Topic: Aneurysm Faculty: Pathology Course: ATOT 2nd year - Aneurysm: Definition, types, pathogenesis - Aortic dissection Reference: Ramadas Nayak - Textbook of Pathology for Allied Health Sciences

1. ANEURYSM
Dr. Salman Ansari
MBBS

2. Aneurysm
● Definition
● Types
● Pathogenesis
● Aortic dissection
● Effects of hypertension

3. Aneurysm
● Definition: localized, abnormal, permanent dilation of a blood vessel
or the heart due to weakening of wall
(“LAPD”: localised, abnormal, permanent dilation)
● Can be congenital or acquired

5. Types of aneurysms
Classified on the basis of:
● Origin
● Location
● Appearance
● Pathogenetic mechanism
● Composition of wall

6. Origin
● Congenital:
● present since birth
● Acquired:
● atherosclerosis(commonest)
● Marfan’s syndrome
● Syphilis
● trauma

7. Location
Depending upon which type of blood vessel is involved
● Artery
● Vein
● heart

8. Appearance
Based on shape of aneurysm
● Fusiform: spindle-shaped
● Saccular: spherical outpouching
● Cylindrical: parallel dilatation
● serpentine
● dissection/dissecting hematoma: when blood enters/dissects between
the layers of the arterial wall
● Arteriovenous or racemose: communication between an artery and
vein

10. Pathogenetic mechanism
Based on pathogenetic mechanism:
● Atherosclerotic (arteriosclerotic) aneurysms are the most common
type.
● Syphilitic (luetic) aneurysms found in the tertiary stage of the
syphilis.
● Dissecting aneurysms (Dissecting haematoma) in which the blood
enters the separated or dissected wall of the vessel.
● Mycotic aneurysms which result from weakening of the arterial wall
by microbial infection.
● Berry aneurysms which are small dilatations especially affecting the
circle of Willis in the base of the brain

13. Composition of wall
● True aneurysm: involves all three layers of wall(intima, media and
adventitia)
● false aneurysm/pseudoaneurysm: due to trauma, only one layer of
wall is involved - a hematoma develops in this layer

15. Pathogenesis
Aneurysm develops due to weakening of the vessel wall either due to:
1. Inadequate abnormal synthesis of connective tissue of the vessel
wall or
2. Increased degradation of connective tissue.

16. Aortic dissection
Definition:
● when blood from aortic lumen enters into the aortic wall and
travels along the layers of media to form a blood-filled space
within the aortic wall
● If it ruptures through the adventitia, it is fatal
Etiology:
● hypertension
● Marfan syndrome
Classification:
Type A and type B

18. Morphology:
● Dissection occurs between middle and outer thirds of tunica media
● May either out through adventitia into thorax/abdomen
● Sometimes, it may open back into lumen of aorta, creating a “false
channel”(double lumen)
Clinical features:
● Sudden onset of severe pain, radiating to the back
If rupture occurs, leads to death

20. Complications
● Rupture, leading to massive hemorrhage and death
● Compression of adjacent structures
● embolism

21. Hypertension
Definition:
Systolic blood pressure above 160 mm Hg and/or diastolic pressure
above 90 mm Hg.
Causes:
1. Primary/essential/idiopathic hypertension: 95% of cases
2. Secondary hypertension: when there is an identifiable cause

22. Consequences of hypertension
● Risk factor: hypertension is a major modifiable risk factor for
atherosclerosis
● Diseases produced: HTN can lead to:
● Cardiac hypertrophy
● Congestive heart failure(hypertensive heart disease)
● Ischemic heart disease(IHD)
● Subarachnoid hemorrhage
● Hypertensive encephalopathy
● Accelerated or malignant hypertension: Rapid rise in BP(SBP>200
mmHg or DBP>120 mmHg), which can result in:
● Renal failure
● Retinal hemorrhage

23. Summary
● Definition
● “LAPD”
● Types
● Origin
● Location
● Cause
● Composition of wall
● Shape

26. References:
Ramadas Nayak Textbook of Pathology for Allied
Health Sciences
Questions:
salman.s.ansari92@gmail.com
For notes: