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Acute Kidney Failure

Acute Kidney Injury

Acute kidney failure (acute kidney injury or acute renal failure) is the abrupt loss of the kidney's capacity to remove metabolic wastes from the blood and to maintain fluid and electrolyte balance in the body for optimum health. AKF, if left untreated, is potentially fatal.


Presentation

The presentation depends on the etiology and the stage of the acute kidney failure. Mild forms may be asymptomatic and are identified on laboratory examination. More severe cases may present with lethargy, fatigue, confusion, anorexia, nausea, and weight gain. The patient may be anuric, oliguric, pass normal volumes of urine or may even complain of polyuria.

Easy Bruising
  • bruising, and pale skin (from anemia); ...[emedicinehealth.com]
  • bruising , or blood in the stool Excessive thirst Frequent hiccups Problems with sexual function Menstrual periods stop (amenorrhea) Shortness of breath Sleep problems Vomiting Exams and Tests Most people will have high blood pressure at all stages of[mountsinai.org]
Tachypnea
  • Vital signs are assessed frequently, and fever, tachycardia, tachypnea or bradypnea, and hypotension are reported. The electrocardiogram is monitored for arrhythmias.[medical-dictionary.thefreedictionary.com]
Fatigue
  • The patient was admitted with acute kidney failure for 3 times and due to a history of proximal weakness, fatigue, and muscular cramps after physical activities a glycogen-storage disease was suspected.[ncbi.nlm.nih.gov]
  • His complaints were weakness and fatigue for more than one week. Four days before admission, he went to his general practitioner for these complaints and also for painful elbows. His physician prescribed diclofenac and esomeprazole.[ncbi.nlm.nih.gov]
  • Again, the increase in fatigue is because of the kidney failure.[diabetes.co.uk]
  • Symptoms may include swelling, nausea, fatigue, itching, difficulty breathing, and symptoms of the disorder that caused the acute kidney injury. Serious complications include heart failure and high levels of potassium in the blood.[merckmanuals.com]
Congestive Heart Failure
  • Hypovolemia – volume depleted, hemorrhage, intravascular volume depletion from congestive heart failure or cirrhosis.[foamcast.org]
  • These comorbidities include diabetes mellitus, congestive heart failure, acute hypotension (requiring pressors or intra-aortic balloon pump), ST-elevation myocardial infarction, and volume depletion.[circ.ahajournals.org]
  • Clinical findings • Cardiovascular Congestive heart failure, myocardial infarction, arrhythmias, cardiac arrest occur in up to 35% of patients with ARF.[medical-dictionary.thefreedictionary.com]
  • Nine times out of 10, these patients are readmitted with decompensated congestive heart failure,” Dr. Anderson noted. Instead, patients need to go home with more diuretic than they came in on, not less.[todayshospitalist.com]
  • Acute renal failure in patients with congestive heart failure occurs because of decreased renal blood flow.[aafp.org]
Weight Gain
  • Healthy Weight Gain during Pregnancy Pregnancy Diet Chart: Underweight or Overweight? Child bearing imposes both physical and mental strain on the body and mind. To be able to counter this, it is important that the mother has a healthy...[columbiaasia.com]
  • More severe cases may present with lethargy, fatigue, confusion, anorexia, nausea, and weight gain. The patient may be anuric, oliguric, pass normal volumes of urine or may even complain of polyuria.[symptoma.com]
  • You may need to reduce your calorie intake, since the sugar in the dialysate may cause weight gain. Hemodialysis. Hemodialysis can be performed at home or in a dialysis center or hospital by trained health care professionals.[hopkinsmedicine.org]
  • gain of 3 to 5 lb (1.4 to 2.3 kg) in 1 week.[medical-dictionary.thefreedictionary.com]
  • Patients with severe cases, however, may be symptomatic and present with listlessness, confusion, fatigue, anorexia, nausea, vomiting, weight gain, or edema. 15 Patients can also present with oliguria (urine output less than 400 mL per day), anuria (urine[aafp.org]
Nausea
  • Wicked Dreams 7 Oregon 18 Nausea and vomiting, abdominal pain pain 6.6 WBCs, protein 30 Increased cortical echogenicity, no hydronephrosis "Synthetic marijuana" 8 New York 33 Nausea and vomiting 3.3 Not available Not performed Spice Gold 9 Oregon 27[cdc.gov]
  • Symptoms may include anorexia, nausea, and vomiting. Seizures and coma may occur if the condition is untreated. Fluid, electrolyte, and acid-base disorders develop quickly.[merckmanuals.com]
  • Other symptoms of acute tubular necrosis include tiredness, swelling, lethargy, nausea , vomiting, abdominal pain , kidney pain , loss of appetite, and rash . Sometimes there are no symptoms.[emedicinehealth.com]
Vomiting
  • […] and vomiting, flank pain 6.3 WBCs, RBCs, epithelial casts, granular casts Not available Blueberry-flavored 4 Wyoming 18 Nausea and vomiting, flank pain 4.1 Hyaline casts, WBCs No increased cortical echogenicity or hydronephrosis Blueberry-flavored or[cdc.gov]
