MFDS Human Disease 1 — Questions and Answers
Question 1: Which haematological finding is pathognomonic of pernicious anaemia?
- Microcytic hypochromic red cells
- Hypersegmented neutrophils and macrocytosis (Correct answer)
- Target cells
- Spherocytes
Correct answer: Hypersegmented neutrophils and macrocytosis
Pernicious anaemia (B12 deficiency) causes megaloblastic changes including hypersegmented neutrophils (>5 lobes) and macro-ovalocytes on the blood film.
Question 2: The oral manifestation of poorly controlled type 1 diabetes mellitus includes:
- Increased caries resistance
- Accelerated periodontitis and xerostomia (Correct answer)
- Gingival hyperplasia
- Hyposalivation alone
Correct answer: Accelerated periodontitis and xerostomia
Uncontrolled diabetes is associated with accelerated periodontal disease due to impaired neutrophil function, increased susceptibility to xerostomia and altered wound healing.
Question 3: A patient on long-term corticosteroids is at risk of which complication during dental surgery?
- Malignant hyperthermia
- Adrenal crisis due to adrenal suppression (Correct answer)
- Prolonged bleeding
- Anaphylaxis to LA
Correct answer: Adrenal crisis due to adrenal suppression
Long-term corticosteroids suppress the hypothalamic-pituitary-adrenal axis; patients cannot mount a normal cortisol response to surgical stress, risking adrenal crisis.
Question 4: Hereditary haemorrhagic telangiectasia (Osler-Weber-Rendu disease) presents with oral telangiectases and:
- Prolonged PT and APTT
- Recurrent epistaxis and mucocutaneous telangiectases (Correct answer)
- Thrombocytopenia
- Factor VIII deficiency
Correct answer: Recurrent epistaxis and mucocutaneous telangiectases
HHT is an autosomal dominant condition causing abnormal vascular structures (telangiectases and AVMs) leading to recurrent spontaneous bleeds, particularly epistaxis.
Question 5: Which systemic condition is most commonly associated with erythema multiforme?
- Crohn's disease
- Herpes simplex virus infection (Correct answer)
- Systemic lupus erythematosus
- HIV infection
Correct answer: Herpes simplex virus infection
The most common precipitant of recurrent erythema multiforme is herpes simplex virus (HSV) infection, which triggers an immune-mediated reaction.
Question 6: In haemophilia A, which clotting factor is deficient?
- Factor IX
- Factor VIII (Correct answer)
- von Willebrand factor
- Factor XI
Correct answer: Factor VIII
Haemophilia A is an X-linked recessive disorder caused by deficiency of coagulation factor VIII, leading to prolonged bleeding after trauma or surgery.
MFDS Human Disease 1
Which haematological finding is pathognomonic of pernicious anaemia?