A Hamster with Cushing's Disease

Cushing's Disease

Sadly, old age is an inevitable part of life and sooner or later as we advance into old age changes start to occur naturally in the way body systems are controlled. The amount of hormones produced may also change as we get older, and some target tissues become less sensitive to their controlling hormones. As a hamster ages, particularly above 1 year old is the time a hamster is considered around middle aged. And it is at this point, just as it is with humans, many changes can start to take place in the body as they begin to advance into old age. Some may age sooner than others and can start to show age related symptoms from around 15 months old. As those changes start to take place many of the visual signs of aging will become more apparent to the hamster owner. The first noticeable changes of aging are fatigue, a reluctance to engage in physical activity, usually followed later by loosing fur or thinning of the fur. Loosing fur can have many different causes due to a large number of reasons. It is important at this stage not to start confusing secondary issues with more substantial health issues. And it is easy to see why so many hamster owners can mistake normal age related symptoms for Cushing's disease.

As the hamster advances into old age hormone changes and imbalances take place and these can have many different effects on the body. This is a natural part of life. The effects those changes have can be anywhere from mild to severe. The first most conspicuous symptoms of aging is usually fatigue followed by areas of patchy fur. This is mainly due to hormone imbalances which is shared by both male and female. While some changes are more specific to each gender; some of the most commonly shared symptoms include fatigue and skin problems in addition to hair loss. This can be directly attributed to irregular levels of hormones in the body. Hair loss can be induced by other hormones formed in other glands, including the pituitary, thyroid, parathyroid, thymus, pineal and the adrenal glands.

So what is Cushing's disease? And how can you tell if a hamster has Cushing's disease or some other age related symptoms. Cushing's disease occurs when adrenal gland production of cortisol is chronically deficient; this results in elevated ACTH levels (Adrenocorticotropic hormone.) ACTH controls the hormones released by the adrenal gland that support blood pressure, metabolism, and the body's response to stress. The most common form of Cushing’s disease is caused by the overproduction of a hormone by the pituitary gland. The pituitary gland is located under the brain and is separate from the brain. However, a tumor in this gland (not a brain tumor) can be very serious because a pituitary gland that does not work efficiently can cause problems with other organs in the body. This is called pituitary dependent Cushing’s disease.
Some pets with Cushing’s disease may have a tumor on one of the adrenal glands which is called adrenal dependent Cushing's disease. In mammals, the adrenal glands (also known as suprarenal glands) are endocrine glands that sit at the top of the kidneys. They are chiefly responsible for releasing hormones in response to stress through the synthesis of corticosteroids. In very rare cases the adrenal glands can become either overactive or under active. Overactive adrenal glands may produce too much cortisol which in turn causes the condition known as Cushing’s disease.
A pituitary tumor or an adrenal tumor, the result is the same, a chronic excess of blood cortisol. In effect, the animal is being poisoned by producing too much cortisol and cannot rely on its own body mechanism to regulate the blood cortisol levels. There is no simple test to diagnose Cushing's disease in hamsters in the early stages and vets usually diagnose Cushing's disease based on the clinical symptoms of the disease. But many of the clinical signs and symptoms are not unique to Cushing's and could reflect a number of other health, or age, related issues. Although the symptoms of Cushing's disease tends to be varied and can appear gradually and progressively just as it does with normal aging ailments.
Cushing's disease includes hair loss, a pot bellied appearance due to elevated liver enzymes, increased appetite, increased drinking (known as polydipsia) and an increase in urination (known as Polyuria.)

hamster with age related fur lossA male hamster with significant and patchy fur.