  • Any warning signs of AKI, such as vomiting or producing little urine, require immediate investigation for AKI and treatment. People who are dehydrated, or at risk of dehydration, may need to be given fluids via a drip.[nhs.uk]
  • Other symptoms of acute tubular necrosis include tiredness, swelling, lethargy, nausea , vomiting, abdominal pain , kidney pain , loss of appetite, and rash . Sometimes there are no symptoms.[emedicinehealth.com]
Loss of Appetite
  • You may experience the following: Peeing less than normal Swelling in your legs, ankles , and feet (caused by your body holding on to fluid) Drowsiness or feeling very tired Shortness of breath Itching Loss of appetite Confusion Throwing up or feeling[m.webmd.com]
  • Some of the symptoms of acute kidney failure are: Urinating less or not at all even when you are drinking fluids Swelling all over the body or swelling of just the legs, feet, or ankles Confusion Drowsiness and tiredness Loss of appetite Nausea and vomiting[summitmedicalgroup.com]
  • Other symptoms of acute tubular necrosis include tiredness, swelling, lethargy, nausea , vomiting, abdominal pain , kidney pain , loss of appetite, and rash . Sometimes there are no symptoms.[emedicinehealth.com]
Hiccup
  • Decreased appetite Decreased sensation , especially in the hands or feet Fatigue or slow sluggish movements Flank pain (between the ribs and hips) Hand tremor Heart murmur High blood pressure Nausea or vomiting, may last for days Nosebleeds Persistent hiccups[nlm.nih.gov]
  • Effects may include a metallic taste in the mouth, prolonged nausea and vomiting, incessant hiccuping, itching all over the body, fluid retention, unintended weight loss and an over-all feeling of fatigue and sluggishness.[livestrong.com]
  • […] worse include: Abnormally dark or light skin Bone pain Drowsiness or problems concentrating or thinking Numbness or swelling in the hands and feet Muscle twitching or cramps Breath odor Easy bruising , or blood in the stool Excessive thirst Frequent hiccups[mountsinai.org]
Asterixis
  • Other presentations of acute kidney injury may include development of uremic encephalopathy (manifested by a decline in mental status, asterixis, or other neurologic symptoms), anemia, or bleeding caused by uremic platelet dysfunction.[aafp.org]
  • […] in Patients with Acute Renal Failure and Uremia* Symptoms Anorexia Fatigue Mental status changes Nausea and vomiting Pruritus Seizures (if blood urea nitrogen level is very high) Shortness of breath (if volume overload is present) Physical findings Asterixis[aafp.org]
Metallic Taste
  • taste in the mouth Bruising easily Changes in mental status or mood Decreased appetite Decreased sensation , especially in the hands or feet Fatigue or slow sluggish movements Flank pain (between the ribs and hips) Hand tremor Heart murmur High blood[nlm.nih.gov]
  • Effects may include a metallic taste in the mouth, prolonged nausea and vomiting, incessant hiccuping, itching all over the body, fluid retention, unintended weight loss and an over-all feeling of fatigue and sluggishness.[livestrong.com]
  • Decreased urine production Body swelling Problems concentrating Confusion Fatigue Lethargy Nausea, vomiting Diarrhea Abdominal pain Metallic taste in the mouth Seizures and coma may occur in very severe acute kidney failure.[emedicinehealth.com]
Hypertension
  • Due to uncontrollable hypertension, our patient was hospitalized at the intensive care department where intravenous nifedipine was started, with good instantaneous control of blood pressure.[ncbi.nlm.nih.gov]
  • The patient has a past medical history of hypertension, obesity, diabetes, and GERD. The patient states he has not filled his prescriptions for any of his medications in months and cannot remember what his medications are.[step2.medbullets.com]
  • Nitrate therapy may help reverse fluid shifts by reducing hypertension temporarily through vasodilatation.[ems1.com]
  • Decreased blood flow to the kidney, such as from hypercalcemia (high blood calcium level) or severe heart disease A disease or condition that affects the kidneys, such as hypertension (high blood pressure) or diabetes A blockage in the kidney or ureter[drugs.com]
  • .), and the Department of Anesthesiology and Critical Care Medicine (L.S.C.) and Department of Medicine, Division of Renal Diseases and Hypertension (L.S.C., P.L.K.), George Washington University Medical Center — both in Washington, DC; and the National[nejm.org]
Hypotension
  • The cause is usually ischemic (from prolonged hypotension) or nephrotoxic (from an agent that is toxic to the tubular cells).[aafp.org]
  • Hypotension (eg, cardiogenic shock, sepsis, anaphylaxis). Cardiovascular (eg, severe cardiac failure, arrhythmias).[patient.info]
  • […] variety of clinical conditions, which act through the same pathophysiologic mechanisms, namely: Hypoxia Ischemia Nephrotoxicity Risk Factors AKI is common in conditions involving: Hypovolemia Sepsis Pre-existing disease of the heart, kidney or liver Hypotension[news-medical.net]
  • Hypotension secondary to decreased cardiac output, blood volume or massive vasodilation is the most common prerenal cause of AKI.[ems1.com]
Tachycardia
