Common Medical
Problems
in Opossums

Dermal Septic Necrosis/"Crispy Ear"
Toxic Shock Syndrome Coming soon...
Necrotizing Fasciitis Coming soon...
Urinary/Genital Tract Infection, aka Cushingoid Syndrome Coming soon...
Metabolic Bone Disease

Dermal Septic Necrosis

Excerpt- "Crispy Ear" Syndrome...aka..Dermal Septic Necrosis/Gangrene
-A.M. Henness, DVM
©1995, National Opossum Society
General Pathogenesis: Any bacterial agent is a candidate for cause of this condition. Apparently, in dogs, it is especially prevalent with hypersensitivity reactions to certain Staphylococcus sp. Infectious sites from bites or other wounds, dental disease, or other systemic infectious processes are primary sources for bacterial spread. Serious, body-wide infection may affect the heart and valves, kidneys, liver, etc., and are all possibly well-established before one sees the peripheral effects (i.e. pinna, toes, fingers, tail).

Presentation in the Pinna:

There are two forms of the condition:

  1. "wet" form, with well-demarcated subepidermal seromatous bullae on the margins. They resemble hematomas seen in dogs secondary to trauma of the ear (as from chronic ear shaking). Given time and appropriate antibiotic this might resolve or progress to slough, and then the "dry" form. This "wet" form usually has a peracute course and may signal a gravely ill patient.
  2. "dry" form, is more typically seen, and may have an insidious course over weeks or months. It may be mistaken for fly strike in wild or outdoor housed opossums. The lesions appear as dried and fixed, well-demarcated areas. Often affected tissue are easily peeled off the seemingly normal portions, leaving a bleeding margin which only appears healthy.
Presentation in the Tail:
  • is essentially identical to the "dry" form on the pinna and may affect any length from the tip proximally. Rarely, lesions appear as isolated lesions proximally. There is a well-demarcated margin, but the lesion only poorly pulls away, probably due to the fibrous nature of these tissues.
Presentation in the Digits:
  • is also essentially as in the "dry" pinna form. It may be preceded by hemorrhage, visible under the nails, and by decrease in circulation to the tips of the affected fingers or toes. The lesions do not usually uniformly affect the digits of even the same appendage. They will easily progress to involve the hand or foot. Appearance of digital lesions also tends to signal very serious systemic disease.

Photographs of DSN


~UPDATE~ DERMAL SEPTIC NECROSIS

-A.M. Henness, DVM
©1996, National Opossum Society

The term "crispy ear" refers to the most common form of Dermal Septic Necrosis (DSN), the proper name for this disease syndrome. The original article (please see "Possum Tales Vol 6, No.1) discusses its general pathogenesis; both describe the appearance of lesions in its various forms. This update section reinforces the necessity for early recognition and outlines effective treatment and appropriate monitoring.
Because the opossum with DSN may appear to be "generally well", other than its lesions, caregivers, and even veterinarians (!), may be lulled into false belief: "It's OK; we can wait to deal with this," or "he looks healthy to me, these crusts are of no concern."
This is a serious systemic infection! Only the extent and severity of infection varies from patient to patient. To avoid organ involvement/damage, or death after a short or protracted illness, one must begin appropriate antibiotic treatment ASAP! One dare not delay! And one dare not discontinue treatment prematurely!
Diagnosis, treatment, and monitoring REQUIRES:
  1. initial and follow-up complete physical assessments.
  2. initial and subsequent CBC (minimum of PCV, est. WBC with differential, and total protein) to monitor progress.
  3. urinalysis with culture and sensitivity. This test (unless no growth) helps choose correct antibiotics. Only rarely can one obtain culturable material from lesions. Even with a negative C&S, the UA can still give clues to progress.
Presentation: The animal with DSN may demonstrate a variety of non-specific problems/changes: appetite; urine or BM; behavior; attitude; sleep/activity cycles. The lesions typical for DSN appear at one or more cutaneous sites, in the effusive or dry form (+/- crusts), or a combination of both. In decreasing frequency, sites include: pinna, tail, nail-beds/digits, lips/nostrils, hands, feet, torso, limbs. The effusive form is always a more aggressive illness!

PROTOCOL
Treatment: The "search" for the correct drug/drugs is still a potential problem where C&S is unobtainable. However, from my experience with well over 150 patients with DSN (to date), I have found the best approach is as follows, in order of "search". If one sees evidence of clinical response within 2-3 days of starting a drug/drugs, continue that antibiotic(s); if none, go to the next in order.

Monitoring: physical assessment, CBC, and UA evaluated at 1-2 week intervals to verify response, 1-4 week intervals thereafter. Duration of treatment discussed at the end.


The specific drugs listed in the protocol will not be presented on the website. We will, however, gladly discuss the opossum and possible treatment options with you.

Metabolic Bone Disease


Please see the full text of Dr. Henness's article NUTRITIONAL METABOLIC BONE DISEASE: Its Causes . . . Its Cure.

Photographs of MBD

 

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