L5: Aneurysms & diseases of veins Flashcards
What is the definition of aneurysms?
- Localized abnormal dilatation of arterial wall forming a sac.
What is the iteology of aneurysms?
Due to weakening of the wall and/or increase of blood pressure.
It may be true or false.
What is the pathogenesis of aneurysms?
- Two processes are responsible for aneurysm formation:
1. Weakening of arterial wall which may be: “سديت”
congenital: As Berry aneurysms of brain (cerebral arteries).
traumatic: As arterio-venous fistula. “Like a bullet”
Inflammation: As polyarteritis nodosa, T.B. syphilis, emboli of subacute bacterial endocarditis, and bilharziasis.
Degenerative: As atheroma and intracerebral microaneurysm in hypertension.
- Stretching of the weakened wall: by increased pressure (hypertension)
What are the types of aneurysms?
- True & false
What is the definition of true aneurysm?
- The wall of the aneurysmal sac is part of the arterial wall.
What is the definition of false aneurysm?
- The wall of the sac is not the vessel wall.
What is the shape of true aneurysm?
- It may be saccular or fusiform.
What are examples of true aneurysm?
❖ Syphilitic aneurysm of thoracic aorta: It may be saccular or fusiform.
❖ Atherosclerotic aneurysm of abdominal “weaker than thoracic” aorta: It is fusiform.
What are examples of false aneurysm?
- It may be of fibrous tissue after traumatic rupture of artery and organization of the hematoma, or arterio-venous fistula.
What are the complications of aneurysm?
1- Pressure on surrounding: More with syphilitic and produce superior mediastinal syndrome manifested by dyspnea, dysphagia and hoarseness of voice.
2- Rupture: More with atheromatous (internal heamorrhage)
3- Thrombosis and organization and may be embolization.
What is the site of dissecting aneurysm?
- Occurs only in the aorta with splitting of the media into two parts inner and outer and in between blood accumulates (producing 2 telescoped tubes).
What is the cause of dissecting aneurysm?
- It is due to medial damage by Erdheim’s medial necrosis, Marfan’s syndrome and may be atherosclerosis.
What is the pathogenesis of dissecting aneurysm?
Weakness of the aortic media.
1- Blood enters the media either from tear in the sliding intima over a weak loose media.
2- Due to rupture of unsupported vasa vasorum.
3- The blood accumulates and splits the weak media into outer and inner layers forming the walls of the aneurysm.
What is the fate of dissecting aneurysm?
1- Healing may occur either by clotting and organization of the blood in the media or rupture into the lumen of Aorta.
2- Rupture of the aneurysm with fatal hemorrhage.
3- Extension into the aortic branches and may narrow their opening leading to ischemia.
What are the types of aortic aneurysms?
“ASD”
1- Atheromatous aneurysms: Commonest, occur in descending abdominal aorta below the level of renal artery, It is fusiform.
2- Syphilitic due to diffuse syphilitic lesions in tertiary syphilis: It occurs in arch of aorta and may be saccular or fusiform.
3- Dissecting.
What are the types of cerebral aneurysms?
“My Coin”
1- Congenital berry aneurysms at circle of Willis (small, multiple):
- Occur in the circle of Willis at sites of medial weakness at the bifurcations.
- They are the most common cause of subarachnoid hemorrhage.
2- Intra-cerebral micro-aneurysms of benign hypertension.
3- Mycotic aneurysms due to emboli of subacute bacterial endocarditis.
4- Atheromatous.
What is the definition of varicose veins?
- It is dilatation, elongation, thickening and tortousity of veins.
What are the sites of varicose Viens?
1- Superficial veins of the lower limbs (Long saphenous vein): in persons who spend much of their time standing.
2- Varices of the esophagus:
- Veins of lower 1/3 oesophagus and cardia of the stomach.
- Found in portal hypertension as in liver cirrhosis or bilharzial fibrosis.
3- Hemorrhoids: varices of the internal or external hemorrhoidal plexus of the rectum (piles )
4- Varicocele: varices of the pampiniform plexus of the spermatic cord
5- Caput Medusa: around the umbilicus.
What is the pathogenesis of varicose veins?
Is divided into Predisposing & exciting factors
What are the predisposing factors for varicose veins?
- Congenital weakening of veins or valves.
- Familial tendency.
What are the exciting factors for varicose veins?
- The increased venous pressure leads to stretching of the venous wall.
This may be due to either:
1- Prolonged standing (effect of gravity) as in police soldiers: It affects long saphenous vein.
2- Chronic constipation and straining at stool: It leads to piles
3- Obstruction of venous return: As in cases of liver cirrhosis, bilharzial fibrosis, pressure by pregnant uterus, enlarged prostate, cancer rectum ….. Etc.
What are the complications of varicose veins?
- Local chronic venous congestion and persistent edema in limbs and secondary ischemic skin changes, including stasis dermatitis and ulcerations.
- Hemorrhage: Haematemesis and melena from esophageal varices.
- Thrombosis and embolism.
- Varicose ulcers which are premalignant (gives rise to squamous cell carciroma).
❖ It occurs in the lower inner part of the leg above medial malleolus. - Inflammations leading to septic thrombophilibitis, septic emboli and pyemia.
