Addison’s Disease and Its Presentation
After a long break due to the Christmas and New Year holiday, group 7 finally had a day to present on Addison’s disease.
Virtually, everyone undergoes stress be it mental or physical and how come they recover soon, that’s because there is a secretion of cortisol by glucocortisol the Zona fasciculate, a layer of the adrenal cortex. So what happens if this secretion stops and how does the body respond to stress?
Addison disease result in the inability or the deficiency of the adrenal cortex to secrete its hormone. (Adrenocortical hormone). The adrenal cortex is sub-divided into three layers namely
*Zona glomerulosa which is responsible for the secretion of mineralocorticoid aldosterone which utilizes cholesterol to synthesis sex hormones including estrogen, progesterone, testosterone amongst others
Zona fasciculate, which secrete glucocortisol, the cortisol. Their secretion is controlled by the hypothalamic pituitary axis via adrenocorticotropic hormone (ACTH)
Zona Reticularis which secretes the adrenal androgens dehydroepinandrosterone (DHEA) and androstenedione
It is important to state that all human steroid hormone including those produced by the adrenal cortex are synthesized from cholesterol. What happens when these hormones are not secreted due to certain factors i.e. adrenalism result of Addison disease.
Causes of Addison Disease
Atrophy or injury if the adrenal cortex autoimmunity against the cortices in about 80% cases resulting in atrophy.
Tuberculosis causes the destruction of the adrenal glands or invasion of the adrenal cortices by cancer
Another case could be adrenal insufficiency due to impaired function of the pituitary gland which fails to produce sufficient ACTH, low ACTH causes decrease production of cortisol; and aldosterone.
Symptoms of Addison’s Diseases
Deficiency in mineralocorticoid results in reduction of renal tubular Na+ reabsorption and consequently loss of Na+, Cl- and water into urine resulting in decrease ECF volume other consequences includes hyponatremia, hyperkalemia and mild acidosis which can result in shock. This is due to the failure of potassium and hydrogen ion exchange for sodium reabsorption
Glucocorticoid deficiency results in lack of cortisol causing decrease in the mobilization of both proteins and fats from tissues thus depressing many other metabolic functions resulting in weak muscles; deficiency of cortisol also makes the patients highly susceptible to the deteriorating effects of different types of stress.
Melanin pigmentation: there is pigmentation of mucous and skin melanin appears as blotches on the skin. Due to decrease in cortisol secretion, there is no feedback to the hypothalamus thus there is increased secretion of ACTH by the hypothalamus as well as simultaneous increase in the secretion of Melanocytes Stimulating Hormone. Increased ACTH in the blood causes pigmenting effect.
The possible way of correcting Addison disease is hormonal replacement, small quantities of mineralocorticoids and glucocorticoids are administered.
Don’t forget to share