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Common names or abbreviations:
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canine panosteitis (07)
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chronic osteomyelitis of young German shepherd dogs
(07)
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endosteal proliferation of new bone (08)
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enostosis (03, 07, 08, 10)
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eopan (08)
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eosinophilic panosteitis (03)
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eosinophilic panosteitis of young German shepherd
dogs (07)
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growing pains (02, 11)
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hematogenic chronic osteomyelitis (10)
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juvenile osteomyelitis (03)
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long-bone disease (10)
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osteomyelitis of young German shepherd dogs. (03)
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pano (09)
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shifting leg lameness (01)
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wandering lameness (02, 09)
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Description or definition:
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Panosteitis (PAN' os-te-I-tis) which means,
literally, inflammation of
every part of the bone (pan- + Gr. osteon bone + itis), was first
described
in European veterinary literature in 1951 (07).
It is an inflammation inside the long bone of a
fast-growing adolescent
large or giant breed dog*, most often the German shepherd (01, 02, 03,
04).
Usually the afflicted is male. However the female
sometimes develops this
disease at time of first heat (01, 02, 03). The bone most often affected
and,
usually, affected first is the ulna, one of the two long bones in the
lower
forelimb (10).
Although the origin of panosteitis is unknown there
is thought to be a
genetic component (04) with episodes being triggered by physiological
stress
(03, 07). There may also be a viral trigger (04, 07). Growth rate may be a
factor (10) as may be an allergic response, a metabolic phenomenon or a
parasite infestation (07, 11).
Symptoms appear abruptly. For no apparent reason
the dog begins to limp.
Pain may become so severe the dog is reluctant to use the leg at all (12).
He may also become lethargic and/or feverish, loosing both appetite and
weight (10).
Palpation of the middle of the affected leg will
elicit a pain response from the
dog (01, 03, 04, 05, 10, 12 ). Often the pain and accompanying lameness
appear to "shift" from one leg to another, usually from a
forelimb to a
hindlimb and then back (02, 03, 07). The "shift" in pain comes
about as the
disease resolves in one bone and begins in another (02, 03, 07).
There is no human counterpart for panosteitis (10).
Although the disease is self-limiting (02, 03) and
disappears as the dog reaches
maturity, it is cyclic in nature (04) and may continue to recur for up to
a year
and sometimes longer (04). The pain ranges from moderate to excruciating,
with the worst of it lasting from one to two months (04). The lameness
lasts
from two to three weeks for each affected bone (07, 08, 11). Often there
are
painfree interludes between periods of lameness (11). The entire cycle can
last from 90 to 190 days (02, 07). Time elapsed between cycles varies from
160 to 180 days (07).
Panosteitis generally occurs in dogs between five
and 18 months of age
(07, 08), although episodes of the disease have been reported in German
Shepherd dogs as young as two months (04) and as old as five years (07).
Bones affected are in the lower foreleg (ulna and
radius), upper foreleg (humerus),
the thigh (femur) and the lower hind leg (tibia). There are no reports
that the fibula
(the other long bone in the lower hind leg) is affected (05, 07, 10).
To understand what happens during an episode of
panosteitis, consider the
structure and function of the long bone.
Long bones, essentially hollow tubes with fortified
and knobby ends, do
more than keep legs (and arms) straight. They provide "hooks"
for tendons,
manufacture blood (13) and store calcium and phosphorus (13).
The hollow middle section (staff) of the long bone
is filled with
blood-producing marrow and fat cells (adipocytes) (07) which die as bone
cells (osteoblasts) are produced. Panosteitis is called a disease of the
fat
tissue in the bone marrow (06), a disease of osteoblasts (10), a disease
of
the fatty bone marrow (10) and a disease of the adipose bone marrow (07).
During periods of rapid growth fibrous material
develops in the bone
marrow.
For the unlucky dog, it is a case of too much, too
soon. There isn't enough
space inside the bone shaft for everything being produced there.
