Aneurysms, Dissections, Vasculitis, and Peripheral Artery Disease (Nichols)

Question 1

what is an aneurysm?

Answer 1

A DISCRETE AND LOCALIZED dilatation (outpouching) of blood vessel [or heart]

Question 2

what is an aortic dissection?

describe the two types.

Answer 2

tearing of the tunica intima squeezes arterial blood from the lumen into the tunica media. it then tunnels (“dissects”) a second lumen.
TYPE A: involves ascending aorta –> more common & more serious.
TYPE B: descending aorta ONLY.

Question 3

what is ectasia?

Answer 3

NON-DISCRETE AND NON-LOCALIZED dilation of a blood vessel or duct. often tortuous, like medical school.

Question 4

what are fibrillins?

Answer 4

extracellular glycoproteins needed for structuring elastin fibers.

Question 5

describe Marfan syndrome.

Answer 5

an inherited disease of defective FIBRILLIN. causes a long, thin body and AORTIC DISSECTIONS.

Question 6

describe Ehlers-Danlos syndromes.

Answer 6

clinically and genetically heterogenous group of inherited disorders due to defects in synthesis or structure of FIBRILLAR COLLAGEN.

Question 7

describe cystic medial degeneration.

Answer 7

it’s the loss of smooth muscle cells and elastic fibers in tunica media of large arteries.

Question 8

describe vasculitis.

Answer 8

a heterogenous group of diseases that cause inflammation of blood vessels. mostly autoimmune, mostly treatable, but can be life-threatening.

Question 9

aortic aneurysms. give me epidemiology, pathogenesis, pathology, signs and symptoms, diagnosis, treatment, and complications.

Answer 9

EPIDEMIOLOGY: common; primarily in old people; runs in families. men > women. white > other races.
PATHOGENESIS: atherosclerosis (provides inflammation) + genetic degeneration of tunica MEDIA. incr MMPs +/- decr tissue inhibitors of MMPs. can also be caused by genetic defects in fibrillin or collagen (Marfan), infection (mycotic), or vasculitis (autoimmune, eg. giant cell arteritis).
PATHOLOGY: 75% in abdominal aorta (usually w/ thrombus). usually manifests as cystic medial degeneration.
SIGNS AND SYMPTOMS: maybe back pain.
TO DIAGNOSE: imagining.
TREATMENT: stent or open repair.
COMPLICATIONS: RUPTURE (incr risk w/ incr diameter); mural thrombus formation; embolism of atheroma or thrombus; obstruction of aortic branches; aortoenteric fistula.

Question 10

aortic dissections. give me epidemiology, pathogenesis, pathology, signs and symptoms, diagnosis, treatment, and complications.

Answer 10

EPIDEMIOLOGY: uncommon. most common in late middle age. men > women. black > other races.
PATHOGENESIS: intimal tear. medial dissection associated w/ cystic medial degeneration.
PATHOLOGY: Type A involves ascending aorta (more common, more serious). Type B ONLY involves descending aorta.
SIGNS AND SYMPTOMS: sudden severe sharp “tearing” chest pain anteriorly (Type A) or between scapulae (Type B). pain MOVES AS DISSECTION PROGRESSES. +/- arm pain and weakness (subclavian); altered mental status (carotid); collapse (rupture).
TO DIAGNOSE: transesophageal echo or CT/MRI
TREATMENT: treat Type A w/ antihypertensives + surgery. treat Type B with either surgery or antihypertensives.
COMPLICATIONS: occlusion of aortic branches. rupture into pericardium (common) or left pleural cavity (less comnon).

Question 11

Marfan Syndrome. give me epidemiology, pathogenesis, pathology, signs and symptoms, diagnosis, treatment, and complications.

Answer 11

EPIDEMIOLOGY: autosomal dominantly inheritance of FBN1 gene.
PATHOGENESIS: mutated FBN1 gene (fibrillin-1) causes abnormal fibrillin w/ excess TGF-beta activation. this causes cystic medionecrosis of the ascending aorta –> dilation and predisposition to dissection.
PATHOLOGY:
SIGNS AND SYMPTOMS:
TO DIAGNOSE:
TREATMENT: beta-blockers; maybe angiotensin-2 receptor blockade.
COMPLICATIONS: aortic dissection causes death in up to 45% of cases

Question 12

Ehlers-Danlos Syndrome. give me epidemiology, pathogenesis, pathology, signs and symptoms, diagnosis, treatment, and complications.

