WHY VETERINARIANS SUICIDE

Good day dear friends and colleagues, it has moved my heart in the past few months with some news, that are not so new actually, but every day they become more frequent. Each time there are more and more Veterinarians taking a dangerous step, and I would like to take a little space in this blog to talk about this issue that is not only in the USA, but also worldwide.

Some studies have identified a relationship between suicide and occupation, including Health Care and Veterinary profession.

The rate of suicide in the Veterinary profession has been pegged as close to twice that of the Dental profession, more than twice that of the Medical profession, and 4 times the rate in the general population.

The 2012 CVMA National Survey Results on the Wellness of Veterinarians found that 19% of respondents had seriously thought about suicide and 9% previously attempted suicide. Of those who had seriously thought about it, 49% felt they were still at risk to repeat. The risk is real. The numbers are compelling.

Suicidal talk is a major warning sign for suicidal risk and should always be taken seriously. The myth suggests that suicidal talk is just attention-seeking behavior, while in truth it is an invitation to help the person to live. If help isn’t forthcoming, especially after they’ve made themselves vulnerable by having disclosed sensitive thoughts and feelings, they may feel it will never come. Without appropriate response, suicidal talk — which begins with suicidal thoughts — can escalate to suicidal acts.

Anecdotally it may seem that pet ownership is protective, but research has not demonstrated an association between pet ownership and suicide. In fact, the loss of a beloved pet can be a risk factor for suicide.

Although folklore includes tales of suicide among animals, modern naturalistic studies of thousands of animal species in field situations have not identified suicide in nonhuman species. Death by suicide is strictly a human phenomenon.

The widely acknowledged risk factors for suicide in the general population include personality factors, depression (as well as other forms of mental illness), alcohol and drug abuse, inherited factors, and environmental factors (including chronic major difficulties and undesirable life events). Although the specific factors contributing to the increased rate of suicide in the veterinary profession have not yet been determined. The following factors may contribute to the increased risk of suicide in our profession: personality factors, undergraduate training, professional isolation, work-related stressors, attitudes to death and euthanasia, access to and knowledge of means, psychiatric conditions, stigma around mental illness, and suicide contagion.

Veterinarians tend to be high achievers, and high achievers have tendencies to perfectionism, conscientiousness, and neuroticism, all of which can be risk factors for mental illness. Similarly, veterinarians with a preference for working with animals rather than people, may have a higher risk of depression as a result of relative social isolation.

Many veterinarians in private practice work in relative isolation where there is often little supervision and access to assistance from veterinary colleagues, an environment ripe with the potential for professional mistakes. The considerable emotional impact of such mistakes may contribute to the development of suicidal thoughts.

Inadequate professional support and professional mistakes, along with other work-related stressors such as long working hours; after hours on-call duties; conflictual relationships with peers, managers, and clients; high client expectations; unexpected clinical outcomes; emotional exhaustion (compassion fatigue); lack of resources; limited personal finances; concerns about maintaining skills; and the possibility of client complaints and litigation can all contribute to anxiety and depression, which increase vulnerability. Long-term exhaustion (burnout), characterized by disillusionment and demoralization, may also increase vulnerability.

Veterinarians in private practice are commonly required to engage in the active ending of life, with strong beliefs in quality of life and humane euthanasia to alleviate suffering. Likewise, those in food production are required to end the lives of animals via the slaughter of livestock. Active participation in the ending of animal life may alter views on death and the sanctity of human life, and in the face of life’s challenges, enable self-justification and reduce inhibitions towards suicide, making suicide seem a rational solution.

Veterinarians have access to and knowledge of prescription medications (including drugs for anesthesia and euthanasia), increasing the potential for misuse. With ready access and knowledge, such substances could be used not only as a (maladaptive) means of coping, but also as a means to suicide, potentially being a key factor in the high rate of suicide in the profession 

Just as mental illnesses such as depression and substance misuse and dependence are associated with suicide in doctors, by extension, they may also be a factor in suicide by veterinarians. Two-thirds of people who die by suicide suffer from a depressive illness.

