Acute urinary problems Flashcards
What two things are measured in AKI and help to define AKI? What is the main clinical clue?
- Serum urea and CREATININE
- REDUCED URINE OUTPUT is the main clinical clue (consider AKI in anyone with reduced urine output)
What are the magic numbers in AKI
What patients does this not really work for?
STAGE 1: Creatinine increased by 26umol (or more) from baseline within 48 hours or 150% in 7 days (risk)
STAGE 2: 200% (injury)
STAGE 3: Creatinine rise to 354umol or increase of 300% (failure)
**CKD patients have higher creatinine, so these values are for healthy patients
What is creatinine?
Limitations of creatinine?
-Creatinine is a breakdown of skeletal muscle that is excreted by the kidneys (majority glomerulus so good estimate of filtration)
Creatinine=most useful marker, however affected by:
• Muscle mass
•eGFR can fall to half before creatinine rises past upper limit
• Dilution
- Urea is easily influenced by protein turnover (diet, etc) and hydration status
What are the most common pre-renal causes of AKI?
What can hypo perfusion lead to?
PRE RENAL CAUSES AKI (the most common-70%)
-Nearly always due to HYPOPERFUSION of the kidney
•Hypovolaemia (burns, heamorrgae, D+V, pancreatitis)
•Reduced cardiac output (heart failure/MI)
•Distributive shock sepsis (vasodilation) or anaphylaxis
•Altered blood flow to kidneys (NSAIDs/ACEis/renal artery stenosis/hepatorenal syndrome)
*Hypoperfusion can lead to acute tubular necrosis (ATN) (which is an intra-renal cause)
What are some common intra-renal causes of AKI?
remember they can e split up into 3 parts
INTRA-RENAL CAUSES AKI (20%) 1) Glomerulus •Glomerulonephridities (e.g. SLE/HSP) •ATN (Acute tubular necrosis-often from pre renal) 2) Interstitial •Nephrotoxic drugs/infection/infiltration (e.g. sarcoid/myeloma free light chains) 3) Vessels •Vasculitis/HUS/TTP/DIC/malignant HTN
What are some common post-renal causes of AKI?
can either have within renal tract or extrinsic
POST-RENAL CAUSES AKI
-Bilateral obstruction of urinary flow out of the kidneys (leading to hydronephrosis)
Within renal tract
- Stone
- Malignancy
- Stricture
- Infection
Extrinsic compression
- Pelvic malignancy
- BPH
- Retroperitoneal fibrosis
- Congenital (posterior urethral valves)
What are some risk factors for developing AKI?
Risk factors for AKI
- Age >75
- CKD (eGFR < 60)
- Drugs (always look for newly started medications)
- Dehydration
- Cardiac failure
- Peripheral vascular disease
- Diabetes
- Chronic liver disease
History, Examination, Investigations for AKI?
AKI
History
-have you been ill recently
-have you had any recent scans
Examination
- Palpable bladder? (retention)
- Palpable kidneys/renal bruits?
- SKIN (rashes)
- JOINTS (arthritis)
- fever
- systemically unwell?
Investigations
- URINALYSIS: (blood/protein/infection)
- BLOODS: FBC/UsEs (Serum creatinine, K+)/CK/LFT (hepato renal syndrome)/CRP/clotting/ABG (metabolic acidosis)/ blood film (HUS)
- IMAGING: Renal USS and bladder scan
How should you initially manage a patient with AKI?
AKI MANAGMENT
ABCDEG> treat sepsis if found then USTOP
USTOP
- Us and Es (creatinine and POTASSIUM)
- Treat hyperkaleamia if present - Sepsis - screen and treat with BUFALO
- Toxins - stop nephrotoxins
- Optimise blood pressure
-mucous membranes/HR/BP/CRT/JVP/oedema and crackles
•hypovolemic>give IV 0.9% saline. Inotropic support if volume not regularising (ICU)
•Overloaded>restrict fluids and talk to senior-diuretics - Prevent harm
- Treat COMPLICATIONS e.g. hyperkalaemia (ECG), pulmonary oedema, pericarditis
- Identify CAUSE (dipstick, USS-obstruction)
- Renal replacement therapy?
