Health Conditions

Hypertension

Abnormally elevated blood pressure. In dogs, hypertension is almost always secondary to an underlying condition such as kidney disease, Cushing's disease, or diabetes. Sustained hypertension damages target organs including the eyes, kidneys, heart, and brain.

Hypertension is defined as sustained systolic blood pressure above 160 mmHg in dogs (normal range: 110-140 mmHg systolic). Unlike humans, where essential (primary) hypertension is common, canine hypertension is almost always secondary — caused by an underlying disease process.

Causes of Canine Hypertension

Renal Disease

Chronic kidney disease is the most common cause of secondary hypertension in dogs. The relationship is bidirectional: kidney disease causes hypertension through sodium retention and renin-angiotensin-aldosterone system activation, and hypertension accelerates kidney damage through glomerular injury.

Endocrine Disease

  • Cushing’s disease: cortisol excess causes hypertension through multiple mechanisms including sodium retention and vascular reactivity changes
  • Hypothyroidism: associated with mild hypertension in some dogs
  • Diabetes mellitus: vascular and renal changes contribute to elevated blood pressure
  • Pheochromocytoma: adrenal tumor producing excessive catecholamines, causing episodic severe hypertension

Other Causes

  • Protein-losing nephropathy
  • Obesity
  • Medications (corticosteroids, erythropoietin)

Target Organ Damage

Sustained hypertension damages organs with delicate vascular beds:

  • Eyes: hypertensive retinopathy — retinal detachment, retinal hemorrhage, hyphema. Sudden blindness may be the presenting sign of undiagnosed hypertension.
  • Kidneys: glomerular damage, proteinuria, accelerated progression of existing kidney disease
  • Heart: left ventricular hypertrophy, increased cardiac workload
  • Brain: disorientation, seizures, cerebrovascular events

Blood Pressure Measurement

Accurate blood pressure measurement in dogs requires:

  • Doppler sphygmomanometry or oscillometric devices
  • Appropriately sized cuff (cuff width approximately 40% of limb circumference)
  • Quiet environment to minimize stress-induced elevation (“white coat effect”)
  • Multiple measurements averaged to confirm sustained elevation

Treatment

Treatment addresses both the underlying cause and the elevated pressure:

  • ACE inhibitors (benazepril, enalapril): first-line antihypertensive, also renoprotective
  • Amlodipine: calcium channel blocker, effective when ACE inhibitors alone are insufficient
  • Dietary sodium moderation
  • Treatment of underlying disease: addressing the primary condition often improves blood pressure control

Blood pressure monitoring should be part of routine senior wellness screening, particularly in dogs with kidney disease, endocrine disorders, or unexplained retinal changes.