Caregiver Resources

Glossary of Terms

Clinical language translated into plain words, so you can follow what your vet is telling you and ask better questions along the way.

A to Z

Terms you may hear

This glossary spans every letter from A to Z and covers veterinary neuroanatomy, common clinical abbreviations, and the medications and disease abbreviations caregivers most often encounter for kidney disease, diabetes, hypertension, thyroid disorders, Cushing's disease, and heart conditions. These definitions are written for pet owners and are not a substitute for veterinary advice. Never start, stop, or adjust a medication without your veterinarian's guidance. If your vet uses a word that isn't here, or one of these definitions doesn't match what you were told about your own dog, ask. The exact details of a diagnosis or treatment plan always come from the veterinarian who examined your dog.

A

ACE Inhibitor (Angiotensin-Converting Enzyme Inhibitor)
A class of medication that blocks an enzyme involved in narrowing blood vessels and retaining sodium. ACE inhibitors are used to help manage high blood pressure, heart failure, and protein loss from the kidneys. Benazepril and enalapril are commonly used examples in dogs.
ACTH (Adrenocorticotropic Hormone)
A hormone released by the pituitary gland that signals the adrenal glands to produce cortisol. Several diagnostic tests for adrenal gland disease are based on measuring how the adrenal glands respond to ACTH.
ACTH Stimulation Test
A diagnostic test in which a synthetic form of ACTH is given and cortisol is measured before and after, to see how strongly the adrenal glands respond. A weak response can confirm hypoadrenocorticism (Addison's disease), while an exaggerated response can support a diagnosis of hyperadrenocorticism (Cushing's disease).
Acute Kidney Injury (AKI)
A sudden loss of kidney function developing over hours to days, in contrast to the gradual decline seen in chronic kidney disease. Causes include toxins, severe dehydration, infection, and disruption of blood flow to the kidneys. With prompt treatment, kidney function can sometimes improve, unlike the typically irreversible course of CKD.
Acute Onset
A sudden, rapid onset of signs, as opposed to a gradual or chronic progression. Strokes are, by definition, acute events.
AD
Auris dexter, the right ear. Used on veterinary prescriptions and exam notes for ear medications and findings.
Adrenal-Dependent Hyperadrenocorticism
A less common form of Cushing's disease caused by a tumor of the adrenal gland itself, which produces excess cortisol independent of normal pituitary control.
Amlodipine
A calcium channel blocker and the first-line medication most commonly used to treat hypertension in cats. In dogs, it is often added to an ACE inhibitor when blood pressure remains high, particularly when it is related to kidney disease.
Amygdala
A small, almond-shaped structure deep within the temporal lobe, part of the limbic system, involved in processing emotional responses such as fear.
Anisocoria
Unequal pupil size between the two eyes. It can be a sign of a neurological problem affecting the eye itself or the nerves that control the pupil.
Anticoagulant
A medication that interferes with the blood's clotting process, used to help prevent or slow the formation of blood clots.
Antiplatelet
A medication that reduces the tendency of platelets to clump together and form a clot. Often prescribed after a stroke or thromboembolic event to help reduce the risk of another one.
Arachnoid Mater
The middle of the three protective membranes (meninges) surrounding the brain and spinal cord, located between the dura mater and the pia mater.
ARB (Angiotensin Receptor Blocker)
A class of medication, related to ACE inhibitors, that blocks the action of a hormone involved in narrowing blood vessels. Telmisartan is the ARB most commonly used in veterinary medicine, often for blood pressure control and to reduce protein loss from the kidneys.
AS
Auris sinister, the left ear. Used the same way as AD, but for the left side.
Ataxia
A loss of coordinated muscle movement, causing a wobbly, uncoordinated, or drunken-looking gait. It is different from weakness; the muscles still work, but the brain has trouble coordinating them.
Atenolol
A beta blocker sometimes used in dogs and cats to help manage certain heart rhythm problems or other forms of heart disease.
Atlas (C1)
The first cervical vertebra, which supports the skull and allows the head to nod.
Atrophy
The wasting or shrinking of muscle tissue, often from disuse, nerve damage, or prolonged inactivity.
AU
Auris uterque, both ears. Often seen on ear medication labels, such as an instruction to apply drops AU.
Axis (C2)
The second cervical vertebra, which allows the head and neck to rotate.
Azotemia
An elevated level of nitrogen-containing waste products, such as BUN and creatinine, in the blood. It is a laboratory finding rather than a specific diagnosis, and can result from kidney disease or from other causes, such as dehydration, that reduce blood flow to the kidneys without permanent damage.
↑ Back to top

