thyroid clinical cases - university of the west indies at
TRANSCRIPT
Thyroid clinical cases
Dr. Colette George
Case 1
O 46 year old woman with weight gain and
tiredness. Physical examination
unremarkable
O TSH - 1.4 uiu/ml (0.4 – 4.0)
O Free T4- 14.3 pmol/l (10.0 -22.0)
O Total T3- 1.0 nmol/l (1.3 – 2.6)
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 1
O She is started on T3 (Cytomel)
O 2 months later
O TSH- 0.03 uIU/ml ( 0.4-4.0)
O FT4- 8.0 pmol/l (10.0-22.0)
O Total T3- 2.3 nmol/l (1.3-2.6)
O Thyroxine- T4 is added
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 1
O 2 months later, presents with weight loss
and palpitations
O TSH- <0.001 uIU/ml
O FT4- 24.0 pmol/l
O Total T3- 3.2 nmol/l
O IATROGENIC HYPERTHYROIDISM!!!
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Lesson 1
O Avoid treatment of isolated low T3 in the
presence of normal TSH and Free T4
O T3 treatment will lead to appropriate
suppression of TSH which will suppress
endogenous T4 production.
O Low T4 in a patient treated with T3 is an
appropriate response. Addition of T4 at this
stage will likely lead to hyperthyroidism
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 2
O 23 year old referred presents with goitre
O TSH- 0.3 uIU/ml
O Free T4 (not done)
O Started on Carbimazole 20 mg bd
O 3 months later, goitre even bigger
O TSH- >75 uIU/ml
O Free T4- <5 pmol/l
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Lesson 2
O The problem- Iatrogenic hypothyroidism
O She was likely never thyrotoxic
O Thyrotoxicosis usually associated with a suppressed (not just a little low) TSH
O Be wary of diagnosing hyperthyroidism based on a single low TSH. Should be followed by T4+/- T3
O Do not treat for hyperthyroidism without a firm diagnosis
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3
O 45 year old woman
presents with weight
loss, heart racing,
and frequent bowel
movements.
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3- other possible clinical signs?
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3- other possible clinical signs?
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3- other important clinical signs
Of hyperthroidism- all Of Graves disease
O Tremor
O Lid lag
O Lid retraction
O Sweaty palms
O Palmar erythema
O Brisk relaxation phase of tendon reflexes
O Proximal myopathy
O Exophthalmos
O Thyroid acropachy
O Pre-tibial myxoedema
O Thyroid bruit
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3- TFTs
O TSH: 0.00 uIU/ml
O Free T4: > 77.0 pmol/l
O Total T3: 6.7 nmol/l
O Any further investigations needed or could
be done?
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3- ultrasound
Both lobes of the thyroid are enlarged with an
inhomogenoeus echotexture. No focal nodule
is seen. Increased vascularity is noted all over
the gland. This is suggestive of……..”
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3- technetium scans
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3- Autoantibodies
O TSH receptor antibodies- 18.26 IU (0-1.75)
O TPO antibodies – 234 WHO u its (0-100)
O Diagnosis- Graves’ disease
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3- treatment options
O Symptomatic relief
O Propranolol- treats tachycardia and peripheral features
O Bisoprolol- tachycardia
O Verapamil if contraindication to beta blocker
O Lowering thyroid hormone levels
O Thionamides (Carbimazole.or Propylthiouracil)
O Radioactive iodine
O Surgery
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3- treatment
O Started on
O Propranolol 40 mg po tds
O Carbimazole 20 mg po bd
O Six weeks later
O TSH- 0.01 uIU/ml
O Free T4- 12.4 pmol/l
O How do you explain the low TSH?
O What do you do now?
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3
O Reduce dose and reduce to lowest possible
does that maintains the euthyroid state
O Four months later she is maintained on 10
mg po od
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3
O 8 months into treatment she calls you and
says she is pregnant- 5 weeks amenorrhoea.
