Diastolic Dysfunction (Pulmonary hypertension) Flashcards

1
Q

What is pulmonary hypertension?

A
  • Increased pressure in the lungs
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2
Q

Which values are considered pulmonary hypertension

A
  • > 30 mmHg systolic
  • > 10 mmHg diastolic
  • Pulmonary artery
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3
Q

What affects afterload with pulmonary hypertension?

A
  • Pulmonary venous/left atrial pressure

- Increase in these pressures would increase afterload, decreasing stroke volume and cardiac output

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4
Q

What affects preload with pulmonary hypertension?

A
  • Systemic or pulmonary venous return

- If increased, will increase preload, increase stroke volume, and increase cardiac output?

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5
Q

What can increase pulmonary venous return?

A
  • Any left heart disease that results in increased left atrial size will increase left atrial pressure
  • Any pulmonary venous obstruction
  • Loss of pulmonary vessels
  • Increased right-sided cardiac output (anemia, fever, exercise; large left to right shunts)
  • A mass can cause pulmonary venous obstruction too (enlarged hilar lymph nodes too)
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6
Q

What is most common cause of increased pulmonary venous return?

A
  • Any left sided heart disease
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7
Q

What contributes to pulmonary blood pressure?

A
  • Cardiac output X Pulmonary vascular resistance

- SEE TABLE AND THINK ABOUT THIS

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8
Q

What large L–> R shunts can increase pulmonary venous return (AKA increased volume within the lungs)?

A
  • Patent ductus arteriosus (PDA)
  • Ventricular septal defect (VSD)
  • Atrial septal defect
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9
Q

Exercise induced pulmonary hypertension

A
  • Pushing blood through the lung
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10
Q

What can cause a loss of pulmonary vessels

A
  • Pulmonary thromboembolism
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11
Q

Again, what three things contribute to Virchow’s triad?

A
  • Endothelial injury
  • Blood stasis
  • Hypercoagulability
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12
Q

What can lead to endothelial injury leading to pulmonary hypertension?

A
  • Heartworm disease***

- Vasculitis

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13
Q

What can lead to hypercoagulability leading to pulmonary hypertension?

A
  • Hyperadrenocorticism
  • Protein-losing nephropathy
  • Inflammatory disease (e.g. IMHA)
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14
Q

What parts of Virchow’s triad can neoplasia impact?

A
  • Any of them
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15
Q

What can lead to loss of pulmonary vessels

A
  • Pulmonary thromboembolism (anything impacting Virchow’s triad)
  • Pulmonary vasoconstriction (hypoxemia)
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16
Q

Impact of hypoxemia on pulmonary vessels?

A
  • NORMALLY leads to vasodilation systemically
  • In your lungs, it’s opposite
  • They constrict as you don’t want to perfuse an area that’s not ventilated
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17
Q

Causes of hypoxemia

A

Primary lung disease vs high altitude

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18
Q

Primary lung disease that can lead to hypoxemia

A
  • Chronic obstructive pulmonary disease (COPD or chronic bronchitis)
  • Pulmonary fibrosis (West Highland White Terriers)
  • Collapsing trachea (COMMON)
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19
Q

Diagnosis pf pulmonary hypertension

A
  • cardiac catheterization

- Echocardiogram

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20
Q

What is the gold standard diagnosis for pulmonary hypertension?

A
  • Cardiac catheterization

- Measures direct pressures in the PA, pulmonary capillaries, and pulmonary veins

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21
Q

Echocardiogram for diagnosis of pulmonary hypertension

A
  • Indirect measurement of pulmonary pressures
  • Only definitive if tricuspid or pulmonic regurgitation is present
  • Use modified Bernoulli equation to estimate pressures
  • Can look for secondary signs like concentric hypertrophy too
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22
Q

Treatment for pulmonary hypertension

A
  • TREAT THE UNDERLYING DISEASE

- Viagra or sildenafil

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23
Q

Sildenafil MOA

A
  • Phosphodiesterase type V inhibitor (specific for the lung)
  • Specifically vasodilates the pulmonary vasculature
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24
Q

Prognosis for pulmonary hypertension

A
  • Depends on underlying disease
  • Usually guarded
  • Most common are left heart disease, which are not curable
  • Also have respiratory signs, which are not curable
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25
Q

Who gets Dirofilaria immitis?

A
  • Canines (the favorite)

- Felines (not as often)

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26
Q

Heartworm incidence

A
  • Spreading

- Definitely increasing

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27
Q

What is required for L1 to go to l3?

A
  • 64° for 30 days

- If it dips below 64° average, doesn’t seem to support mosquito survival

28
Q

Heartworm life cycle

A
  • just know it
29
Q

What stage of worm does mosquito inject into bite wound?

A
  • L3

- Infective 3rd stage larva

30
Q

How long does it take to go from L3 to L4?

A
  • 1-2 weeks in the body
31
Q

How long to become an adult heartworm from L4?

