Ovarialzysten

Sometimes female guinea pigs with symmetrical hair loss in the flanks are seen. The animals are normally healthy, without further changes of the skin and without itching. This can be caused by the presence of ovarian cysts, which build up in guinea pigs frequently. The hormones (estrogens) produced in these cysts are responsible for the hair loss, why this occurs only in the flanks is unknown.

HAMEL found in 70 - 90% of dissected female guinea pigs ovarian cysts, above all in single held animals. Zysts form out of not ovulating follicles in the ovary, this means, they follow a heat, where no ovulation occurs. The ovaries can become the size up to a hen's egg, unfortunately most time it is not a single great cyst, but it consists of several small blisters filled with liquid.

Ovarian cysts of a guinea pig. This ovary (size of about 4 x 2 cm) contains several small blisters filled with liquid (arrows)

The influence of estrogens can change the behaviour of the animals. They can show a never ending heat and jump up on other guinea pigs, could be very active and thereby loose weight. As they put lots of marks in the bedding, they are responsive to infections of the urinary tract and the uterus, because the vaginal membrane is opened.

Not all cysts are hormonal active, smaller remain usually symptom-free and unnoticed. Since this cysts can take a large part of the abdominal cavity, there can be problems with the food intake. Caused by then hairloss, the animals sometimes look like plucked chickens.

Diagnosis is made by by palpation, X-rays or ultrasound. X-rays are often not specific. The best results are found by ultrasound investigation, so cysts of each size are recognized easily.

Ultrasound picture of an ovarian cyst of a guinea pig. The black circle is the ovary filled with liquids (these are echoless, because they do not reflect the ultrasound and present themselves black in the sonography.)

Treatment is dependent on the kind of the disturbances, caused by the cysts. There is no need to treat small cysts without symptoms, hormonal active cysts can be treated with hormones (Gestagen, HCG, Buserelin) or homoeopathic. As initial treatment a series of 3 injections at intervals of 14 days prove successful, in many cases the effect is no long-term solution, treatment must after few months take place again. Periodical injections are necessary in an interval of approximately 5 months.

Treatment of choice is the surgical remove of the ovaries. It is indicated, if the cysts make problems or other health risks cause of their size. In the meantime the anaesthesia and operation techniques developed in a way, that surgery in guinea pigs is no greater risk then in other small animals.

Several small cysts, a large cyst right down had to be opened during surgery.

As guinea pigs have an induced ovulation, which can be released by the "jumping up" of the boar, it is recommended as a preventive measure, to hold female guinea pigs in groups as well as together with a (neutered) male. As female piggies and neutered males often jump up on other piggies in heat, this can avoid the development of ovarian cysts.

Ovarian cysts in guinea pigs