Thyroid disease Flashcards
CLINICAL APPLICATION
Tips for examining the thyroid?
- Low in neck, feel for thyroid cartilage (adams apple in m) then inferior and laterally
- Moves on swallowing
- Listen for bruit
- Retrosternal extension?
! Always check cervical lymph nodes
CLINICAL APPLICATION
Which thyroid function tests are available?
Advantage and disadvantage of measuring TSH?
- TSH
- Free T3/T4 (FT3/FT4)
- Thyroid antibodies e.g. Anti-TPO AB, TRAB-TSH receptor auntoantibody
Good at testing thyroid function
TSH is slow to respond to change (approx 6 weeks) and assumes normal pituitary function
How does the prevalence of autoAB correlate to disease states?
High prevalence of autoAB in autoimmune disease
- Many are sequestered/ intracellular
! A negative autoAB doesnt mean its not an autoimmune disease
What types of thyroid autoimmune disease exists?
‘destructive’ - target thyroid AI destruction
‘stimulatory’ - stimulate TSH receptor
State 5 common symptoms of hypothyroidism
- Heavy menstruation
- Asymptomatic
- Lethargy
- Mild weight gain
- Cold intolerance
- Constipation
State 5 common symptoms of SEVERE hypothyroidism
- Goitre
- Carpal tunnel
- Effusions
- Bradycardia
- Stupor/coma
- Facial puffiness
- Flaking dry skin
- Diffuse hair loss
- Hoarseness
State 3 primary causes of hypothyroidism
Give a secondary cause
- Autoimmune hypothyroidism
- Hypothyroidism after treatment for hyper (Iatrogenic)
- Thyroiditis
- Drugs (lithium, amiodarone)
- Congenital
6 Iodine deficiency (not applicable to UK)
Disease of the hypothalamus or pituitary gland
CLINICAL APPLICATION
What investigation would be appropriate for suspected hypothyroidism?
Blood serum
Thyroid autoantibodies?
No imaging necessary
CLINICAL APPLICATION
Standard treatment for hypothyroidism?
Start: Thyroxine (T4) 100ug daily
- shorter symptomatic period
- in elderly/IHD start with 25ug and increase in increments over 4-6 weeks
Aim: normal FT4 without TSH suppression
**normal is different/person
State 5 symptoms of hyperthyroidism
- Loose bowel
- Weight loss (with increased appetite)
- Lack of energy
- Heat intolerance
- Anxiety/ irritability
- Oligomenorrhoea
- Increased sweating
- Increased thirst
- Palpitations
- Pruritis (itch)
- Weight gain
State 5 signs of hyperthyroidism
- Tremor
- Warm, most skin
- Tachycardia
- Brisk reflexes
- Thyroid bruit
- Muscle weakness
- Atrial fibrillation
- EYE SIGNS (TED/TAO)
In which condition do 20% of patients show eye signs like those in hyperthyroidism?
What causes these?
State 5 symptoms of TED/TAO?
What investigation might be useful here?
Graves (increased in smoking patients)
Autoantibody mediated, inflammation of orbital tissues (fat, muscle, conjunctivae, eyelids) except eyes itself
- Itchy/dry
- ‘Prominent’ eyes
- Diplopia/ loss of sight
- Loss of colour vision
- Redness/swelling of conjunctiva
- Unable to close eyes fully
- Ache/pain/tightness in/behind eye
CT, especially if “worrying” symptoms (last 5)
Graves is a common cause of hyperthyroidism. Comment on its epidemiology and mechanism of disease
State 5 other causes of hyperthyroidism
Graves accounts for 75% of cases, mainly women aged 30-50. Autoantibody stimulates the TSH receptor, causing excess TH production and goitre
- Toxic multinodular goitre
- Toxic adenoma
- Thyroiditis
- Drugs e.g. amiodarone
- Gestational
Comment more on gestational hyperthyroidism
- placental b-human chronic gonadotrophin is structurally similar to TSH and TSH- like action on the thyroid
- increased likelihood is hyperemesis (twin pregnancy)
- settles after first trimester
CLINICAL APPLICATION
What investigations might suggest a diagnosis of Graves?
If Graves:
- FHx of automimmue thyroid/endocrine disease
- Goitre with bruit
- Thyroid eye disease (20%)
- Positive thyroid autoantibody titre
- TSH-receptor autoantibodies (graves)
CLINICAL APPLICATION
What investigations would be appropriate in suspected hyperthyroidism ?
- Thyroid function tests (TSH, FT3, FT4)
- Autonervous function of the thyroid
- May not require imaging
- Thyroid uptake scan (isotope scan) : functional- darker areas suggest increased activity
CLINICAL APPLICATION
Suggested medical therapy treatment for Graves
Success rate?
