▪️ Steroids Flashcards
Identify the different layers of the adrenal cortex
Capsule
Cortex
> zona glomerulosa, zona fasciculata and zona reticularis
Medulla
Identify some different types of corticosteroids, including examples
- Glucocorticoids e.g. cortisol
- Mineralocorticoids e.g. aldosterone
- Sex steroids
Outline the HPA axis
Hypothalamus > (CRH) > Ant Pituitary > (ACTH) > Adrenal Cortex > (CORT) > [ negative feedback to Hypothalamus + Ant Pituitary ]
Identify six metabolic actions of glucocorticoids Identify six metabolic actions of glucocorticoids
- Glycogenolysis
- Gluconeogenesis
- Hyperglycaemia
- Proteinolysis
- Lipolysis (low conc.) / lipid deposition (high conc.)
- Redistribution of fat
Identify five effects of glucocorticoid deficiency
- Hypoglycaemia
- Weight loss
- Nausea
- Hypotension
- Underweight
Identify five effects of glucocorticoid excess
- Hyperglycaemia
- Weight gain
- Increased appetite
- Hypertension
- Cushingoid
Identify four effects of mineralocorticoid deficiency
- Hyponatraemia
- Dehydration
- Hypotension
- Hyperkalaemia
Identify three effects of mineralocorticoid excess
- Hypernatraemia
- Hypertension
- Hypokalaemia
Describe the pharmacokinetics for corticosteroids
- High oral bioavailability (diffuse easily)
- Metabolised by liver, eliminated by kidney
- Hepatic and renal clearance (decreases with age)
Identify the various different routes of administration for steroid drugs and provide an example drug for each
- Intravenous e.g. methylprednisolone
- Oral e.g. prednisolone
- Inhaled e.g. beclomethasone
- Topical e.g. betamethasone
- Intra-articular e.g. triamcinolone
Describe five effects of corticosteroids on the immune system
- Inhibition of B and T cell responses
- Reduced phagocytic function
- Immunosuppression
- Reduced inflammation
- Reduced transcription of cytokines
Briefly, describe the mechanism of action of steroid hormones
The steroids are lipid soluble and can cross the cell membrane. They enter the target cells, combine with a high affinity receptor forming an active complex that then binds to selective sites in the chromatin (DNA). The interaction between the hormone–receptor complex and the genome activates or derepresses transcription or post-transcriptional regulation of RNA synthesis.
What are the clinical uses of steroid drugs?
- Inflammatory disease
- Immunosuppression
- Malignancy
- Adrenal insufficiency
- Cushing’s disease diagnosis
What are the indications for corticosteroid replacement therapy?
- Deficiency
- Addison’s disease
- Adrenolectomy
Which drugs can be used for corticosteroid replacement therapy and what is their dosage?
- Hydrocortisone (cortisol) 20 - 30 mg daily
- Fludrocortisone (aldosterone) 50 - 300 μg daily
Which inflammatory diseases are treated by corticosteroids?
- Asthma
- GI disease
- Nephrotic syndrome
- Rheumatoid arthritis
- Inflammatory skin conditions
Describe the use of steroids in pregnancy
A single course of antenatal corticosteroids is offered to women who are at risk of preterm birth (24-34 weeks of gestation)
Which steroids are given to women at risk of preterm birth?
- Betamethasone 12 mg given IM in two doses
- Dexamethasone 6 mg given IM in four doses
What are the side effects of mineralocorticoids?
- Fluid retention
- Hypertension
- Hypokalaemia
What are the side effects of glucocorticoids?
- Osteoporosis
- Avascular necrosis
- Peptic ulcers
- Increased infections
- Hypertension
- Diabetes
Describe the Cushingoid fat distribution
- Central obesity
- Dorso-cervical fat pad
What are the effects of corticosteroid on bone?
- Inhibition of osteoblast formation
- Increased osteoclast proliferation
- Reduced calcium absorption in gut
- Reduced sex steroid production
- Osteoporosis
How does adrenal suppression occur?
- Suppression of HPA axis occurs after 3 weeks
- Prednisolone > 20 mg will suppress HPA axis
- May persist for years, if long term treatment
What precipitates a hypo-adrenal crisis?
Abrupt withdrawal of steroids
