Also, because euthanasia solution is caustic, intra‐abdominal administration of euthanasia solution is not the best route of administration if an animal has an enteric (gastrointestinal) disease and histopathological analysis is anticipated.
The clinical history (including duration) and knowledge about any therapy are both vital to the appropriate interpretation of findings. In a shelter with the capacity to provide medical resources, necropsy may be limited to animals that have received medical care, such as antibiotics, which can compromise postmortem culture results. It is always beneficial to perform a necropsy on a more recently affected or moribund animal, rather than one that had recovered but might be weakened and subject to a secondary disease process.
Figure 5.2 Euthanasia can cause artifactual changes to tissues. Here the granular, dull texture of the region of lung defined by the arrows is caused by intrathoracic contact with beuthanol during intracardiac euthanasia.
5.3.2 Documentation
5.3.2.1 Written Data
Pre‐mortem information: Historical and clinical information are equally as important in the investigation as transcribing observations at the necropsy. Pre‐mortem information includes clinical signs, date of intake and onset of illness, location held in the shelter, and all treatments received. Especially in a shelter, this information is necessary to identify patterns of susceptibility to disease over time, whether geographical, age‐related, treatment‐associated, time of year, etc. This information is also essential to interpret the necropsy and histological lesions, and/or to compare future or past cases. Pre‐mortem and historical information can be written on a separate form or can be included on the necropsy form itself.
Necropsy results: There are several well‐organized necropsy templates available (see resources below) and a shelter should have copies of one of these on hand. Which directions, forms, and/or templates are used are not important; they are designed to remind the prosector (the person doing the dissection) to be methodical, thorough, and consistent. It is important to try to be as objective as possible in reporting observations; specifically, to describe abnormalities without presuming cause (without adding interpretation). For example, if the liver appears large, the organ should be weighed or, if there is no scale, describe how this interpretation was made: “The edges of the liver lobes were rounded and the caudal aspect of the liver extended to….” The features (shape, position, color, consistency) should also be noted if the liver is abnormal. In this same example, the objective gross diagnosis is “hepatomegaly,” or large liver. Knowing if a liver is too big or too small is useful, as the differential causes are entirely different, but the interpretation of organ size based on weight relies on its comparison (ratio) with the bodyweight of the animal.
If an organ or system was not examined, this should also be noted (e.g. if only the abdominal cavity and gastrointestinal system were examined and sampled, there should be a note on the report saying that organs within the thoracic cavity were NOT examined).
5.3.2.2 Photographic Data
Visual data can have great importance in the communication of necropsy findings, and with digital hegemony, most shelters own or have access to a digital camera. Photographic data is complementary to the written description of a lesion and can be even more persuasive than a written report in the legal documentation of findings. A photograph should never be substituted for a written record since two‐dimensional photographs can only rarely fully represent the texture, cut surface, depth, and extent of any single lesion or systemic process.
5.4 Steps in Performing a Necropsy
5.4.1 The Materials Needed for a Necropsy
Not all the listed equipment will be needed to perform each necropsy, but Table 5.2 is a good starting list of the things that should be on hand for any given situation. Maintaining a devoted “necropsy kit” can save time.
5.4.2 General Information
There is no single CORRECT method to perform a necropsy, but consistency is important. If a cadaver is opened in the same way for each necropsy, one is more likely to recognize/discriminate abnormalities of any sort (e.g. size, position, color). Even in the case where the animal's disease appears to be limited to, for example, the respiratory system, the author recommends that the animal's body be opened in the same way so that both body cavities are examined visually. Respiratory distress can arise from abnormalities in organs not present within the thoracic cavity. In addition, concurrent diseases, if present, can be very important to disease progression. The most common example of this seen in shelters is immunosuppression caused by viral diseases like canine distemper virus, which can predispose a dog to a “secondary” infection such as bacterial pneumonia, or parvovirus (panleukopenia) in a dog or cat, which can predispose the infected animal to other enteric pathogens.
Table 5.2 Necropsy kit.
| 1) Camera |
| 2) Notebook or Pathology Form |
| 3) Protective clothingGloves (latex, nitrile, or rubber)BootsMask (to cover mouth and nose)Eyewear or goggles |
| 4) InstrumentsSharp knife (and/or scalpel)Knife sharpenerScissorsForcepsSmall shearsRuler |
| 5) Collection gearSpecimen container (plastic) with a tight‐fitting lid for fixed samples (plastic tubs, Rubbermaid, specimen cups, Tupperware type)10% buffered formalin (for fixed specimens/histology)Plastic bags with closure (whirl‐pack, zip‐lock) for unfixed samples (fresh or frozen)Tags (to identify specimens)Collection vials (can be used for urine, blood, joint fluid, etc.) |
| 6) Transport/shipping containersIce packsHeavy‐duty bags, or leak‐proof containersPacking material (preferably absorptive) |
| 7) Cleaning and disinfecting materials |
Step by step instructions on how to perform a necropsy are available from several books and web‐based sources. Five sources are listed below. While not all these protocols specifically use dogs and cats as models, the general approach to a necropsy is similar in all domestic species. The 5th listed resource by Severidt, for example, although specifically addressing cattle, has an excellent section on sample handling and submission.
5.4.2.1 Resources for Performing a Complete Necropsy
1 The Veterinary Necropsy Report Checklist and Guidelines form (DD Form 1626) was created by the Armed Forces Institute for Pathology (AFIP), Division of Veterinary Pathology. It can be found at https://www.esd.whs.mil/Portals/54/Documents/DD/forms/dd/dd1626.pdf (or search veterinary pathology, Form 1626).It is a comprehensive, 12‐page document with sections for data and interpretation (pages 1‐2), gross necropsy findings (pp. 3–8) and a detailed necropsy protocol (pages 9‐12). Included is a tissue checklist (page 7) to record tissues collected during the necropsy.
2 The Necropsy Book by Drs. John M. King, Lois Roth‐Johnson, David C. Dodd and Marion E. Newsom. This succinct, small book guide is available
