Extremity and Visceral Aneurysms

Overview

Definition

An aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms is a bulging, weakened area of a blood vessel, usually an artery, that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel.

Classification

• Types:
  • True aneurysm True aneurysm Thoracic Aortic Aneurysms: involves all 3 layers of the vessel wall with ≥ 1 layer intact
  • Pseudoaneurysm Pseudoaneurysm Not an aneurysm but a well-defined collection of blood and connective tissue outside the wall of a blood vessel or the heart. It is the containment of a ruptured blood vessel or heart, such as sealing a rupture of the left ventricle. False aneurysm is formed by organized thrombus and hematoma in surrounding tissue. Thoracic Aortic Aneurysms: blood escapes into surrounding tissues and forms a hematoma Hematoma A collection of blood outside the blood vessels. Hematoma can be localized in an organ, space, or tissue. Intussusception around the artery as a result of a tear in the vessel wall.
• Shape:
  • Saccular aneurysm Saccular Aneurysm Subarachnoid Hemorrhage: sac-like bulging on 1 side of a blood vessel
  • Fusiform aneurysm Fusiform aneurysm Brain Aneurysms: elongated spindle-shaped dilation of a blood vessel

Etiology

• Atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis (both extremity and visceral aneurysms)
• Trauma
• Iatrogenic Iatrogenic Any adverse condition in a patient occurring as the result of treatment by a physician, surgeon, or other health professional, especially infections acquired by a patient during the course of treatment. Anterior Cord Syndrome (e.g., dialysis Dialysis Renal replacement therapy refers to dialysis and/or kidney transplantation. Dialysis is a procedure by which toxins and excess water are removed from the circulation. Hemodialysis and peritoneal dialysis (PD) are the two types of dialysis, and their primary difference is the location of the filtration process (external to the body in hemodialysis versus inside the body for PD). Peritoneal Dialysis and Hemodialysis fistula Fistula Abnormal communication most commonly seen between two internal organs, or between an internal organ and the surface of the body. Anal Fistula)
• Behçet syndrome (most commonly pulmonary artery Pulmonary artery The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs. Lungs: Anatomy aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms)
• Hereditary conditions:
  • Marfan syndrome Marfan syndrome Marfan syndrome is a genetic condition with autosomal dominant inheritance. Marfan syndrome affects the elasticity of connective tissues throughout the body, most notably in the cardiovascular, ocular, and musculoskeletal systems. Marfan Syndrome
  • Ehlers-Danlos syndrome Ehlers-Danlos syndrome Ehlers-Danlos syndrome (EDS) is a heterogeneous group of inherited connective tissue disorders that are characterized by hyperextensible skin, hypermobile joints, and fragility of the skin and connective tissue. Ehlers-Danlos Syndrome

Extremity Aneurysms

Upper-limb aneurysms

Upper-limb aneurysms are rare and can involve the branches of the aortic arch Aortic arch Mediastinum and Great Vessels: Anatomy extending to the hand Hand The hand constitutes the distal part of the upper limb and provides the fine, precise movements needed in activities of daily living. It consists of 5 metacarpal bones and 14 phalanges, as well as numerous muscles innervated by the median and ulnar nerves. Hand: Anatomy. Symptoms are caused by thrombus formation, distal emboli, or local expansion. Most upper-extremity aneurysms should be surgically repaired to reduce the risk of stroke.

Location:

• Proximal: involve the subclavian or axillary arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology
• Distal: involve the ulnar, palmar, or brachial arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology

Etiology:

• Most commonly due to trauma
• Idiopathic Idiopathic Dermatomyositis

Clinical presentation: 