  • ., history of vomiting, diarrhea, diuretic overuse, hemorrhage, burns) Weight loss, orthostatic hypotension and tachycardia Thirst and reduced fluid intake Poor skin turgor Cardiac disease Dilated neck veins, S 3 heart sound, pulmonary rales, peripheral[aafp.org]
  • ., tachycardia and hypertension), and approximately five times more likely to be associated with hallucinations ( 8 ). In addition, an increase in the occurrence of seizures has been reported with SC use ( 9 ).[cdc.gov]
  • Other signs and symptoms may include orthostatic hypotension and tachycardia.[todaysgeriatricmedicine.com]
  • Vital signs are assessed frequently, and fever, tachycardia, tachypnea or bradypnea, and hypotension are reported. The electrocardiogram is monitored for arrhythmias.[medical-dictionary.thefreedictionary.com]
Petechiae
  • Pallor, rash, bruising: petechiae, purpura and nosebleeds may suggest inflammatory or vascular disease, emboli or disseminated intravascular coagulation. Pericardial rub.[patient.info]
  • Checking the patient for areas of small, purple or red spots (petechiae), hemorrhage beneath the skin (purpura), and bluish discoloration of a fairly large area of the skin (ecchymosis) can lead to a diagnosis of an inflammatory or vascular cause for[encyclopedia.com]
Pruritus
  • Symptoms may include: Appetite loss General ill feeling and fatigue Headaches Itching ( pruritus) and dry skin Nausea Weight loss without trying to lose weight Symptoms that may occur when kidney function has gotten worse include: Abnormally dark or light[mountsinai.org]
  • View/Print Table TABLE 1 Key Symptoms and Physical Findings in Patients with Acute Renal Failure and Uremia* Symptoms Anorexia Fatigue Mental status changes Nausea and vomiting Pruritus Seizures (if blood urea nitrogen level is very high) Shortness of[aafp.org]
Back Pain
  • C) or chills Muscle aches Night sweats Very little or no urine output Swelling of your hands, legs, or feet Back pain Abdominal pain Extreme tiredness 2000-2016 Krames StayWell, 780 Township Line Road, Yardley, PA 19067. All rights reserved.[mountnittany.org]
  • pain 9.1 Protein trace Increased cortical echogenicity, no hydronephrosis Synthetic cannabinoid, not otherwise specified 11 Kansas 26 Nausea and vomiting, abdominal pain / back pain 7.7 Within normal limits Increased cortical echogenicity Mr.[cdc.gov]
  • pain Fever Rash Nosebleed Causes of Acute Kidney Failure There are three main reasons your kidneys fail all of a sudden: Something is stopping blood flow to your kidneys.[m.webmd.com]
Muscle Twitch
  • As AKI progresses, you may have any of the following: Decrease in the amount of urine or no urination Swelling in your arms, legs, or feet Weakness, drowsiness, or no appetite Nausea, flank pain, muscle twitching or muscle cramps Itchy skin, or your breath[drugs.com]
  • twitching Seizures or coma (in severe cases) Stomach and back pain Fever Rash Nosebleed Causes of Acute Kidney Failure There are three main reasons your kidneys fail all of a sudden: Something is stopping blood flow to your kidneys.[m.webmd.com]
  • twitching as a result of increasing potassium levels (hyperkalemia) Changes in the electrocardiogram such as elevated or peaked T waves associated with hyperkalemia Recall that in AKI these signs and symptoms will occur over just a few hours or days.[ems1.com]
Muscle Weakness
  • Muscle weakness. When your body's fluids and electrolytes — your body's blood chemistry — are out of balance, muscle weakness can result. Permanent kidney damage.[mayoclinic.org]
  • Complications of acute kidney injury The most serious complications of acute kidney injury are: high levels of potassium in the blood – in severe cases, this can lead to muscle weakness, paralysis and heart rhythm problems fluid in the lungs (pulmonary[nhs.uk]
  • Neuromuscular manifestations include muscle weakness and cramps as well as an increased incidence of rhabdomyolysis.[academic.oup.com]
  • Potassium intake is restricted because, in renal failure, potassium is not excreted by the kidneys, and hyperkalemia may produce muscle weakness and cardiac rhythm disturbances.[medical-dictionary.thefreedictionary.com]
Oliguria
  • Oliguria was observed in 72.2% of the patients. Perinatal asphyxia was present in 29.8% of the neonates, sepsis in 28.5%, respiratory distress syndrome in 25.2%, dehydration in 24.2%, and heart failure in 21.2%.[ncbi.nlm.nih.gov]
  • Peritoneal dialysis was started at a mean of 51 hours after transplantation for treatment of anuria (5 patients, 50%), oliguria (3 patients, 30%), fluid overload or hyperkalemia (1 patient each, 10%) and continued for a mean of 101 /- 90.5 (range, 33[ncbi.nlm.nih.gov]
  • Sudden and sustained deterioration of the kidney function characterized by decreased glomerular filtration rate, increased serum creatinine or oliguria.[icd10data.com]
  • This patient’s oliguria with acutely elevated BUN and plasma creatinine suggest that he is in acute renal failure (ARF).[foamcast.org]
  • Patients with AKI frequently have oliguria that is not fluid responsive.[clinicaladvisor.com]
Anuria
