The Urinary system
More about the Kidney
Anatomy and Physiology of the Kidney
The kidneys lie along the borders of the Psoas muscles and are therefore obliquely placed. The position of the liver causes the right Kidney to be lower than the left. The Adult Kidney weighs about 150g. The kidneys are supported by the perirenal fat (which is enclosed in the perirenal fascia), the renal vascular pedicle, abdominal muscle tone, and the general bulk of the abdominal viscera. Variations in these factors permit variations in the degree of the renal mobidity. The average descent on inspiration or on assuming the upright position is 4-5cm.
The Adult Ureter is about 30cm long, varying in direct relation to the height of the individual. It follows a rather smooth S curve. Areas of relative narrowing are found
- at the ureteropelvic junction
- where the ureter crosses over the iliac vessels, and
- where it passes through the bladder wall.
The Adult bladder normally has a capacity of 350ml-450ml. Where empty, the Adult bladder lies behind the pubic symphysis and is largely a pelvic organ.
General/Patient note and main urologic symptoms
The Kidneys play a central role in the maintenance of a constant internal environment for body cells in response to cellular catabolism and wide variations of dietary intake. It achieves this by regulating extracellular fluid and solute concentrations by the excretion of salts, water, metabolic waste products and foreign substances. The process involves the production of a plasma Ultrafiltration of 180L per day. This passes down to about 2 million tubules from which essential solutes and water reasbsorbed into the blood and non-essential solutes secreted from the blood into the remaining fluid which becomes the final urine. The other functions of the kidney incude hormone production and the production of glucose by breaking down other non-carbohydrate substrates (gluconeogenesis).
Main Urologic symptoms
Systemic manifestations, local and referre pain (Kidney pain, Pseudorenal pain, ureteral pain, vesical pain, prostatic pain, testicular pain, epididymal pain, back and leg pain), gastrointestinal symptoms of urologic disease, symptoms related to the act of urination (frequency, nocturia and Urgency, burning sensation during urination, symptoms of prostatic obstruction, symptoms of urethral obstruction, incontinence, oliguria and anuria, Pneumaturia, cloudy urine, bloody urine, enuresis (an inability to control urination. Use of the term is usually limited to describing individuals old enough to be expected to exercise such control) ), other objective manifestations (Urethral discharge, skin lesions of the external genitalia, visible or palpable masses, edema, bloody ejaculation, gynecomastia, size of penis in infant or child), complaints related to sexual problems.
Typical renal pain is usually felt as a dull and constant ache in the Costovetebral angle (pix 3, just by the right) just lateral to the sacrospinalis muscle below the 12th rib. This pain often spreads along the subcostal area towards the umbilicus or lower abdominal quadrant. It may be expected in those renal diseases that cause typical pain. Such disease include cancer, chronic pyelonephritis, staghorn calculus, tuberculosis, polycystic Kidney, and hydronephrosis (is distension and dilation of the renal pelvis calyces, usually caused by obstruction of the free flow of urine from the kidney) due to mild ureteral obstruction. The pressure within the renal pelvis is normally close to zero. When this pressure increases because of obstruction or reflux, the pelvis and renal calices dilate. The degree of hydronephrosis that develops depends upon the duration, degree and site of the obstruction. The higher the obstruction, the greater the effect upon Kidney.
Altered Urination can be in the following forms, dysuria, pollakiuria, precipitant urination, frequent urination, urinary difficulty, chronic urinary retention, paradoxical ischuria. In chronic Urinary retention, this may cause little discomfort to the patient even though there is great hesitancy in starting the stream and marked reduction of its force and caliber. Constant dribbling of urine (paradoxic incontinence) may be experienced. It may be likened to water pouring over a dam. Urinay incontinence (Enuresis) can be in various forms such as, true incontinence (free urine outflow without any true cause), stress incontinence (uncontrolled urine outflow due to stress, fear, anxiety), urge incontinence (free and uncontrolled urine outflow when the urge arises), paradoxic incontinence. Strictly speaking, enuresis means bedwetting at night. It is physiologic during the first 2 to 3 years of Life.