Now I would like to say something that perhaps could sound a little rare, specially for all of those who have known me for less than 5 years long. About 11 years ago I had attempted suicide, perhaps more than 4 times by then, from which I had been taken to the hospital for substances abuse, I was not a Veterinarian yet, although I know the feeling. About 8 years ago somebody talked to me about Christ, and before you begin to judge or say that this is a religious comment, maybe you should stop right there and open up your mind and read this.
I was going through the hardest times of my life, I knew what rejection was, I knew what the feeling of not being able to do things right was, but let me tell you something, Christ changed me completely.
I was never the same after I took Him in my life. I started the Veterinarian career, I finished it, and to be honest, even with all the pressure, Christ held me, comforted me, and loved me when nobody else did, if you are a Veterinarian, or just a person that likes animals and their care, this is also for you, Christ is more powerful than we could even imagine, movies are quite short, stories are nothing compared to what He really is. But you know what, the most important thing is that Christ loves you no matter what, and He will strength you and hold you as long as you let Him do so.

So for all my Veterinarian colleagues out there, hold on, and pray, just stop right there, Christ will change things completely, even when He's silent, He will turn things in your favor just because He can and because He loves you!
And think about your four paw patients, those who can't speak but surely are much more thankful than humans, think of how you can help the creations of God, and how humble and beautiful our profession surely is!
If you need any kind of help with depression, or have any suicidal thoughts, don't hesitate, contact me, or talk to someone you feel trust in, but please just stop right there, and talk about it, you are a very valuable person, unique, and definitely important!

Thank you for taking your valuable time to read this until the end.

MVZ Carolina Pruneda

References:
http://www.bostonglobe.com/lifestyle/2016/09/18/why-many-veterinarians-commit-suicide/iCCgr46bIJpgEeesPHTe2L/story.html?event=event25
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4266064/
http://stevedalepetworld.com/depression-suicide-veterinary-medicine/
https://www.businessinsider.com.au/most-suicidal-occupations-2011-10#4-veterinarians-are-154-times-more-likely-to-commit-suicide-16
http://www.care2.com/causes/why-is-the-suicide-rate-for-veterinarians-so-high.html#15048451623692&action=expand_widget&id=0&data=
http://www.startribune.com/veterinarians-at-high-risk-for-suicide-and-the-job-could-play-a-role/392775791/

CHROMOSOMES IN OUR PETS!

Have you ever wonder how many chromosomes do cats and dogs have compared to humans?

To Understand this, we most remember what the DNA is.

DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).

The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people. The order, or sequence, of these bases determines the information available for building and maintaining an organism, similar to the way in which letters of the alphabet appear in a certain order to form words and sentences.The 22 autosomes are numbered by size. The other two chromosomes, X and Y, are the sex chromosomes. 

DNA bases pair up with each other, A with T and C with G, to form units called base pairs. Each base is also attached to a sugar molecule and a phosphate molecule. Together, a base, sugar, and phosphate are called a nucleotide. Nucleotides are arranged in two long strands that form a spiral called a double helix. The structure of the double helix is somewhat like a ladder, with the base pairs forming the ladder’s rungs and the sugar and phosphate molecules forming the vertical sidepieces of the ladder.

An important property of DNA is that it can replicate, or make copies of itself. Each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of bases. This is critical when cells divide because each new cell needs to have an exact copy of the DNA present in the old cell.

In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.

Chromosomes are not visible in the cell’s nucleus—not even under a microscope—when the cell is not dividing. However, the DNA that makes up chromosomes becomes more tightly packed during cell division and is then visible under a microscope. 

Each chromosome has a constriction point called the centromere, which divides the chromosome into two sections, or “arms.” The short arm of the chromosome is labeled the “p arm.” The long arm of the chromosome is labeled the “q arm.” The location of the centromere on each chromosome gives the chromosome its characteristic shape, and can be used to help describe the location of specific genes.