B

BAR
Bright, Alert, Responsive. Shorthand on an exam note describing a patient that appears normally engaged with its surroundings.
Basal Nuclei (Basal Ganglia)
Clusters of gray matter deep within the cerebrum that help regulate voluntary movement.
Benazepril
An ACE inhibitor commonly prescribed for dogs with kidney disease or heart disease, used to help reduce blood pressure and protein loss through the kidneys.
Beta Blocker
A class of medication that slows the heart rate and reduces the workload on the heart by blocking the effects of certain stress hormones. Atenolol is a commonly used example in veterinary medicine.
BID
Twice daily, from the Latin bis in die. A common dosing frequency for medications.
Bilateral
Affecting both sides of the body.
Blood-Brain Barrier
A protective layer of cells lining the brain's blood vessels that tightly controls which substances can pass from the bloodstream into brain tissue.
BP
Blood Pressure.
Brainstem
The lower part of the brain that connects to the spinal cord. It controls many vital functions, including the nerves involved in balance, eye movement, and the face.
BUN
Blood Urea Nitrogen, a value measured on bloodwork that reflects kidney function. Kidney disease is one of the most common causes of secondary hypertension in dogs.
↑ Back to top

C

Calcium Channel Blocker
A class of medication that relaxes blood vessels and, in some forms, can also affect heart rate. Amlodipine, used for hypertension, and diltiazem, used for certain heart rhythm problems, are both calcium channel blockers.
Cauda Equina
The bundle of spinal nerve roots that continues within the vertebral canal after the spinal cord itself ends, named for its resemblance to a horse's tail.
Caudal
A directional term meaning toward the tail or rear of the body. The opposite of rostral.
Caudal Vertebrae (Coccygeal Vertebrae)
The vertebrae that make up the tail. Dogs typically have between 20 and 23, though the exact number varies by breed.
Cerebellum
The part of the brain that fine-tunes movement and balance. Damage here often produces tremors, exaggerated movements, and a wide-based, wobbly stance.
Cerebral Aqueduct
A narrow channel that connects the third and fourth ventricles, allowing cerebrospinal fluid to flow between them.
Cerebral Cortex
The outer layer of the cerebrum, made up of gray matter, responsible for processing sensory information and coordinating complex behavior.
Cerebral Hemispheres
The left and right halves of the cerebrum.
Cerebral Peduncles
Bundles of nerve fibers on the underside of the midbrain that carry signals between the cerebrum and the lower parts of the brain and spinal cord.
Cerebrospinal Fluid (CSF)
The clear fluid that surrounds and cushions the brain and spinal cord. A sample can sometimes be collected to help diagnose certain neurological conditions.
Cerebrovascular Accident (CVA)
The clinical term for a stroke: a sudden interruption of blood flow to part of the brain that damages brain tissue. "Cerebrovascular" refers to the blood vessels of the brain, and "accident" here means a sudden, unplanned event, not a lifestyle mishap.
Cerebrum
The largest part of the brain, divided into two hemispheres, responsible for functions such as sensory processing, learning, and voluntary movement.
Cervical Vertebrae
The seven vertebrae that make up the neck region of the spine, labeled C1 through C7.
Choroid Plexus
Specialized tissue within the brain's ventricles that produces cerebrospinal fluid.
Chronic Kidney Disease (CKD)
A long-term, usually progressive loss of kidney function. CKD is one of the most common causes of secondary hypertension in dogs and is generally managed with diet, medications, and ongoing monitoring rather than cured.
Cingulate Gyrus
A curved structure on the inner surface of the cerebrum, part of the limbic system.
Circle of Willis
A ring-like network of connected arteries at the base of the brain. In dogs, it is supplied mainly by the paired internal carotid arteries and the basilar artery, and it provides some redundancy in blood supply, so if one vessel becomes narrowed or blocked, blood can sometimes be rerouted through others.
Circling
Repeated walking in one direction, usually toward the side of the brain that has been affected. A common sign in dogs with vestibular disease or certain types of stroke.
Clopidogrel
An antiplatelet medication commonly prescribed after a stroke or other thromboembolic event, or in cats with hypertrophic cardiomyopathy, to help reduce the risk of future clots.
CNS
Central Nervous System, made up of the brain and spinal cord.
Coagulation
The process by which blood clots, also called clotting. It is the body's normal mechanism for stopping bleeding, but it can also occur abnormally in some disease states.
Colliculi (Rostral and Caudal)
Paired bumps on the roof of the midbrain. The rostral colliculi are involved in visual reflexes, and the caudal colliculi are involved in auditory reflexes.
Congestive Heart Failure (CHF)
A condition in which the heart can no longer pump efficiently enough to meet the body's needs, leading to a backup of fluid into the lungs or abdomen. CHF is managed with medications rather than cured.
Contralateral
On the opposite side of the body from a given point of reference. Some neurological signs appear on the side of the body opposite the part of the brain that was affected.
Corpus Callosum
A thick band of nerve fibers that connects the left and right cerebral hemispheres, allowing them to communicate.
Cranial Nerves
The twelve pairs of nerves that emerge directly from the brain rather than the spinal cord, controlling functions such as eye movement, facial sensation and movement, and swallowing.
Creatinine
A waste product of normal muscle activity that is filtered out of the blood by the kidneys. Blood creatinine concentration is one of the main laboratory values used to evaluate kidney function, though it can also be influenced by a pet's muscle mass.
CRT
Capillary Refill Time, a quick check of circulation performed by briefly pressing on the gums and timing how fast the pink color returns.
CT (Computed Tomography)
An imaging technique that uses X-rays taken from many angles to build cross-sectional images. It is faster than MRI but generally shows less detail in soft tissue like the brain.
↑ Back to top

