Renal Artery Aneurysm is a disease of renal artery which results following weakness in the wall of the artery. The weakness of arterial wall causes protrusion or aneurysm bulging outward. In several cases at the time of diagnosis dilation of renal artery is twice or larger in size when compared with normal arterial lumen. Renal arterial aneurysm may be asymptomatic or in some instances cause a variety of symptoms. In this article, we will read about the causes, symptoms, and treatment of Renal Artery Aneurysm.
How Do We Define Renal Artery Aneurysm?
- Renal Artery Aneurysm can be described as a dilated section of the renal artery, which becomes almost twice its normal size.
- Renal Artery aneurysm or Pseudoaneurysms can be symptomatic as well as asymptomatic.
- Symptomatic Renal Artery Aneurysm or pseudoaneurysm is symptomatic because of hypertension, abdominal pain, blood in the urine and renal infarction.1
- Asymptomatic Renal Artery Aneurysm usually is benign but there is always a chance that it may rupture as it grows in size.
- Asymptomatic Renal Artery Aneurysm is silent weakness of the renal artery and bulging of arterial wall may eventually rupture.
- Asymptomatic renal artery aneurysm is often incidentally diagnosed following MRI or CT study of the abdomen.
- The aneurysm is often surgically repaired.
- Arterial wall weakness is observed in patients suffering with Ehlers-Danlos disorder, which is autosomal dominant genetic disorder.
Causes Of Renal Artery Aneurysm
Majority of Renal Artery Aneurysms are idiopathic (unknown cause) and cause is often unknown.
Causes of Renal Artery Aneurysm Are As Follows-
- Smooth Muscle Disease-
- Smooth muscle disease like Fibromuscular Dysplasia may cause weakness of the muscular layer of renal artery, which results in aneurysm.
- Fibromuscular dysplasia and hydronephrosis has been observed in patient suffering with renal artery aneurysm.2
- Genetic Disorder-
- Ehlers-Danlos Syndrome is genetic disorder and causes smooth muscle and fibrous tissue weakness.
- Kawasaki Disease- Autosomal disease results in inflammation of renal artery and weakness in mucosal as well as sub-mucosal layer of the artery.
- Infection- The infections like staphylococcus aureus, syphilis are blood infections may also lead to formation of Renal Artery Aneurysm.
- Trauma- Blunt trauma can cause partial injury of the arterial wall.3
- Surgical Injury- The arterial wall injury during surgery or anastomosis can cause weakness in the wall resulting in aneurysm.
Types Of Renal Artery Aneurysm
True Renal Artery Aneurysms:
- Weakness- all 3 layers of the arterial wall.
- Inherited disorder
- Saccular or fusiform shaped aneurysm
- Most common cause are Fibromuscular Dysplasia and Ehlers-Danlos syndrome.
False/Pseudoaneurysm of Renal Artery: 4
- Weakness in arterial wall is partial. All 3 layers may not be weak.
- Secular in appearance
- Mostly caused by blunt abdominal trauma
- Following surgical trauma.
- Intrarenal aneurysm is either true or false aneurysm.
- Intrarenal aneurysm is 10% of all renal arterial aneurysm.
- Associated with:
- Polyarteritis Nodosa
Symptoms Of Renal Artery Aneurysm
Symptoms of Renal Artery Aneurysm-
- Flank Pain- Severe flank pain, may radiate to spine
- Abdominal Pain- Pain may be on the side of umbilicus
- Renal Arterial Dissection- Pain may be associated with dissection of arterial wall5
- Renal Infarction- Flank or abdominal pain is secondary to renal artery infarction.
- Secondary to renal artery stenosis
- Activates the renin-angiotensin system
- Increased angiotensin II levels resulting in fluid retention and vasoconstriction
- Function of the Renal System
- Renal function is decreased
- Renal Infarction
- Bleeding may be secondary to tear of arterial mucosal layer or rupture of intra parenchymal aneurysm.
- Frank blood suggests rupture of aneurysm within arterial lumen.
Diagnosis of Asymptomatic Renal Artery Aneurysm
- Most Renal Artery Aneurysm (RAAs) are asymptomatic
- Incidental Finding- Renal Artery Aneurysm is found during investigation of other intra-abdominal symptomatic diseases.
- Image studies assist in diagnosis of Renal Artery Aneurysm (RAA)
- Computed tomography (CT)
- Duplex ultrasonography
- Magnetic resonance imaging (MRI)
- Magnetic resonance angiography (MRA)
Diagnosis of Renal Artery Aneurysm
Majority of Renal Artery Aneurysms are found incidentally when imaging is done to rule out other pathological conditions of the kidneys. The imaging performed is usually a CT scan or an MRI of the abdomen and/or pelvis. If an aneurysm gets significantly enlarged, then it may be detected with a Renal Duplex Ultrasound.
Treatment For Renal Artery Aneurysm
Asymptomatic Renal Artery Aneurysm-
- The progress of aneurysm is observed with frequent image studies.
- Surgical Treatment-
- Significant growth at the time of initial diagnosis.
- Continuous rapidly growing aneurysm is also treated by surgery.
Treatment For Symptomatic Renal Artery Aneurysm-
- Indicated for mild to moderate pain
- Motrin, Celebrex and Naproxen
- Indicated for severe pain
- Vicodine, Oxycodone and Morphines
- Lisinopril- Angiotensin inhibiting enzyme
- Aneurysm which is less than 1.5 cm is embolized with coil
- Results are excellent4
- Complications are rupture or kidney infarct.
- Surgery For Renal Artery Aneurysm:
- Surgery is indicated for following condition:-
- Aneurysm larger than 2 cm
- Embolization causing renal infarct
- Renal artery rupture.
- Surgery is indicated for following condition:-
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