Kidney

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Kidney

• The kidneys are paired organs, which have the
  production of urine as their primary function

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• The two kidneys are bean-shaped organs located
  near the middle of the back, just below the rib
  cage to the left and right of the spine.
• Each about the size of a fist, these organs act
  as sophisticated filters for the body.
• They process about 200 quarts of blood a day to
  sift out about 2 quarts of waste products and
  extra water that eventually leave the body as
  urine.

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• Blood enters the kidneys through arteries that
  branch inside the kidneys into tiny clusters of
  looping blood vessels.
• Each cluster is called a glomerulus, which comes
  from the Greek word meaning filter.
• The plural form of the word is glomeruli.
• There are approximately 1 million glomeruli, or
  filters, in each kidney.
• The glomerulus is attached to the opening of a
  small fluid-collecting tube called a tubule.
• Blood is filtered in the glomerulus, and extra
  water and wastes pass into the tubule and become
  urine.
• Eventually, the urine drains from the kidneys
  into the bladder through larger tubes called
  ureters.

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• secondary functions concerned with homeostatic
  functions.
• These include the regulation of electrolytes,
  acid-base balance, and blood pressure.
• In producing urine, the kidneys excrete wastes
  such as urea and ammonium
• The kidneys also are responsible for the
  reabsorption of glucose and amino acids.
• Finally, the kidneys are important in the
  production of hormones including vitamin D, renin
  and erythropoietin.

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• Located behind the abdominal cavity in the
  retroperitoneum, the kidneys receive blood from
  the paired renal arteries, and drain into the
  paired renal veins.
• Each kidney excretes urine into a ureter, itself
  a paired structure that empties into the urinary
  bladder.

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• The substance, or parenchyma, of the kidney is
  divided into two major structures superficial is
  the renal cortex and deep is the renal medulla.
• Grossly, these structures take the shape of 8 to
  18 cone-shaped renal lobes, each containing renal
  cortex surrounding a portion of medulla called a
  renal pyramid (of Malphigi).
• Between the renal pyramids are projections of
  cortex called renal column

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• Renal physiology is the study of kidney
• function,
• while nephrology is the medical
• specialty concerned with diseases of the
• nephron,
• which is the functional unit of the kidney.

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Glomerular Diseases

• Many diseases affect kidney function by attacking
  the glomeruli, the tiny units within the kidney
  where blood is cleaned.
• Glomerular diseases include many conditions with
  a variety of genetic and environmental causes,
  but they fall into two major categories
• Glomerulonephritis (gloh-MEHR-yoo-loh-nef-RY-tis)
• Describes the inflammation of the membrane tissue
  in the kidney that serves as a filter, separating
  wastes and extra fluid from the blood.
• Glomerulosclerosis (gloh-MEHR-yoo-loh-skleh-ROH-si
  s)
• Describes the scarring or hardening of the tiny
  blood vessels within the kidney.
• Although glomerulonephritis and
  glomerulosclerosis have different causes, they
  can both lead to kidney failure.

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• Each glomerulus-and-tubule unit is called a
  nephron.
• Each kidney is composed of about 1 million
  nephrons.
• In healthy nephrons, the glomerular membrane that
  separates the blood vessel from the tubule allows
  waste products and extra water to pass into the
  tubule while keeping blood cells and protein in
  the bloodstream.

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• Glomerular diseases damage the glomeruli, letting
  protein and sometimes red blood cells leak into
  the urine.
• Sometimes a glomerular disease also interferes
  with the clearance of waste products by the
  kidney, so they begin to build up in the blood.

