Thyroid lumps and diagnosis Flashcards

Describe the anatomy of thyroid gland • Understand thyroid physiology • Discuss common causes of thyroid swellings • Understand the general approach, laboratory and Imaging studies in the evaluation of thyroid swellings • Describe clinical and imaging features of thyroid swellings • Outline treatment strategies

1
Q

When does the first endocrine gland (thyroid) develop?

A

24 days

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2
Q

What structure thickens to begin the development of the thyroid?

A

Endodermal thickening in the primordial pharynx

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3
Q

What divides into two lobes?

A

Thyroid diverticulum

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4
Q

How is the thyroid attached to the tongue?

A

By the thyroglossal duct

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5
Q

What occurs at week 7?

A

Thyroglossal duct degenerates and is replaced by the pyramidal lobe in 50% of people

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6
Q

Where does the thyroid gland lie anatomically?

A

Anterior to the 2nd/3rd tracheal ring

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7
Q

What occurs are week 7?

A

Colloid in thyroid follicles

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8
Q

Which cells make up the thyroid?

A

Follicular cells

Para-follicular cells

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9
Q

What do follicular cells do?

A

produce and secrete Triiodothyronine (T3) and etraiodothyronine or Thyroxine (T4)

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10
Q

What do T3 and T4 do?

A

Regulates metabolism of various tissues and organs

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11
Q

What do para-follicular cells do?

A

Release calcitonin

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12
Q

What is the function of calcitonin?

A

important hormone for maintaining Ca homeostasis

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13
Q

What role does the hypothalamus play in the regulation of thyroid hormone synthesis?

A

Releases thyroid releasing hormone which stimulates pituitary gland

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14
Q

What role does the pituitary gland play in the regulation of the thyroid hormone synthesis?

A

releases thyroid stimulating hormone

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15
Q

Name the metabolic effects of the thyroid hormones?

A
Lipid and carbohydrate metabolism
• Growth
• Development (foetal and neonatal brain) • Cardiovascular system
• Central nervous system
• Gastrointestinal system
• Reproductive system
• Bone turnover
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16
Q

Name the etiological classification of thyroid swellings

A

Simply goitre
Inflammatory
Neoplastic
Other

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17
Q

What are the potential anomalies of thyroid gland development?

A

Persistence of thyroglossal duct results in thyroglossal cyst or fistula
• Rarely thyroid bud fails to descend to form the lingual thyroid
• May descend too far into the mediastinum to form the retrosternal goitre
• Thyroid bud may fail to divide into two resulting in absent thyroid lobe

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18
Q

Name the benign causes of thyroid swellings

A
  • Multinodular goitre
  • Hashimoto’s thyroiditis
  • Cysts; colloid, simple, haemorrhagic - Follicular adenoma
  • Oxyphil adenoma
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19
Q

Name the malignant causes of thyroid swellings

A
  • Papillary Ca
  • Follicular Ca
  • Medullary Ca
  • Anaplastic Ca
  • Primary lymphoma - Metastatic Ca
20
Q

Name the types of solitary thyroid nodules

A
  • Adenoma
  • Cyst
  • Dominant nodule in a multinodular goitre
  • Colloid goitre
  • Localised form of thyroiditis
  • Thyroid carcinoma
21
Q

What are the function symptoms (hyper/hypothyroidism)?

A
– Lethargy
– Weight loss/ gain
– Palpitations/bradycardia – Mood Change/swings
( Anxiety/ Depression)
– Diarrhoea/ Constipation
– Susceptibility to temperature
– Menstrual Abnormalities
– Fertility Problems
– Dry hair/skin
– Weak muscles
– Eye signs ( Exophthalmos/ Proptosis/ Puffy eyes)
22
Q

What changes in structure must you look for when assessing a ‘lump’?

A
  • Lump, smooth goitre , asymmetrical – Size
    – Speed of onset or growth
    – Other neck lumps / lymph nodes
23
Q

What are the associated symptoms?

A

problems with:

Breathing/ Stridor
– Pressure
– Swallowing
– Change in Voice

24
Q

How should you examine a patient with a lump?

A

Feel from behind first
Trachea where is it?
Palpate lobes either side one at a time: symmetry and size
Ask patient to swallow Can I get below the swelling ( assess retrosternal extension)?
Lymph nodes: (lateral level II- V)

25
Q

What does a thyroid function test assess?

A

TSH

  • FT4
  • FT3
26
Q

What antibody tests are taken?