• Pulsatile mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast
• Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways in digits
• Arm Arm The arm, or “upper arm” in common usage, is the region of the upper limb that extends from the shoulder to the elbow joint and connects inferiorly to the forearm through the cubital fossa. It is divided into 2 fascial compartments (anterior and posterior). Arm: Anatomy swelling Swelling Inflammation
• Neurologic deficits Neurologic Deficits High-Risk Headaches:
  • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Numbness
  • Paresthesia
  • Weakness
• Thrombus formation
• Acute limb ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage: 6 Ps PS Invasive Mechanical Ventilation of arterial occlusion
  • Pulselessness Pulselessness Cardiac Arrest
  • Pallor
  • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Poikilothermia Poikilothermia Cold to the touch. Acute Limb Ischemia (inability to maintain core body temperature Body Temperature The measure of the level of heat of a human or animal. Heatstroke)
  • Paresthesia 
  • Paralysis
• Microemboli:
  • Finger pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination
  • Ulceration Ulceration Corneal Abrasions, Erosion, and Ulcers
  • Subungual splinter hemorrhages Splinter hemorrhages Endocarditis

Diagnosis:

• Ultrasonography and color Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography)
• CT
• MRI
• MRA MRA Imaging of the Heart and Great Vessels
• DSA (digital subtraction angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery)

Management:

• Endovascular surgery with stent placement
• Open resection with revascularization Revascularization Thromboangiitis Obliterans (Buerger Disease)

Lower limb: popliteal aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms

Epidemiology: 

• Popliteal aneurysms are the most common lower-limb aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms.
• Men > women 
• Mean age at presentation: 65 years
• 60% are symptomatic; 40% are asymptomatic incidental findings.

Risk factors (for atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis):

• Smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases
• Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension
• Diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus
• Cardiac disease
• Older age: > 55
• Hyperlipidemia

Clinical presentation:

• Palpable mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast at the back of the knee ( popliteal fossa Popliteal fossa The popliteal fossa or the “knee pit” is a diamond-shaped, fat-filled, shallow depression on the posterior aspect of the knee joint. The popliteal fossa is located at the dorsal aspect of the knee and contains an increased number of lymph nodes as well as structures of the neurovascular system that travel from the thigh to the lower leg. Popliteal Fossa: Anatomy)
  • Bilateral in 50% of individuals
  • Usually called aneurysmal > 2 cm
• Acute limb ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage: 6 Ps PS Invasive Mechanical Ventilation of arterial occlusion
  • Pulselessness Pulselessness Cardiac Arrest
  • Pallor
  • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Poikilothermia Poikilothermia Cold to the touch. Acute Limb Ischemia
  • Paresthesia 
  • Paralysis
• Compressive symptoms
  • Knee pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Paresthesia or numbness (sciatic, peroneal, or tibial nerves)
  • Varicose veins Varicose veins Enlarged and tortuous veins. Chronic Venous Insufficiency 
• Chronic ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage
  • Claudication
  • Rest pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • “ Blue toe syndrome Blue toe syndrome A condition that is caused by recurring atheroembolism in the lower extremities. It is characterized by cyanotic discoloration of the toes, usually the first, fourth, and fifth toes. Discoloration may extend to the lateral aspect of the foot. Despite the gangrene-like appearance, blue toes may respond to conservative therapy without amputation. Peripheral Artery Disease”: digital ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage with intact large-vessel circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment from cardiac emboli
• Rupture → severe knee pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways with swelling Swelling Inflammation

Diagnosis:

• Duplex ultrasonography Duplex ultrasonography Ultrasonography applying the doppler effect combined with real-time imaging. The real-time image is created by rapid movement of the ultrasound beam. A powerful advantage of this technique is the ability to estimate the velocity of flow from the doppler shift frequency. Hypercoagulable States
  • Best diagnostic test
  • Visualizes thrombus
  • Measures diameter
  • Excludes other anatomic abnormalities such as Baker cyst
• CTA CTA A non-invasive method that uses a ct scanner for capturing images of blood vessels and tissues. A contrast material is injected, which helps produce detailed images that aid in diagnosing vascular diseases. Pulmonary Function Tests/ MRA MRA Imaging of the Heart and Great Vessels for elective surgeries

Management:

• Medical:
  • Risk factor modification (e.g., smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases cessation, control blood pressure)
  • Anticoagulation Anticoagulation Pulmonary Hypertension Drugs for acute limb ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage or critical stenosis Stenosis Hypoplastic Left Heart Syndrome (HLHS) (risk of thrombosis Thrombosis Formation and development of a thrombus or blood clot in the blood vessel. Epidemic Typhus)
  • Serial imaging may be done for smaller aneurysms.
• Surgical indications:
  • Acute limb ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage
  • Elective aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms > 2 cm
  • Thrombus on imaging
  • Symptomatic individuals with collateral circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment