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• Furthermore, loss of blood proteins like albumin
  in the urine can result in a fall in their level
  in the bloodstream.
• In normal blood, albumin acts like a sponge,
  drawing extra fluid from the body into the
  bloodstream, where it remains until the kidneys
  remove it.
• But when albumin leaks into the urine, the blood
  loses its capacity to absorb extra fluid from the
  body.
• Fluid can accumulate outside the circulatory
  system in the face, hands, feet, or ankles and
  cause swelling.
• Top

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Symptoms of glomerular disease

• proteinuria large amounts of protein in the
  urine
• hematuria blood in the urine
• reduced glomerular filtration rate inefficient
  filtering of wastes from the blood
• hypoproteinemia low blood protein
• edema swelling in parts of the body

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• some of these symptoms have signs, or visible
  manifestations
• Proteinuria may cause foamy urine.
• Blood may cause the urine to be pink or
  cola-colored.
• Edema may be obvious in hands and ankles,
  especially at the end of the day, or around the
  eyes when awakening in the morning, for example.

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DIAGNOSIS

• URINE ANALYSIS-
• protein in the urine-
• which may be referred to as nephrotic range if
  levels are very high.
• Red blood cells in the urine
• are a frequent finding as well, particularly in
  some forms of glomerular disease .
• Urinalysis provides information about kidney
  damage by indicating levels of protein and red
  blood cells in the urine.

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• Blood tests-measure the levels of waste products
  such as
• creatinine
• urea nitrogen
• To determine whether the filtering capacity of
  the kidneys is impaired.
• If these lab tests indicate kidney damage,
• ultrasound or an x ray to see whether the shape
  or size of the kidneys is abnormal.
• These tests are called renal imaging.

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• But since glomerular disease causes problems at
  the cellular level.
• kidney biopsya procedure in which a needle is
  used to extract small pieces of tissue for
  examination with different types of microscopes,
  each of which shows a different aspect of the
  tissue.
• A biopsy may be helpful in confirming glomerular
  disease and identifying the cause.

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• causes glomerular disease-
• A number of different diseases can result in
  glomerular disease.
• It may be the direct result of an infection or a
  drug toxic to the kidneys,
• or it may result from a disease that affects the
  entire body, like diabetes or lupus.
• Many different kinds of diseases can cause
  swelling or scarring of the nephron or
  glomerulus.
• Sometimes glomerular disease is idiopathic,
  meaning that it occurs without an apparent
  associated disease.

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• can overlap
• that is, a disease might belong to two or more
  of the categories.
• For example, diabetic nephropathy is a form of
  glomerular disease that can be placed in two
  categories
• systemic diseases, since diabetes itself is a
  systemic disease,
• and sclerotic diseases, because the specific
  damage done to the kidneys is associated with
  scarring.

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Proximal tubule

• The proximal tubule is the portion of the duct
  system of the nephron leading from Bowman's
  capsule to the loop of Henle.
• The most distinctive characteristic of the
  proximal tubule is its brush border (or "striated
  border").
• The luminal surface of the epithelial cells of
  this segment of the nephron is covered with
  densely packed microvilli forming a border
  readily visible under the light microscope.
• The microvilli greatly increase the luminal
  surface area of the cells, presumably
  facilitating their resorptive function.

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• The proximal tubule as a part of the nephron can
  be divided into two sections,
• pars convoluta
• pars recta.
• Differences in cell outlines exist between these
  segments, and therefore presumably in function
  too.

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• Pars convoluta
• The "Pars convoluta" is the initial convoluted
  portion.
• In relation to the morphology of the kidney as a
  whole, the convoluted segments of the proximal
  tubules are confined entirely to the renal cortex.

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• Pars recta
• The "Pars recta" is the following straight
  (descending) portion.
• Straight segments descend into the outer medulla.
• Secretion
• Many types of medications are secreted in the
  proximal tubule

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• Substance -salt and water -salt and
  waterapproximately two-thirds.
• organic solutes (primarily glucose and amino
  acids)-100
• Potassium-65
• Urea-50
• Phasphate-80

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• Pathophysiology in kidney disease
• Proximal tubular epithelial cells (PTECs) have a
  pivotal role in kidney disease.
• Malignant
• Most renal cell carcinoma, the most common form
  of kidney cancer, arises from the convoluted
  tubules.

