Diagnosis and Treatment of Urinary Tract Infections

In healthy people, urine in the bladder is sterile; no bacteria or other infectious organisms are present. The urethra, the channel that carries urine from the bladder out of the body, contains either no infectious organisms or too few to cause infection. However, any part of the urinary tract can become infected. These infections are usually classified as lower or upper urinary tract infections; lower refers to infections of the urethra or bladder, and upper refers to infections of the kidneys or ureters.

Urinary tract infections are so common and so serious in long term effects that meticulous attention must be paid to the details of diagnosis and treatment. Urinary tract infection is undoubtedly the commonest cause of "renal hypertension" in women and a frequent cause in men.

The organisms that cause infection usually enter the urinary tract by one of the two routes. The most common route by far is through the lower end of the urinary tract-the opening at the tip of a man's penis or the opening of exits at the vulva. The result is an ascending infection that spreads up the urethra. The other possible route is through the bloodstream, usually directly to the kidneys. Urinary tract infections may be caused by bacteria, viruses and fungi or a variety of parasites.

Bacteria:

Bacterial infections of the lower urinary tract - the bladder and urethra - are very common. They are more common in male than in female new-borns but become about 10 times more common in girls than in boys by age 1. Roughly 5 per cent of adolescent girls develop urinary tract infections at some time or other, but adolescent boys rarely do. Among people between the ages of 20 and 50, urinary tract infections are about 50 times more common in women than in men. More then 85 times more common in women than in men. More than 85 per cent of urinary tract infections are caused by bacteria from a person's own intestine or vagina. Ordinarily, however, bacteria that enter the urinary tract are washed out by the flushing action of the bladder as it empties.

Acute urinary tract infections may be confined to the bladder, but more often the infection involves the urethra and kidneys as well. In many cases, anatomic defects of the genitourinary tract produce obstruction or stasis, which favour invasion and persistence of pathogenic organisms.

The organism most frequently found are gram-negative bacilli, i.e., Escherichia coli, Enterobacter (Aerobacter) erogenous, Paracolon species, Pseudomonas aeruginosa, Proteus vulgaris, and Salmonellae; and gram-positive cocci, i.e., Streptococci (enterococci) and Staphylococci.

Viruses:

Infections by the herpes simplex virus type 2 (HSV-2) affect the penis in men and may affect the vagina in women. If the urethra is affected, urination may be painful and emptying the bladder may be difficult.

Fungi:

Fungal infections of the urinary tract are most commonly caused by Candida (yeast that causes candidiasis) in people who have a bladder catheter in place. Rarely, other types of fugus, including those that causes blastomycosis (Blastomyces) or coccidinomycosis (Coccidioides) can also infect the urinary tract. Fungi and bacteria often infect the kidneys at the same time.

Parasites :

A number of parasites including, worms can cause urinary tract infections. Malaria, a disease caused by protozoan parasites carried by mosquitoes, can block the small blood vessels of the kidneys or can rapidly damage red blood cells (haemolysis), causing acute kidney failure.

Trichomoniasis, also caused by a protozoa, is a sexually-transmitted disease that can produce copious greenish-yellow, frothy discharge from the vagina. Rarely, does the bladder becomes infected. Trichomoniasis in men usually produces no symptoms, although it can cause inflamation of the prostate gland. (Prostatitis) Schistosomiasis, a worm infection, can affect the kidneys, urethra and bladder and is a common cause of severe kidney failure among people who live in Egypt and Brazil. The infection can cause persistent bladder infections that may eventually result in bladder cancer. Filariasis, a threadworm infection, obstructs lymphatic vessels, causing lymphatic fluid in the urine. (Chyluria) Filariasis can cause enormous swelling of tissues (elephantiasis), which may involve the scrotum and legs.

Essentials of Diagnosis

  1. Sudden onset of chills and fever with frequent and urgent urination. There is burning sensation on urination as well as pain and tenderness in the costovertebral angle over the kidneys.
  2. Headache, prostration, nausea and vomiting.
  3. Urine contains pus (pyuria), few to many red cells granular and white cell casts, small to moderate amounts of protein and bacteria.
  4. Leucocytosis: rapid sedimentation rate. Occasional bacteria.

