thyroid hormones, hyper/hypofunction.ppt

Thyroid hormones, thyroid hypo/
hyperfunction, goiter, inflammation
and malignancies
Seminar room, Department of Radiodiagnosis LUTH
Wed 7th March 2018
11.30 – 12.30pm
'Modele Olowoyeye MBBS, RVT, RDMS, MSc, PhD, FMCR Senior Lecturer in
Radiology, CMUL, Unilag
Consultant Radiologist, LUTH

The Thyroid gland
• A large bi lobed ductless
endocrine gland located
anterior to the trachea
and connected by an
isthmus.
• Secretes hormones that
regulate metabolism,
growth and development.
ꟷ Thyroxine (T4)
ꟷ Triiodothyronine (T3)
….active form
ꟷ Calcitonin
https://goo.gl/images/BD1Q1d

Goitre
• A neck swelling due to an
enlarged thyroid gland.
• May be associated with
hyper or hypothryoidism
• Over 90% of goitre cases
worldwide are as a result of
iodine deficiency.
• Most goitres are of a benign
nature.
https://en.wikipedia.org/wiki/Goitre, http://homeomiracles.com/thyroid/html/Articles-7.htm

Types of Goitre
• Uninodular goiter
– may be an inactive or a toxic nodule.
• Multinodular goiter
– multiple inactive or toxic nodules (toxic multinodular)
• Diffuse goiter
– the whole gland is enlarged due to hyperplasia.
• Toxic multinodular goiter is associated
with hyperthyroidism and thyroid cancer.

Hyperthyroidism
• Hyperthyroidism (Hyperfunction) ↑ synthesis, ↑
secretion of thyroid hormones leads to a
hypermetabolic condition called thyrotoxicosis.
• The causes include
– Graves' disease (most common)
– Toxic multinodular goitre
– Toxic adenoma
– Thyroiditis
– Factitious intake of thyroxine
– Ovarian causes (struma ovarii, molar pregnancy).

Clinical Features of hyperthyroidism
https://goo.gl/images/n1WPT1

Laboratory Investigations
• Serum assay of both free T4 (fT4) and
supersensitive TSH is required for diagnosis
because fT4 may be normal and thyrotoxicosis
is due to T3 toxicosis.
• In patients suspected of T3 toxicosis, serum free
T3 (fT3) measurement is indicated.

Radiological investigations
• Chest X-rays
• Barium swallow
• Ultrasound +/- FNAC
• Computed Tomography Scan
• Magnetic resonance imaging
• Radionuclear studies.

• Radioactive iodine
uptake (RAIU) test.
• Normal uptake of Iodine-
123 is between 15 and
25%.
• ↓ Low uptake in thyroiditis
• ↑ uptake in Graves' disease
• With thyroid nodules uptake
is uneven.
https://en.wikipedia.org/wiki/Radioactive_iodine_uptake_test

Management
• Three forms of therapy are available: anti-thyroid
drugs, surgery and radio-active iodine.
• Treatment may also be necessary for
complications e.g. atrial fibrillation, cardiac
failure, ophthalmopathy.
• The methods used will vary according to the
cause and severity of the disease, the patient’s
age and resources available.

Anti-thyroid drugs
• Thionamides (carbamizole or propylthiouracil)
– commonly used for most patients with the hope of
achieving long-term remission.
• Useful in children, pregnant women, while
awaiting surgical or radioiodine therapy, those
who refuse or have contraindications to surgery,
in cases of thyroid crisis or heart failure, relapse
after thyroidectomy.

Anti-thyroid drugs contd.
• Therapy may last for 1-2 years
• The long term therapy may lead to side effects (due to
agranulocytosis within the first 3 months).
• Patients with rash or sore throat should discontinue
treatment and seek medical advice immediately.
• Beta-blockers such as propanolol or atenolol are useful
for symptomatic relief initially, provided there are no
contraindications, e.g. asthma.

Surgery
• Thyroidectomy in Graves' disease, toxic
multinodular goitre or toxic adenoma.
• Indications
– Failed medical treatment ie relapse after using anti-
thyroid drugs, non-compliance etc.
– Large goitres, especially with pressure effects.
– Patients who prefer surgery.
– A relative indication is severe progressive
ophthalmopathy.