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• Non-malignant
• Acute tubular necrosis occurs when PTECs are
  directly damaged by toxins such as
• Antibiotics (e.g. gentamicin),
• Pigments (e.g. myoglobin and sepsis (e.g.
  mediated by lipopolysaccharide from gram negative
  bacteria).
• Renal tubular acidosis (proximal type) (Fanconi
  syndrome) occurs when the PTECs are unable to
  properly reabsorb glomerular filtrate so that
  there is increased loss of bicarbonate, glucose,
  amino acids and phosphate.

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• Diseases of the kidney are diverse, but
  individuals with kidney disease frequently
  display characteristic clinical features. Common
  clinical presentations include the nephritic and
  nephrotic syndromes,
• acute kidney failure,
• chronic kidney disease,
• urinary tract infection, nephrolithiasis, and
  urinary tract obstruction.

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• Nephritic syndrome (or acute nephritic syndrome)
• Is a collection of signs (known as a syndrome)
  associated with disorders affecting the kidneys,
  more specifically glomerular disorders.
• It's characterized by having small pores in the
  podocytes of the glomerulus, large enough to
  permit proteins (proteinuria) and red blood cells
  (hematuria) to pass into the urine.
• By contrast, nephrotic syndrome is characterized
  by only proteins (proteinuria) moving into the
  urine.
• Both nephritic syndrome and nephrotic syndrome
  result in hypoalbuminemia due to protein mainly
  albumin moving from the blood to the urine.

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• Hematuria can be caused by bleeding anywhere in
  the urinary tract, but if the RBCs are trapped in
  urinary casts, it is more likely that the
  bleeding originated in the nephron, and Nephritic
  syndrome becomes more probable .

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• Signs and symptoms
• Nephritic syndrome is characterized by
• hematuria (blood in the urine), with red blood
  cell (RBC) casts present in the urine
• proteinuria (protein in the urine) - small
  amounts of protein are lost in the urine, but
  this is usually trivial (lt3.5 g/day)
• hypertension (high blood pressure)- mild
• uremia - due to retention of waste products

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• and variable renal insufficiency, with
• azotemia (elevated blood nitrogen)
• oliguria (low urine output lt400 mL/day)
• The main features are hypertension and RBC casts.
  The proteinuria in nephritic syndrome is not
  usually severe, but may occasionally be heavy
  enough to be in the range usually found in
  nephrotic syndrome.
• Mnemonic PHAROH Proteinuria, Hematuria,
  Azotemia, RBC casts, Oliguria, Hypertension.

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• Nephrotic syndrome (NS), also known as nephrosis,
  is defined by the presence of-
• Nephrotic-range proteinuria,
• Edema,
• Hyperlipidemia.
• Hypoalbuminemia.
• Nephrotic-range proteinuria in adults is
  characterized by protein excretion of 3.5 g or
  more per day.

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Acute Renal Failure

• Acute renal failure (ARF) is the rapid breakdown
  of renal (kidney) function that occurs when high
  levels of uremic toxins (waste products of the
  body's metabolism) accumulate in the blood.
• ARF occurs when the kidneys are unable to
  excrete (discharge) the daily load of toxins in
  the urine

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• Based on the amount of urine that is excreted
  over a 24-hour period, patients with ARF are
  separated into two groups
• Oliguric patients who excrete less than 500
  milliliters per day (lt 16 oz/day)
• Nonoliguric patients who excrete more than 500
  milliliters per day (gt 16 oz/day)

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• In nonoliguric patients, the urine is of poor
  quality (i.e., contains little waste) because the
  blood is not well filtered, despite the fact that
  an adequate volume of urine is excreted.
• Both kidneys are failing when ARF occurs.
• One normally functioning kidney can maintain
  adequate blood filtering.

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• Definition
• Chronic kidney failure is a gradual loss of your
  kidneys' filtering ability, usually due to high
  blood pressure or diabetes.
• When kidney function is seriously impaired,
  dangerous levels of fluid and waste can quickly
  accumulate in your body.
• In the early stages of chronic kidney failure,
  you may have few signs or symptoms.
• Many people with chronic kidney failure don't
  realize they have a problem until their kidney
  function has decreased to less than 25 percent of
  normal.