As for Acute retention, it is the sudden inability to urinate. The patient experiences increasingly agonizing suprapubic pain associated with severe urgency to urinate and may dribble only small amounts of urine. Oliguria and Anuria may be caused by acute renal failure (due to shock or dehydration), fluid-ion imbalance, or bilateral ureteral obstruction. Proteins in Urine is called Proteinuria. It can be pathologic and Non-pathologic (which is also physiologic or orthostatic). Therefore, proteinuria of any significant degree (2-4 +) is suggestive of 'medical' renal disease (parenchymal involvement). Bacteria in Urine is called bacteriuria. A presumptive diagnosis of bacterial infection may be made on the basis of results of microscopic examination of the urinary sediment.
There is a simple laboratory experiment called the Three-glass maneuver, used to test for pyuria. In the sediment from clean-voided midstream specimen from men and those obtained by supra-pubic aspiration or catheterization in women, more than 5-8 white blood cells per high-power field is generally considered abnormal (pyuria). Abnormal Urine specimen can be in the form of altered Urine output or pathological urine sediments and patients with recurrent urolithiasis (stones in kidneys) may have an underlying abnormality of excretion of calcium, uric acid, oxalate, magnesium or citrate. Another simple laboratory experiment is the Two-glass maneuver, used to determine blood in Urine (Hematuria). The presence of even a few red blood cells in the urine (hematuria) is always abnormal and requires further investigation. If red blood cells predominate in the initial portion of the specimen, they are usually from the anterior urethra; those in the terminal portion are generally from the bladder neck or a source above the bladder neck (bladder, ureters or kidneys).
General complaints and manifestations
Patients with diseases of the kidneys most commonly complain of pain in lumbar region, disordered urination, oedema, headache, and dizziness. They may also complain of deranged vision, pain in the heart, dyspnoea (difficulty in breathing), absence of appetite, nausea, vomiting, and elevated body temperature. But diseases of the kindeys may also proceed without any symptoms of renal or general clinical insufficiency.
If the patient complains of pain, its location should first of all be determined. Pain of renal origin often localizes in the lumbar region. If the ureters are affected, the pain is felt by their course. If the bladder is involved, pain is suprapubical. Radiation of pain into the perineal region is characteristic of an attack of nephrolithiasis. The character of pain should then be determined. It is necessary to remember that the renal tissue is devoid of pain receptors. The pain is felt when the capsule or the pelvis is distended -Dull and boring pain in the lumbar region occurs in acute glomerulonephritis, abscess or the perirenal cellular tissue, in heart decompensation ("congestive kidney") in chronic pyelonephritis (usually unilateral) and less frequently in chronic glomerulonephritis. Pain arises due to distension of the renal capsule because of the inflammatory or congestive swelling of the renal tissue.
2. Sharp and suddenly developing pain on one side of the loin can be due to the renal infarction (The death of an area of tissue in the kidney due to a localized lack of oxygen. Usually results from an interruption in the blood supply). The pain persists for several hours or days and then subsides gradually. The pain is rather severe in acute pyelonephritis: inflammatory oedema of the ureter interferes with the normal urine outflow from the pelvis and thus causes its distension. The pain is usually permanent. Some patients complain of attacks of severe piercing pain in the lumbar region or by the course of the ureter 3 The pain increases periodically and then subsides, i.e. has the character of renal colic. Obstruction of the ureter by a calculus or its bending (movable kidney) is the most common cause of this pain, which is usually attended by spasmodic contraction of the ureter, retention of the urine in the pelvis, and hence its distension. The spasmodic contractions and distension of the pelvis account for the pain. Pain in renal colic radiates into the corresponding hypochondrium and most frequently by the course of the ureter to the bladder, and to the urethra. This radiation of pain is explained by th presence of nerve fibres (carrying the impulses from kidneys, ureters, some organs and the corresponding skin zones) in the immediate vicinity of th relevant segments of the spinal cord. This facilitate propagation of the excitation. Patients with renal colic (like those with colic of other aetiology) are restless; they toss in bed. Patients with severe pain of other aetiology would usually lie quiet in their beds (movements may intensify the pain).