Radioiodine Therapy
• I-131 is safe and appropriate in nearly all types of
hyperthyroidism except uncontrolled, severe and
complicated hyperthyroidism.
• It should NOT be used in children, pregnancy and
women who are breast feeding.
• Following treatment, patients should avoid close contact
with the above group of people for up to 10 days and
avoid pregnancy for at least 4- 6 mths.
• Follow-up to detect post-Rx hypothyroidism.

Management of complications
due to Thyrotoxicosis

Thyrocardiac complications
• Thyroid cardiomyopathy may occur in especially in
elderly patients with prolonged poorly controlled
thyrotoxicosis.
• Digoxin and beta-blocker may be used to treat rapid
atrial fibrillation and control the heart rate.
– In the presence of heart failure, cardiac dilatation,
thrombus on echocardiogram, history of embolization
and associated valvular heart disease, antic
Anticoagulation is also advised.
Practice Guidelines for Thyroid DisordersThe Malaysian Consensus 2000

Hypokalaemic periodic paralysis
• In addition to treating the thyrotoxicosis
hypokalemia is corrected by given
– Oral potassium (potassium chloride, Slow-K) 1.8 - 3.6
g daily.
– Spironolactone 75 mg daily in divided doses

Dermopathy (Pretibial Myxoedema)
• Skin lesions resulting
from the deposition of
hyaluronic acid
• Local steroid application
under occlusive
dressings may be
effective.
https://en.wikipedia.org/wiki/Pretibial_myxedema

Ophthalmopathy
• Exophthalmos is a feature of
Graves’ disease and may occur
in the absence of thyroid
dysfunction.
• The presence of ophthalmopathy
necessitates full thyroid
function assessment.
• Even though the fT4 is normal,
TSH may be normal, suppressed
or elevated.
https://goo.gl/images/n1WPT1

Ophthalmopathy
• CT or MRI scan for unilateral
exophthalmos to exclude retro-
orbital tumours.
• The degree of proptosis should
be serially documented to help in
the decision regarding active
treatment.
• Combined management with an
ophthalmologist is
recommended.
• CT scan showing an
orbital mass with
associated proptosis.
https://plasticsurgerykey.com/the-diagnostic-approach-to-the-patient-with-proptosis/

Ophthalmopathy
• Mild cases may require only reassurance.
• In moderate exophthalmos, elevation of the head of the
bed and taping of eyelids at night, sunglasses and
methyl-cellulose eye drops to prevent dryness may
suffice.
• In severe disease, high dose steroids, immuno-
modulatory drugs, surgery or irradiation may be
necessary.
• Anti-thyroid treatment should be carefully monitored to
avoid hypothyroidism which can worsen the eye
condition.

Thyroid Crisis
• A worsened hyperthyroid state with one or more organ
failure and mortality rate of 20 - 30 %.
• Occurs following stress, concurrent infections, surgery
or pregnancy.
• Clinical features include severe thyrotoxicosis,
hyperpyrexia and neuro-pychiatric manifestations such
as delirium.
• Rx includes rehydration, lowering the temperature, Beta-
blockers, Oral or IV potassium iodide or I/V Sodium
Iodide or oral Lugol's iodine, Anti-thyroid drugs such as
Carbimazole or propylthiouracil, Corticosteroids.

Hypothyroidism
• Thyroid hypofunction or Hypothyroidism is due
to deficiency of thyroid hormones resulting in a
hypometabolic state.
• Primary causes
– autoimmune thyroid disease
– thyroid agenesis
– post-thyroidectomy
– post-radioiodine therapy
• Secondary causes
– hypopituitarism

Laboratory Investigations
• Serum T4 and TSH assay.
• Serum TSH assay.
– Elevated in primary hypothyroidism and is
useful in assessing adequacy of treatment.
• Thyroid antibody assay (anti-thyroid peroxidase
and anti-thyroglobulin) for autoimmune thyroid
disease.

• To rule out agenesis or autoimmune causes
of hypothyroidism.
– Ultrasound +/- biopsy
– Computed Tomography Scan
– Magnetic resonance imaging
– Radionuclear studies.

