Causes of High Blood Pressure (Hypertension)

1. Primary (Essential) Hypertension — ~90–95% of cases

Lifestyle & Metabolic Factors

• Overweight/Obesity — accounts for 65–75% of the risk for primary hypertension. Excess visceral fat activates the sympathetic nervous system (SNS) and the renin-angiotensin-aldosterone system (RAAS), raising BP. Leptin released by fat cells stimulates the hypothalamus to increase SNS activity.
• High sodium (salt) intake — excess sodium causes fluid retention, expanding blood volume and raising BP
• Physical inactivity (sedentary lifestyle)
• Excess alcohol consumption
• Low potassium intake — potassium helps relax blood vessel walls; low intake raises BP

Genetic & Family Factors

• Family history of hypertension — strong hereditary component; multiple genes are involved
• Rare monogenic (single-gene) disorders (Liddle syndrome, Gordon syndrome, etc.) account for <1% of all hypertension

Age-Related

• Arteries become stiffer with age → isolated systolic hypertension is common in older adults (>60 years)

Other Contributing Factors

• Stress and chronic psychological tension → sustained SNS activation
• Sleep apnea → intermittent hypoxia raises sympathetic tone

2. Secondary Hypertension — ~5–10% of cases

Kidney Disorders (most common secondary cause)

• Chronic kidney disease (CKD), glomerulonephritis, diabetic nephropathy
• Polycystic kidney disease (PKD)
• Renovascular disease (renal artery stenosis) — reduced blood flow to the kidney triggers excess renin/angiotensin II production

Hormonal/Endocrine Disorders

• Primary hyperaldosteronism (Conn's syndrome) — adrenal gland overproduces aldosterone → sodium retention
• Pheochromocytoma — adrenal tumor secreting adrenaline/noradrenaline → episodic or sustained BP surges
• Cushing's syndrome — excess cortisol
• Hypothyroidism or hyperthyroidism

Sleep Disorders

• Obstructive sleep apnea — very common, especially in overweight men; repeated oxygen drops activate the sympathetic nervous system

Medications & Substances

• NSAIDs (ibuprofen, naproxen) — cause fluid retention
• Oral contraceptives / hormonal therapy
• Decongestants (pseudoephedrine)
• Stimulants (amphetamines, cocaine)
• Steroids (prednisolone, dexamethasone)
• Cyclosporine (immunosuppressant)
• Erythropoietin (EPO)

Vascular Causes

• Coarctation of the aorta — narrowing of the main artery
• Atherosclerosis — hardening of arteries reduces elasticity

Other

• Diabetes mellitus — damages blood vessels and kidneys over time
• Thyroid or parathyroid disease

Key Risk Factors Specifically Relevant for Older Men (like a father)

Causes of High Blood Pressure

Primary Hypertension (90–95% of cases) — no single cause

• Obesity/Overweight — #1 modifiable cause (65–75% of risk)
• High salt intake
• Sedentary lifestyle
• Excess alcohol
• Family history/genetics
• Aging (arteries stiffen over time)
• Chronic stress
• Sleep apnea

Secondary Hypertension (5–10%) — identifiable underlying condition

• Kidney disease (most common secondary cause)
• Renal artery stenosis (narrowing → excess angiotensin II)
• Primary hyperaldosteronism (adrenal overproduction)
• Pheochromocytoma (adrenal tumor)
• Diabetes
• Hypothyroidism/hyperthyroidism
• Medications — NSAIDs, steroids, decongestants, oral contraceptives
• Obstructive sleep apnea
• Smoking

What to Do

1. Confirm whether it's primary or secondary hypertension
2. Get blood/urine tests (kidney function, blood sugar, electrolytes, thyroid)
3. Discuss lifestyle changes + medication if needed

Your Father's Blood Tests — Analysis & Why BP Remains High

📋 Summary of Lab Results (07 May 2026)

Why His BP May Still Be High Despite Antihypertensive Medication

1. 🔴 Anaemia (Haemoglobin 11.6 — significantly low)

• When haemoglobin is low, the heart compensates by pumping faster and harder to deliver enough oxygen to the body
• This increases cardiac output, which raises blood pressure
• Anaemia also causes compensatory sympathetic nervous system activation — the same mechanism that raises BP
• The anaemia itself may be contributing to or worsening his high BP, creating a cycle that antihypertensive drugs alone cannot fully control

2. 💊 Warfarin & Bleeding Risk Contributing to Anaemia

• Warfarin is an anticoagulant — it can cause slow, occult GI bleeding, leading to iron-deficiency anaemia
• His INR of 2.91 is therapeutic, but even within range, minor ongoing bleeding can cause anaemia over time
• Anaemia from chronic blood loss → compensatory high BP → harder to control with antihypertensives

3. Resistant/Pseudo-Resistant Hypertension (from Goldman-Cecil Medicine)

• Medication non-adherence — most common cause overall
• Insufficient drug dose or wrong combination
• "White coat" hypertension — BP only high in clinic, normal at home
• Heavy arterial calcification (common in older men)

• NSAIDs (ibuprofen, naproxen, diclofenac) — block prostaglandins, cause fluid retention, directly antagonize antihypertensive drugs. Note: NSAIDs also dangerously increase bleeding risk with warfarin
• Decongestants (cold medicines with pseudoephedrine)
• Herbal supplements (St. John's Wort, yohimbine — also interact with warfarin)
• Antidepressants (venlafaxine, fluoxetine)
• Glucocorticoids (steroids)

• Primary aldosteronism (excess aldosterone from adrenal gland) — most common
• Obstructive sleep apnea — very common in older men, often undiagnosed
• Chronic kidney disease
• Renal artery stenosis
• Pheochromocytoma
• Hypothyroidism (also worsens anaemia)
• Obesity

⚠️ Key Concerns to Raise with His Doctor

1. Anaemia needs investigation — iron studies, B12/folate, stool occult blood test to check for GI bleeding from warfarin
2. If anaemia is treated, BP may improve — treating the underlying anaemia reduces the compensatory cardiac overload
3. Check for hidden BP-raising medications — especially NSAIDs (very dangerous with warfarin)
4. Sleep study if he snores or has poor sleep
5. Blood tests to rule out secondary hypertension: aldosterone/renin ratio, kidney function, thyroid function
6. Warfarin + NSAIDs = dangerous — must be avoided as it raises both BP and serious bleeding risk