- Review drug chart
- Monitor fluids (catheter) and U+Es
What common drugs are nephrotoxic?
AL DIAMOND
Antihypertensives e.g. ACEi, ARB, BB, CCB, AB
Lithium
Diuretics (especially potassium sparing)
Intravenous contrast /immunosupresants
Antibiotics - gentamicin (aminoglycosides) + nitrofurantoin
Metformin
Opioids
NSAIDs
Digoxin (aggravates hyperkaleamia)
What are drugs may increase risk of urinary retention?
Drugs that increase risk of urinary retention
- Anticholinergics
- Opioids
- Benzodiazepines
- NSAIDs
- Calcium channel blockers
- Antihistamines
- Alcohol
How would a patient in urinary retention present?
What investigations should you do for someone having urinary retention?
Urinary retention
- An enlarged, tender bladder that is dull to percussion
- Anuria
- Possible associated delirium
Investigations:
Bloods: FBC, UsEs, Glucose, PSA
Imaging: USS renal, CT pelvis/abdo/ MRI/CT head look for neuro cause if unexplained
Who is acute urinary retention more common in and why?
- MEN
- Due to prostatic hypertrophy
- Also common post-operatively and due to urethral stricture
What are some common causes of acute urinary retention?
What are some causes of urinary retention in women?
Urinary retention
- Bladder calculi
- Bladder cancer
- Faecal impaction
- Urethral strictures
Urinary retention in women
- Retroverted gravid uterus
- Atrophic urethritis
- MS (multiple sclerosis)
- Prolapse
- Pelvic mass
What are some specific things you’d want to check on history and examination in urinary retention?
URINARY RETENTION
- *ALWAYS SUSPECT SPINAL PATHOLOGY**
- History-ask about caudal equine syndrome (saddle anaesthesia/change in sensation, incontinence, lower back pain, changes in movement or sensation in legs)
-Exam- do PNS exam, PR (anal tone and also prostate) and pre/post BLADDER SCAN
How should acute urinary retention be managed?
Urinary retention
- Urethral catheterisation (if no CI) or consider supra-pubic if urethral not possible
- Use 3 way catheter if clots
- Alpha blocker (Tamsulosin) given to prepare for TWOC
Testing urine
-Once urine has been passed then DIP IT for infection and treat that
How will renal colic present?
Intermittent flank or loin pain that might also travel down to the groin
SEVERE PAIN that comes and goes in waves - this pattern of pain is due to ureteric peristalsis
Might also have urinary symptoms of:
- Anuria, dysuria, increased frequency, urgency, suprapubic tenderness, changes in smell or colour of urine, haematuria, sweating, fever, N&V
What is a common cause of renal colic?
KIDNEY STONES (Sweaty, N&V, and excruciating pain will predominate)
How should you investigate someone with renal colic pain?
KUB USS Urine dip - blood leucocytes Pregnancy test in women CT Bloods: FBC, U&E, WCC, CRP
How should someone with renal colic be managed initially?
Painkillers (might need IV)
FLUIDS - really important to keep patient hydrated.
Shock therapy can break down stones to make them easier to pass
How will testicular torsion present?
What will appear like on examination?
- Sudden onset SEVERE PAIN in the testicles, upper thigh, groin or lower abdomen
- Vomitig
O/E:
- Red, Swollen, tender testis
- ABSENCE of cremasteric reflex
- Testicle lies higher
- might lie more horizontally than vertically
Who is testicular torsion most common in?
- Boys in neonatal period and then again between the ages of 11-30 (peak during puberty)
- Bell clapper deformity
How should testicular torsion be investigated?
- It shouldn’t. If you suspect torsion you need to contact uro-surgery immediately because it is time sensitive
- Emergency surgery within 6-12 hours to preserve the testicle
How do we define a UTI?
UTI
- Infection of either lower urinary system i.e. urethra (urethritis), bladder urinary system (cystitis), prostate (prostatitis)
- Or upper (anything above bladder) i.e. renal pelvis (pyelonephritis)
What are some symptoms of UTI? (8)
UTI
- ↑Frequency
- ↑Urgency
- Dysuria (pain on urination)
- Blood in urine (cystitis)
- Supra pubic tenderness (bladder may be distended)
- Foul smelling ± Cloudy urine
- Confusion (elderly)
- Systemic features uncommon but can happen (sweating, fever, N+V)
What sort of symptoms would make you concerned that the LUTI had become an UUTI?