Congestion
builds (10). Discomfort evolves into pain. The dog starts to limp.
Then the fibrous material is gradually absorbed
into the inner walls of
the bone shaft and new bone is deposited on the outer surface of the bone.
The congestion abates as does the pain (10).
Panosteitis doesn't occur simultaneously in all the
long bones of the affected
dog and this is why this painful condition is said to migrate or wander.
X-rays of the affected bone are likely to show
increased density in the congested
marrow cavity (01, 02, 04 ). Although usable X-rays may be difficult to
obtain
because of the transient nature of the disease, using radiographs can rule
out other
diseases (03, 07) such as hypertrophic osteodystrophy (05), elbow or hip
dysplasia,
cruciate ligament injury, osteochondritis dissecans (OCD) or
osteochondrosis (OC),
both developmental cartilage abnormalities occurring in the joints of
growing dogs (03).
There are no elevated enzyme levels with
panosteitis or any consistent blood work
abnormalities (03, 07). However, some dogs have been found to have one or
the
other of two blood disorders concurrently with panosteitis. Both
Hemophilia A
and von Willebrand's Disease (vWD) have been linked to panosteitis (10).
There is no proven way to prevent the disease, but
methods to manage the
symptoms are available.
Treatment consists of rest and the use of
analgesics (03). Sometimes Rimadyl or
Etogesic is prescribed. Although corticosteroids may be used for the most
serious
cases (04, 07), steroids, in general, are not recommended for the growing
pup (03).
Intravenous therapy may be required for rehydration (08).
Although vigorous exercise is unwise, moderate
exercise is recommended to build
and maintain muscle mass (09).
Maintaining the pup, nutritionally, is another
matter. People stew about what to
feed the growing pup who either has panosteitis or may be at risk for
developing it.
Some say the condition or the risk for developing
it is intensified by feeding calorie-
dense diets and over-supplementing with calcium and phosphorus. Therefore,
some
recommend changing from puppy food to either an adult formula dog food or
a
large breed puppy slow growth formula.
Others say giving a growing pup a low-protein,
low-calcium adult formula food will
lead the pup to overeat to satisfy his energy requirements and, in so
doing, overload
on calcium.
Therefore, others recommend continuing to feed
puppy food, but to give only the
amount necessary to meet energy requirements and promote growth.
Calcium and
vitamin supplements should be avoided (10).
It is also suggested that the pup be kept slender
(04).
For X-rays and a picture of the canine skeleton as
well as technical and detailed
discussions of panosteitis see the linked references.
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* also has been seen/reported in the Airedale
terrier, basset hound,
Doberman pinscher, German short-haired pointer, golden retriever, Great
Dane,
Irish setter, Labrador retriever, miniature schnauzer, Samoyed, St.
Bernard
and the Scottish terrier. (06, 07) and the Rottweiler and beagle (10).
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References and Links:
04) http://www.vetinfo.com/dencyclopedia/depano.html
Encyclopedia of Canine Veterinary Medical Information Panosteitis Mike
Richards DVM includes one view of proper diet to feed at-risk pup.
05) http://www.southpaws.com/news/97-2-lameness.html
Summer 1997 News > Large Breed Puppies and Lameness
includes: comparison of panosteitis and hypertrophic osteodystrophy.
12) http://siriusdog.com/pano.htm
Skip first two parts. Article of interest is the third one.
13) http://www.batw.com/netpet/articles/bones.html
Bone and Blood Supply to Bones NetPet presents an Online Gross Anatomy
Lecture (c)1995 Bonnie Dalzell, MA ~ outline for lecture given at
University of Pennsylvania, School of Veterinary Medicine.
14) "Dorland's Illustrated Medical
Dictionary," 25th edition, W.B. Saunders, Philadelphia, London,
Toronto, 1974.
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Photos, Diagrams, etc. :
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