  • Peritoneal dialysis was started at a mean of 51 hours after transplantation for treatment of anuria (5 patients, 50%), oliguria (3 patients, 30%), fluid overload or hyperkalemia (1 patient each, 10%) and continued for a mean of 101 /- 90.5 (range, 33[ncbi.nlm.nih.gov]
  • A type 1 excludes note is for used for when two conditions cannot occur together, such as a congenital form versus an acquired form of the same condition. posttraumatic renal failure ( ICD-10-CM Diagnosis Code T79.5 Traumatic anuria 2016 2017 2018 2019[icd10data.com]
  • Clinically, AKI is recognised by decreasing urine volume (oliguria or anuria) and a rise in serum creatinine.[patient.info]
  • Etiology Pathogenesis based upcome etiology (look at etiology) Prognosis lower rates of recovery in patients 65 years of age increased risk of end-stage renal disease, chronic kidney disease, and mortality Presentation Symptoms may be asymptomatic oliguria anuria[step2.medbullets.com]
Seizure
  • Seizures and coma may occur if the condition is untreated. Fluid, electrolyte, and acid-base disorders develop quickly. Diagnosis is based on laboratory tests of renal function, including serum creatinine.[merckmanuals.com]
  • ., alcohol, cocaine) Seizure Traumatic crush injury Hypercalcemia (high level of calcium in the blood) caused by the following: Deposition of calcium in tissue Vasoconstriction (reduced diameter of blood vessels) Both ischemic and nephrotoxic ARF cause[healthcommunities.com]
  • Additionally, you may have shortness of breath, nausea, fatigue, drowsiness, chest pain, chest pressure, seizures and even coma in severe cases. However, in some cases, the urine output remains in normal levels.[worldpulse.com]
  • EMS providers will likely consider more common causes of respiratory distress, chest pain or seizures. Pay close attention to the history of the illness and the timing of the physical findings.[ems1.com]
  • […] you may notice some or all of the following problems: Not enough urine Swelling in your legs, ankles or feet Feeling tired Trouble catching your breath Feeling confused Nausea Pain or pressure in your chest If you have very severe AKI, you may have seizures[kidneyfund.org]
Confusion
  • More severe cases may present with lethargy, fatigue, confusion, anorexia, nausea, and weight gain. The patient may be anuric, oliguric, pass normal volumes of urine or may even complain of polyuria.[symptoma.com]
  • Feeling confused, anxious and restless, or sleepy. Some people may not have any symptoms. And for people who are already quite ill, the problem that’s causing the acute kidney failure may be causing other symptoms.[worldkidneyday.org]
  • If you are confused about the difference between acute renal (also called kidney) failure and chronic kidney failure, you came to the right place.[davita.com]
  • SEEK CARE IMMEDIATELY IF: You are breathing fast, have a fast heart beat, or feel confused, dizzy, or lightheaded. You are passing little to no urine. You cannot eat or drink because you are vomiting (throwing up).[drugs.com]
Headache
  • […] but I've had very few headaches. So, they don't know what's causing it yet, I've got to go back on Monday for a scan and biopsy, and they took another arnful of blood from me today.[diabetes.co.uk]
  • ., heart, liver) Overuse of pain medicines called “ NSAIDs ”, which are used to reduce swelling or relieve pain from headaches, colds, flu, and other ailments. Examples include ibuprofen, ketoprofen, and naproxen.[kidney.org]
  • Cola-colored urine followed by oliguria (decreased urine output) or anuria (no urine output) Headaches. High blood pressure may trigger headaches. Hypertension, or high blood pressure.[encyclopedia.com]
  • Accumulation of urea and other nitrogen-containing substances in the bloodstream lead to a number of symptoms, such as fatigue , loss of appetite , headache , nausea and vomiting . [4] Marked increases in the potassium level can lead to abnormal heart[en.wikipedia.org]
Lethargy
  • Hughson, MD, of Shorsh General Hospital in Kurdistan, said the patients complained of weakness and lethargy. They presented with serum creatinine levels of 2.6–3.8 mg/dL and estimated glomerular filtration rate (eGFR) of 22–34 mL/min/1.73 m 2 .[renalandurologynews.com]
  • Other symptoms of acute tubular necrosis include tiredness, swelling, lethargy, nausea , vomiting, abdominal pain , kidney pain , loss of appetite, and rash . Sometimes there are no symptoms.[emedicinehealth.com]
  • More severe cases may present with lethargy, fatigue, confusion, anorexia, nausea, and weight gain. The patient may be anuric, oliguric, pass normal volumes of urine or may even complain of polyuria.[symptoma.com]
  • The dizziness and lethargy I thought might have been becasue I wasn't eating enough, so I starting eating more, even though I've completley lost my appetite recently - another sign of kidney failure.[diabetes.co.uk]
Altered Mental Status
  • There may be other causes for altered mental status that might be present. Remember to check blood glucose levels and treat as necessary.[ems1.com]
  • Other complications may follow as uremia develops, e.g., altered mental status, anorexia, arrhythmias, and fluid overload. The specific cause is identified and removed if possible.[medical-dictionary.thefreedictionary.com]