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• The main goal of treatment of chronic kidney
  failure is to halt or delay progression of the
  disease, usually by controlling the underlying
  cause.
• Chronic kidney failure can progress to end-stage
  kidney disease, which is fatal without artificial
  filtering (dialysis) or a kidney transplant.

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• Symptoms
• Signs and symptoms may include some or many of
  the following
• High blood pressure
• Decreased urine output or no urine output
• Darkly colored urine
• Anemia
• Nausea or vomiting

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• Loss of appetite
• Sudden weight change
• A general sense of discomfort and unease
  (malaise)
• Fatigue and weakness
• Headaches that seem unrelated to any other cause
• Sleep problems
• Decreased mental sharpness

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• Definition of Pyelonephritis
• Pyelonephritis is a serious bacterial infection
  of the kidney that can be acute or chronic.
• It presents with dysuria (painful voiding of
  urine), abdominal pain (radiating to the back on
  the affected side)
• and tenderness of the bladder area and the side
  of the involved kidney (costovertebral angle
  tenderness) which may be elicited by performing
  the kidney punch

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• In many cases there are systemic symptoms in the
  form of fever, rigors (violent shivering while
  the temperature rises), headache, and vomiting.
• In severe cases, delirium may be present.
• Severe cases of pyelonephritis lead to sepsis, a
  systemic response to infection characterized by
  fever, a raised heart rate, rapid breathing and
  decreased blood pressure (occasionally leading to
  septic shock).

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• Causes
• Most cases of "community-acquired" pyelonephritis
  are due to bowel organisms that enter the urinary
  tract.
• Common organisms are E. coli (70-80) and
  Enterococcus faecalis.
• Hospital-acquired infections may be due to
  coliforms and enterococci, as well as other
  organisms uncommon in the community (e.g.
  Klebsiella spp., Pseudomonas aeruginosa).
• Most cases of pyelonephritis start off as lower
  urinary tract infections, mainly cystitis and
  prostatitis.

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• Pathology
• Acute pyelonephritis is an exudative purulent
  localized inflammation of the renal pelvis
  (collecting system) and kidney.
• The renal parenchyma presents in the interstitium
  abscesses (suppurative necrosis), consisting in
  purulent exudate (pus) neutrophils, fibrin, cell
  debris and central germ colonies
  (hematoxylinophils).
• Tubules are damaged by exudate and may contain
  neutrophil casts. In the early stages, glomeruli
  and vessels are normal.

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• . Gross pathology often reveals pathognomonic
  radiations of hemorrhage and suppuration through
  the renal pelvis to the renal cortex.
• Chronic infections can result in fibrosis and
  scarring.
• Xanthogranulomatous pyelonephritis is a form of
  chronic pyelonephritis associated with
  granulomatous abscess formation and severe kidney
  destruction.

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• Diagnosis
• The presence of nitrite and leukocytes (white
  blood cells) on a urine dipstick test in patients
  with typical symptoms are sufficient for the
  diagnosis of pyelonephritis, and are an
  indication for empirical treatment.
• Formal diagnosis is with culture of the urine
  blood cultures may be needed if the source of the
  infection is initially doubtful.
• If a kidney stone is suspected (e.g. on the basis
  of characteristic colicky pain, disproportionate
  amount of blood in the urine),
• X-rays of the kidneys, ureters and bladder (KUB)
  may assist in identifying radioopaque stones.

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• In patients with recurrent ascending urinary
  tract infections, it may be necessary to exclude
  an anatomical abnormality, such as vesicoureteral
  reflux (urine from the bladder flowing back into
  the ureter) or polycystic kidney disease.
  Investigations that are commonly used in this
  setting are ultrasound of the kidneys or voiding
  cystourethrography .

