Endocrine Flashcards
What is Cushing syndrome?
The clinical manifestation of pathological hypercortisolism from any cause
Exogenous corticosteroid exposure is the most common cause.
What is the most common cause of endogenous Cushing syndrome?
Cushing’s disease, caused by an ACTH-secreting pituitary adenoma
Responsible for 70-80% of cases.
What are some common presentations of Cushing syndrome?
Weight gain with central obesity, facial rounding, plethora, proximal muscle weakness, thinning of the skin
Also includes metabolic complications.
List some metabolic complications associated with Cushing syndrome.
- Diabetes mellitus
- Dyslipidaemia
- Metabolic bone disease
- Hypertension
What should be excluded before testing for Cushing syndrome?
Exogenous corticosteroid use
Name one of the four high-sensitivity tests for hypercortisolism.
Late-night salivary cortisol
Other options include low-dose dexamethasone suppression testing, 24-hour urinary free cortisol, and 48-hour dexamethasone suppression testing.
What should be done if a patient has a positive initial screening test for hypercortisolism?
At least one additional test should be used to confirm hypercortisolism.
What should be measured once endogenous hypercortisolism is confirmed?
Plasma ACTH
If ACTH is suppressed, what should diagnostic testing focus on?
The adrenal glands
If ACTH is not suppressed, what conditions should be sought?
Pituitary or ectopic disease
What is the primary treatment of choice for endogenous Cushing syndrome?
Surgical resection of the pituitary adenoma or adrenal adenoma causing hypercortisolism
What are multiple endocrine neoplasia (MEN) syndromes?
Rare hereditary tumour syndromes characterised by the development of multiple endocrine tumours.
MEN syndromes include MEN1 and MEN2 with distinct characteristics and associated tumours.
What gene is associated with MEN1?
Mutations in the tumour suppressor gene MEN1.
MEN1 is crucial for regulating cell growth and preventing tumour formation.
What is the diagnostic criteria for MEN1?
Patients must have ≥2 MEN1-associated tumours, 1 associated tumour with a 1st-degree relative, or a diagnosed pathogenic mutation of MEN1.
This diagnostic approach helps in early identification and management of the syndrome.
List the endocrine tumours associated with MEN1.
‘3 Ps’
- Parathyroid adenomas
- Pituitary adenomas
- Pancreatic tumours
- Gastrinomas
- Neuroendocrine/carcinoid tumours from bronchial/gastric/thymic origin
- Adrenal cortical tumours
- CNS tumours, including meningiomas
- Thyroid tumours
What are the non-endocrine tumours associated with MEN1?
- Cutaneous tumours
- Lipomas
- Facial angiofibromas
These non-endocrine manifestations can also be significant in the clinical presentation of MEN1.
What is the common association of primary hyperparathyroidism in MEN1?
At least 90% of patients develop primary hyperparathyroidism by 50 years of age.
This statistic highlights the importance of monitoring for hyperparathyroidism in MEN1 patients.
What mutations are involved in MEN2?
RET proto-oncogene mutations.
These mutations lead to the development of medullary thyroid cancer and/or phaeochromocytoma.
What are the subgroups of MEN2?
- MEN2A (Sipple’s syndrome)
- MEN2B
What features are associated with MEN2A?
‘2ps and one M’
- Medullary thyroid cancer
- Phaeochromocytoma
- parathyroid adenomas with hyperparathyroidism
(* Hirschsprung’s disease
* Cutaneous lichen amyloidosis )
MEN2A is characterized by a combination of these features, which can vary among patients.
What features are associated with MEN2B?
‘2 Ms and 1 P’
- Medullary thyroid cancer
- Phaeochromocytoma
- Marfanoid body habitus
(* Mucosal intestinal ganglioneuromatosis )
What defines familial medullary thyroid cancer?
- Family patterns of isolated medullary thyroid cancers
- Pedigrees of multiple carriers > 50 years of age
- No other MEN2 manifestations
This form focuses on isolated occurrences of medullary thyroid cancer without broader MEN2 features.
What is the importance of medical management in MEN syndromes?
Medical management of hormonal hypersecretion is important for symptom control.
Hormonal imbalances can lead to significant health issues if not managed appropriately.
What is the role of surgical intervention in MEN syndromes?
Most tumours require surgical evaluation, though surgical cure is not always possible.
The surgical approach can vary based on tumour type and patient health.
What is indicated for patients with MEN2 regarding thyroidectomy?
Prophylactic thyroidectomy in childhood is indicated in MEN2.