Workup

Most persons with AKF are asymptomatic; if at all, the symptoms are generalized and physical examination is not conclusive. Oftentimes, the disorder is detected incidentally from the results of blood and urine tests during consultation for some other medical condition or purpose.

Laboratory predictors of AKF:

  • Azotemia: Elevated blood urea nitrogen (BUN]) and creatinine.
  • Fluctuating electrolyte levels in the blood (may be abnormally high or low): Impaired perfusion.
  • Anemia: Severe kidney failure is severe. The red blood cell count is low.

Urine output per unit time or metabolic waste excreted should be measured. Proteins and useful substances are excreted when kidney tissue is damaged. In case of renal retention, urine remaining in the bladder after micturation is measured by inserting a catheter into the bladder. This is done in postrenal failure due to enlarged prostate.

Dark-colored urine is due to the presence of creatinine and other substances in concentrated form. Microscopy will reveal blood, pus cells and casts as indicators of disease. Measurement of electrolyte levels can help identify the cause of AKF.

Ultrasonography of the kidneys and bladder can confirm specific causes of kidney failure [10]. Biopsy can be done for histological assessment, if needed.

Creatinine Increased
  • The second aim was to remark that this syndrome is characterised by a spectrum of progressive damage, from mild creatinine increase to renal injury to a more severe form, failure: this important concept should increase clinicians awareness to every form[ncbi.nlm.nih.gov]
  • Stage II, acute kidney injury, is when the creatinine increases by over 200 percent. And stage III is when it increases by over 300 percent, or a threefold increase.[ucsfhealth.org]
  • What if the creatinine increased only 0.1 mg/dl each day? Answer: AKI cannot be diagnosed until the creatinine reaches 3.6 mg/dl (1.5x baseline).[clinicaladvisor.com]
  • The magnitude of acute serum creatinine increase after cardiac surgery and the risk of chronic kidney disease, progression of kidney disease, and death . Arch. Intern. Med. 171 , 226–233 (2011). 79. Coca, S. G. , Singanamala, S. & Parikh, C. R.[nature.com]
Hyponatremia
  • Treatment of hyponatremia is generally free-water restriction. In patients with severe AKI and more profound hyponatremia, renal replacement therapy may be necessary.[renalandurologynews.com]
  • ., hyponatremia), the clinician must be cautious to interpret laboratory data in the clinical context. The most obvious example is with laboratory errors or errors in reporting.[clinicaladvisor.com]
  • ., hyperkalemia, hyperphosphatemia, hypermagnesemia, hyponatremia, hypernatremia, metabolic acidosis) is important.[aafp.org]

