Adrenal disease Flashcards
Zones of the adrenal glannd and products?
Zona Glomerulosa –> Mineralocorticoids
Zona Fasiculata –> Glucocorticorticoids
Zona Reticularis –> Androgens
Medulla –> Catecholamines
Congenital adrenal hyperplasia
Autosomal recessive disorders resulting from mutations in genes coding enzymes mediating the biochemical steps of production of mineralocorticoids, glucocorticoids or sex steroids from cholesterol by the adrenal glands
21 hydroxylase deficiency –> loss of aldosterone and cortisol and excess androgens
11 Beta hydroxylase deficiency –> loss of cortisol and excess aldosterone and androgens
17Alpha hydroxylase deficiency –> mild disease with overproduction of androgens
Presentation of CAH?
Inadequate mineralocorticoids –> vomiting due to salt-wasting leading to dehydration and death
Due to excess androgens:
- functional and average sized penis in cases involving extreme virilization (but no sperm)
- ambiguous genitalia, in some females
- early pubic hair and rapid growth in childhood
- precocious puberty or failure of puberty to occur
- excessive facial hair, virilization, and/or menstrual irregularity in adolescence
- infertility due to anovulation
Treatment of CAH
Severe CAH presenting in neonate –>
- replace mineralocorticoid with hydrocortisone
- Fluid replacement
- Determine sex of the child
Prevent precocious puberty
Anti-andogens in females
Causes of adrenal insufficiency?
Addisons - primary adrenal failure
Pituitary - apoplexy, trauma or tumors
Hypothalamic - trauma or tumours
EXOGENOUS STEROIDS
Causes of addisons disease?
Autoimmune +++ - 90% developed countries TB destruction Adrenal haemorrhage Cancer - primary or mets Ketoconazole CAH
Clinical features of Addison’s disease
Low cortisol –>
- High ACTH –> pigmentation
- Hypoglycaemia
- Weight loss
- Fatigue
Low Aldosterone –>
- Salt wasting
- Hyperkalaemia
- Hypercholaemic acidosis
- Water retention
- Hypotension
Diagnosis of Adrenal insufficiency?
Screening = early morning cortisol
- <80 is diagnostic
- > 450-500 rules out
Short synacthen test - 359mcg IV
Check Cortisol and ACTH at baseline then cortisol half hrly
- Cortisol >550 = rules out
- <550 = adrenal insufficiency ? cause
Insulin tolerance test = gold standard but contraindicated if seizures or IHD
HIGH ACTH = Primary Adrenal insufficiency otherwise secondary cause
Adrenal CT = ? tumour related cause
What must you check for if diagnosing a patient with hypothyroidism?
Adrenal insufficiency –> Autoimmune polyglandular syndrome
APS = syndrome of multiple endocrine autoantibodiy production due to loss of thymic negative selection
If treating hypothyroid and co-existing adrenal insufficiency will precipitant an adrenal crisis
Treatment of adrenal insufficiency?
Acute = hydrocortisone 100mg IV stat then 50mg QID and wean
Primary = fludrocortisone 100-200mcg/day
Secondary = hydrocortisone 20mg/day
STRESS COVER
When does synthetic glucocorticoid therapy suppress natural glucocorticoids?
> 5mg/day for > 4 weeks
Morning administration of physiologic strength less likely
Recovery can take up to 12 months
Action of glucocorticorticoids
Hyperglycaemia Muscle catabolism Lipogenesis Anti-inflammatory Bone catabolism Hypertension
Clinical presentation of cushings syndrome?
More specific:
- Bruising
- Striae - purple and wide
- Proximal myopathy
- Facial plethora
Less discrimatory:
- Central obesity and facial fullness
- Buffalo hump
- Depression and fatigue
- Impaired cognition
- Menstural abnormalities
- Poor skin healing
- Hypertension
Diagnosis of Cushing’s syndrome
EXCLUDE EXOGENOUS STEROIDS
Need 2 out of 3:
- Midnight salivary cortisol
- Urinary free cortisol
- Overnight 1mg dexamethasone suppression test
- -> ACTH level
- <10 = ACTH independent = adrenal cause
- > 20 = ATCH dependent = pituitary or ectopic
Adrenal source = adrenal CT
Pituitary source = Brain MRI –> petrosal sinus sampling
Ectopic source = CT CAP
Conditions associated wit hypercortisolism in the absence of Cushing;s syndrome
Pregnancy Depression EtOH dependence Glucocorticoid resistance Morbid obesity DM States of high stress - chronic exercise, anorexia, physical stress