D

Deficit
A loss or reduction of normal function, as in a "proprioceptive deficit."
Diabetes Mellitus (DM)
A condition in which the body cannot properly regulate blood sugar, usually because it does not produce enough insulin. Dogs with diabetes mellitus typically require insulin therapy to manage the condition.
Diencephalon
The part of the forebrain that includes the thalamus and hypothalamus, sitting between the cerebrum and the brainstem.
Differential Diagnosis
A list of the possible conditions that could explain a patient's signs, narrowed down through history, examination, and testing. Often abbreviated DDx.
Dilated Cardiomyopathy (DCM)
A disease of the heart muscle in which the heart's chambers become enlarged and weakened, reducing its ability to pump blood effectively. It is a recognized cause of congestive heart failure in dogs, particularly in certain breeds.
Diltiazem
A calcium channel blocker sometimes used to help manage certain heart rhythm problems.
Disconjugate Nystagmus
Nystagmus in which the two eyes move in different directions or patterns from one another. This is an unusual finding that points toward central rather than peripheral vestibular disease.
Diuretic
A class of medication that increases urine production, used to help remove excess fluid from the body. Furosemide is the diuretic most commonly used to manage congestive heart failure.
Dorsal
A directional term meaning toward the back or top side of the body. The opposite of ventral.
Dorsal Root
The portion of a spinal nerve that carries sensory information into the spinal cord.
Dorsal Root Ganglion
A cluster of nerve cell bodies located on the dorsal root of a spinal nerve, just outside the spinal cord, that processes incoming sensory information.
Dura Mater
The tough, outermost of the three protective membranes (meninges) covering the brain and spinal cord.
Dx
Diagnosis.
Dysmetria
Inaccurate, poorly judged movement that overshoots or undershoots its target. A sign often associated with cerebellar dysfunction.
↑ Back to top

E

Edema
Swelling caused by excess fluid in tissue. Cerebral edema refers to swelling within the brain itself.
Embolism
The blocking of a blood vessel by material, such as a blood clot, fat, or fibrocartilage, that traveled there from somewhere else in the body.
Embolus
A piece of material, such as a blood clot, that travels through the bloodstream from where it formed to a different location, where it can block a smaller vessel.
Enalapril
An ACE inhibitor commonly used in the management of congestive heart failure, easing the workload on the heart and helping to lower blood pressure.
EOD
Every other day, a dosing frequency used for some medications.
Epidural Space
The space between the dura mater and the bony walls of the vertebral canal.
Epithalamus
A small region of the diencephalon that includes the pineal gland.
Etiology
The cause or origin of a disease. A finding described as "idiopathic" has no identifiable etiology, even after testing.
Euthyroid Sick Syndrome
A temporary drop in thyroid hormone levels caused by an unrelated illness, medication, or stress, rather than true thyroid disease. It can mimic hypothyroidism on bloodwork, which is one reason a veterinarian may recommend repeat or additional thyroid testing rather than diagnosing hypothyroidism from a single low T4 result.
↑ Back to top

F

Facial Nerve Paralysis
Loss of function in the nerve that controls the muscles of the face, which can cause a drooping lip, ear, or eyelid on one side.
Feline Ischemic Encephalopathy (FIE)
A cause of sudden, stroke-like neurological signs in cats, such as circling, seizures, and behavior change. In at least some cases, it has been linked to the aberrant migration of Cuterebra (botfly) larvae into the brain, where the parasite can damage or trigger spasm of a major cerebral artery and cut off blood flow to part of the brain. It tends to occur in outdoor cats, most often during warmer months when these parasites are active.
Fibrocartilaginous Embolism (FCE)
A sudden injury to the spinal cord caused by a small piece of disc material entering the spinal cord's blood supply and blocking it. The onset and underlying mechanism are similar to an ischemic stroke, but FCE affects the spinal cord rather than the brain.
Foramen Magnum
The large opening at the base of the skull through which the spinal cord passes to connect with the brain.
Forebrain (Prosencephalon)
The most rostral (forward) of the brain's three major divisions, made up of the cerebrum and the diencephalon.
Fourth Ventricle
A fluid-filled cavity located between the brainstem and the cerebellum, which connects to the central canal of the spinal cord.
Free T4
The portion of thyroxine (T4) that circulates in the blood unattached to carrier proteins. Because it is less affected by non-thyroid illness than total T4, it is often used as a follow-up test when an initial T4 result is abnormal or inconclusive.
Frontal Lobe
A region of the cerebral cortex involved in movement and some aspects of behavior.
Fundic Exam
An examination of the back of the eye, called the fundus, using an instrument that lets the veterinarian view the retina and its blood vessels. Changes seen on a fundic exam can be a sign of high blood pressure or other systemic disease.
Furosemide
A loop diuretic widely used to manage congestive heart failure by helping the body eliminate excess fluid that builds up in the lungs or abdomen.
↑ Back to top

