Endocrinology Flashcards
What antibody to Grave’s and Hashimoto’s have in common?
Anti-TSH Receptor antibodies
- Grave’s: activate receptor
- Hashimoto’s: inhibit receptor
Pt presents with sweating and wt loss despite increased appetite. On examination, you note diffuse goitre + bruit, pretibial myxoedema (shin rash) and their eyes gritty. They smoke.
Likely diagnosis? Investigations?
Management?
Grave’s disease
Investigations:
TFT - low TSH, high T3
Serology - TRAb, Anti-TPO
Management:
1. Propanolol - immediate relief
- Carbimazole
- titrate down if healthy
- titrate up if elderly
OR Block & Replace with Carbimazole + Thyroxine
- 131_I
- Thyroidectomy
+ Stop smoking! (big RF for Grave’s eye disease)
Pt presents with constipation, wt gain and numbness in their hands. Their hair appears brittle and their skin dry/. Examination reveals cardiomegaly and bradycardia, as well as a large tongue. They also have a positive Hertoghe sign.
Likely diagnosis, investigations, management + risks
Hypothyroidism
TFT - high TSH, low T3
Serology - Hashimoto’s?
Management:
LEVOTHYROXINE
(Risks = osteoporosis, arrhythmia)
+ annual TSH check
Pt presents with constipation, wt gain and numbness in their hands. Their hair appears brittle and their skin dry/. Examination reveals Goitre, hypertrophy and hyperplasia.
Likely diagnosis, risk factors, investigations, management + risks
Hashimoto’s thyroiditis
RF: Turner’s/ Down’s syndrome; HLA-DR5; T1DM, SLE, etc
Inv: TFT - high TSH, low T3
GOLD: High Anti-TPO (Anti-thyroid Peroxidase Ab).
Low Thyroglobulin Ab. Anti-TSH_R Ab
Pt arrives from the Middle East complaining of fatigue, constipation and neck swelling.
Exam reveals large, diffuse, non-tender goitre.
TFT shows hypothyroidism. Serology is negative. Likely cause?
IODINE DEFICIENCY
- most common world-wide cause
- Middle-East, Nepal, South-America
What drugs interfere with levothyroxine absorption?
IRON - Ferrous Sulphate
- take Levothyroxine THEN iron 2-4 hrs apart
Calcium chloride
Digoxin
Hormone Replacement Therapy
Half life of levothyroxine
4-6 weeks
Pt presents with heat intolerance, sweating and palpitations. She is 11 weeks pregnant. TFT reveals raised T3 and low TSH.
Management?
PROPYLTHIOURACIL (PTU)
Carbimazole is contraindicated in 1st trimester of pregnancy (crosses placenta > aplasia cutis)
Painful goitre
De Quervain’s thyroiditis
Secondary causes of Hyperthyroidism
Amiodarone Lithium TSH-adenoma Choriocarcinoma (B-hCG activates TSH receptor)/ gestational Struma ovarii
Thyroid storm management
IV Propanolol
IV digoxin
Propylthiouracil via NG tube THEN Lugol’s Iodine 6hrs later
Prednisolone/ HC
Grave’s disease cardinal features
Diffuse goitre + bruit Pretibial myxoedema (shin rash) Infiltrative eye disease - exophthalmos - periorbital oedema - opthalmoplegia
Pt diagnosed with thyrotoxicosis and is started on Carbimazole + Propanolol. She initially felt better but now complains of a sore throat.
Management?
STOP CARBIMAZOLE + FBC
SE: Agranulocytosis > Neutropenia > sepsis
*also a side-effect of PTU
Pt is 7 weeks into pregnancy and has a Hx of hypothyroidism. It is well managed with levothyoxine.
TFT shows:
- fT4 = 18 (11-22)
- TSH = 2.1 (0.17-3.2)
Management?
Increase Levothyroxine by 25 mcg + Repeat TFT in 4 weeks
EVEN IF IN EUTHYROID STATE
- in preg, there is ^fT4 until week 12 :: foetus is dependant on maternal T4 until their foetal T4 develops at wk12.
Pharmacology + SE of Carbimazole
Inhibits Thyroid Peroxidase in Follicular cells > inhibits iodination of tyrosine residues in thyroglobulin > stops T3/4 production.
SE: Rash, pruritus, agranulocytosis (> neutropenia > sepsis)