In humans, each cell normally contains 23 pairs of chromosomes, for a total of 46. Twenty-two of these pairs, called autosomes, look the same in both males and females. The 23rd pair, the sex chromosomes, differ between males and females. Females have two copies of the X chromosome, while males have one X and one Y chromosome.

Now moving on with the diferences between cat and dog's chromosome vs humans, first of all we find that the number is different.

Dogs have 39 pairs of chromosomes, for a total of 78. This works out to 76 autosomes and two sex chromosomes. As with other mammals, the karyotype of male dogs is XY whereas females' karyotype is XX

Although dogs have 39 pairs of chromosomes (compared to 23 pairs for humans), dogs have fewer genes overall. Researchers sequencing the canine genome have identified around 19,000 dog genes compared to the 25,000 or more genes in the human genome. Despite having 6,000 fewer genes than humans, dogs exhibit a diverse range of phenotypes, from animals as large as a Great Dane or St. Bernard to toy dogs weighing no more than a few pounds. Geneticists think the canine genome may be especially prone to gene duplications and chromosomal rearrangements compared to the genomes of humans and other mammals.

Most cats, including domestic breeds, have 19 pairs of chromosomes for a total of 38. Some types of cat in South America, however, have only 36 chromosomes, including ocelots, kotkots and margays. Dogs have more than double the number of chromosomes with 39 pairs.

Hopefully this information is somewhat useful, or at least fills in the curiosity of some of us.

MVZ Carolina Pruneda

FLEA CONTROL PRODUCTS AND THEIR MECHANISMS

Good day colleagues and friends, today we will talk about about some of the most important chemical products that we can use and prescribe for flea control and elimination.

1. Selamectine: this one contains Avermectins and derivatives (a group of macrocyclic lactones produced by soil bacterium Streptomyces avermitilisand derivatives). It can be topic applied, it hits all stages, especially larvae, and even eggs. Its efficiency is over 90%, residual protection for over 20 days. And the way it works is that it opens of chloride channels in muscle membranes of arthropods.

2. Fipronil (Front-Line): it contains phenylpyrazole insecticide. It can also be topic applied as a spot-on. It hits adult and off-host stages. This one it's very cool because it's efficiency is over 90%, residual protection for ~90 days. The way it works is by blocking (GABA)-gated chloride channels in central nervous system, paralyzing the fleas and ticks so eventually they will release the skin of the animal and fall and die.

3. Imidacloprid (Advantage): it's chemistry is pretty basic, it contains chloronicotinyl insecticide, and it is also topical. It also hits adult and off-host stages. It's efficiency goes by 90%, residual protection for ~20-40 days. It's mechanism it's a little more complex, because it competitive inhibits at nicotinic acetylcholine receptors of the nervous system, which may take a little while to work, but it does work!

4. Nitenpyram: this one it's similar to imidacloprid, it contains chloronicotinyl insecticide but this one goes by mouth, and it only affects the adult stages. However this is one within 8 hours, 100% of fleas are killed, remain active in the blood for 48 hours. It's mechanism is the sae as the Imidacloprid, but because it goes systemic it acts faster.

5. Pyrethroids: this one is similar to pyrethrins, natural compounds produced by the flowers ofChrysanthemum spp. It goes topical, it only hits adult stages. it is more than 90% effective  in number of cat fleas for 28 days. This one opens the sodium channels in the nervous system.

6. Pyriproxyfen: it goes topical, it hits larval and eggs stages, it has a significant reduction in flea numbers and almost 100% elimination over the period of six months. It releases juvenile-hormone analog (JHA), so the flea grows backwards and eventually can no longer live.

7. Lufenuron: it can be administered orally or by injections, it hits larval and eggs stages. We can observe a 90% decrease in number of adult fleas emerging from eggs for ~200 days after treatment. This one is an insect-growth regulator (IGR), which inhibits chitin synthesis.

8. Methoprene: because this one goes always as a flea collar, it's not very recommended, especially in kittens, because the kitten may bite it, chew it, or even worse eat it, so it may be toxic for them. It is somewhat effective because it hits larval and eggs stages and lasts for 4 to 6 months on a dog and up to a year on cats. 

