CR10: Diseases of Blood Vessels Part 1

What defines a hypertensive crisis?

180/120 mmHg or greater

What other diseases can hypertensive crisis lead to?

• Heart attack (myocardial infarction)

• Stroke or TIA

• Aortic dissection

• Pulmonary edema

What is an aortic dissection?

A tear in the wall of the aorta that creates a false lumen, causing blood to flow through the wrong lumen.

What defines a hypertensive urgency?

180/120 mmHg with no associated end-organ damage.

What defines a hypertensive emergency?

Elevated blood pressure (180/120) associated with acute end-organ damage (due to vasoconstriction).

What is the most significant risk factor in hypertensive crisis?

Medication non-compliance.

What are other risk-factors for hypertensive crisis?

Pregnancy, pharmacological agents, and drugs of abuse.

Ex: antidepressents, antipsychoitics, and cocaine can increase BP.

What symptoms are associated with ischemic or hemorrhagic stroke?

Neurological deficits

What symptoms are associated with increased intracranial pressure?

Nausea and vomiting

What symptoms are associated with myocardial ischemia?

Chest pain

What symptoms are associated with aortic dissections?

Back pain, pain radiates toward the back based on the section of the aorta affected

What are the symptoms of pulmonary edema?

Dyspnea (breathlessness)

What are the symptoms of heart failure?

Chest pain, dyspnea, nausea, blurred vision

What are some retinal findings associated with hypertension?

Soft and hard exudates, macular star, papilledema, retinal edema, hemorrhages, and Gunn sign.

What is arteriosclerosis?

Gradual hardening of the arteries (loss of elasticity).

What is atherosclerosis?

Gradual buildup of plaque (atheroma) in the innermost layers of medium and large arteries.

What vessel layer is primarily affected in atherosclerosis?

Tunica intima (innermost layer)

What vessels does atherosclerosis primarily affect?

Medium and large arteries

(Aorta, coronary arteries, carotid arteries, femoral arteries, iliac arteries)

How are veins histologically different than arteries?

• Veins have a smaller tunica media (less elasticity)

• Veins are collapsed (less pressure and more compliance)

• Veins have thinner walls

What type of plaque buildup do we see in atherosclerosis?

Buildup of smooth muscle cells, lipids, calcium, and cellular debris, and macrophages transformed into foam cells with a fibrous cap.

What is the role of macrophages in atherosclerotic plaque?

Macrophages engulf fats and then undergo oxidation, becoming foam cells.

What is the first step in atheroma formation?

Accumulation of lipids and fibrous thickening in the intima, creating an intimal coat.

What is the second step in atheroma formation?

Coalescence of individual lesions and degenerative necrosis of the centers → formation of cavities of lipid-rich debis called atheromata.

What is the third step of atheroma formation?

Buildup and necrosis extends to the tunica media → disintegration of the intimal lining over atheromata → calcification of lesions.

What is arteriolosclerosis?

The thickening of walls of small arteries/arterioles throughout the body.

What is the role of arterioles?

They connect large arteries to capillaries.

What are causes of arteriolosclerosis?

High BP, diabetes, high cholesterol, kidney disease.

What is Monckeberg medial sclerosis?

Dystrophic ring-like calcification in the tunica media of small-medium sized arteries.

What is the etiology of Monckeberg medial sclerosis?

Unknown.

What types of vessels are affected in Monckeberg medial sclerosis?

Small to medium sized vessels

(Major lower limb arteries, head and neck, pelvic/uterine arteries)

What blood vessel layers are affected by Monckeberg medial sclerosis?

The tunica media is mostly affected. Intima is not affected, so lumen is not obliterated → vessel is still open.

What is hyaline arteriolosclerosis?

Thickening of the arteriolar wall due to leakage of plasma proteins into the vessel wall.

What is the cause of hyaline arteriolosclerosis?

Longstanding benign hypertension and diabetes.

How does hyaline arteriolosclerosis appear on a stain?

Stains bright magenta with periodic acid-Schiff (PAS) stain and has a glassy texture.

In which organ is hyaline arteriolosclerosis most prominent?

In the kidneys.

What is the etiology of hyaline arteriolosclerosis?

Unknown etiology.

What is the main feature of hyaline arteriolosclerosis?

Microangiopathy (damage of small vessels)

What is microangiopathy?

Hyaline thickening and luminal narrowing of small arteries and arterioles.

What are other characteristics of microangiopathy/hyaline arteriolosclerosis?

Degeneration of the internal elastic lamina, replacement of smooth muscle with collagen.

How does hyperplastic arteriolosclerosis begin?

Begins with hypertrophy of smooth muscle cells in the tunica media, causing an onion skin appearance.

What are the next stages of hyperplastic arteriolosclerosis?

Reduplication of the elastic lamina/basement membrane → growth of new cells in the intima and collagen deposition → necrotizing changes and lumen obliteration

What disease does hyperplastic arteriolosclerosis lead to?

Malignant hypertension (hypertensive emergency). Patient presents with diastolic BP >120 mmHg, retinal hemorrhages, and papillary edema.

What is an aneurysm?

A bulge or balloon in the wall of a blood vessel.

Are aneurysms more common in arteries or in veins?

Arteries.

What are the symptoms of an aneurysm?

Severe stabbing chest pain that radiates to the back; severe headache (if in the brain)

What is the major danger of an aneurysm?

Can lead to rupture and sudden death.

What are the types of aneurysm (by shape)?

Saccular aneurysm → sac on one side

Fusiform aneurysm → bulge on both sides

Dissecting aneurysm → tear in the vessel wall

What types of aneurysms occur in the Circle of Willis?

Berry aneurysms affecting the anterior, posterior, and medial cerebral arteries.

What type of aneurysm is commonly seen in the abdomen?

A large fusiform aneurysm. (Don’t palpate before auscultation!)

Where does an atherosclerotic aneurysm usually appear?

In the abdominal aorta.

What is an atherosclerotic aneurysm?

Common type of aneurysm involving thinning and fibrous replacement of tunica media.

What is a syphilitic aneurysm?

A rare type of aneurysm causing inflammatory destruction of the media and fibrous replacement.

Where does a syphilitic aneurysm commonly occur?

In the ascending thoracic aorta and arch.

What is a berry aneurysm caused by?

A congenital defect in the elastic lamina/media (in the internal elastic lamina).

Are berry aneurysms common?

Yes

What is an infective/mycotic aneurysm?

Aneurysm caused by destruction of the wall by bacteria/fungi in an infected thrombus.

How common is an infective/mycotic aneurysm?

Very rare, but can occur anywhere in the body.

What two congenital diseases lead to increased risk of aneurysms?

Marfan syndrome and Ehlers-Danios syndrome.

What is Marfan Syndrome?

Genetic disorder with very long legs and arms; characterized by cardiac and ocular abnormalities and increased risk of aneurysm.

What is Ehlers-Danlos Syndrome?

A connective tissue defect that can increase the likelihood of an aneurysm.

What are the consequences of an aortic dissection?

Double-channeled aorta → blood flows through false lumen → blood collects in pericardial sac → hemopericardium → heart can no longer expand → cardiac tamponade

What can lead to impaired filling of the heart?

Cardiac tamponade (filling of the pericardial sac with blood). Heart can no longer expand and fill with blood.