Suprarenal Disorders

 

General Adaptation Syndrome

The fight or flight response is a short term measure to deal with an imminent threat. However, long term exposure can result in deleterious effects. This can be seen in the general adaption syndrome. The persistent exposure to stress can cause a reaction which is characterised by three stages.

1)      Alarm

This stage is the fight or flight response. Under normal circumstances this process will resolve the dangerous situation, and the animal would return to a state of homeostasis.

 

2)      Resistance

The factor which is causing the stress continues to be a problem. More factors will be secreted to help counteract the stressor. Aldosterone will be released in an attempt to raise blood pressure by increasing the volume of blood. Adrenalin will break down fats and cortisol will stimulate proteolysis in order to compensate for glucose required for the increased activity. In this stage arousal is lower than the alarm phase, however there is still a lot of strain on the body. At this stage the body is struggling to cope with the demands being made.

 

3)      Exhaustion

In this phase stores in the body run out, this is sometimes known as chronic stress. Adrenal hormone levels drop due to exhaustion of supplies. Blood sugar is reduced causing fatigue and wasting of the body, particularly muscles. Due the repression of the immune response illness and infection can become a problem. At this stage mental and physical break down will begin to occur.

The general adaption theory was originated by Hans Selye. He experimented on rats and put them in stressful situations for long periods of time. These experiments led to the identification of the three stage of the stress response, which were later found to occur in many different animals including humans. In humans stressors tend to be less physical threat, and more psychological. Factors which can lead to prolonged stress in humans are wide ranging, and can include;

·         Financial worries

·         Relationship issues

·         Birth, deaths and marriages

·         Homelessness

·         Lack of sleep 

·         Alcoholism

·         Depression

·         And many more

 

 

Cushing's Syndrome

Cushing’s syndrome is caused by over exposure to the suprarenal hormone; cortisol over an extended period of time. People who suffer from Cushing’s often have very thin limbs, and an obese torso. An image of a dog suffering from Cushing's can be seen below, this shows the classic thin limb and fat torso shape. As well as this sufferers feel fatigued and weak. High blood pressure is another symptom. Finally skin weakness and easily bruising are also a sign. The most common cause of Cushing’s is and over production of cortisol due to tumour formation on the suprarenal gland. Normally this is fairly treatable with surgery. Another key cause is the over production of cortisol due to medication taken for another illness. By stopping this course of treatment the symptoms should go away.

Image courtesy of Flickr found under the creative commons licence

 

 

 

Addison’s Disease

Addison’s disease is a rare disease affects around one person in every 150 million. This disease is caused by a shortage of cortisol and other steroid hormones in the body due to degradation or loss of function of the adrenal cortex. In this disease the pathway signalling the release of cortisol is still intact, however the hormone is still not released. Symptoms of Addison’s disease include:

·         Fatigue

·         Muscular weakness or pain

·         Joint pain

·         Loss of appetite and gastrointestinal problems

·         Skin becoming darker

·         Low blood pressure

The causes of Addison’s disease are not well known, however they are thought to include tuberculosis, chronic fungal infections, and a variety of cancers or physical damage to the suprarenal gland. Unfortunately there is no cure for Addison’s, however it is easily medicated with hormone replacement.