Urinary System Flashcards
How is AKI defined?
An abrupt reduction in kidney function defined by either:
- An absolute increase in serum creatinine >26umol/l within 48 hours
OR
- >50% increase in serum creatinine from baseline in 7 days
OR
- A 25% fall in eGFR within 7 days (children + young people)
Oligouria <0.5ml/kg/hr for at least 6 hours (8 hours for children)
How do you assess the severity of an AKI? (6)
- Fluid overload - signs of pulmonary oedema (crackles, expansion breath sounds, dull percussion), JVP, peripheral oedema
- Fluid depletion - postural hypotension, tissue turgor, dry mouth, sunken eyes, cap-refill
- Hypotension >90/60
- Urine output - oliguria or anuria
- Hyperkalaemia - look for ECG signs (tall T waves, flat P waves, broad QRS, sloping ST)
- Acidosis - will cause hyperventilation and cardiac instability
80% of AKIs can be resolved by doing what? (3)
- Fluid assessment + fluid replacement
- Treat acidosis
- Treat sepsis
What can AKI be divided into in terms of categories?
Pre-renal
Intrinsic
Post-renal
Which of the three categories of AKI is most common?
Pre-renal
What happens during pre-renal AKI generally?
There is reduced perfusion to the kidneys and this leads to a decreased eGFR.
What are the causes of a pre-renal AKI? (3)
- Hypovolaemia
- Reduced cardiac output
- Drugs
What are the causes of reduced cardiac output that can lead to a pre-renal AKI? (4)
- Cardiac failure
- Liver failure
- Sepsis
- Drugs
Which drugs can lead to a pre-renal AKI? (4)
Drugs that reduced blood pressure, circulating volume or renal blood flow
e. g.
1. ACEi
2. ARBs
3. NSAIDs
4. Loop diuretics
What are the causes of intrinsic (renal) AKI? (5)
- Toxins and drugs
- Vascular
- Glomerular
- Tubular
- Interstitial
What are the toxins or drugs that can cause a renal AKI?
- Antibiotics
- Contrast
- Chemotherapy
What are the vascular causes of renal AKI? (4)
- Vasculitis
- Thrombosis
- Athero/thromboembolism
- Dissection
What is the glomerular cause of intrinsic AKI?
Glomerulonephritis
What are the tubular causes of intrinsic AKI? (3)
- Acute tubular necrosis
- Rhabdomyolysis
- Myeloma
What are the interstitial causes of intrinsic AKI? (2)
- interstitial nephritis
2. Lymphoma infiltration
What is the main post-renal cause of AKI?
Obstruction
What are the obstructions that can occur that lead to post-renal AKI? (6)
- Renal stones
- Blocked catheter
- Enlarged prostate (BPH)
- Genitourinary tract
- Tumours/masses
- Neurogenic bladder
What is the definition of stress incontinence?
Involuntary leakage on effort or exertion, or on sneezing or coughing
What is urgency urinary incontinence?
Involuntary leakage accompanied by, or immediately preceded by, a sudden compelling desire to pass urine which is difficult to defer (urgency). UUI is part of a larger symptom complex known as overactive bladder (OAB) syndrome.
What is overactive bladder syndrome?
It is urinary urgency (with or without urgency incontinence) which is usually associated with increased frequency and nocturia. OAB may be further described as either, OAB ‘wet’ where incontinence is present or OAB ‘dry’ where incontinence is absent.
What is mixed urinary incontinence?
Both stress and urgency incontinence; involuntary leakage associated with both urgency and physical stress (exertion, effort, sneezing, or coughing)
What is overflow incontinence?
Detrusor under activity or bladder outlet obstruction results in urinary retention and leakage of urine. There may be straining to urinate or the person may feel the bladder has been incompletely emptied
What are the risk factors for developing stress incontinence? (8)
- Increasing age
- Pregnancy and vaginal delivery - muscles and connective tissue can be weakened during delivery, and damage may occur to pudendal and pelvis nerves
- Obesity - due to pressure on pelvic tissues and stretching and weakening of muscles and nerves from excess weight
- Constipation - straining may weaken pelvic floor muscles
- Deficiency in supporting tissue e.g. prolapse, hysterectomy or lack of oestrogen
- Family history
- Smoking
- Drugs - ACEi - by causing cough and worsening stress incontinence
What causes urgency urinary incontinence?
The symptoms of an overactive bladder are thought to be caused by involuntary contractions of the detrusor muscle during the filling phase of the micturition cycle.
Urgency incontinence is idiopathic in most women.
