Endocrinology, diabetes and metabolic medicine for MRCP Part 1

A 48-year-old man reports that his wedding ring and shoes no longer fit, with increased sweating and headaches over 3 years. He has a prominent jaw, large hands and new hypertension. IGF-1 is markedly raised, and growth hormone fails to suppress during an oral glucose tolerance test. What is the most likely diagnosis?

1. Constitutional large build Normal habitus rather than disease. Insidious acral and facial change with a raised IGF-1 and non-suppressing growth hormone makes it a consideration.
2. Pituitary incidentaloma without excess hormone A non-functioning adenoma. Insidious acral and facial change with a raised IGF-1 and non-suppressing growth hormone separates it.
3. Pseudoacromegaly from insulin resistance Acromegaloid features without growth hormone excess. Insidious acral and facial change with a raised IGF-1 and non-suppressing growth hormone redirects it.
4. Familial features Inherited facial characteristics. Insidious acral and facial change with a raised IGF-1 and non-suppressing growth hormone makes it a consideration.
5. Acromegaly correct Correct. Insidious acral and facial change with a raised IGF-1 and non-suppressing growth hormone is acromegaly.

The point: Acromegaly is caused by excess growth hormone, almost always from a pituitary somatotroph adenoma, occurring after the growth plates have fused (before fusion it causes gigantism). Growth hormone drives insulin-like growth factor 1 (IGF-1) from the liver, and the clinical features develop insidiously over years: coarsening facial features, a large jaw and tongue, enlarging hands and feet (rings and shoes no longer fit), sweating, headaches, carpal tunnel syndrome, and metabolic effects including impaired glucose tolerance or diabetes and hypertension. A large adenoma can compress the optic chiasm to give a bitemporal hemianopia or reduce other pituitary hormones. Screening is with a raised IGF-1; the confirmatory test is failure of growth hormone to suppress during an oral glucose tolerance test, and an MRI of the pituitary then locates the adenoma. First-line treatment is transsphenoidal surgery; medical therapy with somatostatin analogues (such as octreotide), a growth hormone receptor antagonist (pegvisomant) or dopamine agonists is used when surgery is incomplete, and radiotherapy is a further option. Untreated acromegaly carries excess cardiovascular mortality and a raised risk of colonic polyps and cancer, so treatment aims to normalise IGF-1 and growth hormone.

Source: Society for Endocrinology — acromegaly Society for Endocrinology · tier 2, specialty society or college

A 48-year-old man reports that his wedding ring and shoes no longer fit, with increased sweating and headaches over 3 years. He has a prominent jaw, large hands and new hypertension. IGF-1 is markedly raised, and growth hormone fails to suppress during an oral glucose tolerance test. What is the most appropriate investigation?

1. Glucose and cardiovascular risk assessment For the metabolic complications. Insidious acral and facial change with a raised IGF-1 and non-suppressing growth hormone makes it useful.
2. Pituitary hormone profile For hypopituitarism from a large tumour. Insidious acral and facial change with a raised IGF-1 and non-suppressing growth hormone makes it thorough.
3. Visual field assessment For chiasmal compression. Insidious acral and facial change with a raised IGF-1 and non-suppressing growth hormone makes it important.
4. Serum IGF-1 The screening test, raised in acromegaly. Insidious acral and facial change with a raised IGF-1 and non-suppressing growth hormone makes it central.
5. Oral glucose tolerance test with growth hormone measurement correct Correct. Failure of growth hormone to suppress during a glucose tolerance test confirms acromegaly.

The point: Acromegaly is caused by excess growth hormone, almost always from a pituitary somatotroph adenoma, occurring after the growth plates have fused (before fusion it causes gigantism). Growth hormone drives insulin-like growth factor 1 (IGF-1) from the liver, and the clinical features develop insidiously over years: coarsening facial features, a large jaw and tongue, enlarging hands and feet (rings and shoes no longer fit), sweating, headaches, carpal tunnel syndrome, and metabolic effects including impaired glucose tolerance or diabetes and hypertension. A large adenoma can compress the optic chiasm to give a bitemporal hemianopia or reduce other pituitary hormones. Screening is with a raised IGF-1; the confirmatory test is failure of growth hormone to suppress during an oral glucose tolerance test, and an MRI of the pituitary then locates the adenoma. First-line treatment is transsphenoidal surgery; medical therapy with somatostatin analogues (such as octreotide), a growth hormone receptor antagonist (pegvisomant) or dopamine agonists is used when surgery is incomplete, and radiotherapy is a further option. Untreated acromegaly carries excess cardiovascular mortality and a raised risk of colonic polyps and cancer, so treatment aims to normalise IGF-1 and growth hormone.

Source: Society for Endocrinology — acromegaly Society for Endocrinology · tier 2, specialty society or college

A 48-year-old man reports that his wedding ring and shoes no longer fit, with increased sweating and headaches over 3 years. He has a prominent jaw, large hands and new hypertension. IGF-1 is markedly raised, and growth hormone fails to suppress during an oral glucose tolerance test. What is the most appropriate management?

1. Treat the metabolic and cardiovascular complications Diabetes and hypertension. Insidious acral and facial change with a raised IGF-1 and non-suppressing growth hormone makes it thorough.
2. Growth hormone receptor antagonist (pegvisomant) For resistant disease. Insidious acral and facial change with a raised IGF-1 and non-suppressing growth hormone makes it an option.
3. Radiotherapy for residual disease A further option. Insidious acral and facial change with a raised IGF-1 and non-suppressing growth hormone makes it adjunctive.
4. Transsphenoidal surgery first line correct Correct. Transsphenoidal surgery is the first-line, definitive treatment for most patients.
5. Dopamine agonist in selected cases For milder or co-secreting tumours. Insidious acral and facial change with a raised IGF-1 and non-suppressing growth hormone makes it flexible.

The point: Acromegaly is caused by excess growth hormone, almost always from a pituitary somatotroph adenoma, occurring after the growth plates have fused (before fusion it causes gigantism). Growth hormone drives insulin-like growth factor 1 (IGF-1) from the liver, and the clinical features develop insidiously over years: coarsening facial features, a large jaw and tongue, enlarging hands and feet (rings and shoes no longer fit), sweating, headaches, carpal tunnel syndrome, and metabolic effects including impaired glucose tolerance or diabetes and hypertension. A large adenoma can compress the optic chiasm to give a bitemporal hemianopia or reduce other pituitary hormones. Screening is with a raised IGF-1; the confirmatory test is failure of growth hormone to suppress during an oral glucose tolerance test, and an MRI of the pituitary then locates the adenoma. First-line treatment is transsphenoidal surgery; medical therapy with somatostatin analogues (such as octreotide), a growth hormone receptor antagonist (pegvisomant) or dopamine agonists is used when surgery is incomplete, and radiotherapy is a further option. Untreated acromegaly carries excess cardiovascular mortality and a raised risk of colonic polyps and cancer, so treatment aims to normalise IGF-1 and growth hormone.

Source: Society for Endocrinology — acromegaly Society for Endocrinology · tier 2, specialty society or college