Kidney Stones/ Renal Calculi

Renal Calculi/ Stones can be formed in the kidney, pelvis or ureter, when the concentration of the components in the urine reaches a level in which crystallization is possible. The process of stone formation is also called nephrolithiasis or urolithiasis.

A Kidney stone is a solid mass that consists of a collection of tiny crystals. There can be one or more stones present at the same time in the kidney or in the ureter. They are generally composed of calcium salt, uric acid, cystic or struvite (triple salt of ammonium, magnesium and phosphorus).

Calcium stones are caused due to excess intake of calcium oxalate, hypervitaminosis D, hyperparathyroidism, prolonged bed test, renal tubular acidosis, and idiopathic hypercalciuria.

Struvite stones are caused mostly due to urinary tract infection.

Uric acid stones are caused due to impaired purine metabolism with increased urinary excretion of uric acid.

Cystine stones are caused due to hereditary metabolic defect in renal tubular reabsorption.

Hot climates leading to over concentrated urine, changes in pH of urine also predispose to stone formation. Deficiency of Vitamin B₆ and magnesium Also play a role in the causation of these stones.

These stones do not produce any symptoms until they begin to move down the ureter, causing pain. The pain is usually severe and often starts in the flank region, often moves to the groin. The patient experiences blood in the urine, severe pain, weakness and in some cases fever.

The role of the dietary management is to relieve symptoms and prevent further complications.

In acute stage with less than 5mm in diameter, it may pass in the urine by drinking large quantities of fluid especially water and needs no specific treatment. Stones more than 7mm in diameter may require surgical treatment or lithotripsy by which large stones are broken down and excreted in the urine.

It is advisable to have liberal fluid intake, a balanced diet and restrict foods based on the main constituents of the stones.

The diet restrictions for different types of stones are:

Type of stone	Diet restriction
Calcium stones -          Phosphate -          Oxalate	Calcium – 400 – 600 mg Phosphorus – 1000-1200 mg
Struvite stones	Low phosphorus diet
Uric acid	Low purine diet
Cystine	Low methionine diet

Potassium content of food can be reduced by leaching the foods rich in the nutrient by the following methods:

• Wash, peel and cut vegetables into small pieces. Soak in warm water for 2-3 hours. Discard water. Add large volume of fresh water and cook the vegetables. Discard water.
• Peel vegetables and cut into small pieces. Bring to boil in a large quantity of water. Discard excess water and cook in a large volume of fresh water. Discard excess water.

Sources of potassium in the diet (Potassium/100 g vegetable) are as follows:

0 - 100 mg	101 – 200 mg	201 mg and above
Beetroort Bottlegourd Broad beans Cucumber Field beans Green mango Peas Lettuce Fenugreek leaves	Bitter gourd Brinjal Cauliflower Cabbage Carrot Onion (small) Radish white Ladies finger Pumpkin Green tomato	Amaranth Coriander leaves Drumstick leaves Spinach Colocasia Potato Sweet potato Tapioca Green papaya Yam

Sources of sodium, calcium, oxalate and Uric acid are as follows:

Post by Faiz Lahori

Dialysis

End stage renal disease (ESRD) is a condition when kidneys have lost all or most of their ability to function with GFR < 5ml/minute. The treatment of ESRD includes dialysis – haemodialysis (HD) and peritoneal dialysis (PD) – and Kidney Transplantation.

The process of dialysis involves cleansing the blood of metabolic wastes, based on the principle of osmosis and diffusion. A semi-permeable porous membrane is used in dialysis to separate the patient blood carrying excess fluid and metabolic wastes and the hypotonic “dialysis fluid” called dialysate. Through osmosis and diffusion, the metabolic waste and excess water move into the dialysate. The pores of the semi-permeable membrane do not permit large particles like protein and RBC to pass through, but smaller water-soluble molecules can pass.

In Haemodialysis (HD), patient’s blood circulates outside the body through what is commonly referred to as an “artificial kidney machine”. An opening is created to connect an artery and a vein. Blood leaves the body via the artery, into the dialyser and after cleansing, flow back to the body via the vein as shown in the picture below.

