Oral pain during head and neck radiotherapy

Correct answer: A. Mucositis

• A. CORRECT. Mucositis is the most common and most debilitating oral complication of chemotherapy. Rapidly dividing basal epithelial cells of the oral mucosa are among the first non-tumour tissues affected, and the resulting ulceration typically appears within one to two weeks, peaks around the end of the second week, and impairs eating, speaking and drug tolerance.
• B. Trismus follows radiation fibrosis of the muscles of mastication and the TMJ capsule, and it develops over months.
• C. Xerostomia is characteristic of RADIOTHERAPY involving the salivary glands. Chemotherapy can reduce salivary flow, but mucositis is the dominant chemotherapy-related oral problem.
• D. Osteoradionecrosis is a complication of RADIOTHERAPY to the jaws, not of chemotherapy, and it appears months to years later — not during treatment.

Correct answer: B. Viscous lidocaine

• A. Nystatin treats candidiasis. There are no removable white plaques and no other features of candidal infection — though candidiasis is a common SUPERIMPOSED problem in this population and should be watched for.
• B. CORRECT. The problem is generalised mucosal pain from radiation and chemotherapy mucositis. Viscous lidocaine 2% provides topical anaesthesia across the whole affected surface, letting the patient eat and maintain nutrition — which matters enormously during cancer treatment. It is often compounded into a 'magic mouthwash' with diphenhydramine and an antacid coating agent.
• C. Alcohol-containing chlorhexidine stings intensely on ulcerated mucosa and has no demonstrated benefit in preventing or treating mucositis. An alcohol-free formulation may be used for plaque control, but not for this pain.
• D. There is no evidence of bacterial infection here. Antibiotics do not treat mucositis and expose the patient to superinfection and Clostridioides difficile risk.

Note: Warn the patient about numb mucosa: no hot food or drink while anaesthetised, and take care not to bite the tongue or cheek. Round out the regimen with bland saline or sodium bicarbonate rinses, meticulous atraumatic hygiene, and daily neutral sodium fluoride to counter the radiation caries that follows the xerostomia.

Correct answer: C. Osteoradionecrosis

• A. Radiotherapy does not produce a bleeding tendency. Concurrent chemotherapy may cause thrombocytopenia, but that resolves after treatment ends.
• B. Local anaesthesia works normally in irradiated tissue.
• C. CORRECT. Irradiated bone is hypocellular, hypovascular and hypoxic. Surgical trauma in that field can precipitate osteoradionecrosis — non-healing exposed necrotic bone which is extremely difficult to treat. The risk is LIFELONG and rises with radiation dose, particularly above 60 Gy, and is greatest in the posterior mandible.
• D. Mucositis resolves within weeks of finishing radiotherapy and does not recur in response to surgery.

Note: This is why the extraction decision belongs BEFORE radiotherapy: remove any tooth of doubtful prognosis at least 2–3 weeks before treatment starts, so the socket can heal in non-irradiated bone. Afterwards, exhaust every restorative and endodontic option before considering extraction.