This preventive measure aims to reduce the risk of developing medullary thyroid cancer.
What is necessary for genetic carriers of MEN syndromes post-surgery?
Lifelong monitoring is required, even after successful operations.
Continuous monitoring helps in early detection of potential tumour recurrence or new developments.
What is the typical age of onset for endocrine tumours in MEN1?
Teenage years
Symptoms may not appear for several years and diagnosis is often delayed until the fourth decade of life.
What is a common presenting feature of MEN1 in about 80% of patients?
Hyperparathyroidism
This can lead to hypercalcaemia and recurrent nephrolithiasis.
What syndrome is associated with hypergastrinaemia in MEN1?
Zollinger-Ellison syndrome
This leads to increased gastric acid secretion.
What condition in MEN1 is characterized by excess growth hormone?
Acromegaly
This can occur due to tumours of the pituitary gland.
What types of tumours in MEN1 are mostly of cosmetic concern?
Angiofibromas, collagenomas, and lipomas
These tumours typically do not cause symptoms.
What is the lifetime risk of developing medullary thyroid cancer (MTC) in untreated MEN2 patients?
More than 95%
MTC can present as early as 2 months old.
What percentage of MEN2 patients develop phaeochromocytoma?
Around 40%
This condition can lead to various symptoms including hypertension.
List some symptoms associated with hyperparathyroidism in MEN2.
- Constipation
- Polyuria
- Polydipsia
- Memory problems
- Depression
- Nephrolithiasis
- Glucose intolerance
- Gastro-oesophageal reflux
- Fatigue
These symptoms are secondary to hypercalcaemia.
What symptoms may indicate the presence of phaeochromocytoma in MEN2?
- Hypertension
- Episodic sweating
- Diarrhoea
- Pruritic skin lesions
- Lump in the neck
Cutaneous lichen amyloidosis can occur, and compressive symptoms may arise from thyroid or parathyroid tumours.
True or False: Symptoms from endocrine tumours in MEN1 typically appear early in life.
False
Symptoms may not appear for several years.
Fill in the blank: Symptoms from tumours of the pituitary gland may cause symptoms by _______ effect.
mass
This refers to the physical pressure that the tumours exert on surrounding structures.
What is Addison’s disease?
Addison’s disease, or primary adrenal insufficiency, is a disorder affecting the adrenal glands, causing insufficient production of adrenocortical hormones (cortisol, aldosterone, & dehydroepiandrosterone).
What percentage of the adrenal cortex needs to be destroyed to produce adrenal insufficiency?
~90% of the adrenal cortex needs to be destroyed.
What is secondary adrenal insufficiency?
Secondary adrenal insufficiency occurs in patients with pituitary or hypothalamic involvement, resulting in low adrenocorticotrophic hormone (ACTH) secretion and adrenal failure.
What are common symptoms of Addison’s disease?
Symptoms include substantial fatigue, weakness, mucocutaneous hyperpigmentation, hypotension, postural hypotension, and salt craving.
What is the ACTH stimulation test used for?
The ACTH stimulation test is performed to confirm or exclude the diagnosis of Addison’s disease.
What type of hormone replacement is required for patients with Addison’s disease?
Patients require mineralocorticoid and glucocorticoid replacement for life.
When should patients increase their glucocorticoid dose?
Patients should increase the dose of glucocorticoid during surgery and any stressful or infectious conditions.
True or False: Over-replacement of mineralocorticoid and/or glucocorticoid can lead to treatment complications.
True
Fill in the blank: Addison’s disease is characterized by insufficient production of _______.
[adrenocortical hormones]
What are the two types of adrenal insufficiency?
The two types are primary adrenal insufficiency (Addison’s disease) and secondary adrenal insufficiency.
What are the potential causes of Addison’s disease?
Causes include a destructive process affecting the adrenal glands or conditions interfering with hormone synthesis.
What is normal range for plasma osmolarity
285-295
What is normal range for plasma osmolarity
285-295
Osmolarity in:
DKA
HHS
- > 290
- > 320
What electrolyte disturbance gives you paraethesia, tetany, spasms of hands/ feet and prolonged QT?
Hypocalcaemia
Which antidiabetic drug can cause lower limb amputation
SGLT2 inhibitors eg canagliflozin
Which anti diabetic drug can cause bladder cancer
Pioglitazone
Which anti diabetic drug can cause vitamin B12 deficiency
Metformin
Which anti hypertensive drugs can worsen glycemic control
Beta blockers and thiazides