Answer 12

EPIDEMIOLOGY: autosomal dominant inheritance of COL3A1 gene.
PATHOGENESIS: mutated COL3A1 gene for type III collagen causes spontaneous rupture of blood vessels and intestines (places rich in type III collagen).
PATHOLOGY:
SIGNS AND SYMPTOMS:
TO DIAGNOSE:
TREATMENT:
COMPLICATIONS:

Question 13

vasculitis. give me epidemiology, pathogenesis, pathology, signs and symptoms, diagnosis, treatment, and complications.

Answer 13

EPIDEMIOLOGY: heterogenous group of diseases that are mostly autoimmune, mostly treatable, some life-threatening.
PATHOGENESIS: two primary categories of vasculitis are infectious or non-infectious (aka primary). infectious causes of vasculitis are fungal (aspergillus), bacterial (pseudomonas), or viral (cytomegalovirus).
PATHOLOGY:
SIGNS AND SYMPTOMS: signs are all nonspecific. fever, myalgias, arthralgias, malaise, “PALPABLE PURURA, focan skin necrosis and ulceration, lots of other shit.
TO DIAGNOSE: biopsy, bitches.
TREATMENT:
COMPLICATIONS: infectious vasculitis can cause a “mycotic” aneurysm (generally not actually caused by fungus).

Question 14

there are lots of diseases that fall under the umbrella of “primary vasculitis.” name them and give the sizes of blood vessels they inflame.

Answer 14

GIANT CELL (TEMPORAL) ARTERITIS: aorta, large/medium arteries.
TAKAYASU’S ARTERITIS: aorta, large/medium arteries.
POLYARTERITIS NODOSA: aorta, large/med arteries, small arteries.
KAWASAKI DISEASE: aorta, large/med arteries, small arteries.
MICROSCOPIC POLYANGIITIS: large/medium arteries, small arteries, arterioles, capillaries, venules.
(WEGENER’S) granulomatosis w/ polyangiitis: large/med arteries, small arteries, arterioles, capillaries, venules, veins.
CHURG-STRAUSS syndrome: large/med arteries, small arteries, arterioles, capillaries, venules, veins.

Question 15

temporal (aka giant cell) arteritis. give me epidemiology, pathology, signs and symptoms, diagnosis, treatment, and complications. don’t worry about pathogenesis. that’s up next.

Answer 15

EPIDEMIOLOGY: common, typically in old white ladies of northern European ancestry.
PATHOLOGY: inflammation is SEGMENTAL, TRANSMURAL, AND GRANULOMATOUS w/ multi-nucleated giant cells centering on internal elastic lamina (destroying it). +lymphocytes, intimal thickening, cell proliferation, and luminal stenosis.
SIGNS AND SYMPTOMS: headache (75%), swollen tender artery, scalp tenderness, visual disturbances, jaw claudication, fever, malaise, weight loss.
TO DIAGNOSE: biopsy, but beware of false negatives due to its segmental nature.
TREATMENT: corticosteroid or anti-TNF therapy.
COMPLICATIONS: blindness.

Question 16

describe the pathogenesis of temporal (aka giant cell) arteritis.

Answer 16

Giant cells attack CALCIFIED internal elastic lamina in arteries and CALCIFIED atrophic tunica media of thoracic aorta.
Immature dendritic cell TLRs bind antigen PAMPs and become activated. Activated dendritic cells abundantly express TLR-4 and release IL-12, 18 and CCL 19, 21 (bind CCR7, which traps activated dendritic cells in arterial wall). These dendritic cells then bind CD4 cells. CD4s release IL-6, 21, 23 + IL-1 and TNF-alpha to activate TH1 cells –> TH1’s release IL-2, 6 (systemic manifestations) and IFN-gamma (activates giant cells). giant cells secrete MMPs and ROIs –> hyperplastic intima. giant cells also secrete VEGF + PDGF.