G

Gait
The pattern or manner in which a dog walks. Abnormalities in gait are among the most common signs of neurological disease.
Geriatric
A term describing the later stage of a pet's senior years, when daily care needs and vulnerability to disease are significantly increased. There is no single age that applies to all dogs; because life expectancy varies widely by breed and size, a dog might be considered geriatric anywhere from around 8 years old in a giant breed to well into their teens in a small breed.
Glomerular Disease
A category of kidney disease affecting the glomeruli, the tiny filtering units within the kidney. Damage to the glomeruli often leads to proteinuria and can contribute to the development of chronic kidney disease.
Gray Matter
Brain or spinal cord tissue made up mostly of nerve cell bodies, giving it a darker appearance than white matter.
↑ Back to top

H

Head Tilt
A persistent tipping of the head to one side, usually toward the affected ear or side of the brain. One of the most recognizable signs of vestibular disease.
Hemiparesis
Weakness affecting one side of the body.
Hemorrhagic Stroke
A stroke caused by bleeding into or around the brain, rather than a blocked blood vessel. Less commonly diagnosed in dogs than ischemic stroke.
Hindbrain (Rhombencephalon)
The most caudal (rearward) of the brain's three major divisions, made up of the cerebellum, pons, and medulla oblongata.
Hippocampus
A curved structure within the temporal lobe involved in memory.
Horizontal Nystagmus
Nystagmus in which the eyes move side to side. It is commonly seen with peripheral vestibular disease but can also occur with central disease.
Hospice Care
A philosophy of care, rather than a specific place or service, focused on comfort and quality of life when a cure is no longer being pursued. Hospice care often includes palliative care as one part of a broader plan that also addresses a pet's and family's emotional needs during this time.
HR
Heart Rate.
Hx
History, as in a patient's medical history.
Hyperadrenocorticism (Cushing's Disease)
A condition caused by the body producing too much cortisol, most often due to a tumor of the pituitary or adrenal gland. It is one of the more common hormonal disorders diagnosed in dogs.
Hypercoagulability
A condition in which the blood clots more easily than normal, which increases the risk of thrombosis.
Hypertension
Persistently elevated blood pressure. In dogs, hypertension is most often secondary to an underlying condition and is a recognized risk factor for stroke.
Hyperthyroidism
A condition caused by excess thyroid hormone production. It is common in older cats but rare in dogs.
Hypertrophic Cardiomyopathy (HCM)
A disease in which the walls of the heart, particularly the left ventricle, become abnormally thickened. HCM is the most common heart disease in cats and can increase the risk of thromboembolism.
Hypoadrenocorticism (Addison's Disease)
A condition in which the adrenal glands produce too little cortisol and, in most cases, too little aldosterone. It is the opposite of Cushing's disease and can cause vague signs such as lethargy, vomiting, and weakness, or a sudden, life-threatening crisis with collapse and electrolyte imbalances. It is diagnosed with an ACTH stimulation test.
Hypothalamus
A small but critical region of the diencephalon that regulates functions such as body temperature, hunger, thirst, and the release of hormones.
Hypothyroidism
A condition caused by insufficient thyroid hormone production. It is one of the more common hormonal disorders diagnosed in dogs, but is rare in cats.
Hypoxia
A condition in which tissue does not receive enough oxygen. Severe or prolonged hypoxia in the brain or spinal cord can lead to permanent tissue damage.
↑ Back to top

I

Idiopathic
A medical term meaning the cause is unknown. "Idiopathic vestibular disease," sometimes called old dog vestibular disease, is diagnosed when vestibular signs appear and no underlying cause can be found after appropriate testing.
IM
Intramuscular, meaning injected into a muscle.
Infarct
An area of tissue that has died because its blood supply was cut off.
Inodilator
A type of medication that both strengthens the heart's contractions and widens blood vessels. Pimobendan is the inodilator most commonly used in veterinary cardiology.
Insulin
A hormone, normally produced by the pancreas, that allows the body to use sugar (glucose) for energy. Dogs with diabetes mellitus typically require insulin therapy, since the disease in dogs is caused by an inability to produce enough insulin on their own.
Intervertebral Disc
The cushion of cartilage located between adjacent vertebrae that absorbs shock and allows the spine to flex.
Intervertebral Disc Disease (IVDD)
A common condition in which an intervertebral disc bulges or ruptures, putting pressure on the spinal cord. It is a leading cause of spinal cord injury in dogs, particularly in breeds with shortened legs and long backs.
Ipsilateral
On the same side of the body as a given point of reference. Some neurological signs occur on the same side as the part of the brain that was affected.
IRIS Staging
A four-stage system, developed by the International Renal Interest Society, used to classify the severity of chronic kidney disease in dogs and cats based on blood creatinine and/or SDMA, then refined further using blood pressure and urine protein levels. It helps guide monitoring and treatment recommendations.
Ischemia
A reduced or inadequate blood supply to a tissue or organ, which deprives it of oxygen and nutrients. Prolonged ischemia can lead to tissue death (an infarct).
Ischemic Stroke
A stroke caused by a blocked blood vessel that cuts off blood flow to part of the brain. The most commonly diagnosed type of stroke in dogs.
IV
Intravenous, meaning given directly into a vein.
↑ Back to top

