T1 L9 HPA axis: clinical aspects Flashcards

1
Q

What are the effects of glucocorticoids?

A
Maintenance of homeostasis during stress
Anti-inflammatory
Energy balance / metabolism
Formation of bone and cartilage
Regulation of blood pressure
Cognitive function, memory, conditioning
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2
Q

Describe the circadian rhythm of cortisol levels

A

Rise during early morning
Peak just prior to awakening
Fall during the day
Low in the evening

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3
Q

What enzyme in the kidney inactivates cortisol?

A

11-B-HSD-2

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4
Q

What is Cushing’s syndrome?

A

Too much cortisol

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5
Q

What are the clinical features and symptoms of Cushing’s syndrome?

A
Weight gain
Central obesity with thin arms and legs
Fat deposition over upper back
Rounded moon face
Thin skin with easy bruising, pigmented striae
Hirsutism
Hypertension
Insulin resistance
Neuropsychiatric problems
Osteoporosis
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6
Q

What are the causes of too much cortisol?

A

Pituitary adenoma: ACTH secreting cells
Adrenal tumour: adenoma
Ectopic ACTH: carcinoid, paraneoplastic
Iatrogenic: steroid treatment

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7
Q

What is Addison’s disease?

A

Too little cortisol

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8
Q

What are the clinical features and symptoms of too little cortisol?

A

Malaise, weakness, anorexia, weight loss
Increased skin pigmentation: knuckles, palmar creases, around mouth, pressure areas, scars
Hypotension / postural hypotension
Hypoglycaemia

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9
Q

What are the causes of too little cortisol?

A

Primary adrenal insufficiency: Addison’s disease, autoimmune, metastases, TB, decreased production of all adrenocortical hormones
Secondary to pituitary disease
Iatrogenic

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10
Q

Describe type I autoimmune polyendocrine syndromes

A

Rare
Onset in infancy
Ar (AIRE) gene
Common phenotype: Addison’s disease, hypoparathyroidism, candidiasis

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11
Q

Describe type II autoimmune polyendocrine syndromes

A

Commoner although still rare
Infancy to adulthood
Polygenic
Common phenotype: Addison’s disease, T1 diabetes, autoimmune thyroid disease

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12
Q

What are some autoimmune conditions that may occur together?

A
Type I diabetes
Autoimmune thyroid disease
Coeliac disease
Addison's disease
Pernicious anaemia
Alopecia
Vitiligo
Hepatitis
Premature ovarian failure
Myasthenia gravis
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13
Q

What is the likely diagnosis of someone with type 1 diabetes mellitus with fatigue, weight loss and hypos?

A

Addison’s disease

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14
Q

What is the likely diagnosis of someone with type 1 diabetes and non-specific GI symptoms / diarrhoea?

A

Coeliac disease

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15
Q

What basal tests are done to assess the HPA axis?

A

Blood: cortisol, ACTH
Urine: cortisol
Saliva: cortisol

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16
Q

What dynamic tests are done to assess the HPA axis?

A

Stimulated: ACTH, CRH, stress e.g. hypoglycaemia
Suppressed: dexamethasone

17
Q

Why shouldn’t you investigate for an endocrine condition unless they have symptoms and signs?

A

Risk of false positive results

18
Q

Why should you never image an endocrine gland until biochemical diagnosis is established?

A

Risk of discovering incidentalomas

19
Q

Describe the urea and electrolytes in Addison’s disease

A

Decreased Na
Increased K
Due to mineralocorticoid deficiency

20
Q

What imaging is done once it is confirmed a patient has Cushing’s syndrome?

A

Chest X-ray
MRI of pituitary
CT adrenals

21
Q

What is the surgical management of Cushing’s disease?

A

Transphenoidal adenectomy

Adrenalectomy

22
Q

What is the management of Addison’s disease?

A

Steroid hormone replacement therapy - usually hydrocortisone

Mineralocorticoid replacement therapy in those with primary adrenal insufficiency

23
Q

Give examples of conditions that require steroidal treatment

A

Severe asthma
COPD
Temporal arteritis
Polymyalgia rheumatica