9. Bravecto: it's main ingredient is Fluralaner, it goes topical, it affects all stages from egg to adult. It is over 95% effective and its effect last over 12 weeks. These compounds have activity against γ-aminobutyric acid- (GABA-) and glutamate-gated chloride channels with significant selectivity for insect neurons over mammalian neurons. This product is very effective, however, we as Veterinarians must be careful when prescribing it to cats, cats under the age of 6 months most not use this product due to high rates on neurological side effects.

Hopefully this post may be helpful and if you can also recommend any other your comments are welcomed!

MVZ Carolina Pruneda

The Cat Area 9 : Ctenocephalides felis

Good day colleagues and friends today we will talk about the most common ectoparasite in cats, yes we are talking about CTENOCEPHALIDES FELIS, a flea that gives all of us veterinarians headaches when we are at the consultation room, because they are stubborn and they jump not only to other patients but also to us veterinarians and owners.

Distribution

But before we get started, it is important to know where this ectoparasite is most common at.

 Cat fleas are commonly found on both cats and dogs in North America, while dog fleas are found in Europe. The two species are distinguished by a slight morphological difference which is detectable only under high magnification. Although it exists worldwide, the cat flea is most commonly found in the United States and Mexico, in and around homes with pets.

Life and Cycle

The Ctenocephalides Felis or cat fleas are small pests measuring about 2mm in length. They are dark brown or reddish in color, typically wingless, but capable of jumping long distances. Their laterally compressed bodies are covered with hair. They have very strong hind legs which enable them to jump from one host to another. In the adult stage, the Ctenocephalides Felis also have mouthparts that allow them to suck blood from their host.

Now let's review this flea's stages and life cycle. Under optimal conditions, a cat flea can complete its entire lifecycle in just two weeks. In adverse conditions, the lifecycle of the cat flea can take upwards of one year. Cat fleas like warm, humid environments, so if they make it into your nice, warm home they can be hard to banish.

Cat fleas have four distinct stages in their lifecycle: eggs, larvae, pupae, and adult.  This cycle usually lasts 30 to 75 days, yet may vary due to external factors, such as temperature and humidity.

Adults: Adults are stimulated to emerge by vibration or an increase in carbon dioxide. They are about one to three mm in size, reddish-brown to black in color, wingless, and are laterally compressed. They possess powerful hind legs which allow them running and jumping through hair, fur, and feathers. Adult cat fleas require fresh blood to produce eggs. This is the only stage in the cat flea life cycle when the fleas live on the pet. Adults live from 4 to 25 days.

Adults feed directly from capillaries. Female fleas can ingest an average of 13.6 µl of blood daily, about 15 times their body weight.

Eggs: Cat flea eggs are laid at the rate of up to one egg per hour, and 20 to 50 eggs per day, which hatch in 2 to 5 days. They are oval, smooth, and about 0.5 mm in size. Due to their dry, smooth surface, the eggs easily fall out of the animal's hair. Though otherwise visible, the white eggs are nearly impossible to see against surfaces such as carpet, bedding, and lawn. It is here where the eggs will remain until the larvae emerge.

Larvae: Within two days of oviposition, wormlike larvae hatch from the eggs. They range from 1.5 to 5 mm in length. This stage lasts 5- 15 days. Larvae lack eyes, legs, are covered with few hairs, and possess dark guts, visible through their thin translucent exoskeleton. Larvae feed on almost any organic debris in the floor covering, but their main dietary component is dried adult cat flea fecal matter.

*Adult flea feces, also known as "flea dirt", consist of relatively undigested blood which dries and falls from the pet to serve as food for the newly hatched larvae. The larvae prefer to develop in areas protected from rainfall, irrigation, and sunlight, where the relative humidity is at least 75 percent and the temperature is 70 to 90°F.

Pupae: Before becoming adults, the larvae spin silk cocoons in which they will develop. Because of the sticky outer surface of the cocoons, dirt and debris are attracted to them and provide camouflage. The pupae remain in the cocoons until they have fully developed into adult fleas.

