Addison's Disease Overview Paper Example

Introduction

Addisons disease refers to the destruction of the adrenal cortex leading to adrenocortical insufficiency and abnormal production of glucocorticoids and mineralocorticoids (Brooke &Monson, 2009). The disease usually becomes elaborate when both adrenal cortices are destroyed. It is rare but the mortality associated with it is high due to addisonian crisis since the hormones are irreplaceable.

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Etiology

Although the disease can occur at any age, it mainly affects adults between thirty to fifty years. According to Hahner (2018), it can also present much earlier in cases of congenital adrenal hyperplasia, poly-glandular autoimmune syndromes, and in disorders of long-chain fatty acids metabolism. There is no known race predilection but the idiopathic autoimmune type is more common in females. The cause of adrenal insufficiency is dependent on the mechanism through which the glands produce inadequate hormones. Accordingly, autoimmune destruction of the adrenal glands is the most common pathophysiology associated with the disease. It occurs through an immune reaction directed towards the enzyme known as 21-hydroxylase (Sarkar &Ghosh, 2012). The destruction can also occur in the setting of metastatic cells in the adrenal glands, hemorrhage, or infections.

Another etiology associated with the disease is adrenal dysgenesis. It is a rare cause that results from mutations of the receptor genes. In addition, the disease may result from impaired steroidogenesis in which there are inadequate steroids for processing cortisol. In this regard, congenital adrenal hyperplasia is the most common abnormality associated with the defect. Acute addison's disease is precipitated by emotional stress bilateral adrenal hemorrhage, bilateral adrenal artery emboli, or bilateral adrenalectomy (Chakera &Vaidya, 2010). In addition, some medications such as ketoconazole are known to interfere with the synthesis of steroids while others like rifampicin increases the rate of normal breakdown in the liver, leading to adrenal insufficiency.

Diagnosis

The diagnosis is based on a comprehensive history and physical examination followed by specific laboratory studies and imaging work. In the laboratory, the primary investigations are focused on assessing the functional capacity of the adrenal glands in the production of cortisol. One crucial test used in this test is known as the rapid ACTH stimulation test or synacthen (Burton, Cottrell, & Edwards, 2015). In this case, administered ACTH leads to production of up to five times the normal output of cortisol. An increase in the blood aldosterone and cortisol 30 minutes after the infusion is an important indicator for the normal functioning of the adrenal cortex. According to Hahner (2018), two criteria exist for diagnosis of the insufficiency. There should be an increase in the baseline cortisol and the value should be more than 20mcg/dl after the thirty or sixty minutes tests. Abnormal mineralocorticoid function is denoted by a low aldosterone value less than 5ng/100ml, which fails to rise after the 30 minutes of ACTH administration.

Other laboratory tests important in the diagnosis include the comprehensive metabolic panel. In the disease, the lab findings may indicate hyperkalemia, mild anion gap metabolic acidosis, and hyponatremia (Burton, Cottrell, & Edwards, 2015). Sodium may also be elevated in the urine and sweat, and an elevated blood urea nitrogen and creatinine. Additional tests may include the complete blood count, thyroid profile, autoantibody testing, and prolactin testing. In severe cases, imaging studies such as a chest radiograph and abdominal CT scan may be used.

Signs and Symptoms and the Differential Diagnosis

The patients present with signs of both cortisol and mineralocorticoid deficiencies. In this case, the presentation to the clinic could be due to features of an acute addisonian crisis or a chronic addison's disease. The crisis is precipitated by stress factors such as infections, surgery, trauma, hypovolemia, or non-adherence to the medications (Chakera & Vaidya, 2010). Some of the significant signs and symptoms include hyperpigmentation of the skin and the mucous membranes due to excess stimulation by the adrenocortical hormone on production of melanin. Other findings probable on the skin include progressive malaise, weight loss, poor appetite, and fatigue (Sarkar &Ghosh, 2012). Orthostasis and dizziness may occur severally due to hypotension caused by inadequate aldosterone. In addition, some patients complain of flaccid muscle paralysis and myalgias precipitated by hyperkalemia. In the gastro-intestinal system, patients present with persistent nausea, vomiting, and steatorrhea. On a comprehensive probing, the patient may indicate a history of using medications known to reduce the functioning of the adrenal cortex. In acute addisonian crisis, the patient may be confused, cyanotic, hyperpyrexia, in shock, and with features of an acute abdomen. On physical examination, female patients may have decreased body hair in the axillary and pubic region sdue to inadequate production of androgens.