In Peritoneal Dialysis (PD), the patient’s peritoneum is used as the semi permeable membrane and excess water and metabolic wastes are removed by injecting the dialysis fluid into the peritoneal cavity as shown in the picture below. After some time, the fluid with the metabolic waste is drained out from the peritoneum. Peritoneal dialysis is less effective than haemodialysis and can result in loss of intact large molecular proteins also.

For long-term use, continuous ambulatory peritoneal dialysis (CAPD) maybe used based on facilities available. In this, the dialysis fluid is exchanged 4-5 times daily.

The objectives of dietary management in ESRD with dialysis are to maintain balance of protein, energy, fluid and electrolytes, calcium and phosphorus, while making up losses of water-soluble nutrients lost in the dialysate.

The Nutrient requirement for adults with End stage renal disease based on type of therapy is as follows:

Therapy	Energy (Kcal/kg BW)	Protein (g/kg IBW)	Fluid (ml/day)	Sodium (g/day)	Potassium (g/day)	Phosphorus (g/day)
Haemodialysis	35	1	500 + urine	Variable	2- 3	1 – 1.2
Intermittent Peritoneal Dialysis (IPD)	30 (40-50 for repletion)	1.2	500 + urine output	2 – 3	2 – 3	1 – 1.2
Continuous Ambulatory Peritoneal Dialysis (CAPD)	25 (40-50 for repletion)	1.2	Minimum or 2000 ml/day + urine output	6 – 8	3 – 4	1.5 - 2

Also read on other Diseases of the Kidney in the Diet Corner column.

Post by Faiz Lahori

Nephrotic Syndrome

Nephrotic syndrome is a disorder where the kidneys have been damaged, causing them to leak protein from blood into the urine. It is also termed as Nephrosis. 

The causes of nephritic syndrome are progressive glomerulonephritis, disease such as diabetes, collagen disease or drug reactions, from exposure to heavy metals, or even from a reaction to toxin venom following a bee sting.

It is characterized by massive oedema and protinuria, hypoalbuminemia (low levels of albumin in blood), hypercholesterolemia (high cholesterol levels in blood) and abnormal bone metabolism. Pedal (foot) and periorbital (around the orbit of the eye) oedema and ascitis (fluid in abdominal cavity) are common. The continued loss of protein may cause tissue breakdown and lead to malnutrition.

As the disease progresses, calcium or phosphate levels in blood maybe altered due to altered Vitamin D levels, resulting in oesteomalacia.

The major objectives of dietary management of this condition are to control and correct protein deficiency and correct and prevent oedema and maintain adequate nutrition to afford better resistance to infection.

The dietary guidelines for nephritic syndrome are as below.

Also read on other Diseases of the Kidney in the Diet Corner column.

Post by Faiz Lahori

Glomerulonephritis – Swelling in the small blood vessels in the head of the Nephron

Image Courtesy: http://www.unckidneycenter.org/

Glomerulonephritis is an inflammatory process affecting the glomeruli – the tuft of capillaries in the bowman’s capsule of a nephron in the kidney.  It is common in its acute form in children 3 to 10 years of age but can also occur in adults past the age 50. It starts suddenly and is short lived, it can either recover completely or lead to development of chronic nephritic syndrome. It is generally caused by streptococcal infection, renal infarction, acute polynephritis and metallic poisoning.

The classic symptoms of glomerulonephritis are haematuria (blood in urine) and proteinuria (protein in urine). Odema and shortness of breath can occur as a result of sodium and water retention and circulatory congestion. Tachycardia (Faster heart rate) and elevated BP may also be present. The patient is aneroxic leading to feeding problems. Presence of oliguria (lower urine production) or anuria (no urine production) and uremia (urea in blood) shows development of acute renal failure.

As a part of dietary management, adequate proteins should be given unless there is development of oliguria or anuria. Salt is restricted in case of oedema, hypertension or oliguria. Sufficient simple and complex carbohydrates have a protein sparing action. Fat should be given based on tolerance. Bed rest and antibiotic drug therapy are the main treatment. The fluid intake will be adjusted to output including losses in vomiting or diarrhea.

The dietary treatment of this condition is as follows:

Also read on other Diseases of the Kidney in the Diet Corner column.

Post by Faiz Lahori