy

**Physical Examination:**
- Back: Point tenderness at T8
- Motor: Bilateral lower extremity weakness (3/5)
- Sensory: Sensory level at T10 (decreased sensation below)
- Reflexes: Hyperreflexia in lower extremities, upgoing plantar responses
- Bladder: Palpable bladder (urinary retention)

### Workup and Results

**MRI Spine (Emergent):**
- Epidural tumor at T8 with severe spinal cord compression
- Near-complete obliteration of thecal sac
- Cord signal changes (edema)

**Labs:**
- CBC: Normal
- Calcium: 10.8 mg/dL (normal)

### Clinical Image

![Spinal Cord Compression MRI](case_01_image.jpg)

*MRI demonstrating malignant spinal cord compression from metastatic tumor causing epidural mass effect with compression of the spinal cord (arrow) and signal changes indicating cord edema.*

### Diagnosis
**Malignant Spinal Cord Compression - Oncologic Emergency**

Clinical features:
- Progressive back pain (worse at night, positional)
- Neurological deficits (weakness, sensory level)
- Bowel/bladder dysfunction (late sign)
- Known malignancy with bone metastases

### Discussion
This case illustrates spinal cord compression:

- **Warning Signs**: The lecture emphasizes that back pain with neurologic symptoms in a cancer patient should prompt urgent evaluation. Pain worse at night or with recumbency is a red flag.

- **Presenting Symptom**: The lecture notes that back pain is the most common presenting symptom, often preceding neurological deficits by weeks. The pain is often described as band-like at the level of compression.

- **Bowel/Bladder Dysfunction**: The lecture identifies bowel/bladder dysfunction as a late finding indicating more severe compression. Urinary retention is more common than incontinence initially.

- **Prognosis**: The lecture states that ambulatory status at diagnosis is the most important predictor of outcome. Patients who are walking when treated usually remain ambulatory; those who are paraplegic rarely recover.

### Treatment Plan
1. **High-Dose Steroids (Immediate):**
   - Dexamethasone 10 mg IV bolus
   - Then 4-16 mg IV every 6 hours
   - Reduces vasogenic edema

2. **Urgent Imaging:**
   - MRI of entire spine (other levels may be involved)
   - CT if MRI contraindicated

3. **Definitive Treatment (within 24-48 hours):**
   - Surgical decompression if:
     - Single level, spinal instability, unknown primary, rapidly progressive
   - Radiation therapy:
     - For radiosensitive tumors (lymphoma, myeloma, breast, prostate)
     - When surgery not feasible

4. **Supportive Care:**
   - Foley catheter for retention
   - DVT prophylaxis (immobility)
   - Pain management
   - Bowel regimen (opioids + immobility)

5. **Oncology/Spine Surgery/Radiation Oncology:**
   - Multidisciplinary urgent consultation

### Teaching Points
1. Back pain in cancer patient = spinal cord compression until proven otherwise
2. High-dose steroids immediately upon suspicion
3. MRI entire spine (25% have multiple levels)
4. Ambulatory status at diagnosis predicts outcome
5. Bowel/bladder dysfunction is a late sign - don't wait for it

---

## Image Reference

For visual reference of oncology emergency concepts, see:
- Radiopaedia: [Spinal cord compression](https://radiopaedia.org/articles/spinal-cord-compression) - MRI findings
- Wikipedia: [Tumor lysis syndrome](https://en.wikipedia.org/wiki/Tumor_lysis_syndrome) - Pathophysiology
- Radiopaedia: [Oncologic emergencies](https://radiopaedia.org/articles/oncological-emergencies) - Overview

---

## Learning Points

1. **Febrile Neutropenia**: ANC <500 + fever = immediate broad-spectrum antibiotics within 60 minutes

2. **TLS Electrolytes**: High K, high phos, high uric acid, LOW calcium

3. **TLS Prevention**: Aggressive hydration + allopurinol/rasburicase in high-risk patients

4. **Spinal Cord Compression**: High-dose steroids immediately; MRI entire spine

5. **Prognostic Factor**: Ambulatory status at diagnosis predicts cord compression outcome