Ruminant Digestive Tract

 

Photo by Dr. Haus

Ruminant Digestive Tract

A ruminant is a category of animals that are able to digest plant-based, difficult to digest food sources that other animals cannot eat.  Ruminants include cattle, sheep, goats, giraffes, deer, and many other species of animals.  Ruminants do this with their extremely large stomach which is full of microorganisms that allow them to ferment these hard to digest plant-based foods.

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Ruminants have ONE stomach that is separated into FOUR compartment.  The four compartments of the stomach are called the rumen, the omasum, the reticulum, and the abomasum.  The rumen is where the majority of the fermentation and breakdown of food materials occurs.  The omasum is where water and other nutrients are absorbed into the body.  The reticulum assists in determining when feed material is small enough to move forward in the digestive tract into the omasum.  If the feed material is too big, it will be funneled back into the rumen for further fermentation.  The abomasum is known as the "true" stomach and is similar to the stomach in other species (such as humans).

 

 

What are Ketones and Why are they Important?

 

Photo by Dr. Haus

What are Ketones?

Ketones are an acidic breakdown product of fats.  When the body is breaking down fats, ketones are one of the substances that are produced.  A normal amount of ketones can be used by the body for energy BUT as more and more fat is being broken down the ketones begin to accumulate.  The accumulation of ketones has SEVERE negative effects in an organism due to their highly acidic nature.

 

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Why are they Important?

When there are too many ketones in the bloodstream an organism enters the state of ketosis (ketoacidosis).  This is a life threatening condition that leads to disorientation, confusion, aggressiveness, coma, and eventually death.  One example of such a state is diabetic ketoacidosis (DKA) which is a MEDICAL EMERGENCY.

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Gluconeogenesis of fats is the process where the body is using fats to produce the glucose the body needs to survive.  The steps of the breakdown of fats (adipose tissue) are noted below:

 

As noted in the above diagram, adipose tissue is broken down into fatty acids and glycerol.  The fatty acids accumulate in the bloodstream and are converted to ketones.  The glycerol is used in gluconeogenesis to produce more glucose for the body.  If this process is happening at too rapid of a rate, the organism risks entering a ketotic (ketoacidotic) state.

Carbohydrate Metabolism

 

Photo by Dr. Haus

Carbohydrate Metabolism

Carbohydrate metabolism refers to how the body breaks down, stores, and uses carbohydrates.  Carbohydrates are one of the four major sources of food and energy in a living organism.  Carbohydrates are the building blocks found in foods that the gastrointestinal organs (stomach, liver, intestines, etc.) need to break down, process, use, and store to allow the organism to survive.

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When a meal is being digested, the body works to break down the carbohydrates into their smallest functional form called monosaccharides.  The majority of this digestion happens in the small intestines and the small intestines is the main location where the monosaccharides are absorbed into the body.

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Glucose is the major monosaccharide that needs to remain in a homeostatic range in the bloodstream.  Homeostatic range is the value range a specific parameter must stay within to keep an organism healthy.  In the case of glucose, glucose concentrations HIGHER than the homeostatic range have severe negative consequences in an organism.  Glucose concentrations LOWER than the homeostatic range equally have severe negative consequences in an organism.  In a normal, healthy organism, the body works VERY HARD to maintain a parameter within its homeostatic range for optimal body functioning and health.

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Glucose is a large and charged molecule that cannot move freely from the inside of the small intestines into the body and thus it relies on facilitated diffusion to be absorbed into the organism.  Facilitated diffusion is where a molecule needs help from a protein to move through the plasma membrane into the cell.  You can think about this like a tunnel that is only opened for the correct traveler.  A glucose transport protein will transport glucose DOWN its concentration gradient.  In the case of the body breaking down food after a meal, the concentration gradient "makes" the glucose want to move into the body and the glucose transport proteins help the glucose move from the small intestines into the body's bloodstream.

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Now, these glucose transport proteins are not always open (except for a variety in the brain, but that is a different blog post).  The signal that tells the glucose transport proteins that they can open to let the glucose pass is insulin.  WITHOUT INSULIN, THE BODY CANNOT ABSORB GLUCOSE INTO THE CELLS.  This is very important because EVERY cell in the body needs glucose to provide it the energy it needs to survive.