Signs of cat fleas infestation, control and treatment.

Cat fleas love the warm, moist, safe haven that’s provided in a cat’s furry coat. Two of the main ways to tell if fleas are making a meal out of our cat patients is to take note of whether they are scratching or biting their skin and fur.

Fleas regurgitate digestive juices onto the skin of a bite site while they suck blood from their prey, and sometimes cats and dogs can have serious allergies to this juice. This allergy is called fleabite allergic dermatitis and can be developed over the course of a dog, cat, or human’s lifetime.

Cats that are allergic to flea bites (flea allergy dermatitis) will exhibit excessive grooming and scratching from just a single bite. It’s also characterized by intense itching, hair loss, reddening of the skin, and secondary infections. The reaction and itching can persist for up to five days.

On the Examination we ought to check the skin around the base of its tail or under the armpits for tiny, moving black dots. There's another way we can tell if our patient has fleas by using a flea comb to comb our patient  and look for flea “dirt” (the feces of fleas) which can alert us to an infestation even without seeing live fleas. The fleas will get caught at the base of the comb’s teeth.

We most advise the owner to monitor the patient for scratching and biting on a regular basis. 

If we find any we must advise the owners to treat the patient as much as the home, indoors and outdoors.

When we advise the owner to treat the home, we should make emphasis on how to do so, inside they must vacuum the floor and carpets (specially carpets), and on the yards we can use pesticides that are garden friendly,

Some of the products we can recommend our patient's owners are: 

To treat the outdoors, pyrethroids may be sprayed in dry shaded areas which the animal frequents, as well as insect growth regulators such as pyriproxyfen and fenoxycarb, which are the most effective outdoor treatments. Methoprene is also commonly used outdoors, but is not stable in sunlight. Since larvae prefer shaded, dry areas, spraying the entire yard is wasteful and irresponsible. For outdoor areas which are difficult to treat (under decks), pet access should be restricted. Outdoor treatment is primarily used in severe cases of flea infestation and may not be necessary if fleas are controlled on the pet and in the home.

 Advise the owners not to leave their pets on the outside at least 4 hrs after using pesticides outside.

Now Let's talk about the patients treatment. By own experience, and other colleagues won't let me lie on this, but fleas and ticks control collars are simply not good at all, for some cats it won't matter, but the majority of the feline patients show skin irritation on the neck, some develop allergies to the chemicals used in those collars, some cats have even been intoxicated because of the owners don't place the collar tight enough or because the cat it's just to restless that start biting and chewing on the collar. The safest ways to treat a cat for ctenocephalides felis will always be fipronil or imidacloprid topical treatments. 

When using a pesticide, always consult the label. Insect growth regulators (IGR) and insect development inhibitors (IDI), administered as a daily or monthly dose, will disrupt egg and larval development but not kill adult fleas. Methoprene and pyriproxyfen are active ingredients of IGRs  and are safe to use on our patients, but also easy on the owners pockets.

We also have other options, as many of us know we also can prescribe shampoos. Insecticidal shampoos contain certain pesticides such as pyrethrins, carbamates, and citrus peel derivatives. Pennyroyal oil, another natural products, are also available in shampoos. However, pulegone, the active ingredient in the oil has dose related toxicity to mammals and may induce lethargy, vomiting, diarrhea, nose bleeds, seizures and possibly death due to liver failure.

Now, it is also important to treat the patient's wounds done by the flea bites, because as we know, fleas can transmit bacteria that may result in an infection, therefore we ought to treat the skin of our patients also with antibiotics, our best option of course is Neosporin antibacterial ointment or by mouth. In case of severe FDA (flea dermatitis allergy), we can also prescribe corticosteroids, personally, I would definitely rather to leave those as a last resource, not only because it may be hard to discontinue them, but also because it could cause undesirable side effects if the condition it's chronic or becomes chronic.