Lower limb: iliofemoral aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms

Epidemiology: 

• 2nd most common peripheral aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms
• 40% of individuals have an associated abdominal aortic aneurysm Aortic aneurysm An abnormal balloon- or sac-like dilatation in the wall of aorta. Thoracic Aortic Aneurysms ( AAA AAA An aortic aneurysm is the abnormal dilation of a segment of the aorta. Abdominal aortic aneurysm is the most common aortic aneurysm, occurring frequently in the infrarenal area. Most aneurysms are asymptomatic, but can cause compression of surrounding structures or rupture, which is a life-threatening emergency. Abdominal Aortic Aneurysms)

Clinical presentation:

• Unruptured:
  • Lower abdominal, back pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways or groin Groin The external junctural region between the lower part of the abdomen and the thigh. Male Genitourinary Examination pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways and numbness in the leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy
  • Leg Leg The lower leg, or just “leg” in anatomical terms, is the part of the lower limb between the knee and the ankle joint. The bony structure is composed of the tibia and fibula bones, and the muscles of the leg are grouped into the anterior, lateral, and posterior compartments by extensions of fascia. Leg: Anatomy edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema due to adjacent vein compression Compression Blunt Chest Trauma
  • Acute limb ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage 
  • Blue toe syndrome Blue toe syndrome A condition that is caused by recurring atheroembolism in the lower extremities. It is characterized by cyanotic discoloration of the toes, usually the first, fourth, and fifth toes. Discoloration may extend to the lateral aspect of the foot. Despite the gangrene-like appearance, blue toes may respond to conservative therapy without amputation. Peripheral Artery Disease = digital ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage with intact large vessel circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment from cardiac emboli
• Ruptured:
  • Acute abdominal, thigh Thigh The thigh is the region of the lower limb found between the hip and the knee joint. There is a single bone in the thigh called the femur, which is surrounded by large muscles grouped into 3 fascial compartments. Thigh: Anatomy, or groin Groin The external junctural region between the lower part of the abdomen and the thigh. Male Genitourinary Examination pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways
  • Hemodynamic instability
• Asymptomatic: incidental finding on exam
  • Palpable thrill/audible bruit 
  • Painless pulsatile swelling Swelling Inflammation in the groin Groin The external junctural region between the lower part of the abdomen and the thigh. Male Genitourinary Examination

Management:

• Medical treatment same as for popliteal aneurysms
• Surgical indications:
  • Symptoms 
  • Coexisting AAA AAA An aortic aneurysm is the abnormal dilation of a segment of the aorta. Abdominal aortic aneurysm is the most common aortic aneurysm, occurring frequently in the infrarenal area. Most aneurysms are asymptomatic, but can cause compression of surrounding structures or rupture, which is a life-threatening emergency. Abdominal Aortic Aneurysms
  • Rapid expansion
  • Iliac artery aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms size > 3 cm

Visceral Artery Aneurysms

Visceral artery aneurysms (VAAs) can affect the celiac artery, the superior and inferior mesenteric arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology, or their branches.

Epidemiology: 

• Rare; incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency is 0.1%–0.2%.
• Splenic artery aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms (60% of VAAs): 
  • 80% > age 50
  • Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: 4x more common in women than in men
  • Seen after liver transplantation Liver transplantation The transference of a part of or an entire liver from one human or animal to another. Hepatocellular Carcinoma (HCC) and Liver Metastases
• Hepatic artery Hepatic artery A branch of the celiac artery that distributes to the stomach, pancreas, duodenum, liver, gallbladder, and greater omentum. Liver: Anatomy aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms (20% of VAAs)
  • 80% are extrahepatic
  • Twice as common in men as in women
  • Higher risk of rupture than other VAAs
  • Many individuals have other VAAs or nonvisceral aneurysms.
• Superior mesenteric artery Superior mesenteric artery A large vessel supplying the whole length of the small intestine except the superior part of the duodenum. It also supplies the cecum and the ascending part of the colon and about half the transverse part of the colon. It arises from the anterior surface of the aorta below the celiac artery at the level of the first lumbar vertebra. Small Intestine: Anatomy aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms (5%–7%):
  • Usually due to atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis
  • Associated with polyarteritis nodosa Polyarteritis nodosa A form of necrotizing non-granulomatous inflammation occurring primarily in medium-sized arteries, often with microaneurysms. It is characterized by muscle, joint, and abdominal pain resulting from arterial infarction and scarring in affected organs. Polyarteritis nodosa with lung involvement is called churg-strauss syndrome. Vasculitides, Behçet syndrome, and systemic connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology disorders
• Celiac artery aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms (3%–4% of VAAs)