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The beta cells in the islets of Langerhans of the pancreas produce and release insulin into the bloodstream.  In a normal, healthy organism, insulin will increase shortly after a meal is eaten to allow the absorbed glucose to go from the bloodstream into the cells providing them the energy they need to survive.

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The opposite of insulin in the body is glucagon.  Glucagon is produced in the alpha cells in the islets of Langerhans of the pancreas to counteract the effects of insulin.  Insulin DECREASES the glucose concentration in the bloodstream by opening the glucose transport proteins so glucose moves INTO the cells of the body.  Glucagon INCREASES the amount of glucose in the bloodstream by causing the body to break down its energy stores to release glucose into the bloodstream.  This yin and yang process allows for the glucose concentration to remain in the homeostatic range and prevents fluctuations of glucose in the bloodstream.

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When glucose is absorbed into the body it will be used in one of three different ways:

1. Used immediately to produce energy for the cells (body)
2. Stored as glycogen (a quick energy source stored in large concentrations in the muscles and liver)
3. Stored as fat for later use
   

Remember, without glucose in the correct concentration in the bloodstream an organism won't be able to survive very long!

Heart Anatomy

  

Photo of Nathan taken by Dr. Haus

The Heart

The heart is the organ that pumps the blood throughout the entire body.  The heart plus all the blood vessels of the body is called the cardiovascular system.  The cardiovascular system ensures that nutrients are brought to and all waste materials are brought away from the cells of the body.

The cardiovascular system is essentially a simple plumbing system.  There are a large amount of pipes of various sizes (blood vessels) and one pump (the heart) that keeps the water (blood) moving.  Understanding the anatomy of the heart is critical to understanding how the heart functions and what is occurring in a sick heart.

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Heart Anatomy

The heart consists of three types of structures:  blood vessels, heart chambers, and heart valves.  Each component of the heart allows the heart to achieve its function of moving blood throughout the body.

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Blood Vessels

The major blood vessels of the heart are the cranial (superior) vena cava, the caudal (inferior) vena cava, the pulmonary artery, the pulmonary vein, and the aorta.  The terms cranial and caudal vena cava are the term for these vessels in quadruped species (species that walk on four legs).  The terms superior and inferior are used in bipedal species such as humans who walk on two legs.

The cranial (superior) vena cava, caudal (inferior) vena cava, and pulmonary artery all carry deoxygenated blood which is blood that has a LOWER amount of oxygen in it.  This blood needs to be delivered to the lungs where carbon dioxide is removed from the blood while oxygen is placed into the blood.  This is done through the process of breathing.  

Remember, an artery moves blood AWAY from the heart regardless of whether the vessel contains a high or low amount of oxygen in it.

The pulmonary vein and aorta carry oxygenated blood which is blood that has a HIGHER amount of oxygen in it.  Oxygenated blood needs to be delivered to the cells of the body to bring them oxygen.  This is done through the heart beating and the blood moving within the vascular system.

Remember, a vein carries blood TOWARDS the heart regardless of whether the vessel contains a high or low amount of oxygen in it.

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Heart Chambers

There are four (4) heart chambers in mammals, birds, and crocodilians.  These heart chambers collect blood while the heart is relaxing and then push the blood in a forwards direction when the heart is beating.  The four (4) heart chambers are the right atrium, the left atrium, the right ventricle, and the left ventricle.

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Heart Valves

Lastly, the four-chambered heart contains four (4) heart valves.  The heart valves prevent the blood from flowing in a backwards direction.  Remember, the blood must move in the forwards direction or else the blood will not be able to flow throughout the body.  When blood moves backwards in a disease state, the body will become sick as there will not be enough oxygen getting to the cells of the body.

The four (4) heart valves are the tricuspid (right atrioventricular) valve, the bicuspid (mitral or left atrioventricular valve), the pulmonary valve, and the aortic valve.