Associated diseases

And just like ticks, fleas also can bring diseases to our patients along with them, some of those diseases are:

Flea allergy dermatitis (FAD) The cat flea is primarily responsible for flea allergy dermatitis (FAD) in both dogs and cats. FAD is a hyper sensitization to antigenic components contained in the saliva of fleas. Cats and dogs that have flea allergies will bite at the base of their tail and rump frequently. Animal become nervous and sleepless, sometimes, they vocalize (yelp or meow) sharply from a single flea bite. Even a few fleas can lead to prolonged itching that causes animal to groom extensively sometimes biting and scratching their skin, which can result in painful lesions.

Dog tapeworm Cat fleas are the primary intermediate host of Dipylidium caninum(cucumber tapeworm or the double-pore tapeworm), the common intestinal cestode of dogs and cats that also rarely occurs in children after accidental ingestion of infected flea. 

Murine typhus Cat fleas are able to transmit murine typhus, also called flea-borne typhus or endemic typhus, a rickettsial disease caused by the organism Rickettsia typhi, which usually is associated with rat fleas (Xenopsylla cheopis).

Flea-borne spotted fever Cat fleas are most common vectors of Rickettsia felis, relatively recently described pathogen, causative agent of flea-borne spotted fever (also called cat flea typhus). In 1994, the first human case of infection was reported in United States. Because the disease has similar clinical manifestation as murine typhus (including high fever, myalgia, and rash) and other febrile illnesses such as dengue, the infection in humans is likely underestimated.

Cat scratch disease (CSD) Cat fleas have recently been implicated in the transmission of Bartonella henselae, the etiologic agent of cat scratch disease (CSD). In immunocompetent humans this infectious disease usually is not serious and associated with papule or blister at the site of injury (scratch or bite) and malaise. Cat scratch disease is a common cause of chronic lymph node swelling (lymphadenopathy) in children. It has been suggested that Bartonella spp. may be responsible for numerous chronic inflammatory conditions of the cat. It was shown that as many as 58% of stray cats can be Bartonella spp. carriers and up to 90% of fleas are infected. The prevalence of the infection is much lower in pet cats (~3%).

Cat anemia Over 50% of cat fleas collected from stray cats were shown to be infected with Mycoplasma haemominutum or Mycoplasma haemofelis associated with infections in cats, which can range from subclinical and subtle anemia to severe hemolytic anemia.

Plague Cat flea was shown to be a competent vector for transmission of plague(causative agent Yersinia pestis). Although not as efficient as rat fleas (Xenopsylla cheopis) C. felis is the most common flea in human habitations in many African countries and threat posed by the ectoparasite cannot be dismissed. Plague transmission is carried out by infected fleas that become "blocked" - a clot of microorganisms hinders flea's feeding forcing the flea to regurgitate overwhelming doses of the pathogen into the host and to seek the next available host.

We hope you like this post and most important that you find it useful. On our next post we will talk about the products that we can use for flea management and their mechanisms.

Cheers and happy holidays!

MVZ Carolina Pruneda

WHY DOGS EXPERIENCE FEAR?

Good day colleagues and friends, about a few days ago a good friend of mine asked me if dogs actually felt fear and how does fear work in dogs. 

It is an undisputed fact that emotions drive behavior, moving the dogs towards comfort and pleasure, or away from discomfort and pain. 
Behavior is influenced by physiological processes including the activity of neurotransmitters and hormones. Neurotransmitters, such as serotonin and dopamine, transmit chemical messages in the brains and bodies of dogs and humans and as a result both have the same physiological reactions to behavioral states such as joy, fear, excitement and pain.

Fear often helps dogs (and pretty much any living being), with self-preservation. We feel fear, as well as related emotions, in order to protect ourselves from danger and to heighten our awareness.

Serotonin, for example, has a profound affect over emotions and is responsible for regulating mood, enhancing a positive feeling and inhibiting aggressive response. 
Dopamine helps to focus attention, promoting feelings of satisfaction. A lack of these neurotransmitters causes irritability, limited impulse control, over reactivity, anxiety and greater sensitivity to pain.

