Thomas Addison (April 1793- June 29 1860) was an English Physician who studied at Guy’s Hospital, London. During his time at Guy’s, Thomas Bateman, an acclaimed dermatologist, brought about his fascination with skin diseases. Addison is known for his discovery of Addison’s disease (a degenerative disease of the adrenal glands) and Addisonian anaemia (pernicious anaemia) – a haematological disorder later found to be caused by the failure to absorb vitamin B12.
Addison’s disease (primary adrenal insufficiency/ hypoadrenalism) is a rare, chronic condition brought about by the failure of the adrenal glands so that not enough cortisol or aldosterone is produced.
The adrenal glands are situated above the kidneys; the inner core (medulla) produces the stress hormone adrenaline whereas the outer shell (cortex) produces the steroid hormones cortisol and aldosterone. Cortisol’s function is to control inflammation, regulate the body’s nutrients, stimulates the liver to produce blood sugar and regulates water content of the body. Aldosterone helps the kidneys to regulate salt and water levels which affect blood volume and blood pressure (your blood pressure drops if your aldosterone levels drop too low).
Adrenal failure is generally brought about as a response to the immune system. When Thomas Addison first discovered the disease in 1855, the main cause was as a complication of TB (this still remains a main cause in developing countries). In third world countries, HIV (AIDS) is becoming an infectious disease that causes adrenal failure. The most common cause of adrenal failure is destructive atrophy- this is where an over-active immune system starts attacking the body’s own organs (including the adrenal glands). This affects more women than men and accounts for 70% of all cases. Rarer causes include adrenal cancer, adrenal haemorrhage (eg. as a result of a car accident) and certain fungal infections.
This disease is not usually apparent until over 90% of the adrenal cortex is destroyed (this can take months to years).
Early stage symptoms:
- Muscle weakness
- Low mood
- Loss of appetite and unintentional weight loss
- Increased thirst
Over time, the symptoms can become more severe and others can also develop
- Hyperpigmentation- darkened patches of skin, gums or lips
- Nausea and vomiting
- Dizziness and fainting
Addison’s disease is treated with medications to replace the missing hormones which will be needed to be taken for the rest of your life. If left untreated, it can be fatal. With the treatment, symptoms can be mainly controlled so the patient can live an active life but they may experience times of fatigue. There may also be associating health conditions such as diabetes or an underactive thyroid.
Addisonian anaemia (pernicious anaemia)
This disease occurs when a lack of vitamin B-12 affects the body’s ability to produce fully functioning red blood cells. This occurs when the immune system attacks stomach cells that produce a protein vital for the absorption of vitamin B-12.
Vitamin B-12 is absorbed into the body through the stomach- gastric parietal cells in the stomach secrete a protein called intrinsic factor. People with pernicious anaemia produce antibodies that attack the parietal cells so that not enough of the protein is produced. As the vitamin B-12 can therefore not be absorbed, the body is unable to produce fully functioning red blood cells. Patients tend to have red blood cells that are underdeveloped or large than normal (megaloblastic anaemia).
Pernicious anaemia is the most common cause of B-12 deficiency in the UK and is most likely to occur in women over the age of 60. Having another autoimmune disease (such as Addison’s disease or vitiligo) can increase the risk of developing pernicious anaemia.
The symptoms vary from patient to patient (most probably due to different physiologies) but according to the Pernicious Anaemia Society, the most commonly reported symptoms include:
- Loss of memory
In order to treat this disease, patients are given injections of vitamin B-12 in the form of hydroxocobalamin and they need to be taken every 3 months for the rest of the patient’s life.