Risk factors: 

• Atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis (32% of VAAs)
• Medial degeneration in fibromuscular dysplasia Fibromuscular dysplasia Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory, medium-sized angiopathy due to fibroplasia of the vessel wall. The condition leads to complications related to arterial stenosis, aneurysm, or dissection. Fibromuscular Dysplasia (24%)
• Abdominal trauma (22%)
• Conditions of increased blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure:
  • Pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care
  • Portal hypertension Portal hypertension Portal hypertension is increased pressure in the portal venous system. This increased pressure can lead to splanchnic vasodilation, collateral blood flow through portosystemic anastomoses, and increased hydrostatic pressure. There are a number of etiologies, including cirrhosis, right-sided congestive heart failure, schistosomiasis, portal vein thrombosis, hepatitis, and Budd-Chiari syndrome. Portal Hypertension (splenic artery aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms)
  • Liver transplantation Liver transplantation The transference of a part of or an entire liver from one human or animal to another. Hepatocellular Carcinoma (HCC) and Liver Metastases
• Heart valve infection
• Connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology disorders
  • Marfan syndrome Marfan syndrome Marfan syndrome is a genetic condition with autosomal dominant inheritance. Marfan syndrome affects the elasticity of connective tissues throughout the body, most notably in the cardiovascular, ocular, and musculoskeletal systems. Marfan Syndrome
  • Ehlers-Danlos syndrome Ehlers-Danlos syndrome Ehlers-Danlos syndrome (EDS) is a heterogeneous group of inherited connective tissue disorders that are characterized by hyperextensible skin, hypermobile joints, and fragility of the skin and connective tissue. Ehlers-Danlos Syndrome
  • Kawasaki disease Kawasaki disease An acute, febrile, mucocutaneous condition accompanied by swelling of cervical lymph nodes in infants and young children. The principal symptoms are fever, congestion of the ocular conjunctivae, reddening of the lips and oral cavity, protuberance of tongue papillae, and edema or erythema of the extremities. Kawasaki Disease
  • Hereditary hemorrhagic telangiectasia Telangiectasia Permanent dilation of preexisting blood vessels creating small focal red lesions, most commonly in the skin or mucous membranes. It is characterized by the prominence of skin blood vessels, such as vascular spiders. Chronic Venous Insufficiency (Osler-Weber-Rendu disease)

Clinical presentation:

• Most VAAs are found incidentally on abdominal imaging done for other reasons.
• Nonspecific symptoms:
  • Malaise Malaise Tick-borne Encephalitis Virus
  • Vague abdominal pain Abdominal Pain Acute Abdomen
  • Nausea Nausea An unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses. Antiemetics or vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia
  • Celiac artery aneurysms can mimic pancreatitis Pancreatitis Inflammation of the pancreas. Pancreatitis is classified as acute unless there are computed tomographic or endoscopic retrograde cholangiopancreatographic findings of chronic pancreatitis. The two most common forms of acute pancreatitis are alcoholic pancreatitis and gallstone pancreatitis. Acute Pancreatitis.
• Embolic event → acute mesenteric ischemia Acute Mesenteric Ischemia Mesenteric Ischemia
• Rupture: 
  • Hemorrhagic shock Hemorrhagic shock Acute hemorrhage or excessive fluid loss resulting in hypovolemia. Hemothorax
  • Acute abdomen Acute Abdomen Acute abdomen, which is in many cases a surgical emergency, is the sudden onset of abdominal pain that may be caused by inflammation, infection, perforation, ischemia, or obstruction. The location of the pain, its characteristics, and associated symptoms (e.g., jaundice) are important tools that help narrow the differential diagnosis. Acute Abdomen 