Key:

1.  Cranial (superior) vena cava

2.  Caudal (inferior) vena cava

3.  Tricuspid (right atrioventricular) valve

4.  Pulmonary valve

5.  Pulmonary artery

6.  Pulmonary veins

7.  Bicuspid/mitral (left atrioventricular) valve

8.  Aortic valve

9.  Aorta

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What is Cardiac Output and Why is it Important?

Photo by Dr. Haus

Cardiac Output

Cardiac output, called CO for short, is the amount of blood that flows out of the left ventricle per minute.  The easier way to define cardiac output is the amount of blood that leaves the heart each time the heart beats.

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Why is Cardiac Output Important?

Cardiac output is extremely important as it is measuring the amount of blood that is being pump throughout the body.  If the cardiac output is too low, that means not enough blood is being pumped out of the heart.  When this occurs, the cells of the body are not receiving the oxygen they need to survive.  The body works EXCEPTIONALLY hard to maintain the correct cardiac output to keep the body alive and functioning. 

 

What is an Electrocardiogram and Why is it Important?

Photo by Dr. Haus

Electrocardiogram

An electrocardiogram, called an ECG/EKG for short, is a way to measure the electrical signals in the heart.

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Why is an Electrocardiogram Important?

The beating of a heart relies on electrical signals that tell the heart to beat in the correct manner.  The ECG allows medical professionals to measure the electrical signals in the heart to determine if there is an electrical problem that needs to be addressed in the patient.

What is an Echocardiogram and Why is it Important?

Photo by Dr. Haus

Echocardiogram

An echocardiogram, also called an echo for short, is an ultrasound of the heart.  An echocardiogram shows all of the anatomy of the heart and its functioning in real time. 

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Why is an Echocardiogram Important?

An echocardiogram is important because it gives medical professionals a way to see the heart to determine if there are any changes in the heart that require treatment.  The echocardiogram can be thought of as the best way to visualize the heart in real-time to determine if there are any changes.

What are Radiographs (X-rays) and Why are they Important?

Photo by Dr. Haus

Radiographs

A radiograph, also called an x-ray, is a way to visualize the inside of the body at a specific point in time.  Radiographs are taken by a machine and are essentially taking a picture of the inside of the patient's body.

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Why is a Radiograph Important?

A radiograph is important because it gives medical professionals a way to see the inside of the body to determine if there are any obvious causes of disease.  Radiographs are good at diagnosing bone diseases and certain diseases of the internal organs like the stomach, intestines, or lungs.

 

What is an Arrhythmia and Why is it Important?

Photo by Dr. Haus

Arrhythmia

An arrhythmia is an abnormal heart rhythm.  You can think of this as a time when a heart is not beating in its normal pattern.

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Why is an Arrhythmia Important?

Arrhythmias are important because a heart that is beating out of pattern is a heart that cannot pump blood effectively to the body.  When a patient has an arrhythmia, it is important to diagnose and treat the condition as quickly as possible.

What is Edema and Why is it Important?

Photo by Dr. Haus

Edema

Edema is swelling that happens when there is too much water pooling in an area of the body.  Scientifically, edema is when there is more than the normal amount of water in the interstitial fluid space (ISF) and the intracellular fluid space (ICF).

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Why is Edema Important?

Edema is important because it is a sign of injury to a specific area of the body.  Edema is an indication that water balance is not normal and it is a sign to a medical professional that an injury has occurred in that specific location.

What is the Jugular Vein and Why is it Important?

Photo by Dr. Haus

Jugular Vein

The jugular vein is the major vein that brings the deoxygenated blood from the head back to the right side of the heart.  There is a left jugular vein and a right jugular vein.

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Why is the Jugular Vein Important?

The jugular vein is important because it is the way the blood from the head gets back to the heart and lungs to get more oxygen and to get rid of the carbon dioxide.  Given the jugular veins' location in the neck, it can be seen relatively easily and is a location where blood can be drawn or fluids given in a patient.

What are the Categories of Kidney Disease and Why are they Important?

