Urinary Tract Obstruction Flashcards
What is obstruction causing dilation of the renal pelvis and/or ureter called?
Hydronephrosis
Common causes of UTO in children.
Most likely congenital abnormalities or urethral valves.
Common causes of UTO in women.
In young women it is probably a pelvic tumour, pregnancy or stones.
Common causes of UTO in men.
Young men = stones
Elderly men = prostatic disease
Explain the pathophysiology of UTO.
Urine continues to form despite the obstruction.
This leads to progressive rise in intraluminal pressure, there is dilation proximal to the site of obstruction and compression and thinning of the renal parenchyma. This leads to reduced size of the kidney.
Acute obstruction is followed by transient renal arterial vasodilation succeeded by vasoconstriction.
Causes of UTO
Calculus, blood clot, sloughed papilla or tumour of renal pelvis, ureter or bladder.
Pelviureteric neuromuscular dysfunction, ureteric stricture, ureterovesical stricture, congenital megaureter, congenital bladder neck obstruction, neuropathic bladder.
Pelviureteric compression, tumours, diverticulitis, aortic aneurysm, retroperitoneal fibrosis, prostatic obstruction.
Clinical features of acute upper tract obstruction.
Loin pain radiating to groin. Can have sumperimposed infection +/- loin tenderness or an enlarged kidney
Clinical features of chronic upper tract obstruction.
Flank pain
Renal failure
Superimposed infection
Polyuria may occur due to the impaired urinary concentration.
Clinical features of acute lower tract obstruction.
Severe suprapubic pain +/- confusion (elderly).
Distended, palpable bladder containing around 600 ml
Dull percussion of bladder
Causes of acute lower tract obstruction.
Prostatic obstruction
Urethral strictures
Anticholinergics
Blood clots
Alcohol
Constripation
Post-op
Infection
Neurological
Clinical features of chronic lower tract obstruction.
Urinary frequency
Hesitancy
Poor stream
Terminal dribbling
Overflow incontinence
Distended palpable bladder +/- large prostate
Causes of chronic lower tract obstruction.
Prostatic enlargement
Pelvic malignancy
Rectal surgery
CNS disease such as transverse myelitis
Complications of chronic lower tract obstruction.
UTI
Urinary retention
Renal failure
Investigations for UTO.
Bloods - U&Es, Crea, FBC, PSA
Urine - Dipstick for blood and MC&S
Ultrasound
If there is hydronephrosis or hydroureter arrange a CT scan
Radionuclide imaging to do a functional assessment
Treatment of upper tract obstruction.
Nephrostomy or ureteric stent
(Stent may cause significant discomfort to patients and they should be warned before)
Alpha blockers can help reduce ureteric stent pain.
Treatment of lower tract obstruction.
Insert a urethral or suprapubic catheter to relieve acute retention.
In chronic you only catheterise if there is pain, UTI, or renal impairment.
Sometimes intermittent catheterisation is done.
Monitor weight, fluid balance and U&Es closely.
Treat underlying cause
After 2-3 days TWOC.
Problems of ureteric stenting
Pain
Trigonal irriation
Haematuria
Fever
Infection
Tissue inflammation
Encrustation
Biofilm formation
Explain obstructive megaureter.
Childhood condition resutling from the presence of a region of defective peristalsis at the lower end of the ureter adjacent to the ureterovesical junction.
This is more common in males.
Presents with UTI, flank pain or haematuria.
Diagnosis is made on imaging with US, CT or if necessary ascending ureterography.
Explain retroperitoneal fibrosis.
Inflammatory fibrotic tissue encases the aorta and ureters.
Three times more common in men than in women and is an IgG4-related disease.
Extraluminal ureteric obstruction leads to unilateral or bilateral obstruction.
Thought to be either an autoallergic response to elakage from atheromatous plaque or a systemic autoimmune disease.
Causes of retroperitoneal fibrosis.
Idiopathic (60-70%)
Secondary such as drugs, malignancy, infection and surgery/radiotherapy.
Clinical features of RPF.
Malaise
Low back pain
Weight loss
Testicular pain
Claudication
Haematuria
Investigations of RPF.
Normochromic anaemia
CKD
Raised ESR and CRP
Increased serum IgG4 levels
USS showing poorly circumscribed peri-aortic mass
Contrast enhanced CT show mass, lymph nodes and tumour.
FDG-PET showing metabolic activity of retroperitoneal mass.
Management of RPF.
Biopsy to exclude underlying infection, lymphoma or carcinoma
Ureteric stenting can be done.
Croticosteroids or rituximab.
Response to treatment done by assessing ESR, eGFR and repead FDG-PET scans.
Obstruction can be relieved surgically by ureterolysis.
Prognostic factors of UTO.
Whether obstruction is partial or complete
Duration of obstruction
Presence or absence of infection
Site of obstruction