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SU22.1-6 | Thyroid and Parathyroid Surgery — PBL Case

CLINICAL SETTING

Mr. Ramesh, a 56-year-old accountant, is referred to the surgical clinic after passing two kidney stones in the past year. He also complains of vague bone aches, constipation, excessive thirst, frequent urination and a recent low mood that his family has noticed. His general practitioner checked his blood and found that his serum calcium was high. He has no neck lump and his voice is normal.

Trigger 1: Stones, bones, groans and moans

Mr. Ramesh's symptoms — renal stones, bone aches, abdominal symptoms and altered mood — cluster together in a recognisable pattern. His repeat serum calcium is confirmed high. The team begins to think about why a man with no neck lump might present in this way.

DISCUSSION POINTS

  • How do the symptoms of stones, bones, abdominal groans and psychic moans relate to a raised serum calcium?
  • Why do parathyroid disorders 'almost never present as a neck lump' but instead through the serum calcium?
  • What single additional blood test, interpreted alongside the calcium, would most help you identify the cause of his hypercalcaemia?
Click to reveal Trigger 2: Diagnose before you image (discuss previous trigger first!)

Trigger 2: Diagnose before you image

Further tests show a raised serum calcium together with an inappropriately raised PTH and a low–normal phosphate. The team is confident of the biochemical diagnosis and discusses what to do next. A junior colleague suggests requesting a sestamibi scan straight away 'to find the adenoma'.

DISCUSSION POINTS

  • What is the biochemical diagnosis, and why does the combination of high calcium with an inappropriately raised PTH confirm it?
  • Why is it a mistake to order a localising scan before the biochemistry is confirmed — what can a scan never do?
  • Once the diagnosis is secure, what is the role of imaging such as sestamibi and ultrasound, and how does this guide the operation?
Click to reveal Trigger 3: Surgery, anatomy and the neighbours (discuss previous trigger first!)

Trigger 3: Surgery, anatomy and the neighbours

Mr. Ramesh is found to have a single parathyroid adenoma and is listed for parathyroidectomy. During consent he asks how the operation is done, whether his voice or his calcium could be affected, and whether the operation will cure him.

DISCUSSION POINTS

  • Using the applied anatomy of the parathyroid glands (number, position, blood supply, embryological origin), explain how the surgeon finds and removes the adenoma.
  • How does parathyroidectomy for a single adenoma cure primary hyperparathyroidism, and which patients with primary hyperparathyroidism should be offered surgery?
  • Which structures near the thyroid and parathyroids are at risk during neck surgery, and what symptoms would alert you to recurrent laryngeal nerve injury or post-operative hypocalcaemia?

Group Task Assignments

  • Draw a labelled diagram of the posterior thyroid showing the four parathyroid glands, their usual positions, their blood supply and their embryological origins (third and fourth pharyngeal pouches).
  • Build a decision flowchart for the work-up of hypercalcaemia that starts with calcium and PTH and ends with the decision to operate, deliberately placing imaging after the biochemical diagnosis.
  • Prepare a short patient-consent briefing for parathyroidectomy covering the benefit (cure) and the two key neck-surgery complications (recurrent laryngeal nerve injury and hypocalcaemia).

Learning Issues

Research these questions and bring your findings to the discussion.

  1. [SU22.5] Describe the applied anatomy of the parathyroid glands: their usual number and position, blood supply from the inferior thyroid artery, and embryological origin from the third and fourth pharyngeal pouches.
  2. [SU22.6] Describe the clinical features of hyperparathyroidism (stones, bones, abdominal groans, psychic moans) and of hypoparathyroidism (hypocalcaemia, Chvostek's and Trousseau's signs).
  3. [SU22.6] Explain the principle 'diagnose the parathyroid before you image it', the biochemical diagnosis of primary hyperparathyroidism, and the indications for parathyroidectomy.
  4. [SU22.1] Outline the structures at risk during thyroid and parathyroid surgery, especially the recurrent and external laryngeal nerves and the parathyroid glands, and the clinical features of their injury.