Clotting Disorders Flashcards
What is hemostasis
Clotting
What is anti-coagulation
Un clotting
True or false
There is always hemostasis and anticoagulation happening in the blood
True
Excess hemostasis can cause formation of thrombi, what are these?
Blood clots
Lack of hemostasis or excess anticoagulation can result in
Spontaneous bleeding
Abnormal hemostasis is common in___ and rare in __ and ___
Common in Dogs
Rare cats and horses
What factors influence clotting
Platelets
Clotting factors
Fibrin
Vitamin K
Why is vitamin K important in clotting
Important for the function of many clotting factors
What is external blood loss
Blood lost to the environment
What is the treatment for severe external blood loss
Replacement by transfusion
What is the treatment for mild external blood loss
None, the body can regenerate it themselves
What is internal blood loss
Bleeding into the third spaces (abdominal cavity, pleural space, SQ space)
What does bleeding into the pleural space cause
Respiratory distress
What does bleeding into the SQ spaces cause
Common in the ventral neck and abdomen, and causes swelling
What is autotransfusion
With internal Blood loss, vessels reabsorb blood
Signs may not be noticeable if absorption is faster or at equal rate to the bleeding
What is a hematoma
Localized accumulation of blood outside the blood vessles (clotted)
Ex. Bruises
What is a petechial hemorrhage
Red pin points on the mucus membranes caused by spontaneous bleeding from capillaries
If blood loss is significant enough, what clinical signs will the patient show
Signs associated with anemia (pale/white MM, weakness, lethargy, low mentation, collapse)
Clinical signs of blood loss depends on
Rate of blood loss
If loss is internal or external
If pathology is present
Treatment of blood loss in general involves
Stopping external blood loss
Replacing any lost blood
Correcting underlying causes/problems
What is Disseminated Intravascular Coagulation (DIC)
A disease that is always secondary to severe systemic pathology (infections, heat stroke, burns, neoplasia) that causes a state of hyper-coagulation
Will also see petechial hemorrhages
What is the acronym for disseminated intravascular coagulation
DIC: Death Is Coming
Why is disseminated intravascular coagulation dangerous
The petechial hemorrhages form microscopic clots in the blood vessels, this uses all of the fibrin and clotting factors so the animal can no longer clot , and they start to bleed out internally
How do you treat DIC
Blood or plasma transfusions
Treat primary problem (infection, heat stroke, burns, neoplasia etc)
What is the prognosis for DIC
VERY POOR
Why is prognosis for DIC so low
Thrombi can obstruct blood flow to organs
Hemorrhages
Haemolytic anemia by shearing of RBCs by fibrin
Signs of DIC
Depends on primary cause
Abdominal pain and distension, fever, petechial hemorrhages, ischemia, hard breathing, wounds wont clot
What is rodenticide poisoning
Poisoning by ingestion of Warfarin,
sweet clover, or dicumarol (LA)
What should you do when you get a call about incoming case of rodenticide poisoning
Ask the owner to bring the package
What is the prognosis for older generation of poisons (warfarin) and why
Has a shorter half life (<55hrs)
Will eventually degrade
Better prognosis
What is the prognosis for newer generation of poisons and why
Majority of the rodenticides these days
Half life of 15-21 days
Considered irreversible
Very poor prognosis
What is the pathology of rodenticide poisoning
Rodenticides deplete Vitamin K from the body (an essential cofator for clotting)
How fast does bleeding occur after rodenticide poisoning causes vitamin K deficiency
Can take up to 2 weeks for clinical sign to occur
What is the range of bleeding severity with rodenticide poisoning
Increased risk of bleeding out with trauma
To
Spontaneous hemorrhage
What are clinical signs of rodenticide poisoning
Hematomas or bleeding that is disproportionate to the trauma experienced
Spontaneous hematomas
Spontaneous bleeding into lungs or abdomen
What is the treatment of rodenticide poisoning
Induce vomitting if <2 hours
Vitamin K1 therapy (first dose injection, then oral supplementation)
Avoid trauma
What is the prognosis of rodenticide poisoning overall
The earlier the treatment the better the prognosis
How long do you need to treat depending on what type of rodentocide
1-12 months
What is used for treatment of rodenticide treatment
Vitamin K1 or K3
K1
Why do you need to be careful when taking blood from rodenticide poisoning patients
They dont have clotting factors to stop the bleed
Never take from the jugular veins
What is aspirin toxicity usually from
Clients giving patients aspirin
Why is aspirin toxicity dangerous
Aspirin inhibits an enzyme required for platelets to stick together and therefore the body cannot clot
Is inhibition by aspirin toxicity reversible or not?
No, it is considered irreversible
What must happen because aspirin toxicty is irreversible
The body must regenerate platelets to replace the non fucntional ones
How long does it take for aspirin toxicity to wear off
21 days
What can aspirin also cause beside lack of clotting
Renal damage
GI ulcers
Liver damage
With vasodilation (like with inflammation) what happens to the fluid volume and blood pressure
Fluid volume stays the same but blood pressure decreases
In the case of vasoconstriction, what happens to fluid volume and blood pressure
Fluid volume stays the same and blood pressure increases
Blockages in blood vessels can occur from
Foreign bodies
Clot formation
What are some examples of vascular accidents/damage
Scratches to the endothelium, punctures, rupture, tears or aneurysms
What is the normal blood pressure for SA and horses
120/80 with a median of 90
What is osmotic pressure
The pressure inside vessels based on the concentration of electrolytes inside the vessel and in the extracellular fluid
The walls of blood vessels are ____ allowing water to move into compartments with lower concentrations of ___
Semi permeable
Sodium
What is oncotic pressure
Pressure in the vessels based on the amount of soluble proteins in the vessels
What is the most important protein in the blood vessels
Albumin
How does albumin help keep water inside the vessels
Because it is too large to move across the blood vessel membrane, so it must stay inside the vessels, keeping water in the vessel as well (along with other large proteins)
What happens when the concentration of albumin or “total proteins” in the plasma are low
Oncotic pressure in the vessels drop and causes less water to be retained in the vessels
How do colloids work?
