What are the initiating and perpetuating causes of systemic hypertension?
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
What are secondary causes of systemic hypertension?
- renal disease
- hyperadrenocorticism (dog)
- hyperthyroidism (cat)
- diabetes mellitus
What clinical signs does systemic hypertension present with?
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
What can you use to treat systemic hypertension?
- beta blockers
- ace inhibitors
- Ca channel blockers
- angiotensin II receptor blocker
What is the goal when treating systemic hypertension?
- 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
What are the causes of pulmonary hypertension?
- 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
What clinical signs are often associated with pulmonary hypertension?
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
What physical findings are associated with pulmonary hypertension?
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
How can you treat pulmonary hypertension?
- 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