Treatment

Complicated and advanced cases of AKF are confined in the intensive care unit of the hospital and treated as a medical emergency. Catheterization, endoscopy or surgery are indicated in cases of postrenal AKF or obstruction of the renal outflow.

Uncomplicated cases of less than 5 days duration, without infection or malignancy may heal spontaneously with palliative procedures alone. Restoring normal kidney function can be attained by:

  • Regulating or restricting the use of certain medications
  • Maintaining proper nutrition.
  • Restricting fluids, dietary sodium, phosphorus and potassium.
  • Regulating blood levels of potassium and phosphate.
  • Initiating dialysis.

For anemia, infusion of crystalloid (normal saline or lactated Ringers) or colloid (in cases of significant hypoalbuminemia) fluids with packed RBCs is recommended [2]. Use of semisynthetic hydroxyethyl starch has been linked to higher mortality rates [11]. Blood transfusion is optional if only 1 unit is required. Fluid resuscitation should be managed by an expert in this procedure.

Proper diet, with protein equivalent to 0.8 to 1 grams per kilogram of body weight (0.4 to 0.5 grams per pound) may be prescribed. No foods that are high in phosphorus (e.g., liver, nuts, dairy products, legumes, and soft drinks) to lower the phosphorus concentration in the blood. Calcium salts (calcium carbonate or calcium acetate) or sevelamer may be taken orally to lower phosphate levels in the blood. To reduce potassium level in the blood, sodium polystyrene sulfonate may be given per orem or via the rectum.

Prolonged AKF leads to the accumulation of metabolic wastes and excess fluids in the blood, necessitating removal of these by hemodialysis. Dialysis is initiated as per need or in some cases repeated for several weeks until the kidneys normal function is restored.

Prognosis

Recovery from acute kidney failure is determined by the nature and location of the underlying cause of the disease. Prognosis is good and full recovery may be expected when the disease process does not involve direct damage to the kidney parenchyma itself. Partial recovery is possible in cases where there is residual pathology. Prognosis is poor when the patient is in the advanced stage of disease at the onset of renal failure. Mortality is high in severe cases of acute renal injury [9].

In a longitudinal study of 1-10 years period, about 12.5% of survivors of acute renal failure had to undergo dialysis; 19-31% of these patients had chronic kidney disease. The mortality rate in hospitalized AKF patients is 40- 50%. The mortality rate among ICU patients with acute kidney failure requiring dialysis is 70-to 80%.

Etiology

The underlying causes of acute kidney failure by location of injury [3]:

Epidemiology

Acute kidney injury is an escalating problem of clinical and public health importance. Two to three cases per 1,000 persons are diagnosed each year [4]. Seven percent of in-patients and 75% of severely ill patients develop the disease in conjunction with multiple organ disorders.

Sex distribution
Age distribution

Pathophysiology

Low blood pressure or slow blood flow to the kidneys diminishes the kidney's filtration function, causing the accumulation of nitrogenous waste products in the blood (prerenal azotemia). Consequently, the kidneys respond to the decrease in glomerular filtration rate by reabsorbing sodium and water back into the blood stream to maintain electrolyte and fluid balance. Baroreceptors in the carotid artery and aortic arch likewise respond by causing vasoconstriction of the glomerular efferent arteriole and dilatation of the afferent arteriole to limit glomerular filtration. The renin/angiotensin/aldosterone system is activated, whereby, angiotensin II, another vasoconstrictor, causes aldosterone to be released and resulting in reabsorption of sodium and water at the renal tubules. Hypovolemia (low blood volume) likewise stimulates the hypothalamus to signal the release of ADH (anitdiurectic hormone or vasopressin), leading to further resorption of water in the tubules thus, concentrating the urine.