A
  • 2-3 months

- Tunnels to blood vessels and molts to L5

32
Q

How long to for patency after becoming an adult?

A
  • 3-4 months
33
Q

How long for patency to occur post-infection?

A
  • 6-7 months
34
Q

Wolbachia

A
  • Rickettsial intracellular, gram neg bacteria
35
Q

Wolbachia relationship to D. immitis

A
  • Symbiotic
  • Assists with D. immitis development
  • Increases D. immitis fecundity
36
Q

What stages are impacted if you kill Wolbachia?

A
  • Fewer L3 becomes L4, and fewer of those become teenagers

- Wolbachia help with development of life stages and facilitate more L1 larvae

37
Q

Diagnosis of heartworm

A
  • Heartworm testing
  • Antigen testing
  • ANtibody testing
  • Microfilaria
38
Q

How long after you wait before you can test for heartworm?

A
  • 6 months post-exposure
39
Q

What are you testing with antigen testing?

A
  • Female reproductive tract

- Infection

40
Q

What does positive antigen test mean/

A
  • Have to have an infection
41
Q

What does antibody test positive means?

A
  • Exposure
42
Q

What are you looking for with Knotts test?

A
  • Microfilaria
43
Q

Positive predictive value and heartworm disease

A
  • Depends on prevalence of the disease
  • If you are here in Pullman, positive predictive is heartworm test is a lot lower
  • Increased likelihood of false positive
  • Don’t test random animals for heartworm
  • In Mississippi, your negative predictive value will be lower
44
Q

What are the stages of heartworm disease?

A
  • Asymptomatic
  • Respiratory signs
  • Cor Pulmonale
  • Right sided CHF
  • Caval syndrome
45
Q

Respiratory signs of heartworm disease

A
  • Cough/tachypnea with exercise
46
Q

Cor pulmonale

A
  • Pulmonary vascular disease –> pulmonary hypertension
47
Q

What side heart failure happens with heartworm disease?

A
  • Pulmonary hypertension
48
Q

Caval syndrome

A
  • Hepatic congestion, intravascular hemolysis with hemoglobinuria
  • If pulmonary arterioles are full, they will go to the heart
  • If it’s even worse, they go the caudal and cranial vena cava syndrome
  • These dogs are usually laterally recumbent and dying
49
Q

Comorbidities of heartworm disease

A
  • Antibody-antigen complex formation –> glomerular deposition –> proteinuria
  • Thrombocytopenia
  • Anemia
50
Q

Concurrent diagnostics for heartworm disease

A
  • CBC
  • Chemistry
  • Urinalysis
  • Chest rads
  • Echocardiogram
51
Q

Why do a CBC for heartworm disease?

A
  • Evaluate for anemia and thrombocytopenia

- May see eosinophilia

52
Q

Why do a chemistry for heartworm disease?

A
  • Renal values
53
Q

Why do a urinalysis for heartworm disease?

A
  • Proteinuria

- If you have protein, do a urine protein to creatinine ratio

54
Q

Why do chest rads for heartworm disease?

A
  • Pulmonary parenchymal and vascular changes
55
Q

Why do echocardiogram for heartworm disease?

A
  • Evaluate pulmonary hypertension
56
Q

What does melarsomine kill?

A
  • Adults
57
Q

Preventative

A

Kills L1, L3, and L4

58
Q

Slow kill method of heartworm disease

A
  • 2+ years
  • Monthly preventative dose of macrocyclic lactones
  • Doxycycline PO BID for 1 month every 3 months
59
Q

Fast kill method

A
  • Adulticide therapy with melarsomine
  • 2 dose: 1st dose and 2nd 24 hours later
  • 3 dose: 1st dose, 2nd dose 1 month later, 3rd dose 24 hours after 2nd dose
  • Exercise restriction the whole time
60
Q

Which is better: slow or fast kill?

A
  • Fast kill method

- Especially treat ASAP if pulmonary hypertension or other co-morbidities are present

61
Q

What is treatment of choice for caval syndrome?

A
  • Surgical removal or worms
62
Q

Why do surgical removal of worms?

A
  • Reduce worm burden to minimize effects of adulticide
63
Q

Treatment for heartworm

A
  • SEE THE CHART IN THE NOTES
64
Q

Feline heartworm disease characteristics

A
  • Infection 5-20% of K9 prevalence
  • Frequently amicrofilaremic
  • Small worm burdens
  • Clinical signs are very similar to feline asthma
65
Q

Diagnosis of heartworm disease in cats

A
  • Antigen: Female reproductive tract
  • Antibody
  • Microfilaria
  • Chest rads
  • Echocardiograph
  • Probably will have other testing first
66
Q

Treatment of feline heartworm disease

A
  • Adulticide therapy not recommended
  • Treat like an asthmatic cat (steroids and wait for the worms to die)
  • Worm extraction?
  • Doxycycline
67
Q

What should be in place throughout all of the heartworm treatment?

A
  • Exercise restriction!!!!