Act like albumin to increase intravascular oncotic pressure and draw in water to increase blood pressure
What is hypertension
AKA high blood pressure
When systolic pressure is >180mmHg
What are the two underlying causes of hypertension
May be physiological or pathological
What is the physiological cause of hypertension
Activation of the sympathetic nervous response (vasconstriction of vessels in the skin and GI tract) moves blood to the heart, lungs, muscles, and brain and increases overall systemic blood pressure
What are the pathological causes of hypertension
No underlying cause, often secondary to a cause
due to baroreceptor dysfunction (blood pressure receptor) which causes vasoconstriction
Or
Due to the inability of the blood vessels to dilate
Primary high blood pressure is mainly ___ in vet medicine
Uncommon
What is arteriosclerosis
Hardening of the blood vessels
What are some diseases that can cause high blood pressure
Hyperthyroidism
Heart failure
Kidney failure
Conditions with excess body water (overload)
Adrenal gland disease that results in over production of adrenaline (causes sympathetic response)
What happens in the body with hypertension
Strains the heart
Causes fluid to move out of the blood vessels into the extravascular space
Where does hypertension cause fluid to move out of vessels the most
In areas with the least pressure (lungs and abdomen)
What happens in the lungs with hypertension
PULMONARY HYPERTENSION
pushes fluids from the vessels into the lungs
Causes pulmonary edema (if it reaches the alveoli)
Causes plural effusion (if it reaches space around the lungs)
What happens in the abdomen with hypertension
ASCITES
Extra fluid in the abdominal space
Increases risks for aneurysms
Exacerbates injuries/trauma
Pressure in the retinal vessels
What can Pressure in the retinal vessels lead to
Sudden blindness, especially in cats
What is hypotension
Low blood pressure
Systolic pressure below 90
True or false
Hypotension is a primary condition
False
It is always secondary
What are some causes of secondary hypotension
Improper heart function
Dehydration
Bleeding
Vasodilation (head trauma, illnesses, inflammation (systemic or local))
Iatrogenic causes (anesthesia, or too much blood collected)
Hypotension may not be noticed with ____ inflammation
Local
Hypotension caused by systemic inflammation (like shock) can causes all blood vessels to
Dilate
What does hypotension do to the kidneys
Decrease in blood flow to the kidneys causes damage (happens the fastest)
What does hypotension do to the brain
Decreased blood flow results in decreased brain functions and may cause death
What does hypotension do to muscles
Decreased blood flow causes acidosis (increased lactic acid), muscle weakness and decreased heart function
What is treatment of hypotension based on
Treating the underlying issue; vasodilation, the heart issues, replacing the body water
What does anaphylaxis cause
Hypotension which causes an increased heart rate
What are some compensation mechanisms of the body that deals with hypotension
If the heart is not functioning well the body will constrict blood vessels
If there is a lack in blood volume the heart will be faster and/or vessels will constrict
If there is a problem with vasodilation the heart will be faster
The goal of compensation is to work with heart ___, blood vessel ___ and body water ____ to maintain certain blood pressures
Heart rate
Blood vessel size
Body water volume
What is a thrombus
A stationary blood clot in blood vessels formed from platelets, fibrin and clotting factors
Produced in the blood vessels, forms in one spot and grows
What are thrombi usually triggered by
Damage to the walls of the vessels (vascular epithelium)
Decreased blood flow
What can damage to the vascular epithelium be from
Infection
Inflammation/trauma
Iatrogenic causes (IV catheters, drugs)
What can cause decresed blood flow
Diseased heart valves
Increased number of RBCs causing increased blood viscosity (thicker) which slows down the flow rate
What does the severity of a thrombus depend on
Location
Species
Underlying disease
Where do thrombi most commonly occur
In veins at the valves (where there is lower pressure)
Thrombi can ___ vessles causing ___
Occlude vessels causing ischemia (lack of blood flow)
What is an embolus AKA thromboembulus
When a thrombus or a piece of thrombus dislodges from its original location and attaches somewhere else
OR
can be a piece of foreign material
Where do emboli/thromboemboli usually occur
Where vessels branch or in capillaries
What are some examples of thromboemboli
The tip of a catheter
Piece of heart worm
What does the disease, signs and prognosis of a thromboemboli usally depend on
Which vessel is be obstructed
What is HCM
Hypertrophic cardiomyopathy
Excessive overgrowth of the heart muscles (affects ventricular volume)
What are cats with HCM at high risk for
Thromboembolic disease (Saddle Thrombus)
Describe the pathology of saddle thrombus in cats with HCM
Because of the disturbance in blood flow it increases the risk of thrombi forming, when it dislodges, it can enter the aorta and lodge in the iliac artery which blocks blood flow to the iliac and femoral arteries
Often block vessels where they branch (get more narrow)
What do cats with a saddle thrombus present with
Extreme pain Paralysis Cold hind limbs + loss of color Almost always have HCM No pulse in the hind limbs Can be acidotic Can causes necrosis
What is the treatment for a saddle thrombus
Blood thinners
But often euthanasia because treatment is so risky
What is the prognosis for a saddle thrombus
Very poor
Could lodge in the coronary arteries and cut off blood flow to the heart or the brain
Always treat as an emergency
