MFDS Oral Medicine 2

Question 1

A patient presents with vesicles and ulcers on the palate and gingiva, preceded by prodromal tingling. Culture confirms herpes simplex virus type 1 (HSV-1). This is the patient's third episode in six months. What is the most appropriate management?

Accepted Answer

Prescribe systemic aciclovir 200 mg five times daily for 5 days for each episode and consider prophylactic aciclovir 400 mg twice daily if recurrences continue

Answer

Recurrent intraoral herpes in immunocompetent patients is managed with systemic aciclovir 200 mg five times daily for 5 days, started within 48 hours of symptom onset. For frequent recurrences (6 or more per year), prophylactic aciclovir 400 mg twice daily can be considered for 6-12 months. Topical aciclovir is ineffective for intraoral lesions. Corticosteroids are contraindicated as they may worsen viral infections.

Question 2

Which oral condition is most characteristically associated with Crohn's disease?

Accepted Answer

Orofacial granulomatosis with lip swelling, mucosal cobblestoning, and linear ulceration in the buccal sulcus

Answer

Orofacial granulomatosis (OFG) is the oral condition most characteristically associated with Crohn's disease. Features include labial swelling (particularly the lower lip), mucosal cobblestoning, linear ulceration in the buccal sulcus, mucosal tags, and angular cheilitis. Biopsy shows non-caseating granulomas identical to those found in intestinal Crohn's disease. OFG may precede intestinal symptoms by years.

Question 3

A 28-year-old woman presents with a burning sensation of the tongue and mouth. Clinical examination reveals no abnormality. Blood tests are normal. She reports the symptoms are worst in the evening and absent on waking. What is the most likely diagnosis?

Accepted Answer

Burning mouth syndrome (BMS)

Answer

Burning mouth syndrome (BMS) is a chronic pain condition characterised by burning sensations in clinically normal oral mucosa. The classic pattern is symptom-free on waking with progressive worsening through the day, peaking in the evening. It predominantly affects postmenopausal women. The aetiology is likely neuropathic. Management includes reassurance, exclusion of local and systemic causes, and consideration of low-dose clonazepam (topical or systemic) or cognitive behavioural therapy.

Question 4

Pemphigus vulgaris and mucous membrane pemphigoid are both vesiculobullous conditions affecting the oral mucosa. What is the key histological difference between them?

Accepted Answer

Pemphigus vulgaris shows intraepithelial (suprabasal) blistering with acantholysis; mucous membrane pemphigoid shows subepithelial blistering with an intact basal layer

Answer

Pemphigus vulgaris involves autoantibodies against desmoglein 3 (and sometimes desmoglein 1), causing loss of cell-to-cell adhesion (acantholysis) in the suprabasal layer, resulting in intraepithelial blistering. Mucous membrane pemphigoid involves autoantibodies against components of the basement membrane zone (BP180, laminin-332), causing subepithelial blistering with an intact basal layer. Direct immunofluorescence shows intercellular IgG in pemphigus and linear basement membrane IgG/C3 in pemphigoid.

Question 5

A patient taking carbamazepine for epilepsy develops a widespread erythematous rash with targetoid lesions, oral ulceration, and conjunctivitis. What is the most likely diagnosis?

Accepted Answer

Erythema multiforme / Stevens-Johnson syndrome

Answer

Stevens-Johnson syndrome (SJS) is a severe mucocutaneous reaction most commonly triggered by drugs, particularly anticonvulsants (carbamazepine, phenytoin, lamotrigine), sulphonamides, and allopurinol. Features include targetoid skin lesions, oral ulceration with haemorrhagic crusting of the lips, conjunctivitis, and systemic illness. SJS involves less than 10% body surface area detachment; more extensive involvement (>30%) is classified as toxic epidermal necrolysis (TEN). Immediate drug withdrawal and supportive care are essential.

MFDS Part 1 Practice Test

MFDS Part 1 Practice Test

MFDS Oral Medicine 2