Hypertension

Question 1

What are the initiating and perpetuating causes of systemic hypertension?

Answer 1

Initiating causes
Chronic fluid accumulation
Persistently increased heart rate
Chronic vasoconstriction

Perpetuating causes
Small arteries changes:
Extravasation of plasma into the vessel wall (hyaline arteriosclerosis)
Vascular smooth muscle hypertrophy
Renal disease

Question 2

What are secondary causes of systemic hypertension?

Answer 2

• renal disease
• hyperadrenocorticism (dog)
• hyperthyroidism (cat)
• diabetes mellitus

Question 3

What clinical signs does systemic hypertension present with?

Answer 3

Only present with end organ damage: > 180 mmHg or if 30 mmHg rise within 48 hours
- Ocular (hypertensive retinopathy)
- Acute blindness, retinal detachment
- Intraocular haemorrhage
- CNS (hypertensive encephalopathy)
- Disorientation, ataxia, stupor
- Seizures, Strokes
- Renal (proteinuria)
- Pu/Pd
- Cardiac (left ventricular hypertrophy)
- Murmur, Arrhythmias
- CHF

Question 4

What can you use to treat systemic hypertension?

Answer 4

• beta blockers
• ace inhibitors
• Ca channel blockers
• angiotensin II receptor blocker

Question 5

What is the goal when treating systemic hypertension?

Answer 5

• Reduce blood pressure
  < 150/95 mmHg
  > 120 mmHg
• Reduce EOD risk
• Decrease proteinuria
• Alleviate clinical signs
• Prevent further deterioration of organ function
• Depends on the underlying disease
• Minimise hospitalisation

Question 6

What are the causes of pulmonary hypertension?

Answer 6

• Alveolar hypoxia with pulmonary vasoconstriction / remodelling
  
  • Severe respiratory disease e.g IPF, neoplasia etc
• Pulmonary vascular obstructive disease
  
  • Pulmonary thromboembolism
  • Heart worm disease
• Pulmonary overcirculation
  
  • Large congenital shunts
• High pulmonary venous pressure
  
  • Left sided heart failure of various causes
• Idiopathic

Question 7

What clinical signs are often associated with pulmonary hypertension?

Answer 7

Suspect PH when you see the following without an obvious cause:
* Persistent respiratory difficulty
* Fatigue
* Exercise intolerance

Most common signs:
* Exercise intolerance
* Cough
* Respiratory difficulty
* Syncope
* BUT remember those cases with left sided congestive heart failure
* Clinical signs of PTE can be very variable and include: dyspnoea, tachycardia, lethargy, altered mentation, vomiting, diarrhoea

Question 8

What physical findings are associated with pulmonary hypertension?

Answer 8

Right sided murmur
With severe PH can have split S2

Signs of primary disease?
- Chronic lung disease – crackles, cyanosis
- Murmur associated with left sided disease if LCHF is the cause
- Right sided murmur > L side!

Right sided heart failure – ascites

Question 9

How can you treat pulmonary hypertension?

Answer 9

• There is no cure
• Few treatment options
• Treat underlying disease
• Sildenafil (Viagra)
  
  • Effective in some cases BUT there is usually limited capacity for pulmonary vasodilation and NB concurrent systemic vasodilation and hypotension!
• Pimobendan
• Oxygen therapy
• Enothelin antagonists - Bosentan