Hair loss caused by Cushing's disease occurs primarily on the body and legs. When Cushing's first appears it starts to manifests itself with fur loss (just as it does with old age) but with Cushing's it is usually symmetrical, meaning both sides of the body starting on the tummy up the flanks, (rear end) legs, then progresses to the rest of the body. With old age, areas of patchy fur can be unpredictable and sporadic starting on the tummy area on to the hind legs then up to the neck and may be patchy on the rest of the body rather than symmetrical. As seen in the image opposite fur is usually patchy and skin tone/coloration does not change as it can with Cushing's. The black spot is a normal part of the hamsters anatomy known as the hip spots (scent glands) The exposed skin is not itchy and the pet may not scratch as with other types of skin diseases or parasitic infestations. These bald patches of fur are associated with the reduction of hormones in the male hamster (testosterone) and the animal may have large patchy areas of fur loss.

With Cushing's disease the pet may have fragile blood vessels and will bruise easily because cortisol causes proteins in the skin to break down and tiny blood vessels to become weaker. One noticeable condition of Cushing's is, as the disease progresses the skin tends to be much thinner and much more fragile than normal skin, with fatty deposits (lumps) that may resemble small tumor like growths, whereas with aging it can become thickened and wrinkly, particularly more so with a male hamster due to the drying and scaling of the epidermis (the outer layer of skin) Both male and females have ostrogen (the female hormone) and testosterone (the male hormone) Males have more Testosterone than the female, and vise versa. Females do secrete some testosterone, and the female hormones, progesterone and ostrogen, which trump the testosterone. As testosterone has the biggest influence on hair loss the effect is not as severe in females as it is with the male hamster. The image opposite shows an old female hamster at 2 years 4 month old with significant thinning hair but no patches of total loss. And the low testosterone levels can lead to a reduction in muscle bulk, and a wrinkled ‘parchment-like’ appearance of the skin.

Age related fur loss is generally first seen starting around the tummy area then onto the hind legs and hips then neck and chest.

hair loss in a hamsterA female hamster with significant thinning hair but no bald patches

Cushing's disease can exhibit the same symptoms, and as they are so similar it can be difficult for someone not familiar with the disease to diagnose correctly, and is easy to see why so many owners and even veterinary surgeons can sometimes misdiagnose age related fur loss for Cushing's disease. Many pet hamster owners when they first see hair/ fur loss on their pet sometimes leap to the assumption that it is Cushing's disease whereas Cushing’s is very rarely seen in hamsters, nonetheless it does happen occasionally but a very rare occurrence.
The prognosis for any animal with Cushing's is poor. There is no cure for the disease and treatment may be limited and costly for such small animals as hamsters. The disease is not caused by neglect or poor husbandry and is not contagious but is thought to be genetically inherited condition.
Cushing's does not mean an instant death sentence for the animal, and many animals can live long and near normal active lives with the disease. But extra care and attention will be needed to ensure they get the extra care needed to cope with the symptoms of the disease. As the disease progresses the animal becomes susceptible to all kinds of infections due to the amount of cortisol in the body as it suppresses the immune system.
The eyes, ears, skin and the urinary tract are the most likely areas to become affected. Also due to the delicate nature of the skin, open sores and wounds in the skin may lead to bacterial skin infections and are very slow to heal, these are commonplace with Cushing's.
All items and toys with sharp or rough edges should be removed from the cage to prevent damaging the delicate skin. The later stages of the disease can also affect joints, bones, muscles, cartilage and other connective tissues, and will eventually hamper physical movements. So it may be wise to house the animal in a single storey cage with only a base floor, and to make sure the animal has a soft substrate to prevent any scratches or injury to the skin that may allow bacteria to enter.

In the 20 years I have bred and cared for hamsters, my hands on personal experience has taught me a great deal about these adorable amazing little creatures by giving me a deep perception and understanding of their most common indispositions.
At first sight of fur loss I tend to put it down to old age until the sign of anything different starts to become more evident.
Hamsters can lose fur or get skin problems at any stage in life due to disease or non-disease conditions. Inc: but not limited to heat, dietary deficiencies, vitamin deficiencies, and parasitic infestations. Parasites can inc: but not limited to Mites, Fleas, Ringworm. So if you begin to see fur loss on your little pet don't leap to conclusions. Just make sure he has his bus pass, and his pension is in order, Oh!! and a zimmer might come in handy.


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