thyroid: clinical cases dr sunil zachariah consultant endocrinologist surrey and sussex nhs trust...
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Thyroid: Clinical Cases
Dr Sunil Zachariah Consultant
Endocrinologist Surrey and Sussex NHS Trust
& Spire Gatwick Park Hospital
Thyroid is the only source of T4 Thyroid secretes 20% of T3,
remainder is generated in extra glandular tissues by conversion of T4 to T3
Normal range
FT4 11.5-23 pmol/l fT3 3-6.7 pmol/l TSH 0.3-5.5 mu/L
Case 1
Female aged 40 years Palpitations, weight loss and mild
proptosis Smallish smooth goitre FT4 80 TSH<0.01
Graves Disease TSH receptor
antibodies Carbimazole Propylthiouracil Treatment
schedule ?Block and replace Permanent cure
Case 2
Female aged 76 years Gradual weight loss Solitary thyroid nodule FT4 32 TSH<0.01
Management toxic Nodule
Radioactive iodine ?FNA first if palpable nodule as low
risk of malignancy in toxic nodule
Case 3
60 year old female 6 weeks post radioiodine
treatment FT4 11 TSH 0.02
Post radioiodine thyroid function
Check 6 weeks after treatment TFTs may fluctuate 50% risk of hypothyroidism
Case 4
Female aged 79 years with fast AF FT4 19.5 TSH 0.2
This case probably not for antithyroid treatment
If overtly hyperthyroid treat Subclinical hyperthyroidism:
Normal FT4, Low TSH Risk factor for Atrial fibrillation,
osteoporosis
Case 5
50 year old man Ventricular tachycardia with poor
LV function Controlled on Amiodarone FT4 50 FT3 7 TSH<0.01
Amiodarone and Thyroid
Inhibits thyroidal iodide uptake Inhibits conversion of T4 to T3
intracellularly Inhibits T4 entry into cells Direct T3 antagonism at level of
cardiac tissue
What does it do to TFTs?
Early[1-10 days]: TSH increase, FT3 decrease, then Ft4 increase after 4 days
Later[1-4 months]: Ft4 increase by 40%, FT3 remains low or normal, TSH levels normalise
Long term: TSH may suppress
Amiodarone induced hyperthyroidism
2-12% Type 1: Iodine overload in abnormal
gland, treat with carbimazole or lithium Type 2: Glandular damage, release of
preformed hormones, treat with prednisolone 0.5-1.25 mg/kg for 3-6 weeks
Management of tachyarrhythmia's: beta blockers if not in CCF
?total thyroidectomy (not radioiodine)
Case 6
30 year old female Recent flu tender enlargement thyroid FT4 28 TSH<0.01
De Quervains thyroiditis
Recheck TFTs-probably hypothyroid by then
Thyroid antibodies and ESR Thyroid scintigram-reduced uptake Symptomatic treatment with
NSAIDs Warn the possibility of recurrence
Case 7
Female age 25 years Hyperpyrexia ITU admission Profound muscle weakness
requiring ventilation FT4 210 TSH<0.01
Thyrotoxic crisis
Carbimazole 60-100 mg via NG tube
Propranolol infusion Profound myopathy and even
neuropathy can be associated with Grave’s
Case 8
65 year old male Pre coronary artery bypass surgery Routine blood tests FT4 3 mU/L TSH 40 pmol/L
Management hypothyroidism with Coronary artery disease
May need to put in stents to allow introduction of triodothyronine and then thyroxine
Some patients symptomatic when thyroxine started/increased
Case 9
Female aged 32 years Weight gain and thyroid FT4 13 TSH 5.5
Sub clinical hypothyroidism
TSH>10 Antibody positive Family history Symptomatic Monitor TFT 6 monthly
Case 10
Hypothyroid on replacement thyroxine 300 mcg
FT4 23 TSH 15
Hypothyroidism requiring high dose replacement
Check tablets each visit-check compliance
Check for malabsorption but unlikely
Probably continue to see but at infrequent intervals
Case 11
Female aged 60 years Found collapsed at home History of epilepsy TFT checked in Causality FT4 8.5 TSH 4.0
Low FT4, normal TSH
Sick euthyroid Possibly
hypopituitary-cortisol/FSH/LH Check medication-can be
secondary to carbamazepine
Sick Euthyroid syndrome
Non thyroidal illness syndrome Low FT4 and T3 Inappropriately normal/suppressed
TSH Context: Starvation, ITU, severe
infections, renal failure, cardiac failure, malignancy
Case 13
Female aged 34 years Secondary amenorrhoea Low TSH Low FT4
Hypopituitarism
FSH/LH/Prolactin/cortisol MRI Pitutary; ?empty fossa ?large
adenoma Start hydrocortisone first if
needed, before thyroxine replacement
Case 14
22 year old female Admitted with hyper emesis
gravidarum Pulse 110 bpm FT4 29 TSH<0.01
Management
Usually HCG induced in which case it will resolve spontaneously by around 14 weeks
If positive thyroid antibodies or history of grave’s disease then treat with PTU
Case 14
A] Palpitations, 10 weeks post partum
Ft4 32 TSH 0.2 B] Tired, 10 weeks post partum FT4 9 TSH 8
POSTPARTUM THYROIDITIS
Incidence varies from 5-11% More common in women with a
family history of hypothyroidism and positive TPO antibodies
CLINICAL FEATURES
Presentation is usually 3-4 months postpartum
Can be hypothyroidism (40%), hyperthyroidism (40%) or biphasic(20%)
Goiter is present in 50% of patients
Pathogenesis
Destructive autoimmune thyroiditis causing first release of thyroxine and then hypothyroidism as the thyroid reserve is depleted
FNAC shows lymphocytic thyroiditis
Diagnosis
Advise routine TFT in females who have positive TPO antibodies and type 1 diabetes
To distinguish from Graves disease use thyroid isotope scan and TSH receptor Ab
Management Most patients recover spontaneously without
requiring treatment If hyperthyroid use beta blockers rather than
antithyroid drugs as the problem is increased release, not synthesis
Hypothyroid phase is more likely to require treatment
Only 3-4% remain permanently hypothyroid 10-25% will recur in future pregnancies
Case 15
Female aged 30 years New Thyroid enlargement
New Thyroid swelling
FNAC if nodule size>1 cm Repeat FNAC in 6 months Impossible to differentiate between
benign and malignant follicular neoplasm using FNAC
Case 16
Long standing goitre FT4 28 TSH 7
Measurable TSH with raised FT4
Heterophile antibodies TSH resistance syndromes TSH oma-very rare
Thyroid hormone resistance
Syndrome characterized by reduced responsiveness to elevated circulating FT4 and FT3, non suppressed TSH
Short stature, hyperactivity, attention deficit
Differential diagnosis includes TSH secreting pituitary tumour
Case 17
27 year old female Follicular Cancer of Thyroid Post surgery, post radioiodine
ablation On Thyroxine replacement (175
mcg) FT4 19.8 TSH 0.05
Follow up of thyroid Cancer
Original diagnosis and treatment If total thyroidectomy and ablative
radioiodine, thyroglobulins usually undetectable if TSH unrecordable
Maintain TSH<0.05