A dog’s nose dominates his brain; in fact the part of the brain dedicated to scent is forty times greater in a dog than in a human. The dog’s brain is literally built around the information it gets from scent and as smell is so closely linked to emotions(hippocampus), this provides even more evidence that the dog’s emotional experience might be even greater than we could ever imagine. 

The dog’s brain is literally built around the information it gets from scent and as smell is so closely linked to emotions.

When a dog is fearful, a number of changes happen in the body. The heart beats faster, blood pressure rises and blood flow is diverted to muscles that prepare for fight or flight. 

Stress from threat causes the dog to ‘shut down,’ effectively freezing him until the threat goes away. In this state of anxiety the dog ceases to learn and becomes more insecure, frightened and/or angry. If he cannot practice avoidance, the only other option left is to bite.

This awareness is thought to be controlled by a section of the brain known as the amygdale.

The amygdale is a section of the dog's brain's limbic system that is responsible for detecting fear and preparing for emergency events. It is surrounded by the pineal gland (gland that produces melatonin so the dog knows when it's time to sleep), and the hippocampus (part of the limbic system that stores memories).

The amygdale is an almond-shaped section of the nervous tissue located in the temporal(side) lobe of the brain. There are two amygdale per dog, one on each side of the brain. They are thought to be a part of the limbic system within the brain, which is responsible for emotions, survival instincts, and memory. However it has been debated with evidence that the amygdale functions independently of the limbic system. 

The hippocampus and the amygdale work in unison with the hypothalamic pituitary adrenal axis (HPA), which is responsible for the release of epinephrine (adrenalin), which provides the necessary fuel an animal needs to flee or fight. 

The amygdale is responsible for the perception of emotions such as anger, fear, and sadness, as well as the controlling of aggression.

The Amygdale is not really a thinking part of the brain, but it's actual job is to become alert from bad memories and just react, triggering the dog's hypothalamus to initiate the fight and flight response.

Sometimes the amygdale can also be an area for seizure activity. This is because a seizure focuses in the amygdale because it produces inexplicable and intense fear.

Also, one of the parts of the brain involved in this higher-order cognition is the prefrontal cortex (PFC). This region of the brain has direct connections to both the hippocampus and the amygdale and appears able to mediate some of the signals coming from those two regions. Functional MRI studies tell us that while fear acquisition involves the amygdala, fear extinction (learning to let go of a fear) involves the PFC as well. We also know that people who have thicker PFCs are better at extinguishing fear associations. This mediation by the PFC is what lets us take a deep breath and choose not to give in to our fears.

Despite of how bad we might think fear is, we ought to remember that fear can be good as well, because fear is important as it protects dogs (and other living being) allowing self-preservation and protection of the species.  So therefore being fearful is not always a bad thing, it's actually good if the dog is fearful of things that can actually pose a threat to his and wellbeing. 

So in a few words and to answer my friend's question, dogs can feel fear, and it works in the same physiological and chemical way as it does in humans.

I hope this post could get you out of doubt, or at least give you an idea of how fear works like in dogs. 

MVZ Carolina Pruneda

MASTICACION EN LOS PERROS (Y SUS PATOLOGIAS)

Buen día amigos y colegas, en este post vamos a repasar una lección de anatomía simple en los perros, la cual nos puede ser de mucha ayuda en algún caso clínico en el consultorio. Vamos a repasar los musculos de la masticación en los perros y vamos a ver en que situaciones o casos nos puede servir recordar este mecanismo.

Primero que nada, vamos a recordar cuales son los músculos que ayudan a la masticación, los cuales son los siguientes: 

MÚSCULOS MASTICADORES

El músculo temporal, el músculo masetero y los músculos pterigoideos forman el grupo de músculos masticadores. Comparten origen embrionario, ya que derivan del I arco faríngeo, e inervación, ya que están inervados por el nervio mandibular. Todos ellos elevan la mandíbula e intervienen, por tanto, en el cierre de la boca. El músculo digástrico, aunque desde el punto de vista ontogénico no pertenece al grupo, colabora con los músculos masticadores.

