Thyroid Disorders - Management MCQs

Urinary tract infection is common in females between the age of 20-40 years owing to their sexual activity. But UTI occurring in elderly females is usually due to anatomical factors. Urothelial malignancies present with hematuria and may be mistaken for UTI. Hence further work up is always needed. A concurrent UTI, if suspected, should be treated and urine should be re tested for persistent hematuria . If confirmeb, she should first be subjected to bladder cystoscopy. Along with this the kidneys and upper urinary tract should be visualized with CT Urogram. Retrograde pyelography is not routinely used, as CT urograms use very minimal contrast agents Reference: Harrison's Principles of Internal Medicine, 21 st ed, Ch:86, 135, Pg:677, 1071.

Thyroxine should be taken at morning in an empty stomach (1 hour before food) as presence of food interferes with absorption from the gut Around 70-80 % of orally administered levothyroxine is absorbed and it occurs within 3 hours of intake after an overnight fast Reference: Liwanpo L, Hershman JM. Conditions and drugs interfering with thyroxine absorption. Best Pract Res Clin Endocrinol Metab. 2009 Dec;23(6):781-92.

Ans. is 'c' i.e., Cricoid Hyaline cartilages Elastic cartilages (do not ossify) Thyroid cartilage Epioglottis Cricoid cartilage Corniculate Basal part of arytenoid cartilage Cuneiform Processes of arytenoid

The majority of gastric cancers are not hereditary, the mutations identified in familial gastric cancer have provided important insights into mechanism of carcinogenesis in sporadic cancers. Germline mutations in CDHI, which encodes E cadherin, a protein that contributes to epithelial intercellular adhesion are associated with familial gastric cancers, which are usually of diffuse type. Mutations in CDH 1 are present in about 50% of sporadic cases of diffuse gastric cancers, while E cadherin expression is drastically decreased in the rest, often by methylation of the CDH I promotor. Lobular carcinoma of breast which also tends to infilterate as single cells, & individuals with BRCA2 mutations are at increased risk of developing diffuse gastric cancers.

Explanation: PTU is preferred in the first trimester due to lower teratogenic risk. Methimazole and carbimazole are associated with congenital anomalies (e.g., aplasia cutis) if used early in pregnancy. Explanation of other options: Methimazole (Option B) and Carbimazole (Option C): Effective but teratogenic in early pregnancy; can be considered after the first trimester if necessary.

The aim of treatment of thyrotoxicosis in pregnancy is the alleviation of symptoms and normalisation of tests in the shortest time. Both propylthiouracil and carbimazole are effective in controlling disease in pregnancy. The use of radioiodine is contraindicated in pregnancy. Surgery is rarely performed during pregnancy and is reserved for patients who do not respond to antithyroid drugs. A block and replace regime should not be used as this will result in fetal hypothyroidism. Reference: Harrison’s Principles of Internal Medicine 20 th edition Ch:377 Pg:2706-07

Toxic thyroid nodules preferentially take up radioactive iodine. This makes them particularly amenable to radioactive iodine treatment. A dose of 300-500 MBq is usually sufficient to cure the thyrotoxicosis. Radioiodine therapy is contraindicated in children and women who are lactating or pregnant, and where the safety of cohabitants from the effects of radioactivity can't be guaranteed. Surgery is the next best option for patients in whom radioiodine is contraindicated or refused. Carbimazole alone or in combination with thyroxine replacement is used in the medical treatment of Grave's disease. Propanolol is a useful symptom reliever for thyrotoxicosis. Reference: Harrison's Principles of Internal Medicine 21 st edition Page:2942

Propylthiouracil is the drug of choice in pregnancy as its greater protein binding reduces the risk of transplacental passage. Methimazole is the active metabolite of carbimazole. Radioactive iodine is contraindicated in pregnancy as it can destroy the fetal thyroid gland. Reference: Harrison's Principles of Internal Medicine 21 st edition Page:2940