What rare side effect may occur?
- Carbimazole/ Prophylthiouracil
- 18 months- 2 years
- Titrate or block replace
Only 1/3 cure, 2/3 relapse
Agranulocytosis- acute condition involving a severe and dangerous leukopenia
CLINICAL APPLICATION
Discuss radioiodine (131I) as a treatment for graves
How is it used?
Which kind of patients is is not suitable for?
Contraindications?
Social effects?
Oral treatment, radioiodine concentrated in thyroid
- Use medical therapy first until euthyroid
- 40% risk of becoming permanently hypothyroid
- Not appropriate for pregnant/ breast feeding women, advice people to prolong time between next pregnancy (6months f, 4months m)
- Contraindicated in those with thyroid eye disease
- Sets off security systems
- Avoid prolonged close contact for 2 weeks (hugging, sleeping together)
CLINICAL APPLICATION
Which patients are suitable for surgery (Sub-total thyroidectomy) for treatment for graves?
Risks?
Patients who are euthyroid pre-operatively
- Anaesthetic
- Neck scarring
- Hypothyroidism
- Hypoparathyroidism
- Vocal cord palsy (due to damage to recurrent laryngeal nerve damage)
CLINICAL APPLICATION
How can the symptoms of graves be controlled?
Risks of no treatment?
B-blockers, not in asthmatics
Risks of no treatment: symptoms worsen, A-Fib –> stroke, Osteoporosis –> fractures
CLINICAL APPLICATION
Standard treatment for a toxic adenoma or toxic multinodular goitre
Initial - short term medical treatment (to control thyroid function tests)
Subsequent: Radioiodine
Important to agree expectations with patient. It may take time to feel ‘normal’ again (mood swings, anxiety, panic, irritability); treatment doesnt help eye disease; risk of weight gain; family planning
CLINICAL APPLICATION
Treatment options for ‘ACTIVE’ thyroid eye disease
- Encourage smoking cessation
- Steroids (pulsed IV methylpred/ oral prednisolone)
- Other immunosuppressive/ steroid-sparing agents
- Radiotherapy
CLINICAL APPLICATION
Treatment options for ‘BURNT OUT’ thyroid eye disease
Effects of no treatment?
- Surgical treatment : orbital decompression, eyelid surgery
May be left with disfigurement causing impaired quality of life and social avoidance
What is thyroid storm (thyrotoxic crisis)?
A life-threatening health condition that is associated with untreated or undertreated hyperthyroidism.
- Hyperpyrexia
- CNS: agitation, delirium
- CVS: tachycardia (>140bpm), atrial dysrhythmias, ventricular dysfunction, HF
- GI: nausea, vomiting, diarrhoea, hepatocellular dysfunction
High mortality rate, ITU care
Degree of hyperthyroidism does not distinguish between thyrotoxicosis from thyroid storm
Who gets thyroid storm?
- Secondary grave sufferers
- Unrecognised
- Incompletely treated : “start-stop”, erratic compliance, beginning of treatment, surgery/radioiodine without adequate preparation
IT IS RARE
What triggers thyroid storm?
- Surgery
- Childbirth
- Acute severe illness: infection, trauma, diabetic ketoacidosis, stroke, pulmonary embolus
What is thyroiditis?
Transient mild thyrotoxicosis (resolves in 1-2months)
- B blockers if required
- Isotope scan would be ‘cold’
- Anti-thyroid drugs have no effect
Longer hypothyroid phase (4-6months)
- May require thyroxine treatment
CLINICAL APPLICATION
When might you consider a diagnosis of thyroiditis?
- Pregnant women/ up to 1 year post-partum
( increased risk if T1DM, FHx thyroid disease, smoker) - Tender thyroid (may be raised inflammatory markers)
- Clinical thyroid status doesn’t fit with lab results
- Patient has no diagnostic features of Graves disease
- Current/ recent treatment with immunomodulatory medication
What other AI endocrine diseases may be associated with AI thyroid disease?
Syndromes?
How would you monitor such patients?
- T1DM
- Pernicious anaemia
- Coeliac disease
- Premature ovarian failure
- Addison’s disease
Turner syndrome, Downs syndrome
Annual thyroid function test screening
Differentiate between euthyroid goitre and thyroid nodules
How would you proceed if suspected thyroid nodule?
EUTHYROID GOITRE
- Common
- More comon in iodine-deficient areas (outside UK)
- May be multinodular
- Usually not clinically worrying
THYROID NODULE
- Thyroid nodule in euthyroid patient
- Exclude thyroid cancer ! (approx 5%)
- Ultrasound
- Fine-needle aspiration biopsy for cytology