Differential Diagnosis:

Acute infection involving the upper urinary tract must be differentiated from other acute causes of abdominal pain as well as from basal pneumonia. Acute pancreatities must also be considered. The presence of pus and bacteria in the urine will usually confirm the diagnosis.

Treatment:

For the treatment of urethritis and ureteritis, antibiotics or antiviral drugs are used depending on the cause of the infection. Urine may be cultured for the identification of bacteria and sensitivity test may be carried out to ensure the appropriate antibiotic from the wide range of choice available currently. Also a sample (urethral swab) of the discharge, if present, is collected and sent to a laboratory for analysis so that the infecting organism can be identified.

For the treatment of cystitis (infection of bladder) in the elderly, infection without symptoms generally require no treatment. As a first step, drinking plenty of fluids often eliminates a mild bladder infection. The flushing action of the urine washes many bacteria out of the body; the body's natural defences eliminate the remainder.

Before prescribing antibiotics, the physician determines whether the person has a condition that would make a bladder infection more severe, such as abnormalities of structure or nerve supply, diabetes, on a weakened immune system that reduces the person's ability to fight infection. Such conditions may require more aggressive treatment, particularly because the infection is likely to return as soon as the persons stops taking antibiotics. Antibiotics may by taken continually in low doses as prevention (prophylaxis) against infection by people who have more than two bladder infections a year.
Urinary Tract Infections Broad Outline Organ Infection

  1. Urethra Urethritis
  2. Bladder Cystitis
  3. Ureters Ureteritis
  4. Kidneys Pyelonephritis

Factors contributing to bacterial urinary tract infections

Ascending Infections:

  1. Infection in the blood stream (septicemia)
  2. Infection of the heart valves (infective endocurditis)

Pyelonephritis:

Pyelonephritis is a bacterial infection of one of the kidneys or both kidneys.

Escherichia coli, a bacterium that's normally found in the large intestine, cause about 90 per cent of kidney infection among people who live in the community but only about 50 per cent among hospitalised patients. Infection usually ascend from the genital area to the bladder. In a healthy urinary tract, the infection is usually prevented from moving up the ureters into the kidneys by the urine flow washing organisms out and by closure of the ureters at their entrance to the bladder. However, any physical obstruction to the flow of urine, such as a kidney stone or an enlarged prostate, or back flow of urine from the bladder into the ureters increases the likelihood of a kidney infection. Infection can also be carried to the kidney, from another part of the body through the bloodstream. For instance, a staphylococcal skin infection can spread to the kidneys through the bloodstream. Other conditions that increase the risk of a kidney infection include pregnancy diabetes, and conditions that reduce the body's ability to fight infection.

Signs and Symptoms :

General signs and symptoms are elaborated in this article under the subheading essential of diagnosis. In addition, in kidney infection there may be pain in the lower part of the back.

Diagnosis:

The typical symptoms of a kidney infection lead a doctor to perform two common laboratory tests to determine whether the kidneys are infected; examining a urine specimen under a microscope and culturing bacteria in a urine specimen to determine which bacteria are present. Ultrasound and X-ray studies (IVU) performed may reveal stones in the kidneys, structural abnormalities, or other causes of urinary obstruction.

Treatment:

Antibiotics are started as soon as the diagnosis of a kidney infection seems likely and the person's urine and blood samples have been taken for laboratory tests. Antibiotic treatment to prevent recurrence of the infection usually continues for two weeks but may last as long as six weeks for men, in whom the infection commonly is more difficult to eradicate. A final urine sample is usually taken 4 to 6 weeks after the antibiotic treatment is finished to make sure the infection has been eradicated. If tests reveal a predisposing condition, such as an obstruction, a structural abnormality, or a stone, surgery may be needed to correct the condition.

People who have frequent kidney infections or whose infections recur after antibiotic treatment is finished may be advised to take a small dose of antibiotic every day as preventive therapy. It may be continued for six months to one year. If the infection returns, therapy may be continued indefinitely.

Submitted By
Dr. Maswoodur Rahaman Prince

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