Photo by Dr. Haus

Categories of Kidney Disease

There are three different categories of kidney disease that tells us the source of the kidney disease.  The three categories of kidney disease are:

Pre-Renal Injuries -  These injuries are due to decreased blood flowing to the kidneys.

Intrarenal (Renal) Injuries -  These injuries are due to damage to the kidney cells (nephrons)

Post-Renal Injuries -  These injuries are due to the inability of urine to flow out of the body (anything that blocks the body from peeing)

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Why are the Categories of Kidney Disease important?

The categories of kidney disease are important because we can look at the blood work and urinalysis of a patient to determine which category of kidney disease is causing the patient's illness.  In this way, we can start to narrow down the possible causes of the patient's clinical signs/symptoms.

What is a Urinalysis (UA) and Why is it Important?

Photo by Dr. Haus

Urinalysis

A urinalysis, also called a UA for short, is a test that measures what is in urine. 

Some examples of what a urinalysis measures are...

Red Blood Cells

pH

Electrolytes (calcium, sodium, potassium, etc.)

Urine Concentration

Glucose (Sugar)

Bilirubin

And many more!

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Why is a Urinalysis important?

A urinalysis is important to get a baseline understanding of a patient's overall health by measuring important values related to the body's function.  This information helps a medical professional narrow down the potential causes of the clinical signs/symptoms of a patient.

What is Body Condition Scoring (BCS) and Why is it Important?

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Body Condition Scoring (BCS)

A body condition score (BCS) is a way to determine how much body fat there is on a patient.  The weight of a patient is not a helpful measure in our veterinary species as their body types vary greatly.    

There are two major types of BCS scales, the 1-9 scale and the 1-5 scale.  The smaller the number, the less fat the patient has on their body.  On a 1-9 scale the ideal score for a patient would be 4 or 5 and on the 1-5 scale the ideal score is a 3.  A patient with a high score is obese while a patient with a low score is emaciated (extremely thin).

The 1-9 scale is used for beef cattle, dogs, cats, horses, etc.  The 1-5 scale is mostly used for dairy cattle, pigs, sheep, and goats.

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Why is Body Condition Scoring important?

Body condition scoring allows us to determine the health status of a patient in regards to their energy balance and overall fat accumulation.  Too little fat and too much fat are both detrimental for patients.  This scoring system allows us to continue monitoring our patients throughout their lives to note any changes which can be an indicator for different disease states or the need to change diet/exercise routines.

Explaination of Case Flow

  

Photo taken by a friend of Dr. Haus's

The sharing of educational materials is a large inspiration for this blog and the case series I am developing is the first type of education materials I plan on creating for this blog.  I want to outline the format for the cases so everyone can take part in this great opportunity to try, learn, and grow!

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The goal for the cases is for everyone to practice and learn.  This will be done through spending 3 days of blog posts to work through cases.  I highly recommend working through the cases with friends, family, pets, frenemies, mortal enemies, the wall, your invisible friend, etc.  The more you talk through these cases the more you will learn and the more you will be able to practice important skills such as problem-solving, communicating science, and thinking like a clinician. 

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I will be creating these blog posts to be accessible to anyone regardless of their scientific background.  All materials will be presented for three different levels to accommodate any learner at any stage of their journey. 

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If you have any cases, topics, or concepts that you want covered please comment them on the blog for inspiration!  Got an upcoming physiology exam and you have no idea what is going on with the renal system?  Let me know and I will put together materials to help!

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Now, let's jump in to understand the Case Flow!

Test Case Tuesday

On test case Tuesday, the initial information related to the patient's case will be shared.  Keep in mind, the species are not what is important - the important part is understanding the science behind the condition.  Animals are not as different from each other or humans as you may think.  If you are interested in veterinary medicine that is great.  If you are interested in human medicine that is great too - our pathophysiology/physiology is not all that different (especially amongst mammals).

At the end of test case Tuesday, you will not know the diagnosis of the patient but can take the time to create your differentials list and get excited for the Thoughtful Thursday blog post.  This is a great time to talk about the case with other people/animals/inanimate objects.

