Urology Flashcards
Foley Catheters
The Foley catheter is the most commonly used – they have an inflatable balloon the bladder end to hold them in position. Catheters can be made of latex, plastic or silicone.
They can be 2 way – one lumen to drain urine and one to inflate the balloon or they can be 3 way – there is an extra lumen to allow irrigation fluid to be passed into the bladder.
The external circumference in millimetres is sized by the French gauge system – they range between 10 and 22 Fr and size 14-16 is usually used for males.
Male Urethral Catheteristion
Use aseptic technique to clean the penis, instil anaesthetic gel into the urethra and introduce the catheter. Once urine begins to drain inflate the balloon and return the foreskin to prevent paraphimosis. Note residual volume of urine and send specimen for bacteriology.
- Complications – local trauma, introduction of infection, urethritis or stricture formation.
- Antibiotics – some centres may advocate the need for routine antibiotic cover e.g. one dose of 80mg gentamycin IM. However in certain situations antibiotics are essential e.g. in patients with metal prosthesis such as hip replacement or if the patient had a heart murmur.
Suprapubic Catheters
Used when urethral catheterisation is not possible e.g. due to a stricture or is inappropriate e.g. when urethral trauma is suspected.
The catheter is inserted into the bladder in the midline 5cm above the pubic symphysis. Before inserting a suprapubic catheter urine should be aspirated using a green needle and syringe and if there is any doubt then an ultrasound is performed.
Haematuria - Causes
Over 35% of patients with haematuria have a urological malignancy e.g. renal cell carcinoma or bladder malignancy.
Other causes can be divided into local and general causes:
- Local – infection (TB, schistosomiasis or UTI), stones, trauma or most importantly malignancy.
- General – bleeding disorders, leukaemia, anticoagulants, haemoglobinopathies or sickle cell.
Haematuria - History
- Is the blood definitely in the urine and not from the rectum or vagina?
- Is this true haematuria? Rifampicin, nitrofurantoin, beetroot and porphyrias cause red urine.
- Is the haematuria associated with loin pain or dysuria – implies caliculi or an infection.
- When does bleeding occur? – at the beginning of otherwise clear stream – suggests a urethral or prostatic lesion or throughout the stream – suggests a bladder, ureter or kidney lesion.
Haematuria - Investigations
- Urine tests – MSU is dip-sticked and sent for MC+S and cytology (for transitional cell carcinoma).
- Haematological tests – FBC to look for anaemia and U+Es to assess renal function.
- Radiological tests – an ultrasound to detect tumours of the renal parenchyma and bladder lesions should be performed first. If a renal mass is found then a CT scan is performed. A plain abdominal x-ray including KUB and IV urogram to view soft tissues can also be performed.
- Special investigations – cystoscopy under local anaesthetic, early morning urine sampling for TB culture and rarely angiography to exclude arteriovenous malformations.
Caliculi - common sites and prevalence
- Caliculi form in collecting ducts and may be deposited anywhere from the renal pelvis to the urethra though classically at the pelviureteric junction, the pelvic brim or the vesicoureteric junction.
- Prevalence – lifetime incidence is 15%, peak age is 20-40 years and the male to female ratio is 3:1.
Caliculi - types of stones
Renal caliculi consist of crystal aggregations – 75% are calcium oxalate, 10-20% are magnesium ammonium phosphate, 5% are urate, 5% are hydroxyapatite and 1% are cysteine.
Calcium oxalate stones mainly occur in metabolic conditions or are idiopathic, magnesium ammonium phosphate stones often occur in UTIs with Proteus, urate stones occur in hyperuricaemia and cysteine stones form when there’s a renal tubular defect.
Caliculi - presentation
Can be asymptomatic or causes haematuria, proteinuria, sterile pyuria, anuria or
- Renal colic – excruciating spasms – loin to groin (or genitals or inner thigh) often with nausea or vomiting. The patient can often not lie still – this can help to differentiate colic from peritonitis.
- Renal obstruction – of the mid-ureter may mimic appendicitis or diverticulitis, of the lower ureter may cause symptoms of bladder irritability and pain in the scrotum, penile tip or labia majora and of the bladder or urethra causes pelvic pain, dysuria and interrupted flow.
- UTI – can co-exist and there is an increased risk if voiding is impaired. Pyelonephritis (fever, rigors, loin pain, nausea, vomiting) or pyonephritis (infected hydronephrosis) can also occur.
Caliculi - examination
In most cases there is no tenderness on palpation.
However in cases where there is retroperitoneal inflammation there may be renal angle tenderness especially on percussion.
Calicui - questions to address
- Why have they got the stone now – ask the patients what they eat (tea, chocolate, rhubarb, strawberries, nuts and spinach increase oxalate levels), what’s their job (can they drink freely or do they become dehydrated), are there precipitating drugs (loop diuretics, antacids, corticosteroids, aspirin, thiazides or allopurinol) or predisposing factors (recurrent UTIs, metabolic abnormalities e.g. in calcium or uric acid metabolism, urinary tract abnormalities e.g. horseshoe kidney, ureterocele or vesicoureteric reflux) or foreign bodies e.g. stent or catheter.
- Is there a family history – increases the risk of developing renal caliculi by three times.
- Is there infection above the stone – fever, loin tenderness or pyuria – needs urgent intervention.
Caliculi - bloods and urine
- Bloods – test FBC, Us and Es, calcium, phosphate, glucose, bicarbonate and urate.
- Urine – dipstick usually positive for blood. Send MSU for microscopy, culture and sensitivities.
Caliculi - imaging
- KUB x-ray (kidneys, ureters and bladder) – calcification in ureters over transverse processes of the vertebral bodies – 80% of stones are visible on x-ray and 99% on CT.
- IV urogram – radio-opaque contrast in injected and several films are taken until contrast is seen down to the level of the obstruction. Contraindications – a known contract allergy, severe asthma, pregnancy or patient currently taking metformin.
- Ultrasound scan – to look for hydronephrosis or hydroureter to identify an obstruction.
- Spiral non-contrast CT – superior to IVU for imaging stones and can help to exclude differential causes of an acute abdomen.
Caliculi - management
Give analgesia – e.g. 75mg IV or IM diclofenac or 100mg suppositories, IV fluids if required and antibiotics if there is an infection e.g. 1.5g cefuroxime TDS.
Stones <5mm in the lower ureter – 90-95% pass spontaneously but increase fluid intake.
Stones >5mm or pain not resolving:
- Medical expulsive therapy – nifedipine or α blockers e.g. tamsulosin ± prednisolone (to decrease inflammation) – most pass within 48 hours and >80% pass within 30 days.
- Shockwave lithotripsy (ESWL – extracorporeal shockwave lithotripsy) – the shockwave shatters the stone so it can pass. Side effects – can cause renal injury.
- Percutaneous nephrolithotomy – keyhole surgery to remove large or multiple stones.
Caliculi - indications for urgent intervention
In some cases a delay in treatment may result in permanent loss of renal function e.g. presence of infection, urosepsis, intractable pain, severe vomiting, impending acute renal failure, obstruction in a solitary kidney or bilateral obstruction.
