MJDF Human Disease 2

Question 1

A patient with haemophilia A requires extraction of a lower molar. What is haemophilia A and how should the extraction be managed?

Accepted Answer

Haemophilia A is an X-linked recessive deficiency of clotting Factor VIII; extraction requires pre-operative factor replacement to achieve adequate factor levels (ideally >50%), liaison with the haematology team, use of local haemostatic measures (tranexamic acid, suturing, oxidised cellulose), and post-operative monitoring

Answer

Haemophilia A is an X-linked recessive condition causing deficiency of clotting Factor VIII. Severity is classified by factor levels: severe (<1%), moderate (1-5%), and mild (5-40%). For dental extractions: liaise with the haemophilia centre, arrange factor VIII replacement to achieve levels >50% (for moderate/severe), consider desmopressin (DDAVP) for mild cases (stimulates Factor VIII release), use tranexamic acid mouthwash (5% solution, 10 mL four times daily for 7 days), ensure primary wound closure (sutures), pack socket with oxidised cellulose, and avoid NSAIDs (impair platelet function). Treatment should ideally be performed at a haemophilia centre.

Question 2

What is the pathophysiology of Type 1 diabetes mellitus and how does it differ from Type 2?

Accepted Answer

Type 1 is autoimmune destruction of pancreatic beta cells causing absolute insulin deficiency (requires insulin replacement); Type 2 involves insulin resistance and relative insulin deficiency (managed initially with lifestyle, then oral hypoglycaemics, and eventually insulin if needed)

Answer

Type 1 diabetes (5-10% of cases) results from autoimmune destruction of pancreatic islet beta cells, usually in childhood/young adulthood, causing absolute insulin deficiency requiring lifelong exogenous insulin. Patients are prone to diabetic ketoacidosis (DKA). Type 2 diabetes (90-95%) involves peripheral insulin resistance and progressive beta cell dysfunction, typically presenting in adults (increasingly in younger people), associated with obesity and physical inactivity. Management progresses from lifestyle modification to metformin, then combination oral agents (sulfonylureas, SGLT2 inhibitors, GLP-1 agonists), and eventually insulin when beta cell function declines.

Question 3

A patient taking warfarin presents with a supratherapeutic INR of 6.0 and spontaneous gingival bleeding. What is the appropriate immediate management?

Accepted Answer

Withhold warfarin, administer oral vitamin K (1-5 mg phytomenadione), apply local pressure to bleeding sites, and refer to the patient's anticoagulant clinic urgently; if bleeding is severe, refer to A&E for possible IV vitamin K and/or prothrombin complex concentrate

Answer

An INR of 6.0 is significantly supratherapeutic (most target ranges are 2.0-3.0 or 2.5-3.5) and carries a high risk of major haemorrhage. Management: withhold warfarin immediately, administer oral vitamin K (phytomenadione 1-5 mg — onset in 6-12 hours), apply local measures to control gingival bleeding (pressure, tranexamic acid mouthwash), and refer urgently to the anticoagulant clinic. If there is severe or life-threatening bleeding, emergency referral to A&E is needed for IV vitamin K (5-10 mg) and prothrombin complex concentrate (Beriplex/Octaplex) for immediate reversal. Recheck INR within 24 hours.

Question 4

What are the key features of an acute myocardial infarction and what should a dental team do if a patient develops symptoms during treatment?

Accepted Answer

Crushing central chest pain radiating to the left arm, jaw, or back, with sweating, nausea, and breathlessness; the dental team should stop treatment, call 999, administer aspirin 300 mg (chewed), GTN spray if available and not contraindicated, high-flow oxygen if SpO2 <94%, and be prepared to commence CPR if cardiac arrest occurs

Answer

Acute MI presents with severe crushing retrosternal chest pain (>15 minutes, not relieved by GTN), often radiating to the left arm, jaw, neck, or back, accompanied by sweating, nausea, dyspnoea, pallor, and anxiety. In the dental surgery: stop all dental treatment immediately, sit the patient upright, call 999, give aspirin 300 mg to chew (if not allergic — inhibits further platelet aggregation), administer GTN sublingual spray (two puffs) if systolic BP >90 mmHg, give oxygen only if SpO2 <94%, monitor vital signs, and be prepared for cardiac arrest (defibrillator available). Do NOT administer IM adrenaline (this is for anaphylaxis, not MI).

Question 5

What is the dental significance of a patient being HIV-positive and what oral manifestations may be seen?

Accepted Answer

HIV-positive patients may present with oral candidiasis, oral hairy leukoplakia, Kaposi's sarcoma, necrotising ulcerative gingivitis/periodontitis, linear gingival erythema, recurrent aphthous ulceration, and HPV-related lesions; these may be the first signs of HIV infection or indicate disease progression and falling CD4 count

Answer

Oral manifestations of HIV are common and may be the presenting feature of undiagnosed HIV infection. Key oral lesions include: pseudomembranous and erythematous candidiasis (most common, especially when CD4 <200), oral hairy leukoplakia (EBV-related, lateral tongue), Kaposi's sarcoma (HHV-8 related, violaceous patches/nodules on palate/gingiva), necrotising ulcerative gingivitis/periodontitis (rapid destruction), linear gingival erythema (band-like erythema along gingival margin), major aphthous ulceration, and HPV-associated papillomas/warts. HAART (highly active antiretroviral therapy) has significantly reduced the prevalence of these lesions. Standard infection control is sufficient for dental treatment — no additional precautions beyond universal precautions are needed.

MJDF Part 1 Practice Test

MJDF Part 1 Practice Test

MJDF Human Disease 2