J

Jerk Nystagmus
The most common pattern of nystagmus, in which the eyes move slowly in one direction and then snap back quickly in the other. By convention, nystagmus is described and named by the direction of this fast phase.
JVD
Jugular Venous Distension, a visible bulging of the jugular vein in the neck, which can be a sign of heart problems affecting blood flow.
↑ Back to top

K

Knuckling
When a paw folds under so the top of the foot touches the ground while walking, instead of the pad. A sign of proprioceptive or motor deficits.
↑ Back to top

L

Lateral Ventricles
The two largest fluid-filled cavities within the brain, one in each cerebral hemisphere, where cerebrospinal fluid is produced.
Lesion
A specific area of damaged or abnormal tissue, such as the area of the brain affected by a stroke.
Lethargy
Reduced energy and an unwillingness to engage in normal activity.
Levothyroxine
A synthetic form of thyroid hormone used to treat hypothyroidism, most commonly in dogs.
Limbic System
A group of interconnected structures, including the hippocampus and amygdala, involved in emotion, memory, and behavior.
Low-Dose Dexamethasone Suppression Test (LDDS)
A diagnostic test for hyperadrenocorticism (Cushing's disease) in which a small dose of a synthetic steroid is given and cortisol is measured over several hours. In a healthy pet, cortisol production drops in response; in a pet with Cushing's disease, it typically does not, and the pattern of results can also help determine whether the disease originates in the pituitary or adrenal gland.
Lumbar Vertebrae
The seven vertebrae of the lower back, labeled L1 through L7, located between the thoracic vertebrae and the sacrum.
↑ Back to top

M

Medulla Oblongata
The most caudal part of the brainstem, connecting to the spinal cord, which controls vital functions such as heart rate and breathing.
Menace Response
A test of vision and the facial nerve in which the examiner moves a hand quickly toward the dog's eye, without touching it or creating air currents, and watches for a protective blink.
Meninges
The three protective membranes, the dura mater, arachnoid mater, and pia mater, that surround the brain and spinal cord.
Mesencephalon (Midbrain)
The part of the brainstem between the diencephalon and the pons, involved in relaying sensory and motor signals and in controlling some reflexes, including those of the eyes.
Methimazole
A medication that reduces thyroid hormone production, most commonly used to manage hyperthyroidism in cats.
Mitotane
An older medication used to treat hyperadrenocorticism (Cushing's disease) by selectively destroying part of the adrenal gland's hormone-producing tissue. It has largely been replaced by trilostane in many practices, though it is still used in some cases.
MM
Mucous Membranes, the moist tissue lining the mouth and other body openings. Their color and moisture are checked as part of a routine exam.
MRI (Magnetic Resonance Imaging)
An imaging technique that uses magnetic fields rather than radiation to create detailed pictures of soft tissue, including the brain. It is the preferred imaging method for diagnosing stroke and many other brain conditions in dogs.
Myelomalacia
Softening or breakdown of spinal cord tissue due to severe damage, such as significant injury or a loss of blood supply.
Myelopathy
A general term for any disease or dysfunction affecting the spinal cord.
Myxomatous Mitral Valve Disease (MMVD)
A degenerative disease of the mitral valve in the heart that prevents it from closing properly, allowing blood to leak backward. It is the most common cause of heart disease and congestive heart failure in dogs, particularly small breeds.
↑ Back to top

N

Neuron
A nerve cell, the basic functional unit of the nervous system.
NPO
Nothing by mouth, from the Latin nil per os. An instruction to withhold food and water, most often used before anesthesia or surgery.
Nystagmus
Rhythmic, involuntary movement of the eyes, often described as flicking back and forth, up and down, or in a circular pattern. A common finding in vestibular disease and in certain brainstem or cerebellar problems. Its specific pattern, such as horizontal, vertical, rotary, positional, or spontaneous, helps a veterinarian judge whether the underlying problem is peripheral or central.
↑ Back to top