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Thoughtful Thursday

On thoughtful Thursday, the diagnosis and basic pathophysiology of the disease will be shared along with questions for each of the different levels of learning.  This is another great time to talk through the questions and answers.  You should take the time to think about how you would communicate this information to people of different scientific backgrounds especially if you are a "science person".  The medicine is the easy part, the hard part is communicating.

I believe much of the distrust of medical/science folks comes from our history of feeling as if we don't need to explain anything and that people should just blindly trust us.  That is not what we need to be doing as a scientific field - we need to work hard to practice communicating scientific information to folks without a scientific background.

Think about the cases, think about your answers, and take the time to look up any information you need to better understand the case, the questions, and the concepts.

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Conclusion Caturday

On Conclusion Caturday I will post the answers to the questions and links to further information based on the different levels of learning.  Take advantage of this time to check your answers, look up further information, and discuss this information with others.  I firmly believe you truly understand something when you can explain it to someone who does not have a strong foundation in the subject.

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Enjoy these cases as much as I enjoy creating them!

 

Dr. Haus's Unsolicited Life Advice Levels

  

Photo by Dr. Haus

Dr. Haus's Unsolicited Life Advice Levels

For this blog, some information will be presented or explained based on three different levels.  These different levels will help anyone have the ability to try, learn, and grow from the educational blog posts.

Remember, your level doesn't matter, the fact you are here is what matters (and I am glad you are here)! 

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Level 1

Level 1 materials are for folks who do not have a science background.  Maybe you haven't take a science class since middle school, maybe you forgot everything from your blow off general science elective from college.  Either way, I am happy you are here because you know a LOT more than you think.

 

Level 2

Level 2 materials are for folks who have some undergraduate science training.  Maybe you are a pre-health student, maybe you are taking science courses out of interest, or maybe you love to read about science.  I plan to prove to you that you know way more than your classes make you think you do.

Level 3

Level 3 materials are for folks who have a strong science background.  Maybe you are in a post-undergraduate health professional program, maybe you are getting your master's in science, or maybe you are a full-fledged health professional.  You can still learn here too and practice with your knowledge-base!  I highly recommend for folks in this category to work through these materials with colleagues and friends to get the most out of it.

 

What is a Differential List and Why is it Important?

Photo by Dr. Haus

Differential List

A differential list is a ranked list of all the diseases/conditions that could be causing the clinical signs/symptoms in a patient.  Differentials are the components of the list.

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For the purposes of this blog, you can create whatever type of differentials list makes the most sense for you.  Below is looking at examples of differentials based on Dr. Haus's Unsolicited Life Advice Levels.

 

Examples of LEVEL 1 Differentials:

Stomach

Brain

Skin

Foot

Mouth

Heart

Lungs

And many more!

Examples of LEVEL 2 Differentials: 

 Infection

Respiratory System

Urogenital System

Diabetes

Cancer

Toxin

Neurological

And many more!

 

Examples of LEVEL 3 Differentials:

Chronic Kidney Disease

Acute Liver Failure

Myxomatous degeneration of the cardiac valves

Hemangiosarcoma

Brucellosis

Intervertebral Disc Disease 

Chocolate Intoxication

And many more!

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Why is a differential list important?

The differential list helps you narrow down the potential causes of disease and helps you create a logical plan to move forward.  In most cases, the final diagnosis of the patient takes time, testing, and the process of elimination.  

The differential list allows the medical professional to prioritize diagnostic tests and treatment plans to get to a final diagnosis as quickly as possible.

 

What is a Signalment and Why is it Important?

 

Photo by Dr. Haus

Signalment

A signalment is the first part of assessing a patient where you are gathering the basic description of the patient.  A signalment consists of the patient's... 

 

Name

 

Age

 

Reproductive Status (intact versus castrated (still has reproductive organs versus does not have reproductive organs))

 

Species/Breed

 

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A farm/herd signalment consists of the...

 

 

Name of farm/farmer 

 

Number of animals

 

Specie(s)

Breed(s)

 

Average Age (if applicable)

Farm Type/Structure/Location

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Signalment Examples:

Rosa is a 5-year-old female intact Siamese cat.