Some cases are caused by:
1. Parkinson’s disease
2. MS
3. Injury to pelvic/spinal nerves
4. Type 2 diabetes / obesity
What can exacerbate urinary urgency? (3)
- Caffeine
- Acidic or alcoholic drinks
- Adverse effects of some dugs - antidepressants and hormone replacement
What medications can decrease bladder contractility? (8)
- ACEi
- Antidepressants
- Antihistamines
- Antimuscarinics
- Beta-adrenergic agonists
- CCBs
- Opioids
- Sedatives and hypnotics
What are the complications of urinary incontinence? (7)
- Impairment of quality of life
- Psychological problems (depression, anxiety, embarrassment)
- Social isolation
- Sexual problems
- Loss of sleep (nocturia)
- Falls and fractures
- Financial problems (cost of products and laundry)
In a history for someone presenting with urge and stress incontinence, what is important to identify?
- Fluid intake and type of fluids e.g. caffeine, alcohol
- Symptoms of a more serious diagnosis e.g. haematuria, persisting bladder pain, recurrent UTIs, constant leakage (fistula)
- Drugs - e.g. ACEi
- Previous history of spinal surgery, prolapse, hysterectomy, obstetric
- Systemic disease e.g. diabetes
- When does the incontinence occur - exertion/coughing or increased frequency and nocturia?
How do you assess how severe urinary incontinence is? (4)
Ask:
- How often is the incontinence - what times, during what activities
- Use of pads or changing clothes?
- How often she passes urine including at night
- Bladder diary for minimum of 3 days - ensuring working and leisure days are included
When should a women presenting with incontinence be referred under a 2 week wait pathway?
If she is older than 45 and has unexplained visible haematuria without UTI or after successful treatment of UTI
OR
over 60 with unexplained non-visible haematuria and dysuria or a raised WCC
What is the management for stress incontinence? (4)
- Manage any reversible causes
- Give lifestyle advice e.g. reduce caffeine intake, reduced weight is BMI >30kg/m
- Stop smoking
- Offer referral for 3 months of supervised pelvic floor muscle training (PFMT) - referral to physiotherapy or nurse specialist etc.
If the 3 months of pelvic floor exercises do not work for stress incontinence, what can be done next?
Refer to specialist - often treatment options include colposuspension, autologous rectus fascial sling and mesh sling - all surgical
or if prefer drug: duloxetine is second line
When should a women presenting with incontinence be preferred to a specialist? (7)
If:
- Bladder palpable on abdo/bimanual examination
- Voiding difficulty
- Pelvic mass that is benign
- Faecal incontinence
- Suspected neurological disease
- Recurrent UTIs
- Suspected fistula
What is the management for urge incontinence AKA urgency urinary incontinence?
- Lifestyle advice etc.
- Bladder training (for at least 6 weeks)
- If symptoms persist despite bladder training:
- anti-muscarinic e.g. Oxybutynin
Tolterodine
If an antimuscarinic drug is contraindicated in someone with urge incontinence, what drug can be given instead?
Mirabegron
What is important to tell patients who are starting antimuscarinic/drug treatment for urge incontinence?
- It can take at least 4 weeks to improve symptoms
- Side effects - dry mouth and constipation - may indicate anticholinergic medication is starting to work
- Need to be reviewed after 4 weeks
What can be offered to a woman who is post-menopausal with vaginal atrophy (dryness)?
Intravaginal oestrogen therapy
What can be prescribed to women experiencing troublesome nocturia (e.g. getting up multiple times a night, experiencing insomnia as a result etc)?
Desmopressin
NICE 2019 concluded what about desmopressin?
It is useful for nocturia but does not reduce incontinence in women (or there is insufficient evidence anyway) - there is also a risk of hyponatraemia with it.
Which form of incontinence is most common in the UK?
Stress incontinence
What is overactive bladder most commonly caused by?
Detrusor muscle overactivity
How does OAB present? (4)
- Frequency of micturition
- Nocturia
- Abdominal discomfort
- Urge incontinence (more common in women)
How is diagnosis of OAB confirmed?