O

Occipital Lobe
A region of the cerebral cortex primarily involved in processing visual information.
OD
Oculus dexter, the right eye. Used in ophthalmologic prescriptions and exam notes.
Old Dog Vestibular Disease
A common name for idiopathic vestibular disease, reflecting how often it is diagnosed in older dogs.
Olfactory Bulb
A structure at the front of the brain that receives and processes information about smell.
Onset
The way and timing in which a condition presents, such as acute (sudden) onset versus gradual onset.
Orthostatic
A term meaning related to standing upright, as in orthostatic hypotension.
Orthostatic Hypotension
A drop in blood pressure that occurs when standing up or moving to a more upright position. It can cause weakness, wobbliness, or fainting, and is associated with a number of underlying conditions affecting the heart, blood vessels, or nervous system.
Orthostatic TIA
A rare form of transient ischemic attack triggered specifically by standing up or moving to a more upright position, rather than occurring at rest. It happens when blood flow to part of the brain is already severely compromised, typically by significant narrowing or blockage of a major artery such as the carotid artery, so that the normal, brief drop in blood pressure that occurs on standing is enough to push blood flow below a critical threshold. This is well documented in human neurology. It has not been specifically reported in veterinary case literature, but the underlying blood flow mechanism is not species-specific, so it is considered a biologically plausible cause of position-triggered neurologic episodes in a dog with severe disease of the carotid or vertebral arteries.
OS
Oculus sinister, the left eye.
OU
Oculus uterque, both eyes.
↑ Back to top

P

Palliative Care
Treatment focused on relieving symptoms and improving comfort, rather than curing the underlying disease. Palliative care can be provided at any stage of a serious illness, including alongside ongoing efforts to treat or manage the underlying condition.
Paraplegia
Paralysis affecting the hind limbs, most often caused by a spinal cord problem located in the back (the thoracic, lumbar, or sacral region).
Paresis
Partial weakness or a reduced ability to move a limb or part of the body. This is different from full paralysis, which is the complete loss of movement.
Parietal Lobe
A region of the cerebral cortex involved in processing sensory information from the body.
PE
Physical Exam.
Pendular Nystagmus
A back-and-forth eye movement of equal speed in both directions, without a distinct fast and slow phase. It is usually present from birth rather than caused by acquired vestibular disease.
Perfusion
The flow of blood through the blood vessels of a tissue or organ, delivering oxygen and nutrients. Reduced perfusion can lead to ischemia.
Phosphate Binder
A medication given with food that reduces the amount of phosphorus absorbed from the diet. Phosphate binders are commonly used to help manage chronic kidney disease.
Physiologic Nystagmus
Normal nystagmus that occurs in healthy animals when the head is turned or moved, as part of the vestibular system's normal function. It is different from pathological nystagmus, which occurs without head movement.
Pia Mater
The innermost, delicate layer of the meninges, which adheres closely to the surface of the brain and spinal cord.
Pimobendan
An inodilator that both strengthens the heart's contractions and widens blood vessels. It is used to manage congestive heart failure caused by myxomatous mitral valve disease or dilated cardiomyopathy in dogs.
Pineal Gland
A small gland in the epithalamus that produces melatonin and helps regulate sleep-wake cycles.
Pituitary Gland (Hypophysis)
A small gland attached to the hypothalamus that produces and releases hormones controlling many body functions.
Pituitary-Dependent Hyperadrenocorticism (PDH)
The most common form of Cushing's disease, caused by a usually small, benign tumor of the pituitary gland that leads to overproduction of ACTH, which in turn drives excess cortisol production by the adrenal glands.
PO
Per os, by mouth. The standard abbreviation used on prescriptions and exam notes for medications given orally.
Pons
Part of the brainstem between the midbrain and the medulla oblongata, which relays signals between the cerebrum and the cerebellum.
Positional Nystagmus
Nystagmus that appears, or changes character, only when the head is held in a particular position, such as tipped back or to the side. It can occur with long-standing peripheral vestibular disease but is also a recognized sign of central vestibular disease, especially if its direction changes with different head positions.
PRN
As needed, from the Latin pro re nata. Used for medications given only when a particular sign occurs, rather than on a fixed schedule.
Prognosis
A veterinarian's informed projection of how a condition is likely to progress and what recovery may look like. A prognosis is an estimate based on the available information, not a guarantee.
Proprioception
The body's sense of where its limbs are in space without looking at them. Dogs with proprioceptive deficits may knuckle over a paw or place their feet awkwardly.
Proteinuria
The presence of an abnormal amount of protein in the urine. In kidney disease, proteinuria can be a sign that the filtering structures within the kidney are damaged, and it is assessed using a urine protein-to-creatinine (UPC) ratio.
Pupillary Light Reflex (PLR)
The constriction of the pupil in response to light, tested as part of a neurological exam.
↑ Back to top

Q

QAR
Quiet, Alert, Responsive. Shorthand similar to BAR, but describing a slightly more subdued, though still normal, demeanor.
QID
Four times daily, from the Latin quater in die.
Quality of Life (QOL)
An ongoing, day-by-day assessment of a pet's overall comfort and wellbeing, often used to help guide decisions about continuing treatment, beginning hospice or palliative care, or other care choices during a serious or chronic illness.
↑ Back to top