Management of hypothyroidism
• L-thyroxine to make the patient clinically and
biochemically euthyroid.
• In hypopituitarism, L-thyroxine therapy is given only after
cortisol replacement to avoid possible adrenal crisis.
• In subclinical Hypothyroidism, (normal T4, ↑ TSH) L-
thyroxine is given to prevent hyperlipidaemia and
coronary artery disease.
• Serum TSH and fT4 assay after 2-3 months of Rx to
determine the maintenance dose and subsequently
every 6 months to 1 year.

Myxoedema Coma
• A complication of long standing hypothyroidism.
• Triggers include stress, infection, drugs (e.g. CNS
suppressants).
• Requires urgent treatment because the mortality is
50%.
– Gradual rewarming with blankets. L-thyroxine or small
doses of tri-iodothyronine, I/V hydrocort, dextrose
solution, correct hyponatraemia, rehydration, adequate
ventilation to prevent hypoventilation and hypercapnoea.
treat precipitating cause.

Congenital Hypothyroidism
• An endocrine disorder resulting from inadequate
thyroid hormone for the metabolic needs of a
newborn infant.
• Incidence is between 1:4000 to 1:5000.
• Asymptomatic at birth. Later present with
prolonged jaundice, poor feeding, constipation
and unusually quiet baby.
• Other features signs such as coarse facies, dry
skin, hoarse cry, umbilical hernia and delayed
milestones appear by 3 – 6 months,

Congenital Hypothyroidism
• Intellectual impairment can be prevented by
early diagnosis and treatment.
• Causes include
– thyroid gland dysgenesis (90% of cases)
– dyshormonogenesis
– iodine deficiency (endemic goitre)

Investigations
• Assay of cord blood for TSH measurement.
– Those with high TSH levels should be recalled
for confirmation of diagnosis by measurement
of TSH and fT4 using venous blood at 7-10
days of age.
• Interpretation of the above results should take into
account the physiological variations of hormone
levels during the neonatal period.
• X-ray measurements for bone age may be useful
but not diagnostic.

Management
• L-thyroxine is given to maintain serum TSH
levels within the normal range and fT4 at the
upper limit of normal for age.
• With early intervention, those affected can
achieve normal intellectual and physical
development.
• Lifelong treatment, except in those with transient
hypothyroidism in which therapy is discontinued
at 2 years of age and patient re-evaluated.

Monitoring
• Patients should be monitored clinically and
biochemically at monthly intervals for the first 6
months then 3-monthly until one year of age;
and thereafter 6-monthly.
• Checklist for monitoring include growth
parameters (weight, height, head
circumference), developmental milestones and
normal bone age progression.

Inflammation of the thyroid gland
(Thyroiditis)

Thyroiditis
• Associated with variable degree of glandular tissue
destruction.
• Presentation may be acute, subacute or chronic.
• The causes are :
• Autoimmune - Hashimoto’s thyroiditis
- Post-partum thyroiditis
- Atrophic thyroiditis
• Infection - Viral thyroiditis (De Quevain’s thyroiditis)
- Acute pyogenic thyroiditis
• Physical - Radiation to the neck
• Idiopathic - Painless thyroiditis
- Riedel’s thyroiditis

Hashimoto’s thyroiditis
• Presents with diffuse firm goitre and symptoms
of hypothyroidism.
• Few patients may present with transient
thyrotoxicosis or have coexisting Graves’
disease.
• More common in females in the fourth and fifth
decade .
• Associated with a positive family history of goitre
or other autoimmune thyroid diseases e.g.
Graves’ thyroiditis or Hashimoto’s thyroiditis.

Postpartum thyroiditis
• Painless gland, autoimmune disorder, presents
with thyrotoxicosis followed by euthyroid and
hypothyroid phases a few months after delivery.
• A proportion of patients may present at the
hypothyroid phase.
• The gland is enlarged in about 50% of cases.
• The thyrotoxic phase lasts for about 2 months
but the hypothyroid phase may last for 2-9
months. About 5% of the patients develop
permanent hypothyroidism.

Subacute (De Quervain's)
thyroiditis
• Pain in the region of thyroid gland which may be
mistaken for pharyngitis.
• Slightly to moderately enlarged gland, firm and
usually exquisitely tender.
• Viral in origin, features of thyrotoxicosis, fever in
severe cases.
• The disease usually passes through a euthyroid
phase followed by a transient hypothyroid phase
prior to full recovery within a few months in the
majority of cases.
• Rarely, permanent hypothyroidism may result.