O What do you advise?
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3
O Change to Propylthiouracil (PTU) for first
trimester of pregnancy
O Recommence Carbimazole for second and
third trimesters
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3
O She delivers a healthy baby, opts not to
breastfeed and continues her Carbimazole.
O 24 months later
O TSH- 1.5 uIU/ml
O FT4- 13.6 pmol/l
O Carbimazole is discontinued
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3
O 3 months after stopping treatment
O TSH 2.34 uIU/ml
O Free T4 12.6 pmol/l
O What do you do now?
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3
O 6 months after stopping treatment
O TSH 0.12 uIU/ml
O FT4 14.6 pmol/l
O Tot T3 2.1 nmol/l
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3
O 9 months after stopping treatment
O TSH 0.02 uIU/ml
O FT4 34.6 pmol/l
O Tot T3 2.8 nmol/l
O What has happened?
O What do you do now?
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3- options for definitive treatment
O Radioactive iodine therapy (RAI)
O Surgery
O She chooses RAI
O You might need to cover with steroids in light
of ophthalmopathy
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3- 7 months after RAI
O She defaults from follow up but presents 7 months later complaining of:
O weight gain
O joint pains
O extreme lethargy
O What has happened?
O What test do you do?
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3- TFTs again
O TSH 39.8 uIU/ml (0.32 – 5.00)
O Free T4 5.0 pmol/l
O What is her diagnosis?
O What treatment if any do you offer her?
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3-
O You start her on Thyroxine at 100 mcg od
O You see her 3 months later
O TSH 0.07 uIU/ml (0.32 -5.00)
O Free T4 17.9 pmol/l (9.0 – 22.2)
O What do you advise now?
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3
O You reduce her dose to 75 mcg
O 3 months later
O TSH 1.34 uIU/ml
O Free T4 22.6 pmol/l
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 3
O She returns a year later. She has been well
apart from GERD. TFTs
O TSH 9.85 uIU/ml
O FT4 11.2 pmol/l
O What might have happened?
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Lessons from case 3
O Several clinical signs and investigations can
help in diagnosing Graves’ disease as cause
of hyperthyroidism
O TSH not useful in monitoring response to
therapy in patients recently treated for
hyperthyroidism
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Lessons from case 3
O Dose of Thyroxine often needs titration
O TSH is best test for monitoring Thyroxine
treatment
O Other factors might necessitate need for
dose adjustment of Thyroxine
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 4
O 71 year old man feeling generally unwell
O Blurred vision comes and goes
O Fainting spell one year ago at bus stop. Had to lie on grass, taken to hospital seen and discharged
O Another spell 4/12 ago, while standing at bus stop. Fell to ground, seen at A+E but felt better and self- discharged
O Third fainting spell recently
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 4-On examination
O BP 156/90 mmHg supine
O BP 136/90 mmHg standing
O Felt unwell on standing and almost
collapsed.
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 4- TFTs
O Free T4- 5.8 pmol/l
O TSH- 5.77 uIU/ml
O What should we suspect?
O What should be done next?
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 4- Other tests
O U+E- Normal
O Cortisol- 78 nmol/l (138 – 690)
O Diagnosis- hypopituitarism
O The hypothyroidism is secondary and not primary
O What is the next step in management??
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Case 4 - management
O Replace cortisol first
O Replace thyroxine
O Image pituitary fossa
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
Lessons from Case 4
O If very low T4 is not accompanied by a markedly
elevated TSH suspect secondary hypothyroidism
even if the TSH is a little elevated
O In cases of secondary hypothyroidism look for
hypoadrenalism before treating with thyroxine
O If hypoadrenalism found it must be treated first
before thyroxine can be replaced
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
TSH- 0.4-4.0 uIU/ml, Free T4- 10-22 pmol/l, Total T3- 1.3-2.6 nmol/l
O Happy independence
O Thank you for
listening
O ??????