Renal infarction is caused by obstruction of kidney blood flow. The obstruction is often sudden due to emboli or thrombus blocking the blood supply to kidney. The lack of blood supply to portion of kidney causes kidney ischemic changes and results in renal infarct. Renal infarct causes severe flank pain that radiates to lower back and is often mistaken for back pain. In this article, we will study in detail about the causes, symptoms, and treatment options available for treatment of Renal Infarction.
How Do We Define Renal Infarction?
- Renal infarction is caused by lack of blood supply to kidney tissue. Hemoglobin in blood carries oxygen to kidney tissue.
- Lack of oxygen causes infarction resulting in kidney tissue necrosis or death.
- The necrose kidney tissue causes hematuria and severe flank pain.
Interruption Of Kidney Blood Supply-
- Oxygenated Blood- Kidney receives oxygenated blood carried through renal artery and it’s branches.
- Arterial Blockade- Complete blockade of renal artery or it’s branches causes total or partial renal (kidney) infarct.
- Partial Renal Infarct- this is most common infarction and is caused by blockade of branches resulting in partial kidney tissue infarct depending on branch of the renal artery.
- Cause Of Blockade Of Renal Artery Or It’s Branch-
- Renal Artery Embolism- Emboli is a solid floating particle of atherosclerotic plaque or blood clot of different size carried by blood from its origin to kidney tissue.1, 2
- Renal Artery Thrombosis- Renal artery or it’s branch may initiate a formation of blood clot within it’s lumen and as it grows in size it causes obstruction to blood flow to kidney tissue.3
- Renal Artery Stenosis- The atherosclerotic plaque in the wall of the renal artery may cause renal artery obstruction.
- Renal Vein Thrombosis-
- A condition called as Hemorrhagic Renal Infarction can be caused from renal vein thrombosis.
Causes of Renal Infarction
Majorities of Renal Infarctions (95%) are caused by thromboembolic events.
Obstruction To Kidney Blood Flow-
- Renal Artery Stenosis
- Renal Artery Embolism
- Atrial Fibrillation2
- Mitral Valve Disease
- Foramen Ovale1
- Renal Artery Thrombosis
- Renal artery aneurysm
- Renal Vein Thrombosis
Low Cardiac Output Results In Low Blood Supply To Kidney-
- Congestive Heart Failure
- Cardiac Surgeries
Symptoms Of Renal Infarction
Some Of The Pertinent Symptoms Of Renal Infarction Are As Follows-
Renal Infarction Symptoms-
- Epigastric Pain- Pain is mostly observed over epigastric dermatome and often radiates to lower back either right or left side depending on the diseased kidney.
- Flank Pain- Severe to very severe stabbing pain may be localized over flank. Pain radiates to lower back either left or right side.
- Abdominal Tenderness- Examination and palpation of the upper abdomen causes severe pain and tenderness over the epigastrium and on the either side of umbilicus. Abdominal examination often follows pain and tenderness. Abdominal pain is not associated with guarding or rebound pain.
- Complaint of urine discoloration like dark yellow or brown urine.
- Low urine output.
- Nausea and Vomiting
- Frequent nausea and occasional vomiting
- Vomiting is associated with predominant pain in lower back and seldom in abdomen.
- Gastrointestinal Bleeding
- Bloody diarrhea
Signs Of Renal Infarction
- Irregular heartbeats
- Atrial fibrillation2
- Tenderness over flank and abdomen
- Atrial fibrillation1, 2
- Abrupt stoppage of warfarin therapy
- History of alcohol abuse
- History of diabetes
- History of hypertension
Diagnosis of Renal Infarction
- Urine is discolored resulting in dark yellow or brown discoloration because of hematuria or frank blood
- Proteinuria- 24 hours collection of urine indicates elevated excretion of protein.
- Microscopic examination indicates presence of red and white blood cells in urine.
- White blood cell count- elevated.
- Creatinine and blood urea nitrogen- elevated.
- LDH- elevated
- Electrolytes- normal
- Liver function test- normal.