Acute pyogenic thyroiditis
• Rare and is usually a result of dissemination
from a septic focus elsewhere.
• Usually presents with fever, pain and signs of
acute inflammation in the thyroid gland.
• Needle aspiration of the thyroid is performed for
diagnosis and identification of the organism.
• Rarely, tuberculosis or anaplastic carcinoma of
the thyroid may present similarly.

Riedel’s thyroiditis
• A rare condition of unknown aetiology
presenting with hypothyroidism and woody hard
goitre.
• Extensive fibrosis of nearby structures like the
trachea and oesophagus may occur
• May be associated with retroperitoneal fibrosis.
• +/- elevated anti-thyroid antibodies but not as
high as those of Hashimoto’s thyroiditis.

Painless thyroiditis
• Of unknown aetiology and is similar to
postpartum thyroiditis except that this is not
associated with pregnancy.

Investigations
• Serum assay of fT4, TSH, T3 to rule out dysfunction.
• Tests to confirm aetiology such as
1. Thyroid autoantibodies (thyroid peroxidase and
thyroglobulin)
2. FNAC for culture and sensitivity in cases of pyogenic
thyroiditis.
3. Isotope uptake scan is useful in differentiating
thyrotoxicosis due to thyroiditis from Graves’ disease.
4. ESR is raised and useful in the monitoring of the activity
of De Quervain’s thyroiditis.

Management
• NSAID or sometimes steroid therapy to relieve pain in de
Quervain’s thyroiditis.
• Anti-thyroid drugs (eg carbimazole) are not indicated.
• Beta blockers may be useful to alleviate symptoms.
• L-thyroxine for hypothyroidism.
– It may be discontinued after 6-12 months in
postpartum or painless thyroiditis.
– Life-long thyroid hormone replacement in
Hashimoto’s thyroiditis
• Antibiotics, +/- surgical drainage in in pyogenic
thyroiditis.

Single Thyroid Nodule (STN)
• The common causes of thyroid nodules are:
– Colloid goitre and cysts
– Adenomatous hyperplasia
– Follicular adenoma
– Thyroid carcinoma
• The incidence of malignancy in solitary nodule by
FNAC is estimated to be 1-2%.
.

High index of suspicion for
malignancy in STN
• Age groups of < 20 years and > 50 years
• Male gender
• Rapid ↑ size and local pressure symptoms eg. dysphagia
and hoarseness of voice
• External neck irradiation during childhood or adolescence
• A firm/hard irregular and fixed nodule
• Ipsilateral cervical lymphadenopathy
• Positive family history
– Familial medullary thyroid cx has autosomal dominant
inheritance
– Papillary thyroid cx is familial in 3% of cases.
• Dominant nodule in a multi-nodular goitre

• Ultrasound scan to determine
1. Single or multiple nodules
2. Changes in size of the nodule.
3. Cystic (↓ risk for malignancy),
solid (20%) or mixed (30% risk)
• With FNAC to distinguish benign
from malignant thyroid nodules.
1. Cannot separate follicular
adenoma from carcinoma so
surgical excision needed for
histological diagnosis.
http://www.hyderabadendocrinology.com/content/thyroid-swelling

• Thyroid scintiscan with 99mTc or 123 I may
separate toxic from cold nodules.
– Cold nodules have about 10-20% incidence of
malignancy.
• Other scans eg. CT and MRI scans are not
useful in the diagnosis of thyroid nodules.

Laboratory investigations
• Thyroid function tests (fT4, TSH and if
indicated, fT3) should be done to evaluate
a hot nodule.

Management
• Colloid cyst may be aspirated for Rx. With recurrence,
surgery may be performed.
• Toxic adenoma is treated surgically or with radioiodine.
• For papillary and follicular carcinoma, total thyroidectomy
then ablative radioiodine and L-thyroxine may be curative.
• Management and prognosis of thyroid cancer depends
factors such as age, histology and TNM classification.
• Anaplastic thyroid carcinoma has a poor prognosis so
palliative Rx using external radiotherapy and in some
cases, chemotherapy.
• Medullary thyroid carcinoma may be part of a Multiple
Endocrine Neoplasia II syndrome. Treatment is surgical
after excluding phaeo-chromocytoma.

