MRCP Part 1 Haematology, Infectious Disease & Dermatology 2

Question 1

A 30-year-old man presents with erythema migrans (expanding bullseye rash) after a camping trip in the New Forest. What is the treatment of choice?

Accepted Answer

Doxycycline 100mg BD for 14–21 days

Answer

Erythema migrans is pathognomonic of early Lyme disease (Borrelia burgdorferi). Doxycycline 100mg BD for 14–21 days is the recommended treatment in the UK. Amoxicillin is an alternative. Early treatment prevents dissemination to joints, nervous system, and heart.

Question 2

A patient with HIV has a CD4 count of 80 cells/mm³ and presents with ring-enhancing lesions on MRI with surrounding oedema. What is the most likely diagnosis?

Accepted Answer

Cerebral toxoplasmosis

Answer

Cerebral toxoplasmosis is the most common cause of ring-enhancing lesions in HIV-positive patients with a CD4 count below 200 cells/mm³. It is caused by reactivation of latent Toxoplasma gondii. Treatment is sulphadiazine plus pyrimethamine plus folinic acid.

Question 3

Which skin condition presents with salmon-pink plaques covered by silvery-white scales, affecting extensor surfaces and scalp?

Accepted Answer

Psoriasis

Answer

Plaque psoriasis presents with well-demarcated, erythematous plaques with silvery-white scale, affecting extensor surfaces (elbows, knees), scalp, and lumbosacral area. Auspitz sign (pinpoint bleeding when scale removed) and Koebner phenomenon are characteristic.

Question 4

A 25-year-old woman presents with an intensely pruritic papular rash in the finger webs, wrists, and waistline, worse at night. What is the most likely diagnosis and treatment?

Accepted Answer

Scabies — treat with permethrin 5% cream

Answer

Scabies is caused by Sarcoptes scabiei mite infestation, presenting with intense nocturnal pruritus, burrows in the finger webs, wrists, and genitalia. First-line treatment is permethrin 5% cream applied from neck to toes. All household contacts must be treated simultaneously.

Question 5

In a patient with suspected meningococcal meningitis, at what point should antibiotics be given?

Accepted Answer

Immediately — before investigations if there will be any delay

Answer

If meningococcal meningitis or meningococcal septicaemia is suspected, IV or IM benzylpenicillin (or ceftriaxone) should be given immediately — before any investigation — as delay significantly worsens outcome. LP can be performed after treatment if meningitis is the primary concern and CT has excluded raised ICP.

MRCP Part 1 Practice Test

MRCP Part 1 Practice Test

MRCP Part 1 Haematology, Infectious Disease & Dermatology 2