Some of the differential diagnosis of addison's disease include adrenal suppression due to corticosteroid therapy, secondary or tertiary adrenal insufficiency, hyperthyroidism, and hemochromatosis. Given that these diseases present in a similar way with the disease, they should be ruled out any time such a patient presents in the clinic. For instance, the adrenal suppression due to corticosteroid therapy has a history of long-term use of the medications and the ACTH is low since the hypothalamus is depressed (Brooke &Monson, 2009). In addition, secondary or tertiary adrenal insufficiency has a history of a known lesion in the brain or pituitary gland and the ACTH is also low (Hahner, 2018). In hemochromatosis, the hyperpigmentation does not occur on the mucosa like in addison's disease. Hyperthyroidism can be ruled out by elevated T3 and T4 levels and suppressed TSH.

Genetic Components

Genetic mutation has been associated with the autoimmune addison's disease. According to Burton, Cottrell, and Edwards (2015), a combination of genetic and environmental predisposition poses a risk of developing the disease. In this case, the genes implicated include the HLA complex, which helps in distinguishing the body's antigens and those that are foreign. The variant of HLA-DRB1 is often associated with an inappropriate immune response that causes the disease through an unknown mechanism. The disease is also linked to other genetic conditions such as the poly-glandular syndrome type 1 and X-linked adrenoleukodystrophy (Brooke &Monson, 2009).

Treatment and Prognosis

Treatment of Addison's disease should involve an endocrinologist whenever possible. In patients presenting with an acute crisis, the initial treatment should include rehydration with isotonic sodium chloride solution to restore the hypotension and shock. 100mg hydrocortisone should then be administered alongside the slow infusion of the IV fluids (Hahner, 2018). After the improvement of symptoms, the dose is reduced and mineralocorticoid therapy is started also. The goal of using corticosteroids is to reduce complications and to prevent morbidity. Other drugs that can be used in both acute and chronic setting include prednisone and fludrocortisone. Close monitoring should be instituted to check for any signs of inadequate replacement such as malaise and dizziness or signs of excess replacement such as cushingoid features (Burton, Cottrell, & Edwards, 2015). Additional concerns requiring individualized care include cases of pregnancy, hypothyroidism, and osteoporosis.

The prognosis of the disease is fatal if left untreated. However, since the advent of synthetic cortisone, the treatment outcomes have been good. Most people with the disease can live normal lives under medications so long as they are cognizant of features of crisis that may require emergency treatment. Notably, diabetic patients with an adrenocortical insufficiency have a higher rate of mortality than the normal diabetic patients by up to four times.

References

Brooke, A., & Monson, J. (2009). Addison's disease. Medicine, 37(8), 416-419. doi: 10.1016/j.mpmed.2009.05.006

Burton, C., Cottrell, E., & Edwards, J. (2015). Addison's disease: identification and management in primary care. American Journal of General Practice, 65(638), 488-490. doi: 10.3399/bjgp15x686713

Chakera, A., & Vaidya, B. (2010). Addison Disease in Adults: Diagnosis and Management. The American Journal of Medicine, 123(5), 409-413. doi: 10.1016/j.amjmed.2009.12.017

Hahner, S. (2018). Acute adrenal crisis and mortality in adrenal insufficiency: Still a concern in 2018!. Journal Of Endocrinology, 79(3), 164-166. doi: 10.1016/j.ando.2018.04.015

Sarkar, S., & Ghosh, S. (2012). Addisons disease. Contemporary Clinical Dentistry, 3(4), 484. doi: 10.4103/0976-237x.107450