 

Charles is a 10-year-old male neutered Labrador Retriever Dog.

 

Petunia is a 3-year-old female intact lactating Holstein Dairy cow.

 

Cherry Oak farm is a 400 Brown Swiss cow dairy facility in central Wisconsin.

 

Tree Lane farm is a 200 Angus Beef cow-calf operation in northwestern Illinois.

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Why is the signalment important?

A patient's signalment identifies the patient and allows the medical professional to start narrowing down the list of potential causes for disease.

Identifying the patient is extremely important to ensure you are not treating the wrong patient.  It would be embarrassing to use the wrong name for a patient you are seeing or have the incorrect records for a patient.

Additionally, having a patient's signalment helps start the process of narrowing down the potential causes for a disease.  If a patient is a chicken you don't want to be considering a pig disease as a potential cause for the patient's clinical signs.  Also, if a dog is castrated (does not have his testicles) it would be embarrassing to tell an owner you suspect the patient has testicular cancer.

 

What is a History and Why is it Important?

  

Photo taken by Dr. Haus

History

The history is the second step of assessing a patient where you are gathering the owner's/patient's medical concerns, medical history, and any other pertinent information about the patient.  A signalment consists of the patient's... 

 

Presenting Complaint (why they are here today)

Medical History

Description of last time patient was normal (if applicable)

 

Description of  the signs of illness

 

Changes and concerns

 

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History Examples:

Rosa is presenting today because her owners feel she is acting more tired than usual.  Rosa had her last menstrual cycle a few weeks ago.  Over the past few days, Rosa has been more lethargic, is not eating very well, is drinking and urinating more than usual, and seems to be licking at her vulvar region excessively.  Rosa vomited bile twice last night.  Today Rosa can barely get up and is looking very ill.  Rosa’s owner also thinks she has been gaining weight because her belly looks bigger.​

Rosa has a dog sister named Ruth and a cat brother named Randy.  No other animals are showing any signs of illness.  Rosa has never had puppies.​

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Marty the mule was born to his horse mother Madeline one day ago.  Marty’s father is a donkey named Mark.  Marty’s birth was completely normal without any complications for mother or baby.  Marty was up and nursing within two hours of delivery and did not show any signs of illness or abnormalities.  Tonight, Marty is acting lethargic, is unwilling to nurse, and has started to breathe heavily.​

Madeline birthed a healthy foal four years ago and a healthy mule by a different jack two years ago.

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Why is the history important?

A patient's history gives us the background information to start narrowing down the list of potential causes of the patient's disease.  This history helps to give us the necessary information to start to piece together the puzzle of what is ailing the patient and how to work up the patient's case.

*Aside, clinical signs is the technical way to refer to a symptom in an animal because animals cannot self-report their ailments.  Symptoms need to be self-reported and expressed by the patient to another person.  

 

We interpret and describe an animal's behavior, thus they are not self-reporting how they feel.  Any animal (or human who cannot express themselves) have clinical signs and not symptoms by definition.

What is a Physical Exam and Why is it Important?

Photo taken by Dr. Haus

Physical Exam

What tends to shock most people is that it is once we get to the THIRD step we physically touch our patient.  A common mistake is to want to jump in and start touching the patient immediately but this step should be completed after obtaining the signalment and history - even better if you assess the patient from afar to get a better picture of their behavior before starting the physical exam.  

In this step, the medical professional will do a thorough examination of each of the important organ systems to feel, look, and assess all the parts of the patient's body.  A short list of some of the physical exam is below...

 

Temperature

Breathing (Respiratory) Rate

Heart Rate (Pulse) 

Oral (Mouth) Exam

Abdominal Palpation

Orthopedic Exam

Skin/Fur Exam

Assessing/Palpating all major organ systems

 

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Why is the physical exam important?  

The physical exam is extremely important to understanding what might be causing the patient's illness and to assess the overall health of the patient.  During the physical exam, the medical professional is able to use their knowledge and experience to find what is normal versus abnormal in the patient to further narrow down and order their list of potential causes of the patient's illness.