The conditions promoting pain should be established. For example pain in nephrolithiasis can be provoked by taking much liquid, jolting nutrition, or the like; pain is provoked by urination in cystitis. Difficult and painful urination is observed in stranguria. Patients with urethritis feel burning pain in the urethra during or after urination.
It is necessary also to establish the agent that lessens or removes the pain. For example, atropine sulphate, hot water-bottle or warm bath in renal colic. Since these remedies only help in spasmodic pain by removing spasm of the smooth muscles, their efficacy in renal colic confirms the leading role of the ureter contraction in the pathogenesis of this pain. Pain of the renal colic-type in patients with movable kidney may lessen with changing posture: urine outflow improves with displacement of the kidney. Pain slightly lessens in patients with acute paranephritis if a bag with ice placed on the lumbar region and if the patient is given amidopyrine and other analgesics.
Many renal diseases are attended by deranged urination: changes in the daily volume of excreted urine and in the circadian rhythm of urination
Secretion of urine during a certain period of time is called diurest Diuresis can be positive (the amount of urine excreted exceeds the volume of liquid taken) or negative (the reverse ratio). Negative diuresis is observed in cases of liquid retention in the body or its excess excretion through the skin, by the lungs (e.g. in dry and hot weather). Positive diuresis occurs resolution of oedema, after administration of diuretics, and in some other cases. Deranged excretion of urine is called dysuria.
Increased amount of excreted urine (over 2L in a day) is called polyuria. can be of renal and extrarenal aetiology. Polyuria is observed in persons who take much liquid, during resolution of oedema (cardiac or renal), and after taking diuretics. Long-standing polyuria with a high relative density of urine is characteristic of diabetes mellitus. In this case polyuria arise due to a deranged resorption of water in renal tubules because of increasing osmotic pressure of the urine rich in glucose. Polyuria occurs in diabetis incipidus because of insufficient supply of antidiuretic hormone secreted into blood by the posterior pituitary. Polyuria also occurs in the absence sensitivity of the tubules to the ADH, in affected interstice of the renal medulla of various nature, in hypokaliaemia (increase of potassium in blood), and hypo- and hyper- calcaemia (increase of calcium in blood).
Persistent polyuria with low specific gravity of urine (hyposthenuria) is usually a symptom of a severe renal disease, e.g. chronic nephritis, chronic pyelonephritis, renal arteriolosclerosis, etc. Polyuria in such cases indicates the presence of a neglected disease with renal insufficiency and decreased absorption in renal tubules.
Decreased amount of excreted urine (less than 500 ml a day) is called iguria. It cannot be connected directly with renal affections (extrarenal iguria). For example, it can be due to limited intake of liquid, during a stay in a hot and dry room, in excessive sweating, intense vomiting, diarrhoea, and during decompensation in cardiac patients. But in certain cases oliguria is the result of diseases of the kidneys and the urinary acts (renal oliguria), such as acute nephritis, acute dystrophy of the kidneys in poisoning with corrosive sublimate, etc.
A complete absence of urine secretion and excretion is called anuria. Anuria persisting for several days threatens with possible development of bacteraemia and fatal outcome. Anuria may be caused by the deranged secretion of urine by the kidneys (secretory anuria) which occurs in severe form of acute nephritis, nephronecrosis (poisoning with sublimate or other ephrotoxic substances), transfusion of incompatible blood, and also some venereal diseases and conditions such as severe heart failure, shock, or profuse blood loss.