- Hypercoagulability screen- abnormal
Computerized Tomography (CT) and Magnetic Resonance Imaging (MRI) of Abdomen-
- Kidney- shows infarct area of kidney and kidney stones
- Abdominal CT-Shows following diseases
- Extensive aortic atherosclerosis
- Thrombosis of superior mesenteric artery.
Electrocardiogram and Echocardiogram
Electrocardiogram And Echocardiogram May Show Following Cardiac Abnormalities-
- Atrial Fibrillation2
- Myocardial Infarction
- Rheumatic Mitral Stenosis
- Thrombus Within Atrium or Ventricle
- Vegetation Over The Cardiac Valve
- Intraluminal Masses in Cardiac Chamber
- Ejection Fraction Less Than 50%,
- Mild Tricuspid and Mitral Valve Regurgitation
- Thromboembolism of Cardiac Origin
- Vegetation is observed over prosthetic and diseased mitral or aortic valve often caused by bacterial endocarditis.
- Calcification and unfolding of the thoracic aorta
- Aneurysm or atherosclerotic plaques in thoracic or abdominal aorta.
Colonoscopy May Show Following Incidental Findings:
- May show signs of ischemic bowel disease.
Treatment For Renal Infarction
Conservative Treatment For Renal Infarction-
- Hydration- Adequate oral fluid
- Diarrhea- Over the counter antidiarrheal medication until diagnosis is confirmed.
- NSAIDs (Non-Steroidal Anti Inflammatory Medications)
- NSAIDs avoided if patient has increased bleeding tendency.
- Mild to moderate pain is treated with NSAIDs
- Severe to very severe pain is treated with opioids.
- Most common opioids used for acute pain is short acting opioids like Hydrocodone (Vicodin, Lortab and Norco)
- Chronic pain lasting more than 3 to 6 months is treated with long acting opioids like Oxycontin and MS Contin. Short acting opioids are used for breakthrough pain.
- Antihypertensive Agents-
- Hypertension associated with renal infarct is treated with Angiotensin converting enzyme inhibitor or angiotensin receptor antagonist.
- Restrict salt intake.
Treatment for Thrombosis and Emboli-
- Heparin Thrombolytic Treatment
- Anticoagulation with intravenous heparin followed by oral warfarin.
- The target is to achieve INR of 2.0–3.0
- INR level of 2.5–3.5 is reasonable and aimed if patient has a history of rheumatic heart disease or a prosthetic valve.
- Intra-arterial infusion of tissue plasminogen activator4
Surgical Treatment For Renal Infarction
- Percutaneous Treatments of Renal Artery Emboli 5
- Percutaneous Endovascular Thrombolysis 3
- Thrombectomy and Stent Placement
- Open Laparotomy Surgery
- Thrombectomy with or without stenting.
1. A suspected case of paradoxical renal embolism through the patent foramen ovale.
Iwasaki M1, Joki N, Tanaka Y, Hara H, Suzuki M, Hase H.
Clin Exp Nephrol. 2011 Feb;15(1):147-50.
2. Acute renal embolism. Forty-four cases of renal infarction in patients with atrial fibrillation.
Hazanov N1, Somin M, Attali M, Beilinson N, Thaler M, Mouallem M, Maor Y, Zaks N, Malnick S.:
Medicine (Baltimore). 2004 Sep;83(5):292-9.
3. Spontaneous renal artery thrombosis: an unusual cause of acute abdomen.
Singh S, Wang L, Yao QS, Jyotimallika J, Singh S.
N Am J Med Sci. 2014 May;6(5):234-6.
4. Successful aspiration and rheolytic thrombectomy of a renal artery infarct and review of the current literature.
Komolafe B1, Dishmon D, Sultan W, Khouzam RN.
Can J Cardiol. 2012 Nov-Dec;28(6):760.e1-3.
5. A case of renal artery embolism treated by selective intra-arterial infusion of tissue plasminogen activator.
Baydar O1, Başkurt M, Coşkun U, Ersanlı M.
Turk Kardiyol Dern Ars. 2013 Sep;41(6):534-6. doi: 10.5543/tkda.2013.54770.