Tanathology in Small Animals
World Small Animal Veterinary Association World Congress Proceedings, 2006
Moisés Heiblum
Veterinary Hospital Universidad Nacional Autonoma de Mexico; Private Practice in Small Animal Behavior, Naucalpan, Mexico

What is Tanathology?

Death is a natural process and a characteristic that we share with all the living creatures, and it is necessary so that life, not the organisms in particular, could continue and evolve (3,5). Even tough death is a natural process; it will always be difficult and painful, since it means a loss of continuity in the existence of the individuals, rupture of bonds, interruption of activities, relations and projects. Before the need to understand and to assimilate in a more suitable way this process, in the recent years, tanathology became an important field in medicine, which tries to help the terminal patients so that they could assume their own death; and at the same time, it helps and prepares the people closest to the patient, during the terminal stages and during the grief.(2,3)

The Biological Process of Death

From the physiological point of view, death has been defined as the irreversible cessation of the vital functions, in the vertebrates, it happens when the nervous central system, the respiratory and the cardiovascular systems stop functioning. The cells and structures that integrate it are disorganized, autolysis begins and the individual loses the ability to interact with his environment in a definitive form, this is known as somatic death(1,8).

The Veterinary Practitioner Facing Pain and Death

The veterinary practitioner has assumed the "privilege" of being able to decide on the life and death of the animals(3), therefore he needs a suitable formation making him fully aware of the huge responsibility that this implies, as well as knowing his own limits.

The veterinarian has the task of educating and sensitizing the owners about companion animals, having acquired an animal, they acquire a commitment with the animal, commitment to take care until the moment of his death. Also it is the veterinarian's responsibility to actively take part in the decisions of critical situations, since he has the mission to promote the animal's welfare, he can influence in an important and positive way the fate of the animals.


Euthanasia (from the greek eu = good and thanatos death) means "Good death" (2,3).

In the context of veterinary medicine, this word has been used to designate the act of inducing death in a calm and easy form, without stress or pain. Medically euthanasia is considered to be the interruption of life, by means of a painless method, which produces a rapid unconsciousness followed by death. It could also be defined as: "the medical administration of a lethal agent with the intention of relieving the patient from an unbearable and untreatable suffering"

In Hebrew there is a term that describes euthanasia as: "mitat jasadim",(5) this means death with compassion and is a form to refer to the act of interrupting the life of an animal with the minimum of suffering. Also the word "compassion means "feeling as the other", either human or animal; understanding kindness, tenderness, mercy, love and the most important thing, companionship. Compassion is to feel together with ... therefore to give an animal a compassionate death, goes beyond the simple fact of taking the animal's life; it involves the responsibility of deciding the moment and means of his death(2,4), but more importantly not leaving him alone during this process, so that having his human friends next to him when his life ends, diminishes not only his physical pain, but also his anxiety and suffering.

It must remain clear that euthanasia is not the solution to all the problems, its purpose is to end with an unbearable suffering(5), when there is no other medical alternative.

Before thinking about euthanasia, an ethically correct attitude is to provide the animal support, attention, avoiding invasive procedures; trying at all times, to make him as comfortable as possible, having no thirst and no pain.

Deciding Euthanasia

It is one of the most controversial topics. It is known that the owners go so far as to form very narrow bonds with their pets. On having died the pet is as if they were losing one member of the family, therefore, the intention of tackling this topic is to offer a point of view and not to try to convince anybody.

Medical Approach

We have to continue a series of steps that should lead us to knowing which is the problem, it's cause, which is the possible treatment (if there is) and much importantly what is going to happen in short, medium and long term with the patient.

The medical approach consists of the following points: Making a clinical history, physical examination, laboratory tests, diagnosis, prognosis, treatment.

Approaching the Subject

It can be much more difficult taking a decision related to euthanasia in the middle of a medical crisis. The veterinarians frequently have difficulty knowing in what moment they must talk to the owners about euthanasia in their animals and at the same time a great discomfort exists in the owner to tackle the topic (3,5). Both the veterinarian and the owner will have to take sufficient time to take the decision without being under a strong emotional tension. There is too much pain in these moments to add a sense of guilt. When will be known that the moment has come?

If there are medical specific signs (seizures, pain) that the owners could observe, the veterinarian will have to mention them. It is advisable to write a list of clinical signs so that the owners could remember easily what they must observe and look for. The bottom line is to be able to measure the level of deterioration and quality of life. These are different for every owner. It is very important to distinguish between pain and suffering. Pain can be controlled by medication, but the suffering can be more difficult to remedy. When it seems that it has more bad days than good ones or more bad moments than good ones, it will be known that in a way there is some kind of suffering.

Euthanasia: How to Face the Inevitable?

To say good-bye to a pet is always difficult and even more when this farewell is a result of a decision as euthanasia.