After glomerular dysfunction, direct damage to the kidneys is brought about by pathophysiological processes involving the inner wall of small blood vessels and death of epithelial cells in the renal tubules or acute tubular necrosis (ATN), secondary to ischemia (lack of oxygen) of the kidneys. Damage is most severe in the proximal part of the tubule and outer layers of the medulla. Incremental reactive oxygen species, decreased ATP, and death of cells are the results of hypoxemia [5]. Immune-mediated reactions such as, activation of complement, participation of cytokines, chemokines, neutrophils, complement-mediated attack on membranes, and vasoactive hormones all contribute to disrupting the integrity of the renal parenchyma. Exposure to poisons, medications, and contrast dye used for x-ray studies may also cause ATN. Toxicity to cells from the dye  and constriction of blood vessels were observed in animal models. These resulted in increased viscosity, low oxygen tension in the blood and poor circulation in the renal medulla [6].

Renal injury at the level of the ureters is associated with blocked tubules resulting from increased internal pressure causing ischemia and degeneration. Presence of monocytes and macrophages, cytokines, free radicals, proteases, and TNF-beta are linked to direct damage on the tubules and fibrosis [7].

The possible involvement of a genetic component in the etiology of AKI is being considered with apolipoprotein E (APO-E) genes [8]. More genes may be anticipated in future studies.

Prevention

The National Institute for Health and Care Excellence (NICE/UK) recommends eliminating the causes of acute kidney failure as the best strategy for prevention [12]. NICE guidance of 2013 emphasizes the importance of early detection of patients at risk by monitoring their urinary output and creatinine levels. Risk factors such as nephrotoxic drugs and iodinated contrast agents should be avoided. These guidelines apply to all acutely ill patients in hospital. An alternative to the use of contrast dye is intravenous volume expansion with isotonic sodium bicarbonate or 0.9% sodium chloride [13].

Summary

Acute kidney failure (AKF), also referred to as acute kidney injury or acute renal failure, is the sudden disruption of renal filtration function, resulting in the accumulation of metabolic wastes and electrolytes in the blood, which is life-threatening. AKF is known to occur in hospitalized patients, especially those who are in an advanced stage of illness and who are, therefore, the most vulnerable among high risk groups. AKF may develop within hours or, at most, a few days, and as such, it is treated as a medical emergency. Presumably, except in the case of a patient with severe disease or multiorgan dysfunction, it is possible to reverse the damage to the kidneys and to recover from AKF.

The organization Kidney Disease: Improving Global Outcomes (KDIGO) considers a case as acute kidney failure when [1]:

  • The urine output is <0.5 mL/kg/hour for 6 hours or
  • Serum creatinine level increase by ≥0.3 mg/dL within 48 hours; or
  • Serum creatinine is ≥1.5 times of baseline, for 7 days prior to consultation.

The pathophysiology of AKF [2] can be classified into three subgroups:

  • Prerenal AKF due to decline in filtration function
  • Intrinsic AKF due to direct damage to the kidneys
  • Postrenal AKF due to impairment of excretory function

The cause of AKF is multifactorial based on the aforementioned classification. It ranges from impairment of blood flow to the kidneys, to infections and malignancies, and obstruction of the ureters. Symptoms are oftentimes generalized or mimic other diseases. Diagnosis is based on laboratory examinations and confirmatory imaging studies of the underlying causes of AKF. The rationale of treatment is to eliminate the causes and to restore the normal functioning of the kidneys. Prevention depends on a large extent on primary health care and avoidance of the predisposing conditions.

Patient Information

Acute kidney failure (AKF) is the sudden inability of the kidneys to filter off excess salts, fluids, and waste materials from the blood, which, if left untreated, can lead to fatal consequences. In-patients who are severely ill, are most likely to develop AKF. Sudden onset and rapid progression of the disease characterize AKF in contrast to chronic kidney disease in which the loss of kidney function is gradual and lasts over a long period of time. The cause of AKF is diverse which ranges from infection, trauma, pathophysiological processes, autoimmunity, systemic diseases, to malignancy. AKF occurs in three stages:

  • Prerenal - impairment of the filtering function.
  • Intrinsic - direct damage to the kidney tissue.
  • Postrenal - obstruction with excretion of urine via the ureters.

Causes

Conditions that predispose to acute kidney failure are: autoimmune diseases (e.g., acute nephritic syndrome and interstitial nephritis); acute tubular necrosis (ATN); severe or sudden dehydrationurinary tract obstruction; and toxicity from poisons or certain medications.

Reduced blood flow that are associated with the following conditions can impair kidney functions. These are: hemorrhageseptic shock, dehydration, low blood pressure, burns, trauma, serious illness, and surgery.

