Acute tubular necrosis (ATN) is a serious disease of renal tubules of the kidney. Acute means sudden in occurrence and necrosis means irreversible cellular destruction or death. Kidney is one of the most important organs in our body. The function of the kidney is to clean the body of any harmful metabolites (wastes) that may be present in the bodily fluids. Kidney dysfunction results in harmful medical conditions. Acute Tubular Necrosis (ATN) causes serious functional abnormalities of kidney.1 In this article, we will discuss in detail the causes, symptoms, and various treatments for Acute Tubular Necrosis (ATN).
Describe Renal Tubule And Its Function?
Anatomy of Renal Tubule-
- Renal Tubules- Kidney is made up of several thousands of microscopic renal tubules. Renal tubule is a funnel shape tube with 3 sections.
- Renal Capsule- Also known as Bowman's capsule. Cup shape funnel is known as Renal Capsule. Renal capsule holds glomerulus within the shallow funnel cup.
- Glomerulus- Glomerulus is a bundle of blood vessels that consist of arterioles and capillaries. The blood vessels (glomerulus) lies within cup shape capsule.
- Renal Convoluted Tubules- Renal convoluted tubule is a U shaped tubule that connects renal capsule to collecting tubule.
Functions of Renal Tubule-
- The function of renal tubule is to discard salt, excessive fluids, and waste products from blood.
- Blood while passing through the glomerulus is filtered through the renal capsule. Water, mineral and metabolites are collected in renal convoluted tubule. Water and minerals are reabsorbed by blood vessels located around the convoluted tube.
- Metabolites (waste), excess minerals and water are then excreted in collecting tubules.
How Is Acute Tubular Necrosis (ATN) Defined?
- Sudden irreversible damage or death of the renal tubule or epithelial cells of the tubule causes acute tubular necrosis.2
- Acute Tubular Necrosis (ATN) causes injury of renal tubule and eventually results in Acute Kidney Failure.
Causes of Acute Tubular Necrosis (ATN)
Causes of Acute Tubular Necrosis (ATN) Are As Follows-
A. Ischemic Causes-
- Medications such as vasoconstrictions when prescribed during life threatening situation causes severe narrowing of kidney arterial system and results in lack of blood supply to renal tubule, which results in renal tubular necrosis.
- Low blood hemoglobin or anemia causes persistent tissue hypoxia and results in tubular necrosis.
- Low blood pressure causes decreased blood supply to kidney tissue and renal tubule resulting in tubular necrosis.
- High Altitude- Low oxygen saturation at high altitude causes kidney tissue hypoxia, which results in acute renal tubular necrosis.
- Respiratory Diseases- Chronic obstructive lung disease or acute respiratory failure often results in acute renal tubular necrosis.
B. Toxic Reaction-
- Presence of harmful substances in blood can also cause damage to the renal tubules.
- Presence of toxins can also alter the function of the renal tubules.
- Antibiotics that may cause renal tubular necrosis are penicillin, ampicillin and rifampicin.3
- Nephrotoxic Drugs-
- Lithium and cyclosporine causes tubular necrosis
- Dye Study
- Dye is often used for radiological studies. Dye if used in higher concentration or quantity can cause kidney toxicity and renal.
Risk Factors for Acute Tubular Necrosis (ATN)
Following are the Risk Factors for Acute Tubular Necrosis (ATN)
- Kidney Infection- Patient suffering with recurrent nephritis and kidney infection is at risk of renal tubular necrosis.
- Kidney Trauma- Blunt or sharp injury of kidney tissue may cause kidney tissue ischemia resulting in renal tubular ischemia.4
- Adverse reaction to blood transfusions.
- Septic Shock resulting in severe hypotension and poor circulation of blood in kidneys.
- Postoperative phase of a major surgery.5
- Complications following surgical procedure of the kidney.
Symptoms Of Acute Tubular Necrosis (ATN)
Acute Tubular Necrosis (ATN) symptoms differ depending on the severity of the disease. Some of its common symptoms are:
Non-Specific Symptoms of Acute Tubular Necrosis (ATN)
- Daytime Drowsiness- Patient is sleepy during daytime.
- Fatigue- Feeling fatigued
- Thirst- Excessive thirst
Specific Symptoms of Acute Tubular Necrosis (ATN)
- Lack of urination
- Edema of feet and abdomen wall
- Swelling in the body
- Hematuria- Blood in urine.
- Proteinuria- Albumen and globulin are excreted in abnormal large quantity in urine.
- Anemia- Low hemoglobin.
Diagnosis of Acute Tubular Necrosis (ATN)
Diagnostic Test Are As Follows-
- Urine Examination-
- Microscopic or frank blood in urine
- Protein in urine
- Blood Examination-
- Low Hemoglobin
- High creatinine and high blood urea nitrogen (BUN)
- Electrolytes- Level of sodium and potassium is low in blood.
- Renal Biopsy-
- Renal biopsy indicates the microscopic tubular necrosis.
- CT Scan of the kidney
Treatment for Acute Tubular Necrosis (ATN)
- Fluid Intake-
- Restrict and match the intake of fluid volume to urine output.
- Monitor Fluid Intake- Treating physician may recommend to monitor the intake of water and other fluids so as to prevent fluid retention. Fluid retention may result in edema feet, liver enlargement and respiratory symptoms.
- Protein Restriction-
- In later phase albumin and globulin are reabsorbed by kidney, so to prevent toxic build up of protein in body restrict intake of protein.
- Restriction of Salt-
- The kidney retains sodium, potassium and chloride. Salt restriction is advised to prevent excessive build up of salt in the body.
- Diuretics are prescribed to remove extra water, which is retained by kidney.
- Kidney Dialysis-
- Some individuals need dialysis to clear the body of waste products and excess water.
Indications for Dialysis-
- Mental confusion
- Fluid retention
- Hyperkalemia- increased potassium level in blood
- Lack of urine output
- Increased BUN and creatinine
Prevention of Acute Tubular Necrosis (ATN)
- Avoid Hypoxia
- Get prompt treatment of hypotension
- Take regular medications for diabetes and hypertension
- Check kidney function following antibiotic treatment or dye study.
1. Apoptosis and acute kidney injury.
Havasi A1, Borkan SC.
Kidney Int. 2011 Jul;80(1):29-40. doi: 10.1038/ki.2011.120. Epub 2011 May 11.
2. Acute renal failure. Pathology and pathogenesis.
Crosson JT, Gulmen S.
Minn Med. 1975 Jan;58(1):18-22, 87.
3. Antibiotic nephrotoxicity.
Morin JP, Fillastre JP, Olier B.
Chemioterapia. 1984 Feb;3(1):33-40.
4. Acute tubular necrosis (vasomotor nephropathy). Review of clinical aspects and report of five cases due to trauma.
Minn Med. 1975 Jan;58(1):23-9, 42.
5. Acute kidney injury after endovascular repair of abdominal aortic aneurysm.
Saratzis AN1, Goodyear S, Sur H, Saedon M, Imray C, Mahmood A.
J Endovasc Ther. 2013 Jun;20(3):315-30.