A
  • Anti TPO
  • Anti Tg
  • TRAb
27
Q

What can be tested in the blood?

A

Calcitonin, FBC, ESR, Ca profile

28
Q

What are the types of imaging studies used to assess thyroid swellings?

A
  • Ultrasonography
  • Nuclear scintigraphy • CT
  • MRI
  • PET-CT
29
Q

What can ultrasonography be useful for?

A

Assess size, anatomy, contents, vascularity of a nodule
• Detect non palpable nodule in 63% patients and 24% additional nodules
• Facilitates FNAC
• Evaluate the recurrence of thyroid swelling
following surgery
• Assess any lymph node presence and adjacent structures in neck

30
Q

What can thyroid scintigraphy be useful for?

A

Assess functional status of a nodule
• Help guide FNAC of nodules
• 5-20% of non functioning nodules malignant
• Functioning nodules nearly always benign
• Patients with suppressed TSH, presence of a functioning nodules obviates the need for biopsy
• Helps detect ectopic thyroid tissue
• Helps detect metastases in thyroid cancer

31
Q

How does thyroid scintigraphy work?

A

Uses Technetium pertechnetate or radioiodine (I-131 or I-123)
• Thyroid follicular cells trap both but organify radioiodine
• Both benign and most malignant thyroid cells concentrate radiotracer < normal thyroid cells

32
Q

What are the causes of hypo-functioning nodules on thyroid scan?

A
  • Cyst
  • Non functioning adenoma • MNG
  • Malignancy
  • Thyroidits
  • Fibrosis
33
Q

What are the causes of functioning nodules on thyroid scans?

A
  • Adenoma
  • MNG
  • Malignancy
34
Q

What are the limitations of scintigraphy?

A
  • poor anatomy
  • no measurements obtained
  • interference by extraneous agents resulting in false negatives
  • unable to distinguish between benign and malignant lesions
35
Q

What are CT/MRI/PET-CT scans useful for?

A
  • Useful in assessing large goitres and their retrosternal extension
  • Evaluate the relationship of thyroid swelling to other neck structures
  • Assess lymph node status in malignant thyroid swellings
  • Help in the evaluation of detecting recurrent thyroid cancers
36
Q

What is FNAC?

A

Fine needle aspiration cytology

37
Q

What are the limitations of FNAC?

A

• Sampling errors
• Cannot distinguish between follicular
adenoma and carcinoma • False negatives

38
Q

How is goitre/nodule treated?

A
  • Conservative – Reassure – Benign/ Euthyroid/ asymptomatic/ no compression symptoms
  • Surgery – tracheal compression/ compressive symptoms/ indeterminate FNA/ Malignant FNA ( +/- Lymph node Surgery)
39
Q

How is thyrotoxicosis treated?

A
• Antithyroid medication 
– Carbimazole
– Propylthiouracil
– Steroids
– Betablockers
• Radioactive Iodine – 131 Iodine
– Definitive treatment for thyrotoxicosis – recurrent or solitary toxic nodule or toxic MNG
– 80% cure one dose/90% cure two doses
– 3-4 weeks away from children
– No pregnancy for 6 months
– Can worsen eye signs ( steroids)
40
Q

What are the indications for the surgical treatment for thyrotoxicosis (excess thyroid hormone) ?

A

Recurrent / Uncontrolled Thyrotoxicosis Solitary Toxic Nodule
Eye disease
Preganancy
Cosmetic
Failed Radioiodine treatment Endocrinologists
Patient choice

41
Q

Name the types of thyroid surgery

A

• Near Total Thyroidectomy ( thyrotoxicosis)
• Lobectomy/ Hemithyroidectomy/ Isthmusectomy ( nodule/ diagnostic)
• Total thyroidectomy ( thyroid cancer)
• Lymph Node Surgery
– Central Neck Dissection ( Level VI- VII) – Lateral Neck Dissection ( Level II-V)

42
Q

How is thyroid cancer treated?

A
  • Surgery
  • Radioiodine Ablation • TSH suppression
  • Radiotherapy
  • Anti cancer drugs
43
Q

What type of gland is the thyroid?

A

endocrine

44
Q

Which hormones does the thyroid secrete?

A

a) Triiodothyronine

b) Thyroxine

45
Q

What is the thyroid gland primarily responsible for regulating?

A

Metabolism

46
Q

Are men or women more likely to be affected by thyroid swellings?

A

Women