ONC 10: Muscostitis & Diarrhea

🌸 1) Drugs that Cause Mucositis & Diarrhea + Pathophysiology

⭐ Oral Mucositis — What causes it?

According to the risk factors chart on page 8

:

Chemotherapy most commonly associated:

• 5-FU (bolus > infusion)

• Doxorubicin

• High-dose melphalan

• mTOR inhibitors → everolimus, temsirolimus

• Targeted agents → sunitinib, sorafenib, afatinib

• Stem cell transplant conditioning regimens

• Radiation to head/neck

⭐ Pathophysiology

On page 7, the diagram shows the FOUR-PHASE injury cycle:

1. Initiation (0–2 days) — DNA damage, ROS

2. Message generation (2–3 days) — NF-κB activation, cytokines

3. Ulceration (10–15 days) — painful lesions, bacteria invade

4. Healing (15–21 days) — epithelial regeneration

That’s why mucositis starts after week 1 and lasts 7–14 days (page 5)

.

🌸 Chemotherapy-Induced Diarrhea — What causes it?

On page 22

:

Drugs most commonly associated:

• 5-FU

• Capecitabine

• Irinotecan (IMPORTANT!!! two types of diarrhea)

• TKIs → afatinib, sorafenib, sunitinib

• Checkpoint inhibitors → ipilimumab, nivolumab

• Radiation to pelvis/abdomen

⭐ Pathophysiology (page 18)

• Acute destruction of intestinal mucosa

• Loss of villi → ↓ absorption

• ↑ secretion of fluids/electrolytes

• Bacterial translocation → sepsis risk

• Can range from mild → necrotizing enterocolitis

🌸 2) How They Present

⭐ Mucositis Presentation (page 5)

• Asymptomatic erythema

• White desquamating patches

• Painful pseudomembranous ulcers

• Dysphagia, odynophagia, poor PO intake

⭐ Diarrhea Presentation (page 18)

• ↑ stool frequency (> baseline)

• Loose/liquid stools

• Abdominal cramping, gas

• Risk of dehydration

• Red flags → fever, neutropenia, bloody stool

🌸 3) CTCAE Grading (EXAMINABLE)

⭐ Oral Mucositis (page 9)

Important exam note:

• Grade 2–3 OR inability to take adequate fluids → see provider within 24h

• Grade 4 OR pain + blisters + fever ≥ 38°C → IMMEDIATE medical attention

⭐ Diarrhea (page 19)

Exam-important flags:

• Grade 1 <24h → outpatient support

• Grade 1 >24h OR Grade 2 → see provider within 24h

• Grade 3–4 OR fever, neutropenia, bloody stool → IMMEDIATE ER

🌸 4) Goals of Therapy

⭐ Mucositis Goals (page 10)

1. Prevent mucositis

2. Reduce pain & dysphagia

3. Reduce complications (infection, FN, dehydration)

4. Maintain oral intake + QOL

5. Minimize risk factors (HSV!)

6. Avoid oral triggers (acidic, spicy foods)

7. Minimize ADRs

⭐ Diarrhea Goals (page 20)

1. Prevent diarrhea-related death

2. Prevent dehydration, AKI, malabsorption, sepsis

3. Reduce stool frequency/severity

4. Maintain ADLs

5. Minimize ADRs

🌸 5) Therapeutic Alternatives

⭐ Mucositis — Treatment (pages 13–15)

Mixed medication mouthwashes (Magic Mouthwash)
You MUST know ingredients + purpose:

BC Cancer Magic Mouthwash contains:

• Diphenhydramine → anti-inflammatory & anesthetic

• Hydrocortisone → anti-inflammatory

• Nystatin → antifungal (needed because steroid ↑ thrush risk)

KEY EXAM LINE (page 13):

⭐ Diarrhea — Treatment (pages 26–30)

🔥 Irinotecan-induced diarrhea (VERY EXAMINABLE)

1. Early onset (<24h)

• Due to cholinergic excess

• Treat with atropine 0.3–0.6 mg IV/SC

2. Delayed onset (>24h)

• Treat with high-dose loperamide:

  • 4 mg STAT, then

  • 2 mg q2h until diarrhea-free x 12h

  • Max 24 mg/day (BC Cancer rule)

Octreotide if refractory.

🌸 6) Non-Drug Measures

⭐ Mucositis Prevention (pages 11–12)

• Soft toothbrush, gentle flossing

• Salt or salt/baking soda mouth rinses

• Maintain hydration

• Avoid alcohol/chlorhexidine/peroxide-based mouthwashes

• Oral cryotherapy (ice chips) for 5-FU bolus or high-dose melphalan

• Manage dental issues before starting chemo

⭐ Diarrhea Non-Drug Measures (page 33)

• 10–12 cups fluid/day

• Small, frequent meals

• Soluble fiber (oats, bananas)

• Avoid insoluble fiber, spicy food, dairy, alcohol, caffeine

• Stop other diarrhea-causing meds if possible

🌸 7) Monitoring Plan

⭐ Mucositis Monitoring (page 16)

Efficacy:

• Pain, ability to chew/swallow

• Oral intake

• Ulcer healing

Safety:

• Burning/stinging from mouthwash

• Thrush (esp. if steroid in mouthwash)

⭐ Diarrhea Monitoring

• Stool frequency & consistency

• Hydration status

• Weight

• Electrolytes

• Fever (≥38°C → ER)

• Symptoms of neutropenia

🌸 BESTIE SUMMARY TABLE FOR EXAM