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• Description of Pyelonephritis
• One of the most common renal diseases, acute
  pyelonephritis is a sudden inflammation caused by
  bacteria.
• It primarily affects the interstitial area and
  the renal pelvis or, less often, the renal
  tubules.

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• .

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• There may be irritative voiding symptoms (burning
  when urinating, a sense of urgency, or increased
  frequency of urination).
• In acute infections, the symptoms develop
  rapidly, the fever noted first, followed by
  possible changes in the color of the urine, and
  then tenderness in the flank.

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• . As the kidney becomes more inflamed, pain, loss
  of appetite, headache, and all the general
  effects of infection develop. This type of kidney
  pain differs from renal colic pain of kidney
  stones in that it is continuous and does not come
  in waves, stays in one spot, and may be worse by
  moving around .

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• Diagnosis of Pyelonep
• Take a medical history,
• perform a physical exam,
• and recommend tests including blood tests and
  blood cultures, urinalysis and urine culture, and
  possibly an ultrasound study of the kidneys

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DIALYSIS

• Dialysis is a procedure that is performed
  routinely on persons who suffer from acute or
  chronic renal failure, or who have ESRD.
• The process involves removing waste substances
  and fluid from the blood that are normally
  eliminated by the kidneys.
• Dialysis may also be used for individuals who
  have been exposed to or ingested toxic substances
  to prevent renal failure from occurring.
• There are two types of dialysis that may be
  performed, including the following

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• peritoneal dialysis
• hemodialysis
• Long-term outlook for ESRD
• People with ESRD are living longer than ever.
  Dialysis treatments (both hemodialysis and
  peritoneal dialysis), however, are not cures for
  ESRD, but will help you feel better and live
  longer. Over the years, ESRD can cause other
  problems such as bone disease, high blood
  pressure, nerve damage, and anemia (having too
  few red blood cells).

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Renal cell carcinoma

• Renal cell carcinoma (RCC, also known as
  hypernephroma) is a kidney cancer that originates
  in the lining of the proximal convoluted tubule,
  the very small tubes in the kidney that filter
  the blood and remove waste products.
• RCC is the most common type of kidney cancer in
  adults, responsible for approximately 80 of
  cases.

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• It is also known to be the most lethal of all
  the genitourinary tumors.
• Initial treatment is most commonly a radical or
  partial nephrectomy and remains the mainstay of
  curative treatment.
• Where the tumour is confined to the renal
  parenchyma, the 5-year survival rate is 60-70,
  but this is lowered considerably where metastases
  have spread.
• It is resistant to radiation therapy and
  chemotherapy, although some cases respond to
  immunotherapy.

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Signs and symptoms

• The classic triad is hematuria (blood in the
  urine), flank pain and an abdominal mass. This
  triad only occurs in 10-15 of cases, and is
  generally indicative of more advanced disease.
• Today, the majority of renal tumors are
  asymptomatic and are detected incidentally on
  imaging, usually for an unrelated cause.

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• Classification
• Clear cell carcinoma
• Papillary carcinoma
• Chromophobe renal carcinoma
• Collecting duct carcinoma

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• Gross examination
• shows a yellowish,
• multilobulated tumor
• in the renal cortex,
• which frequently
• contains zones of
• necrosis, hemorrhage
• and scarring.

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• Light microscopy shows tumor cells forming cords,
  papillae, tubules or nests, and are atypical,
  polygonal and large. Because these cells
  accumulate glycogen and lipids, their cytoplasm
  appear "clear", lipid-laden, the nuclei remain in
  the middle of the cells, and the cellular
  membrane is evident.

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• Some cells may be smaller, with eosinophilic
  cytoplasm, resembling normal tubular cells. The
  stroma is reduced, but well vascularized. The
  tumor compresses the surrounding parenchyma,
  producing a pseudocapsule.
• Secretion of vasoactive substances (e.g. renin)
  may cause arterial hypertension, and release of
  erythropoietin may cause erythrocytosis
  (increased production of red blood cells).

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• .