food Feb 23, 2022

To maintain a constant internal environment (homeostasis), the body eliminates the end products of metabolic activities and excess water in the form of urine through kidneys.
Each human kidney contains approximately 1 million functional units called nephrons. The primary function of these nephrons is to regulate water and soluble substances by filtering the blood,  and excreting excess water and nitrogenous wastes in the form of urine.

Azotemia is a medical  condition that occurs when kidneys have been damaged by disease or an injury which can lead to insufficient or dysfunctional filtering of blood by the kidneys.
As a result, abnormally high levels of nitrogen-containing waste  compounds (such as urea, creatinine, various body waste compounds, and other nitrogen-rich compounds) remain in the blood and kidneys can not get rid of enough nitrogen waste. This causes an elevation of blood urea nitrogen (BUN) and serum creatinine levels and this condition is called azotemia.
The normal reference  range for BUN is 8-20 mg/dL, and serum creatinine is 0.7-1.4 mg/dL.

Azotemia has been classified into prerenal azotemia, intrinsic azotemia or renal azotemia, and postrenal azotemia
Prerenal azotemia is the most common type and can be reversed. It occurs when enough fluid is not flowing through the kidneys. Due to the low flow of fluid, the concentrations of serum creatinine and urea will be raised resulting in prerenal azotemia.
Intrinsic azotemia occurs from infection, sepsis, or disease and the most common cause of intrinsic azotemia is acute tubular necrosis.
Postrenal azotemia can also occur with prerenal azotemia and it is caused by the urinary tract obstruction.
If untreated, or if not identified early, all these types of azotemia can lead to uremia and acute (sudden) kidney failure.


  • Abdominal pain
  • Acute kidney injury
  • Acute renal failure (if azotemia continues to progress over a period of hours or days)
  • Asterixis (flapping tremor)
  • Anuria (absence of urine output)
  • Confusion
  • Decreased alertness
  • Edema
  • Fatigue
  • Fluid retention
  • Increased urination at night
  • loss of appetite
  • loss of energy
  • Nausea and vomiting (a sign that indicates that the disease has worsened)
  • Oliguria (decreased urine output)
  • Orthostatic blood pressure (fluctuates depending on body position)
  • Pale skin
  • Tachycardia (rapid pulse)
  • Thirst
  • Uremic frost (a condition that occurs when urea and urea derivatives are secreted through the skin along with sweat, which evaporates away to leave solid uric compounds, resembling a frost).
  • Xerostomia (dry mouth)


The primary cause of azotemia  is loss of kidney function.
The different types of azotemia may occur due to different causes such as failure of kidney to remove enough nitrogen wastes (prerenal azotemia), urinary tract  obstruction (intrinsic azotemia), infection or disease (postrenal  azotemia).

Other causes may be

  • advanced age
  • cancer treatment ( Drugs used in Chemotherapy are powerful and can damage  kidneys. The dying cancer cells release a significant quantity of nitrogen-containing byproducts resulting in azotemia)
    complications of diabetes
  • dehydration
  • heat exposure
  • heart failure
  • history of renal difficulties
  • lowered blood volume
  • severe burns
  • some medications, particularly nephrotoxic drugs and high doses of steroids
    some surgeries
    Many forms of azotemia are treatable and manageable if they are identified early. However, other health conditions and pregnancy can make treatment difficult. If azotemia is left untreated it can result in death. So, visiting the doctor regularly is important.

Complications, other health issues, and kidney disease or injury identified in late stages may require regular dialysis.

Food and diet care

Diet can play an important role in the prevention and treatment of kidney disorders. Eating foods in the right proportions is a crucial part of the treatment.
A carefully controlled renal diet that is low in sodium, phosphorous, potassium and protein can help patients to arrest deterioration of disease.
Food and diet consisting of low salt, low fat and low cholesterol, with emphasis on fruits and vegetables can cut down the amount of waste in the blood. Following a kidney diet may also help promote kidney function and slow the progression of complete kidney failure.
Whole grains, fruits and vegetables can help lower total and LDL cholesterol and 1% or skim dairy products contain low fat.
Diets that contain moderately restricted protein  such as lean  meat, fish, eggs (limit 2 per week), shellfish, beans, nuts and milk should be taken to meet all the body’s protein needs. Protein intake has to be monitored to 15-20% of the total diet.
To control blood glucose levels, carbohydrate intake has to be reduced.
Vegetable and fiber intake has to be increased to maintain bowel habits.
kidney patients should monitor sodium intake. They should restrict the intake of foods which are rich in salt and sodium such as canned soups, fast foods, salty snack foods, canned vegetables, and processed meats and cheeses
Potassium rich foods such as bananas, oranges, potatoes, spinach and tomatoes should be avoided.
Salt substitutes & seasonings with potassium should be avoided.
Milk and dairy products intake has to be limited to 8 oz per day.
High phosphorus levels can disturb phosphorus and calcium balance in the body. High phosphorus levels can pull calcium out of the bones and make them weak. This also leads to dangerous calcium deposits in the blood vessels, lungs, eyes, and heart. Many high quality protein foods such as meat, cheese, eggs and milk contain phosphorus.
The overall fluid intake has to be monitored because drinking too much may encourage edema. To treat fluid retention, herbs like dandelion, rose tea are useful.
Healthy Foods for kidney patients include, red bell peppers, broccoli, cabbage, cauliflower, garlic, onions, apples, cranberries, blueberries, whole-meal biscuits, broad beans, wholemeal pasta, pear, tea, egg, milk, lean lamb chop, small salmon steak (in small proportions)

For patients who have maintained a healthy body weight, a daily intake of 35 Calories per kilo is recommended.
However, it is essential to take medical advice when deciding how to restrict and balance the food intake.

Personal remedies and lifestyle suggestions

  • The primary remedy is, to correct the cause of the imbalance quickly before the kidneys become damaged.
  • To promote the healthy function of the kidneys and prevent damage, a specific diet has to be followed under the guidelines of a dietitian.
  • Physical activity is to be increased. Being active for 30 minutes or more on most days, can help reduce stress, manage body weight, and maintain blood pressure and blood glucose levels.
  • Blood pressure has to be controlled
  • If diabetic, blood glucose level has to be checked regularly
  • Prescribed medicines have to be taken
  • Getting enough sleep, for 7 to 8 hours each night is needed.
  • Cigarette smoking has to be stopped


A. Sandhya

M.Sc Zoology

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