Conditions that are associated with clotting of blood, leading to AKF include: transfusion reactionhemolytic uremic syndromescleroderma; idiopathic thrombocytopenic thrombotic purpura (ITTP); and malignant hypertension.

Other conditions that can cause complications and damage the kidneys are: infections, such as septicemia and acute pyelonephritisplacenta previa and placenta abruption in pregnancy.

Symptoms

Symptoms that can occur abruptly and progress rapidly in AKF are edema and crackling sound in the lungs (due to fluid retention), nausea and vomitingconfusion, low back pain, dehydration, abdominal pain, and high blood pressure.

Diagnosis

Routine laboratory tests for AKF include serum creatinine, creatinine clearance time, blood urea nitrogen (BUN), serum potassium, serum sodium, urinalysis (microscopy), estimated glomerular filtration rate (eGFR) and certain blood tests (optional). Preferred imaging procedure is ultrasound, others that can be helpful in detecting postrenal dysfunction are X-ray, MRI, and CT scan.

Treatment

Treatment is based on mitigating and if possible, eliminating the conditions which lead to the development of AKF. Complete recovery is not always possible, but repair of the damage to the kidneys should at least restore part of the filtration function and normal physiologic responses. Early detection and prompt intervention can reverse the threat to human life.

Dietary restriction must be observed in terms of kinds and amount of fluids, protein (low), salt (low), carbohydrates (high) and potassium (low) to prevent the accumulation of toxic substances in the kidneys.

Prescriptions of antibiotics, for infection; diuretics, to facilitate excretion of urine; calcium and insulin, to regulate blood potassium levels must be complied with.

Dialysis may be needed to facilitate removal of accumulated nitrogenous waste in the blood. It is mandatory in cases of cessation of micturation, dementia, pericarditis, and high potassium blood level.

References

Article

  1. Kidney disease: improving global outcomes (KDIGO) Acute Kidney Injury Work Group. KDIGO clinical practice guideline for acute kidney injury. Kidney Inter Suppl. 2012; 2:1-138.
  2. Sharfuddin AA, Weisbord SD, Palevsky PM, et al. Acute kidney injury. In: Taal MW, Chertow GM, Marsden PA, et al, eds. Brenner and Rector's The Kidney. 9th ed. Philadelphia, PA: Saunders; 2012.
  3. Lameire N, Van Biesen W, Vanholder R. Acute renal failure. Lancet. 2005; 365:417-430.
  4. Hoste EA, Schurgers M. Epidemiology of acute kidney injury: how big is the problem? Crit Care Med. 2008; 36(4 suppl):S146–S151.
  5. Kaushal GP, Basnakian AG, Shah SV. Apoptotic pathways in ischemic acute renal failure. Kidney Int. 2004; 66:500-506.
  6. Weisberg LS, Kurnik PB, Kurnik BR, et al. Radiocontrast induced nephropathy in humans. Role of renal vasoconstriction. Kidney Int. 1992; 41:1408-1415.
  7. Schreiner GF, Kohan DE. Regulation of renal transport processes and hemodynamics by macrophages and lymphocytes. Am J Kidney Dis. 1990; 258:F761-F767.
  8. Lu JC, Coca SG, Patel UD, et al. Searching for genes that matter in acute kidney injury: a systematic review. Clin J Am Soc Nephrol. 2009; 4:1020-1031.
  9. Goldberg R, Dennen P. Long-term outcomes of acute kidney injury. Adv Chronic Kidney Dis. 2008; 15(3):297–307.
  10. Davis PC, Wippold FJ II, Cornelius RS, et al. ACR Appropriateness Criteria® renal failure. National Guideline Clearinghouse. Accessed: March 24, 2011. 8 p.
  11. Zarychanski R, Abou-Setta AM, Turgeon AF, et al. Association of hydroxyethyl starch administration with mortality and acute kidney injury in critically ill patients requiring volume resuscitation: a systematic review and meta-analysis. JAMA. 2013; 7:678-688.
  12. Fliser D, Laville M, Covic A, et al; A European Renal Best Practice (ERBP) position statement on the Kidney Disease Improving Global Outcomes (KDIGO) clinical practice guidelines on acute kidney injury: part 1: definitions, conservative management and contrast-induced nephropathy. Nephrol Dial Transplant. 2012 Dec; 27(12):4263-72.
  13. Acute kidney injury - Prevention, detection and management of acute kidney injury up to the point of renal replacement therapy; NICE Guidelines (Aug 2013).

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Last updated: 2018-06-22 03:46