The Farewell

As soon as the decision of euthanasia was taken, it is important to allow a moment of privacy between the owner and his partner, preferably in a private place and alone.

We must give them the space so they could cry, embrace and vent all the feelings inside, sometimes the owners suppress these feelings to avoid the embarrassing moments of people watching. This moment of privacy will allow that the owner could express oneself freely. This moment is perhaps one of the most important and as well as it is important it is unique. (2,3,5)

Supporting the Patient

The process of euthanasia for itself already implies an apprehensive state for the pet, for what we must reduce to the maximum any situation that increases this tension.

It is an owner's decision if he wants to be present during the procedure. If the owner does not support the idea of watching his pet die and cries in an exaggerated form, it is preferable that he is not present at that time not to increase the anxiety of the patient.

Where to Perform the Euthanasia?

If the patient is hospitalized, in a critical situation where risk exists to transport it, then the ideal place is the same clinic. If it is in the house or the conditions to be transported are good, the ideal situation is taking it to the place where the patient feels calmer.

How to Perform Euthanasia?

We must perform a procedure that allows the patient to have a "good death". Independently of weather, the patient is canalized previously or not, it is recommended to apply a tranquilizer, which allows the patient to be sedated and diminishes the anxiety. Once the family has said goodbye, the vet proceeds to apply an overdose of anesthetic until a cardio-respiratory arrest takes place.

It is important that the owner knows that when the death comes: the eyes of the patient may remain opened, the heart can keep on beating after the respiration has stopped, there can be sound emissions, there is sphincters relaxation, therefore the bladder and intestine can be evacuated.

At the moment of the euthanasia: you have to create a space for this moment, to avoid any interruption and not to program it in schedule of consultation.

Who Should be Present?

Undoubtedly this decision depends on every family. The ideal thing is, that can be present all those that are a part of the familiar group and who obviously want and could be, if it is possible, do not leave the patient completely alone.(2)

Disposition of the Body

When the euthanasia is over, the owner may ask what to do with the corpse, his sorrow is so big that they usually do not speak about this. That's why it is the veterinarian's responsibility to tell the owners the options about it.

Autopsy: if the cause of the illness is still not determined (later cremation)

To bury it: it is recommended to bury it to a depth of 1.5 meters and the use of lime on the corpse, to eliminate bad smells and in case of having other animals in the house, preventing these from digging the corpse up. Another option is to take it to a pet cemetery.

Cremation: sometimes for lack of space or because this way the owners prefer it.

Grief and Sorrow

To assimilate the death of a pet is a difficult and painful process. Companion animals are usually part of the family. The sorrow is normal and it must be expressed.(2,3)

There are those who decide to keep mourning in a time and not to acquire another pet soon. Others prefer acquiring another pet immediately because they have a lot of love to give. Keep their mind occupied and prevent them to get depressed for the pet that died. Finally there are those who decide to never again have a pet, since the sorrow of losing was so big that they do not feel capable of supporting the same pain again.

What is the correct decision? Every person has the freedom of feeling and of believing what they should consider to be better.

What About the Animals That Stayed in the House?

Sometimes the pain that provokes the death of a pet makes us forget that the other animals that are in the house need us. It is necessary to remember that the animals can form very strong bonds, not only with humans but also with other animals. The animals that stay in the house can suffer from depression on having felt the absence of his partner. (2,3,5)

How can we help these animals to overcome the loss?

 It is important not to change the daily routine, not to reinforce the changes of behavior, try not to change the food, even if they stop eating for a few days.

 Support a regular physical activity.

 Do not overprotect him and do not give all the attention and affection.

 Look for professional help if the change of behavior is very intense or can put his life at risk.


1.  Cotran RS, Kumar V, Robbins SL. Patología Estructural y Funcional. 5a ed. Madrid: Interamericana. McGrawHill; 1995; 1553

2.  Graus A. Eutanasia: reflexión obligada. Revista Investigación Clinica; 1995;47: 217-229

3.  Vanda B. Revista Imagen Veterinaria 2003;3 4-14

4.  Knight, B. Medicina forense de Simpson. 2a. Ed. México, D.F.; El manual moderno, 1999

5.  Rebolledo- Mota F. Aprender a morir. Fundamentos de Tanatología Médica. 3a. Ed. México, D.F.: 1999; 315

6.  Rollin BE. Veterinary Medical Ethics. Ames: Iowa State University Press, 1999; 417

7.  Vanda B. Alteraciones celulares y tisulares. En Trigo FJ,

8.  Valero G. Editores. Patología General Veterinaria. 3a. Ed. México: FMVZ-UNAM; 2002; 417

Speaker Information
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Moisés Heiblum, DVM
Veterinary Hospital Universidad Nacional Autonoma de Mexico
Jardines de San Mateo
Naucalpan, Mexico

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