The urinary tract includes the kidneys, ureters, bladder, (prostate), urethra, and external genitalia. Symptoms perceived by patients reflect the embryological origin as well as the current anatomy of these organs.
Any previous history of urogenital problems, and a specific focus on:
• Colicky pain: intense pain that comes and goes suggests intermittent contraction of a hollow organ, e.g. ureter. Patients with ureteric colic cannot find a comfortable position. Pain may be referred to the genitals.
• Back pain: the kidneys are retroperitoneal.
• Ask about urinary frequency, flow, blood or clots.
• Fever: with chills and rigors (shaking) suggests sepsis (Chapter 38).
• Dysuria: burning pain when passing urine implies urethral inflammation. Abnormal discharge from the genitals suggests STI.
A patient with active renal colic will move around, trying in vain to find a comfortable position; other causes of intra-abdominal pain are usually alleviated by lying still. The abdomen should be palpated for alternative causes of pain (e.g. abdominal aortic aneurysm (AAA), cholecystitis) and the kidneys should be examined for tenderness.
In a patient unable to void urine, a palpable tender bladder that is dull to percussion suggests urinary retention. The external genitalia should be examined if symptomatic, including rectal examination if prostatitis is suspected.
• Ultrasound: can rule out AAA.
• Blood glucose.
• Swabs from urethra/cervix if appropriate.
• Urine dipstick testing is a rule-out test: if leucocytes, nitrites, blood and protein are all negative, the urine does not need to be sent for culture, unless the patient is immunosuppressed. If nitrites and leucocytes are negative, infection is unlikely (-LR = 0.16), but if the patient’s symptoms are very suggestive of UTI, the urine may be sent for culture.
• Urine microscopy – red cell casts imply glomerular bleeding, rather than bleeding elsewhere in the urinary tract.
• FBC, U+E
• LFTs, amylase if abdominal pain.
• Ultrasound is operator and body mass index dependent, can detect bladder size, ureteric and renal pelvis dilatation resulting from obstruction but cannot reliably detect stones.
• CT KUB (kidney, ureters, bladder) detects stones and other intra-abdominal pathology, but involves significant radiation (300 CXR). MRI is an alternative that avoids irradiation.
• Contrast radiography: intravenous urogram (IVU; 250 CXR) has been superseded by CT, but X-ray KUB (75 CXR) can track radio-opaque stones.
Urinary tract infection/pyelonephritis
Females are more prone to UTIs due to the short urethra. Drinking large quantities of water may help flush out mild infection, but more serious infection needs treatment for 3 days with antibiotics: trimethoprim or nitrofurantoin are common recommendations. Men with UTIs and women with recurrent UTIs need antibiotics for 7 days and should be reviewed in an outpatient clinic.
Pyelonephritis occurs when a UTI ascends to the kidney(s). The patient is systemically unwell with fever, loin/back pain, rigors, headache, nausea and vomiting. The kidney(s) are tender on palpation. Emergency Department treatment includes antibiotics (e.g. gentamicin), analgesia and intravenous fluids. Patients who respond to this may be discharged with oral antibiotics (e.g. co-amoxycillin) and GP follow-up.
Urinary tract stones
Some patients, usually for unknown reasons, form stones in their renal pelvis. If the stones pass into the ureter, they cause intense colicky pain, ‘renal colic’ and microscopic haematuria (90%).
NSAIDs, e.g. ketorolac i.v. or diclofenac p.r., are rapidly effective at relaxing ureteric smooth muscle. Morphine is useful for ongoing pain; pethidine (meperidine) should be avoided – opiate- seeking should be suspected if it is requested.
CT confirms the diagnosis, and informs treatment decisions. If there is a stone of less than 5 mm and the pain has resolved, discharge patient on regular NSAID or tamsulosin (an alpha blocking drug that also helps stones pass) with outpatient clinic review.
Patients who are discharged should be warned to return if they develop fever or further significant pain. Otherwise, or if there is evidence of infection, urinary obstruction, renal failure or single kidney, discuss with urology team.
Urinary retention may occur due to mechanical obstruction or neurological impairment, causing acute or chronic retention that may cause renal damage. Ultrasound can confirm a large residual volume of urine in the bladder after voiding.
Catheterisation should be performed urgently to relieve obstruction and pain. If dipstick testing indicates that the patient’s urine is likely to be infected, then catheterisation should be covered by a single shot of gentamicin. If there are blood clots in the bladder, a large irrigation catheter may be needed to flush out the bladder.
If urinary retention occurs in a patient with back pain, consider cauda equina compression (Chapter 17). Constipation, e.g. from opiate analgesics, can cause urinary retention: treating the constipation resolves the retention.
Sexually transmitted disease
Dysuria and/or discharge makes STI more likely than torsion, but if there is any doubt, an ultrasound can confirm normal testicular perfusion. Swabs should be taken and the patient should be followed up in an STI clinic for contact tracing.
Diagnoses not to miss
Common in early adulthood, the spermatic cord twists, causing testicular ischaemia. Torsion is diagnosed clinically by a tender, high-riding testis: ultrasound may confirm the diagnosis, but must not delay surgical exploration.
Infected obstructed kidney
The combination of urinary obstruction and infection can rapidly destroy a kidney. Evidence of possible infection should be sought in patients who have obstruction, e.g. stones, in their urinary tract.
UTIs are uncommon in men, and prostatitis should be considered. The diagnosis is confirmed by a tender prostate on rectal examination, after which urine is taken for culture. Prolonged antibiotic treatment is necessary, e.g. ciprofloxacin for 3 weeks.