R

Recumbency
Lying down. A dog described as "non-ambulatory" or "recumbent" cannot stand or walk without assistance.
Rehabilitation
Therapeutic exercises and treatments aimed at restoring function after injury or illness, similar to physical therapy in humans.
Rostral
A directional term meaning toward the nose or front of the head. The opposite of caudal.
Rotary Nystagmus
Nystagmus in which the eyes move in a circular or rotating pattern, also called rotatory nystagmus. Like horizontal nystagmus, it is commonly seen with peripheral vestibular disease but can also occur with central disease.
RR
Respiratory Rate.
Rx
Prescription.
↑ Back to top

S

Sacrum
The fused group of three vertebrae that connects the spine to the pelvis.
Saddle Thrombus (Aortic Thromboembolism)
A blood clot that breaks loose from the heart, most often in cats with underlying heart disease such as hypertrophic cardiomyopathy, and lodges where the aorta branches to supply the hind legs. It causes sudden pain, cold hind limbs, and an inability to use one or both hind legs, and is a veterinary emergency. Also called feline aortic thromboembolism (FATE).
SDMA (Symmetric Dimethylarginine)
A blood test that can detect a decline in kidney function earlier than creatinine in many dogs and cats. It is used alongside creatinine to help diagnose and stage chronic kidney disease.
Secondary Hypertension
High blood pressure caused by an identifiable underlying condition, such as kidney disease, an endocrine disorder, or certain medications, rather than occurring on its own. Most hypertension diagnosed in dogs is secondary.
Senior
A general term for the earlier stage of an aging pet, sometimes defined as the last quarter of a pet's estimated lifespan. As with "geriatric," there is no fixed age that applies across all dogs, since breed and size strongly influence how quickly a dog ages.
SID
Once daily, from the Latin semel in die. Used in veterinary medicine in place of "QD," the abbreviation more commonly used in human medicine, which carries a recognized risk of being misread as "QID" (four times daily).
Sildenafil
A medication that relaxes and widens blood vessels in the lungs, sometimes used to manage pulmonary hypertension, a complication of some heart and lung diseases.
Spinal Cord
The long bundle of nerve tissue that runs through the vertebral canal, carrying signals between the brain and the rest of the body.
Spinal Nerve
A nerve that connects the spinal cord to the rest of the body, carrying both sensory and motor information.
Spinous Process
The bony projection extending from the back of a vertebra, which can be felt along the midline of the back.
Spironolactone
A potassium-sparing diuretic often used alongside other diuretics, such as furosemide, in the management of congestive heart failure.
Spontaneous Nystagmus
Nystagmus that is present while the head is still, without any particular positioning needed to bring it on. Also called resting nystagmus, it is usually a sign of pathological vestibular disease.
SQ
Subcutaneous, meaning injected under the skin. Also written as SC.
Strabismus
An abnormal positioning of one or both eyes, which do not align in the expected direction. It can occur with vestibular disease or certain cranial nerve problems.
Stroke
The common term for a sudden disruption of blood flow to part of the brain, causing damage to brain tissue. Strokes fall into two main types: ischemic stroke, caused by a blocked blood vessel, and hemorrhagic stroke, caused by bleeding into or around the brain. The clinical term for a stroke is cerebrovascular accident (CVA).
Substantia Nigra
A structure within the midbrain that produces dopamine and plays a role in controlling movement.
Syncope
A temporary loss of consciousness caused by a brief drop in blood flow to the brain, often related to heart or blood pressure problems. It is sometimes mistaken for a seizure or a stroke.
↑ Back to top

T

T4 (Thyroxine)
The main hormone produced by the thyroid gland. Blood T4 levels are the standard first screening test for thyroid disease: a low T4 raises suspicion for hypothyroidism in dogs, while a high T4 supports a diagnosis of hyperthyroidism in cats.
Tectum
The roof of the midbrain, which includes the rostral and caudal colliculi.
Telencephalon
The largest part of the forebrain, made up of the cerebrum, including the cerebral cortex and the basal nuclei.
Telmisartan
An ARB used to help manage high blood pressure and reduce protein loss from the kidneys, increasingly used in both dogs and cats.
Temporal Lobe
A region of the cerebral cortex involved in processing sound and, in many species, aspects of memory.
Tetraplegia (Quadriplegia)
Paralysis affecting all four limbs, most often caused by a spinal cord problem located in the neck.
Thalamus
A structure within the diencephalon that relays nearly all sensory information to the cerebral cortex.
Third Ventricle
A narrow, fluid-filled cavity within the diencephalon, connected to the lateral ventricles and the fourth ventricle.
Thoracic Vertebrae
The thirteen vertebrae of the chest region of the spine, labeled T1 through T13, each paired with a rib.
Thromboembolism
A blood clot that forms in one location and then breaks loose and travels through the bloodstream until it lodges in a smaller vessel, blocking blood flow downstream.
Thrombosis
The process of a blood clot (thrombus) forming within a blood vessel, which can partially or completely block blood flow at that location.
Thrombus
A blood clot that forms within a blood vessel and remains at its point of origin.
TID
Three times daily, from the Latin ter in die.
TPR
Temperature, Pulse, and Respiration, the basic vital signs recorded at most exams.
Transient Ischemic Attack (TIA)
A brief, temporary episode of stroke-like neurological signs caused by a short-lived disruption in blood flow to the brain, sometimes called a "mini-stroke." Unlike a full stroke, the signs resolve on their own, typically within minutes and without lasting damage visible on imaging. TIAs have been documented in dogs, though they are reported less often than full strokes. In people, some TIAs are triggered specifically by a drop in blood pressure on standing in the presence of severe narrowing of the major arteries supplying the brain; this particular trigger has not been well documented in dogs.
Transverse Process
A bony projection extending from each side of a vertebra, which serves as an attachment point for muscles and ligaments.
Tremor
Rhythmic, involuntary shaking, which can be a sign of cerebellar disease, among other causes.
Trilostane
A medication that reduces cortisol production, and the most commonly used first-line treatment for hyperadrenocorticism (Cushing's disease) in dogs.
TSH (Thyroid-Stimulating Hormone)
A hormone released by the pituitary gland that signals the thyroid gland to produce more thyroid hormone. In dogs, an elevated TSH alongside a low T4 supports a diagnosis of hypothyroidism.
Tx
Treatment.
↑ Back to top

