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