Urinary tract infections (UTI) are defined as infections that arise in any part of the urinary tract including kidneys, ureters, bladder, and urethra.
Most commonly urinary tract infections occur in the lower urinary tract consisting of the bladder and the urethra. UTIs commonly occur in women due to their anatomy of the normal urinary tract which includes the onset of infections that don’t require treatments as well. If urinary tract infections occur in males and children, it is always due to abnormalities of the urinary tract which require further investigations.
The incidence of UTI is 50,000 per million and recurrent UTI can cause significant morbidity and complicated UTI can lead to severe renal disease including end-stage kidney disease.
Two types of UTI
- Complicated
- Uncomplicated
Further Urinary tract abnormalities such as stones, or associated diseases such as diabetes mellitus result from urinary tract infections which are called complicated UTIs.
Also, Uncomplicated UTI includes urinary tract infections that occur in functionally normal urinary tracts with normal renal imaging. Persistent or recurrent infections and serious kidney damage are observed rarely in patients with uncomplicated UTI.
Etiology
Commonly UTIs are caused due to
- Transferring of bacteria from the patient’s bowel flora into the urinary tract via ascending transurethral route.
- The other routes that bacteria can extend are via the bloodstream, lymphatics, or direct extension from fistulas.
Symptomatic infections occur due to the virulence of the organisms and most common bacteria are the causative organism of UTIs.
Alterations in host defense mechanisms including urine osmolality, pH, urine flow, uroepithelium, and action of commensals can also result in UTI.
Symptoms of UTI
- Pain and tenderness in the suprapubic region
- Increased frequency of urination
- Painful urination
- Smelly urine and blood in the urine are the commonest symptoms of UTI.
These symptoms mostly occur with lower urinary tract infections including bladder and urethra which is also named Cystitis.
Symptoms such as,
- Fever
- Loin pain
- Systemic manifestations can be due to the extension of infection to the upper urinary tract including kidneys which is also named Pyelonephritis.
Occasionally UTI patients present asymptotically and maybe with atypical symptoms such as abdominal pain and fever. While children with UTI can present with failure to thrive along with being sick and febrile.
Diagnosis of UTI
Diagnosis of UTI is based on the quantitative culture of a clean-catch mid-stream urine sample and the presence or absence of pus in the urine. An uncomplicated UTI doesn’t need any radiological investigations although a complicated UTI might need investigations such as ultrasound, CT, and MRI.
Management of UTI
In single-isolated UTIs, a regime of antibiotics for 3-5 days is recommended including antibiotics as
- Amoxicillin
- Trimethoprim
- Nitrofurantoin
- Cephalosporins
- For resistant organisms antibiotics as Co-amoxiclav can be given
- In severely ill patients’ intravenous administration of antibiotics is considered
A high fluid intake of at least 2 liters per day is recommended during treatment and for the following few weeks. In patients with recurrent infections any predisposing factors for peri urethral colonization, poor bladder defense mechanisms, or any other causes such as renal stones, etc. must be identified and corrected. These patients require intense and prolonged antibiotic treatment.
References
- Kumar and Clerk’s Clinical Medicine -8th Edition- Parveen Kumar, Michael Clark
- Oxford Handbook of Clinical Medicine