Diagnosis:

• Abdominal x-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests may show crescent-shaped calcification.
• Duplex ultrasonography Duplex ultrasonography Ultrasonography applying the doppler effect combined with real-time imaging. The real-time image is created by rapid movement of the ultrasound beam. A powerful advantage of this technique is the ability to estimate the velocity of flow from the doppler shift frequency. Hypercoagulable States
  • Round, hypoechoic Hypoechoic A structure that produces a low-amplitude echo (darker grays) Ultrasound (Sonography) mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast seen
  • Ideal for intrahepatic aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms
  • Indicated in pregnant individuals
• CTA CTA A non-invasive method that uses a ct scanner for capturing images of blood vessels and tissues. A contrast material is injected, which helps produce detailed images that aid in diagnosing vascular diseases. Pulmonary Function Tests or MRA MRA Imaging of the Heart and Great Vessels for surgical planning

Management:

• Early elective treatment is the general approach to minimize the risk of rupture, but there is no consensus guideline for observation versus surgery in VAAs < 2.5 cm.
• Definite surgical indications:
  • Symptomatic VAAs
  • Asymptomatic aneurysms with rapid expansion > 0.5 cm/year
  • Pregnant individuals
  • Pseudoaneurysms (regardless of symptoms) due to higher risk of rupture
• Ruptured VAA:
  • Stabilize individual; transfuse blood and platelets Platelets Platelets are small cell fragments involved in hemostasis. Thrombopoiesis takes place primarily in the bone marrow through a series of cell differentiation and is influenced by several cytokines. Platelets are formed after fragmentation of the megakaryocyte cytoplasm. Platelets: Histology
  • Specific embolization Embolization A method of hemostasis utilizing various agents such as gelfoam, silastic, metal, glass, or plastic pellets, autologous clot, fat, and muscle as emboli. It has been used in the treatment of spinal cord and intracranial arteriovenous malformations, renal arteriovenous fistulas, gastrointestinal bleeding, epistaxis, hypersplenism, certain highly vascular tumors, traumatic rupture of blood vessels, and control of operative hemorrhage. Gastrointestinal Bleeding techniques depend on the location, affected organ, and availability of a skilled interventional radiologist.
  • Endovascular repair with coils
  • Percutaneous thrombin Thrombin An enzyme formed from prothrombin that converts fibrinogen to fibrin. Hemostasis injection (rarely used)
  • Surgical exploration with clipping and evacuation of any hematoma Hematoma A collection of blood outside the blood vessels. Hematoma can be localized in an organ, space, or tissue. Intussusception present

Prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas:

• Ruptured VAAs: 25%–70% mortality Mortality All deaths reported in a given population. Measures of Health Status rate
• Repaired aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms: immediate success in 90%