In certain cases the secretion of urine is normal but its excretion is obstructed mechanically (obstruction of the ureters or the urethra by a calculus, inflammatory oedema of the mucosa, proliferation of a malignant tumour). This is called excretory anuria. It is usually attended by strong pain in the loin, the renal pelves and the ureters. Exctretory anuria is often attended by renal colic.
Renal (secretory) anuria can be of reflex origin, e.g. in severe pain (contusion, fractures of the extremities, etc). Anuria should be differentiated from ischuria, when the urine is retained in the bladder and the patient is unable to evacuate it. This occurs in compression or other affection of the spinal cord, and in loss of consciousness.
Pollakiuria (frequent micturition) is observed in certain cases. A healthy person urinates from 4 to 7 times a day. The amount of excreted urine during one micturition is from 200 to 300 ml (1000-2000 ml a day). But frequency of micturition may vary within wider range under certain conditions: it may decrease in limited intake of liquid, after eating much salted food, in excessive sweating, in fever, and the like, or the frequency may increase (polyuria) if the person takes much liquid, in getting cold, and the like circumstances. Frequent desire to urinate with excretion of meagre quantity of urine is the sign of cystitis. A healthy person urinates 4-7 times during the day time; a desire to urinate during night sleep does not arise more than once. In the presence of pollakiuria the patient feels the desire to urinate during both day and night. In the presence of chronic renal insufficiency and if the kidneys are unable to control the amount and concentration of excreted urine in accordance with the amount of liquid taken, physical exertion, the ambient temperature, or other factors impor tant for the liquid balance in-the body, the patient urinates at about equal intervals with evacuation of about equal portions of urine. This condition is called isuria.
Under certain pathological conditions, the frequency of urination is normal during the day time but increases during night. The amount of urine excreted during night often exceeds the amount of daily urine (nycturia). Nocturnal enuresis (nycturia) and oliguria during day time occur in cardiac decompensation and are explained by a better renal function at night, i.e at rest (cardiac nycturia). Nycturia may concur with polyuria in renal dysfunction, at the initial stage of chronic glomerulonephritis, chronic pyelitis, vascular nephrosclerosis, and other chronic renal diseases (renal1 nycturia). In the presence of isuria and nycturia of renal origin, which arisedue to the loss by the kidneys of their concentrating ability, the specific gravity of the urine is monotonous. The condition is known as isosthenuria. The specific gravity of urine is usually decreased (hyposthenuria). The specific gravity of urine varies from 1.009 to 1.011, i.e. approaches the specific gravity of primary urine (plasma ultrafiltrate) in patients with pronounced nephrosclerosis, which is the final stage of many chronic renal diseases.
Some diseases of the bladder and the urethra are attended by difficult and painful urination. The patient would complain of change in the colour of the urine, its cloudiness, and traces of blood.
Oedema is observed in acute and chronic diffuse glomerulonephritis, nephrotic syndrome, amyloidosis', and acute renal excretory dysfunction (anuria). It is important to ask the patient about the site that was the first to be attacked by oedema, the sequence of oedema spreading, and the rate of intensification of this phenomenon (see "Renal Oedema").
Headache, dizziness, and heart pain may result from kidney affections. These symptoms occur in those renal diseases which are attended by considerable increase in the arterial pressure, e.g. in acute and chronic glomerulonephritis or vascular nephrosclerosis. A pronounced and persistent increase in the arterial pressure can be among the causes of deranged vision (neuroretinitis).
Patients with diseases of the kidneys can complain of weakness, indisposition, impaired memory and work capacity and deranged sleep. Vision may be deranged along with skin itching and unpleasant breath. Dyspeptic disorders sometimes join in: loss of appetite, dryness, vomiting, and diarrhoea. All these phenomena are associated with retention in the body decomposition products due to renal insufficiency which develops at the final stage of many chronic renal diseases, and sometimes in acute diseases attended by retention of urine during several days.