Urodynamic studies
What are the differential diagnoses for OAB? (8)
- Stress incontinence
- Functional incontinence
- Overflow incontinence
- Urinary fistula
- Enuresis
- UTI
- Diabetes
- Bladder cancer
What investigations are performed in someone with OAB? (4)
- Urine dipstick
- Bloods - U&Es, calcium, fasting glucose
- Urodynamic studies - show involuntary contraction of the bladder during filling
- USS of the rental tract and cystoscopy may be required
What are the management options offered in secondary care to people with OAB (this includes urge incontinence basically) who have tried bladder training and oxybutynin? (3)
- Botulinum toxin A
- Nerve stimulation
- Surgical treatment
For someone presenting with any form of incontinence, what investigations should be done? (6)
- Urine dipstick testing
- Examination - digital assessment of pelvic floor muscles, in men DRE
- Post-void residual volume
- Mid-stream urine for cultures if positive dipstick
- Renal function tests
- Urodynamic studies
What are the causes of urinary retention - in men and women respectively? (lots)
In men - benign prostatic hyperplasia, meatal stenosis, paraphimosis, penal contstricting bands, phimosis, prostate cancer
In women - prolapse (cystocele, rectocele, uterine), pelvic mass e.g. uterine fibroid, retroverted gravid uterus
In both - bladder calculi, bladder cancer, faecal impaction, GI malignancy, urethral strictures, foreign bodies, stones
Up to 10% of acute urinary retention episodes are thought to be attributable to drugs. What are the drugs known to cause it? (8)
- Anticholingerics (antipsychotics, antidepressants)
- Opioids and anaesthetics
- Alpha agonists
- Benzodiazepines
- NSAIDs
- CCBs
- Antihistamines
- Alcohol
How do you distinguish between acute and chronic urinary retention?
AUR is usually painful, whilst chronic due to its slow nature is relatively pain free.
What investigations need to be performed for people presenting with acute urinary retention? (4)
- Urinalysis
- MSU
- Bloods - FBC, U&Es, blood glucose, PSA
- Imaging studies - USS, CT scan, MRI/CT brain scan/spinal
What is the initial management for people presenting with acute urinary retention?
- Immediate and complete bladder decompression - catheterisation
- In men - alpha blocker before the removal of the catheter
(Pharmcological treatment for post-operative retention e.g. cholinergic, prostaglandin - these are being explored as alternatives)
What is the secondary management for acute urinary retention caused by prostatic enlargement (after catheterisation)?
- TWOC and an alpha blocker
- Prostatic surgery
- prolonged catheterisation is associated with an increased morbidity
What are the complications of AUR?
- UTIs
- AKI
- Post-obstructive diuresis
- Post-retention haematuria
What can prevent AUR in men with BPH?
5 alpha-reductase inhibitors e.g. finasteride
What does obstruction of the ureter lead to?
- Dilation of the ureter and hydronephrosis
- Pain (particularly if acute)
- Decreased renal function due to back pr ensure causing renal tubular atrophy
- Increased risk of UTI, sepsis and stone formation
In someone with an acute upper urinary tract obstruction, how do they present?
- Flank pain - dull, sharp or colicky, often restless, often radiates to iliac fossa, inguinal area, may have ipsilateral back pain
- Loin tenderness and enlarged kidney on palpation
- Symptoms of UTI and signs of sepsis
- Nausea and vomiting are common with acute obstruction
How does acute lower tract obstruction present?
Usually severe suprapubic pain and evidence of distended bladder
What are the causes of hydronephrosis?
- Renal calculi
- Pregnancy
- BPH
- Malignancy
or
PACT
p - pelvic-ureteric obstruction
a - aberrant renal vessels
c - calculi
t - tumours of renal pelvis
What are the bilateral causes of hydronephrosis? (5)
SUPER
- Stenosis of the urethra
- Urethral valve
- Prostatic enlargement
- Extensive bladder tumour
- Retro-peritoneal fibrosis
What investigations are done for someone with hydronephrosis? (4)
- USS (first line!) - identifies presence of hydronephrosis and can assess kidneys
- IVU
- Antegrade/retrograde pyelography
- CT scan if suspected renal colic
How is hydronephrosis managed? (3 - depends on acute or chronic)
- Remove the obstruction and drainage of urine
- If acute upper urinary tract obstruction then - nephrostomy tube
- If chronic upper urinary tract obstruction then - ureteric stent or a pyeloplasty
Which type of cancer is most common in the kidneys in adults?
Renal cell carcinoma - accounts for over 80% of neoplasms arising from the kidneys
What is the most common cancer in the kidneys in children?
Wilms’ tumours
Where does renal cell carcinoma (RCC) originate?
From the proximal renal tubular epithelium
Which chromosome is associated with RCC?
Chromosome 3 (short arm)
How can RCC’s be subdivided?
- Clear cell RCC
- Papillary
- Chromophobe
- Collecting duct carcinoma
…they are in order of prevalence - clear cell accounts for most RCCs