To Janice and V'orri -
Due to your request - and several others, I am reposting an article that
I wrote several months ago concerning adrenal gland lesions.
Concerning genetic defects - mostof the defects that I have seen have
been in color-diluted strains. When we breed for a certain coat color, we breed
other problems into the line. BTW - tell your vet that the external appearance
of a uterus and ovaries has ABSOLUTELY no relation to the presence of genetic
defects in a litter. The defects are based on poor genetic information in the
fetuses, not the parents.
If there are hidden problems with V'orris health due to poor genetic
makeup, that may complicate a successful surgery. But as he has come this far,
I wouldn't think that there are any serious genetic problems at this time.
The following article may be reprinted by anyone desiring to disseminate this
information in a newsletter or non-commercial publication. This material may
not be altered or changed in any way. Under Title 17 of the U.S. Code, Section
105, copyright protection is not available for any work of the United States
Government.
Adrenal Disease in the Ferret
"My ferret is losing its hair."
While hair loss in the ferret can occur from many causes, I would like
to concentrate on what is the most common and what is becoming the most commonly
talked about reason for serious hair loss -- proliferative lesions of the ferret
adrenal gland.
Ferrets with adrenal lesions - including areas of hyperplasia as well as
both benign and malignant neoplasms of the adrenal cortex - typically all show
the same clinical signs regardless of which type of growth is present. These
signs are fairly diagnostic, and in the majority of cases, are so characteristic
that no other diagnostic tests are required before therapy is instituted.
The signs of adrenal disease in the ferret are well documented (Fox et
al., 1987, Lawrence et al. 1993, Rosenthal et al., 1993) although the cause of
these signs is still somewhat unclear. Adrenal lesions may be seen in animals
ranging from one to seven years of age, with the average being around 3.5 years.
In one study (Rosenthal, 1993), 70% of affected ferrets were female. Hair loss,
or alopecia, is by far the most common clinical sign in affected ferrets. Hair
loss often begins at the tail, and progresses forward over the trunk, flanks,
and abdomen, until hair is only present on the neck, head, and the extremities.
Additionally, in spayed females, the vulva will often become swollen to the
extent that the owner may erroneously believe that the animal is estrus. A
watery mucus discharge from the vulva may also be seen in this animal. (Vulvar
swelling in a spayed female on its own is sufficient cause to warrant abdominal
exploratory surgery). Other clinical signs that may be seen in ferrets with
adrenal lesions include increased scratching, excessive drinking and urination,
anemia, weight loss, and in longstanding cases, difficulty in using the hind
legs.
The cause of the hair loss and vulvar swelling is not currently known.
In other species with hyperadrenocorticism, high circulating levels of adrenal
corticosteroids cause the hair follicles to atrophy and the skin itself to
become thin, resulting in hair loss. But since we know that these ferrets do
not have these high levels of cortisone, this explanation does not suffice for
what we see clinically. A plausible theory has been advanced by specialists at
the animal medical Center in New York City. (Rosenthal, 1993). Citing the fact
that 36% of affected ferrets have high blood levels of estrogen, the believe
that early neutering (most ferrets in the U.S. are neutered before six weeks of
age) cause a population of cells in the adrenal gland which have retained the
ability to secrete gonadal hormones to grow, in essence "filling the void".
High levels of estrogen are well known to also cause hair follicle atrophy, and
would also cause vulvar swelling in females, as is seen in estrus. Based on
this theory, Dr. Fox et al. have labeled this synrome "adrenal-associated
endocrinopathy", an apt and fitting appellation.
The treatment for adrenal disease in ferrets primarily involves removal
of the affected adrenal gland. In most cases, adrenalectomy is performed based
solely on clinical signs. Routine pre-surgical bloodwork should be performed in
all animals over 4 years of age, as would be done for any other type of surgical
procedure. Special diagnostic tests which are used in other species to diagnose
adrenal disease are rarely of use in the ferret. Only 1 of five ferrets in one
study (Lawrence, 1993), and zero of seventeen in another study (Rosenthal, 1993)
In most cases, one gland is noticeably larger than the other and is
removed. For unknown reasons, the left adrenal gland accounts for the majority
of lesions (64%), with the right adrenal gland accounting for 26%, and 8% of
ferrets having disease in both adrenals. Removal of one adrenal gland is
generally well tolerated in ferrets and in most of these cases, if disease is
confined to that gland, clinical signs will cease (i.e., the hair will grow back
and the swollen vulva will diminish to its previous size). In animals with
bilateral disease, removal of one gland and part of another has been done, but
carries a more significant risk of post-operative complications. Ferrets
require at least a portion of one adrenal gland to live.
The surgery itself is not excessively difficult. Removal of the left
adrenal is fairly easy and has a low risk of complication. Due to the position
of the right adrenal near several large blood vessels, it is a more difficult
surgery and requires considerably more expertise on the part of the surgeon. As
always, if your veterinarian has little expertise in performing this surgery, it
is wise to ask for a referral to a more experienced surgeon.
Unfortunately, not all adrenal surgeries end happily. Postoperative
mortality averages from 10% (Tom Kawasaki, personal communication) to 12.5%
(Rosenthal, 1993). The cause of the post-surgical mortality is not known; most
theories center on the inability of the other, unaffected adrenal gland to
produce enough cortisol on short notice, i.e., the hyperfunctioning gland has
caused it to atrophy.
On a personal note - while some owners believe that hair loss is only
cosmetic and would "rather not put their pet through the stress of an
operation", let me categorically state that the changes seen in ferrets with
adrenal disease are cumulative and progressive. Animals with adrenal lesions do
not just lose their hair - they also lose muscle mass, have little energy, and
may develop life-threatening anemia. While the lesions themselves are rarely
life-threatening (in over seventy cases I have only seen two cases of tumor
metastasis), their clinical manifestations are debilitating and greatly decrease
the quality of a ferret's life. (When I noticed the signs of adrenal disease in
one of my ferrets who was six at the time - I had the surgery done immediately.
The hair has grown back, the vulva has reattained its normal size, and she is
more fit than ever.)
Adrenal disease in the ferret is common, and if detected by a watchful
owner or a knowing practitioner, can be easily treated
Get those hairless ferrets checked, and have a festive ferret-filled
holiday season.
1. Fox J.G, et. al. Hyperadrenocorticism in a ferret. JAVMA, 191: 343, 1987.
2. Lawrence, H.J. et al. Unilateral adrenalectomy as a treatment for
adrenocortical tumors in ferrets: Five cases (1990-1992). JAVMA 203: 267-270,
1993.
3. Rosenthal, K.L. et al. Hyperadrenocorticism associated with adrenocortical
tumor or nodular hyperplasia of the adrenal gland in ferrets: 50 cases
(1987-1991. JAVMA 203: 271-275, 1993.
Bruce Williams, DVM
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[Posted in FML issue 0710]
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