U

Unilateral
Affecting only one side of the body.
↑ Back to top

V

Ventral
A directional term meaning toward the belly or underside of the body. The opposite of dorsal.
Ventral Root
The portion of a spinal nerve that carries motor signals out of the spinal cord to muscles.
Vertebra
A single bone of the spine. Dogs have a total vertebral count that varies somewhat by breed due to differences in tail length, but the typical formula is 7 cervical, 13 thoracic, 7 lumbar, 3 sacral, and 20 to 23 caudal vertebrae.
Vertebral Canal
The tunnel formed by the stacked vertebrae through which the spinal cord travels.
Vertebral Column
The full chain of vertebrae from the skull to the tail, also called the spine, which protects the spinal cord and supports the body.
Vertical Nystagmus
Nystagmus in which the eyes move up and down. Unlike horizontal or rotary nystagmus, vertical nystagmus is considered a localizing sign of central vestibular disease rather than peripheral.
Vertigo
A sensation of spinning or disorientation related to the balance system. In dogs, vertigo can only be inferred from observed behavior, such as disorientation or loss of balance, since dogs cannot describe the sensation directly.
Vestibular Disease
A disorder affecting the vestibular system, the network of structures in the inner ear and brainstem that controls balance. Signs include head tilt, loss of balance, circling, and nystagmus.
Vestibular System
The sensory system, made up of structures in the inner ear and corresponding pathways in the brainstem and cerebellum, responsible for the sense of balance and spatial orientation.
↑ Back to top

W

White Matter
Brain or spinal cord tissue made up mostly of nerve fibers, which appears lighter than gray matter due to its fatty insulating coating.
Wide-Based Stance
A stance in which a dog stands with its legs spread further apart than normal, often used to compensate for poor balance or coordination. Commonly seen with cerebellar disease, though it can occur with other types of ataxia as well.
WNL
Within Normal Limits, shorthand used on exam notes when a finding falls inside the expected healthy range.
↑ Back to top

X

X-ray (Radiograph)
An imaging technique that uses a small amount of radiation to create pictures of bones and certain soft tissues. X-rays are useful for evaluating the heart, lungs, and spine, though MRI or CT provide more detail when imaging the brain or spinal cord.
Xiphoid Process
The thin, cartilaginous tip at the rear end of the sternum (breastbone). It is sometimes used as a landmark during a physical exam, such as when listening to the heart or performing chest compressions.
Xylazine
A sedative and pain-relieving medication, classified as an alpha-2 agonist, sometimes used to help keep a dog calm and still for procedures such as diagnostic imaging. It can affect heart rate and blood pressure, so it is used with monitoring.
↑ Back to top

Y

Y/O
Shorthand for "years old," commonly seen on patient charts and intake forms to record a pet's age.
Yew (Taxus) Toxicity
Poisoning caused by ingesting parts of the yew plant, which contains compounds that can cause life-threatening heart rhythm disturbances and sudden death in dogs. Yew is considered one of the more dangerous ornamental plants for pets.
↑ Back to top

Z

Zonisamide
An anticonvulsant medication used to help manage seizures in dogs, sometimes prescribed alongside or in place of other antiepileptic drugs.
Zoonosis
A disease that can be transmitted between animals and people. Diseases described as "zoonotic" require extra precautions to protect both human and animal health.
↑ Back to top
←

Back to Caregiver Resources

See the full library: equipment guides, recovery resources, handouts, and more as they're built.

caninestroke.org/caregiver-resources →

STAY CONNECTED

Be part of what comes next

Whether you're a veterinary professional, a caregiver who has been through this, or someone who wants to help build something that matters, we want to hear from you.

info@caninestroke.org