Differential Diagnosis

Extremity aneurysms

• Popliteal cyst Popliteal cyst A synovial cyst most commonly at the back of the knee. Osteoarthritis (Baker cyst): most common cause of a palpable mass Mass Three-dimensional lesion that occupies a space within the breast Imaging of the Breast in the popliteal fossa Popliteal fossa The popliteal fossa or the “knee pit” is a diamond-shaped, fat-filled, shallow depression on the posterior aspect of the knee joint. The popliteal fossa is located at the dorsal aspect of the knee and contains an increased number of lymph nodes as well as structures of the neurovascular system that travel from the thigh to the lower leg. Popliteal Fossa: Anatomy. Popliteal cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change are formed by the extrusion of synovial fluid from the knee joint Knee joint The knee joint is made up of the articulations between the femur, tibia, and patella bones, and is one of the largest and most complex joints of the human body. The knee is classified as a synovial hinge joint, which primarily allows for flexion and extension with a more limited degree of translation and rotation. Knee Joint: Anatomy and may present similarly to a ruptured aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms, with an acute onset of severe knee pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways if it ruptures. Diagnosis can be made by physical exam, but ultrasonography is confirmatory. These cysts Cysts Any fluid-filled closed cavity or sac that is lined by an epithelium. Cysts can be of normal, abnormal, non-neoplastic, or neoplastic tissues. Fibrocystic Change are commonly associated with osteoarthritis Osteoarthritis Osteoarthritis (OA) is the most common form of arthritis, and is due to cartilage destruction and changes of the subchondral bone. The risk of developing this disorder increases with age, obesity, and repetitive joint use or trauma. Patients develop gradual joint pain, stiffness lasting < 30 minutes, and decreased range of motion. Osteoarthritis or inflammatory arthritis Arthritis Acute or chronic inflammation of joints. Osteoarthritis. Treatment is with direct injection or aspiration of the cyst.
• Peripheral arterial disease (PAD): result of atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis gradually obstructing the arterial lumen and causing decreased blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure to the distal limbs. Symptoms range from claudication to skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions discoloration and ischemic ulcers to gangrene Gangrene Death and putrefaction of tissue usually due to a loss of blood supply. Small Bowel Obstruction. Diagnosis is made by physical exam with decreased palpable pulses. Additional studies include ankle brachial index Ankle brachial index Comparison of the blood pressure between the brachial artery and the posterior tibial artery. It is a predictor of peripheral arterial disease. Peripheral Artery Disease testing and angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery if needed for surgical evaluation. Management is with lifestyle change (e.g., smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases cessation), antiplatelet therapy, and revascularization Revascularization Thromboangiitis Obliterans (Buerger Disease).

Visceral aneurysms

• Biliary colic: aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms in the hepatic arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology may cause RUQ pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways mimicking biliary colic, especially if there is rupture and the individual has associated jaundice Jaundice Jaundice is the abnormal yellowing of the skin and/or sclera caused by the accumulation of bilirubin. Hyperbilirubinemia is caused by either an increase in bilirubin production or a decrease in the hepatic uptake, conjugation, or excretion of bilirubin. Jaundice. Imaging with ultrasonography or CT is essential for differentiating from other etiologies, such as gallstones Gallstones Cholelithiasis (gallstones) is the presence of stones in the gallbladder. Most gallstones are cholesterol stones, while the rest are composed of bilirubin (pigment stones) and other mixed components. Patients are commonly asymptomatic but may present with biliary colic (intermittent pain in the right upper quadrant). Cholelithiasis. Treatment is based on the underlying etiology.
• Pancreatitis Pancreatitis Inflammation of the pancreas. Pancreatitis is classified as acute unless there are computed tomographic or endoscopic retrograde cholangiopancreatographic findings of chronic pancreatitis. The two most common forms of acute pancreatitis are alcoholic pancreatitis and gallstone pancreatitis. Acute Pancreatitis: aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms of the celiac artery may mimic pancreatitis Pancreatitis Inflammation of the pancreas. Pancreatitis is classified as acute unless there are computed tomographic or endoscopic retrograde cholangiopancreatographic findings of chronic pancreatitis. The two most common forms of acute pancreatitis are alcoholic pancreatitis and gallstone pancreatitis. Acute Pancreatitis owing to its retroperitoneal Retroperitoneal Peritoneum: Anatomy location. Presentation is with dull pain Pain An unpleasant sensation induced by noxious stimuli which are detected by nerve endings of nociceptive neurons. Pain: Types and Pathways in the epigastric region Epigastric region Anterior Abdominal Wall: Anatomy that radiates to the back. Ultrasonography is an important diagnostic tool in identifying an aneurysm Aneurysm An aneurysm is a bulging, weakened area of a blood vessel that causes an abnormal widening of its diameter > 1.5 times the size of the native vessel. Aneurysms occur more often in arteries than in veins and are at risk of dissection and rupture, which can be life-threatening. Thoracic Aortic Aneurysms, and laboratory findings may include elevated amylase Amylase A group of amylolytic enzymes that cleave starch, glycogen, and related alpha-1, 4-glucans. Digestion and Absorption and lipase Lipase An enzyme of the hydrolase class that catalyzes the reaction of triacylglycerol and water to yield diacylglycerol and a fatty acid anion. It is produced by glands on the tongue and by the pancreas and initiates the digestion of dietary fats. Malabsorption and Maldigestion.