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Health Issues
 Streptococcal Toxic Shock Syndrome (STSS)
*There is a PowerPoint presentation in the VetsOnly Section that contains more pictures and information for veterinarians.
While the vast majority of the
episodes of Familial Shar-Pei Fever (FSF) seen in Shar-Pei run a
fairly benign course there are occasional exceptions which can have
live-threatening consequences. Over the last few years
Streptococcal Toxic Shock Syndrome (STSS) has been seen more
frequently as a complication of FSF in the Chinese Shar-Pei.
STSS involves infection with a group G streptococcus called
Streptococcus
canis. In the
Shar-Pei cases I've seen this streptococcal infection is a rapidly
progressing, highly invasive process which results in a necrotizing
faciitis and/or STSS leading to a shock-like syndrome and multi-organ
failure. If not recognized early STSS can lead to death in 24
hours or less. A similar syndrome has been seen in human
medicine, the so-called "flesh-eating bacteria".
Necrotizing
Faciitis
I
consider this a
localized
form of streptococcal infection. Dogs with NF tend to develop
extensive soft tissue sloughing along fascial planes. Fascia
is dense connective tissue which covers the muscles. Usually
this syndrome presents as large areas of skin and the underlying
fatty tissue dying and peeling away, hence it has been called "flesh
eating bacteria". Many of these dogs will survive with
debridement or clearing away of the dead tissue, but healing is
prolonged and skin grafts are often necessary. Long-term
management is intense with frequent bandage changes, cleaning of the
wounds, antibiotic therapy and the need for multiple anesthetic
procedures to repair and reconstruct the damaged areas. The
areas I've seen involved are often the hock joints, the flanks and
the abdominal skin.
Streptococcal Toxic Shock Syndrome
STSS seems to be a generalized or systemic form of streptococcal
infection. Streptococcus canis
in a potent exotoxin producer and it is thought that in
cases of STSS the toxin may be responsible for the rapid progression
of sepsis, shock and multi-organ failure (MODS). On necropsy
these dogs show severe edema of the gastrointestinal tract,
congestion of multiple organs, severe pulmonary (lung) congestion
and evidence of thromboembolism (blood clots) all pointing to shock
due to sepsis or toxemia. These dogs typically die within
24-48 hours in spite of aggressive fluid therapy, antibiotic
treatment and intensive supportive care.
Clinical signs in
the localized form of STSS, necrotizing fasciitis, consist of areas
of skin bruising, dead skin and/or areas of sloughing where the skin
is falling away. Usually there is a pus discharge from these
areas. The dogs are very painful, running a high temperature,
depressed and, in general, sick dogs. Often there is a history
of an FSF episode, dog fight wounds, or other traumatic event.
In the generalized or systemic form of STSS symptoms have a much
more rapid onset and are more shock-like such as severe weakness,
rapid heart rate, pale mucous membranes, extreme pain, collapse,
coma and acute death. Many of these dogs develop DIC
(disseminated intravascular coagulation) which rapidly leads to
multiple organ dysfunction syndrome (MODS) and death despite heroic
efforts at treatment.
The cause of this condition is
unknown. It is known that
Streptococcus canis
can be part of the normal bacterial flora of the dog and
that NF and STSS have occurred in other breed. Predisposing
factors in the Shar-Pei may be related to:
- The increased
amounts of mucin in the subcutaneous tissues.
- The prevalence
of FSF in the breed.
- The prevalence of dog fights and bite
wounds in the breed.
- An increase in skin laxity resulting in
more trauma.
- Immune system insufficiencies.
- Perhaps an
increased virulence of some strain of Streptococcus canis.
Diagnosis is based on the
history of previous trauma or FSF episode, bacterial culture and
sensitivity of discharges or tissue samples, and clinical
signs. One important point is that the organism is often
resistant to enrofloxicin (Baytril®) and the
aminoglycosides such as Amikacin® and
Gentocin®. Consider the use of multiple
antibiotic therapy with agents such as Clavamox®,
cephalexin, clindamycin, lincomycin, erythromycin, penicillin and
the potentiated sulfas. Of course, the best approach is based
on sensitivity information from a culture, but that takes some time
to generate.
Treatment of the necrotizing fasciitis
involves appropriate antibiotic selection and administration, and
basic wound care of the affected areas. I have seen dogs have
recurrence of necrotizing fasciitis with repeat FSF episodes.
Usually they seem to slough out the same area every time.
Treatment of the STSS involves intensive care with intravenous fluid
therapy, shock treatment with IV antibiotics, pain management,
steroids (?), and intensive monitoring for the development of DIC,
etc. At this time the prognosis for systemic STSS must be
considered very poor.
Increased owner awareness of NF and
STSS, rapid initiation of appropriate antibiotic therapy and
intensive supportive care are the keys to survival in this
condition. An excellent article on STSS appeared in the
October 15, 1996 issue of the Journal of the American Veterinary
Medical Association, Volume 209, Number 8, pages 1421-1426 by C.
Miller, J. Prescott, K. Mathews et al. entitled "Streptococcal Toxic
Shock Syndrome in Dogs".
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