Monitoring
• Serial thyroglobulin measurements and whole
body iodine scanning are useful for monitoring
for recurrence.
• When serum thyroglobulin level increases,
whole body iodine scanning is indicated.

Multinodular Goitre (MNG)
• Enlargement of the thyroid gland due to multiple nodules.
• May be detected either clinically or via imaging.
• Majority are benign but it is not possible to differentiate
benign from malignant nodules on clinical grounds alone.
• The prevalence of MNG is higher in iodine deficient areas,
women and older individuals.
• Aetiology is often unknown but known causes include
– iodine deficiency
– goitrogen ingestion
– autoimmune disorders
– dyshormonogenesis (usually diffuse in the initial stages).

Clinical features
• Often euthyroid but sometimes hyperthyroid or
hypothyroid patient with painless neck swellings.
• Occasionally, may present with painful swelling
with sudden increase in size due to haemorrhage.
• Large MNGs can extend retrosternally and cause
superior vena cava obstruction or stridor.
• Pressure symptoms and cervical
lymphadenopathy indicate the possibility of
malignancy.

• Ultrasound scan to determine
1. Number of nodules
2. Changes in size of the nodule.
3. Cystic (↓ risk for malignancy),
solid (20%) or mixed (30% risk)
• With FNAC to distinguish benign
from malignant thyroid nodules.
– Cannot separate follicular
adenoma from carcinoma so
surgical excision needed for
histological diagnosis.
http://www.hyderabadendocrinology.com/content/thyroid-swelling

Laboratory investigations
• Thyroid function tests (fT4, TSH and if
indicated, fT3) should be done to evaluate
a hot nodule.
• Thyroid antibody assay (anti-thyroid
peroxidase and anti-thyroglobulin).

Management
• Small, asymptomatic goitres need no treatment.
• +/- Thyroxine suppression therapy
– contraindicated in patients with ischaemic heart disease.
• Anti-thyroid drugs for symptom alleviation.
• Surgery, for large goitres with compressive symptoms and
for cosmetic reasons.
– With partial thyroidectomy, recurrence rate is high and
subsequent surgery carries a higher risk of
complications.
• Radioiodine therapy is not recommended for large non-
toxic goitres as multiple high doses are required and
response is poor.

Thyroid ultrasound scan
• Normal Study. The two lobes of the thyroid
lie on either side of the trachea.

Computed Tomography
• Normal CT scan. The
carotid arteries are
arrowed.
• T= Trachea,
• S= stenocleidomastoid
muscle.

Radionuclide scan
• Normal Iodine scan.

Chest X-ray
• A normal chest x-ray (Left image)
• A chest x-ray showing deviation and compression of the
trachea by a retrosternal goitre (Right image)
http://www.endocrinesurgeon.co.uk/index.php/what-tests-may-be-performed-prior-to-thyroid-surgery

Chest X-ray
• The trachea is
compressed and
narrowed by a
goitre

Barium Swallow
• The oesophagus
displaced to the right
by a goitre

• Scintigraphy.
• Iodine 123 scan
showing a functioning
(Hot) nodule in the left
lobe.

Ultrasound scan
• Colloid cyst in the right thyroid lobe
http://www.ultrasoundcases.info/case-list.aspx?cat=276

Ultrasound scan
• Thyroid adenoma with cystic degeneration
http://www.ultrasoundcases.info/case-list.aspx?cat=276

Ultrasound scan
• Adenoma appearing as a solid nodule (N) in the
right lobe

CT scan
• CT scan showing an intrathoracic goitre
displacing the trachea to the right.

MRI
• Coronal T1 weighted MRI showing a large left
sided goitre extending into the thorax.

Differential diagnosis of neck swelling
• Thyroglossal cyst seen anteriorly in the
neck.

Differential diagnosis of neck swelling
• T2-weighted MRI
scan in another
patient showing a
thyroglossal cyst
as a high signal
intensity area
anteriorly in the
neck.

Summary
• The thyroid gland is a very important endocrine
gland that affects homeostasis.
• Laboratory investigations and imaging
modalities with cytology/histology can used to
arrive at the diagnosis.
• With appropriate treatment and interventions,
patients may improve in their clinical state.

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