1. M. temporal
Se origina en la fosa temporal y se inserta en la apófisis coronoides de la mandíbula.

Función: Eleva la mandíbula.

Inervación: Nervio mandibular.

2. M. masetero
Se origina en el arco cigomático y en la parte caudal del hueso maxilar y se inserta en la fosa masetérica de la mandíbula. En función de la dirección que toman sus fibras se distinguen las porciones superficial, que es la más grande, media y profunda.

Función: Eleva la mandíbula.

Inervación: Nervio mandibular.

3. Mm. pterigoideos
Los dos músculos pterigoideos se disponen medialmente a la mandíbula. El músculo pterigoideo medial es, con diferencia, el más grande, y también el más rostral de los dos. Se origina en la fosa pterigopalatina del cráneo y se inserta en la fosa pterigoidea de la mandíbula y en la cara medial de la apófisis angular. El músculo pterigoideo lateral es mucho más pequeño y se sitúa caudalmente al medial. Se origina en la cara lateral del hueso esfenoides y se inserta en la cara medial del cóndilo de la mandíbula.

Función: Ambos músculos elevan la mandíbula.

Inervación: Nervio mandibular.

4. M. digástrico
Se origina en la apófisis paracondilar del occipital y se inserta en el borde ventral de la mandíbula.

Función: Abre la boca.

Inervación: La doble inervación del músculo es una muestra de su doble origen ontogénico. El nervio facial inerva el vientre caudal (que deriva del II arco faríngeo). El nervio mandibular inerva el vientre rostral (que deriva del I arco faríngeo). Ambos vientres, en el caso del perro, están separados únicamente por una intersección tendinosa que no siempre es bien identificable.

Ahora vamos a revisar algunas  de las patologías o casos en los que pudiésemos necesitar esta información:

-miopatia inflamatoria mandibular/facial
-bruxismo (masticación rapida)
-incapacidad para abrir o cerrar la boca)
-dificultad para vocalizar, gemir mientras trata de comer
-el hueso mandibular puede estar fuera de lugar
-perdida del apetito / anorexia
-dolor al masticar los alimentos

Algunas de las causas de los transtornos de la articulacion temporomandibular en perros son:

-lesiones o traumas en la articulacion
-traumas en los musculos de la masticacion
-fractura de la articulacion
-estres en la articulacon despues de cargar objetos pesados por periodos prolongados de tiempo.
-labio leporino (congenito)
-fisura labiopalatina (congenito)
-hendidura palatina

Como podemos diagnosticar a nuestro(s) pacientes?

Nuestra primer herramienta es el examen físico, que incluye la observación, la palpación y revisión con herramientas simples como tal vez una linterna para ver con más detalle la parte de atrás del paladar o de la faringe y laringe, guantes para poder abrir bien el hocico del paciente y poder bien si hay alguna anormalidad.

Si notamos algo anormal en nuestro examen físico, también nos podemos apoyar en otras herramientas como los rayos X, en estas como ya sabemos, podemos ver hueso si sospechamos de alguna fractura, o inclusive con el kilo voltaje y mili amperaje adecuado se pueden apreciar también los músculos faciales en caso de alguna anomalía en el movimiento o en la palpación. 

Si bien tenemos acceso a la resonancia magnética de imagen (MRI), también se puede recurrir a esta, preguntando primeramente al propietario si el paciente tiene algún implante metálico/microchip de identificación/chip para localización/rastreador/marcapasos/clavos de alguna fractura previa o cualquier tipo de metal en su cuerpo. En la resonancia magnética de imagen podremos apreciar con mayor precisión si hay algún tejido anormal obstruyendo los músculos de la articulación temporo-mandibular, o inclusive podremos apreciar actividad calórica de las células en caso de alguna infección que no pueda verse a simple vista en el examen físico.

Dependiendo de nuestros hallazgos es el tipo de tratamiento hacia el cual nos debamos inclinar, siempre tomando muy en consideración la edad del paciente y la raza.

Esperemos que esta publicación les haya gustado, y  nos sirva de repaso para futuras ocasiones.

MVZ Carolina Pruneda