Common Medical
Problems
in Opossums

General Pathogenesis:

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.

~UPDATE~ DERMAL SEPTIC NECROSIS

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.

PROTOCOL

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.