Threadworm, AKA enterobius vernicularis, appears frequently in MRCP questions, usually in relation to patients in institutions.
They tend to present with perianal itching.
Treatment is mebendazole 100mg (or piperazine if the patient happens to be under 2 yrs of age)
On that pleasant note, on to the last battle of the day, pseudohypoparathyroidism