What is the treatment for upper UTI
Upper UTI
- MORE SYSTEMIC SYMPTOMS OF UNWELL
- Fever and rigors
- Sweating
- Malaise
- Vomiting and loss of appetite
- Loin/back pain
Treatment of UPPER UTI (pyelonephritis)
- 7-10 day course of CIPROFLOXACIN
- Co-amoxiclav can be used
What is the most common cause of UTI?
E. Coli = most common (80% in community)
- Staphyloccous saprophyticus (skin commensal)
- Proteus mirabilis
- Klebsiella pneumonia
- Pseudomonas
How do we investigate a UTI
Urine dip (look for nitrites - sensitive, leucocytes, protein, blood) Urine microscopy and culture
- Urine dipstick (MSU)
-look for +Nitrites +Leucocytes (+Blood)
-will always be +ve in catheter
•if +ve then just treat empirically and send off MC+S
•if -ve but symptomatic → MSU - Also send for MC&S
> 105 organisms/ml = diagnostic
if <105 organisms/ml and pyuria e.g. > 20 WBCS/mm = may still be significant - Sexual history + swabs if appropriate –
- VVS
- ECS w/ NAATS
- Urethral swab
Initial management of UTI for MEN
(what and how long for)
What do you give if acute prostitis?
UTI treatment MEN
7 day course of trimethoprim/nitrofurantoin (if egfr >30)
Prostatitis - 4 week course of ciprofloxacin because quinolines penetrate prostatic fluid
Initial management of UTI for WOMEN? (uncomplicated vs complicated)
UTI management for WOMEN
- 3 day course of trimethoprim (or nitrofurantoin but only if eGFR > 30)
- Symptoms should resolve in 48hrs
Complicated (e.g. impaired renal function, abnormal urinary tract, immunosuppressed) longer e.g. 7 days
What is the treatment for pregnant women with a UTI?
1st line
2nd line
Which antibiotics must be avoided in pregnancy?
UTI in pregnancy
1st line: oral Nitrofurantoin (unless at term)
2nd line (no improvement or unsuitable): oral amoxicillin (only if culture susceptible), or cefalexin.
Avoid:
- Trimethoprim (1st trimester)
- Nitrofurantoin (term)
- Quinolones e.g. ciprofloxacin (all pregnancy)
- Sulphonamides (all pregnancy)
How can you tell the difference between AKI and someone with chronic kidney problems?
CKD patients will have high phosphate and low calcium
What is the definition of bacteriuria?
Whats it called if there is no bacterial growth?
UTI bacteriuria
-defined as 10^5 organisms/ml of fresh MSU (mid stream urine)
-Symptoms but no bacterial growth = Abacterial cystitis (otherwise known as urethral syndrome)
What is it called when you find bacteria on MSU but there are no symptoms of UTI?
ASYMPTOMATIC BACTERURIA
- bacteria >10^5 in urine but with no UTI symtptoms
- don’t always need treatment
- PREGNANT WOMEN NEED TREATMENT
When would you do imaging for UTI?
What is the imaging of choice?
Imaging for UTI Do an USS + referral to urology CTKUB if: -men with upper UTI -recurrent (more than 2 in one year) -failure to respond to treatment -pyelonephritis -abn. organism (immunocompromised) -persistent haematuria
In an elderly patient that comes in confused, what two urinary problems should you always consider?
UTI
ACUTE URINARY RETENTION (post void bladder scan) <200ml unlikely
What is a complication of catheterisation after acute urinary retention?
Post obstructive diuresis can occur after catheterisation -prolonged polyuria
- excessive salt and water loss
How do you treat catheter sample UTI?
Catheter sample bacteria
- all will have bacteria, send MSU only if symptomatic
- change catheter before starting antibiotics per local guidelines
What are symptoms of prostatitis
- Pain in perineum, rectum, scrotum, penis, bladder, lower back
- Fever
- Malaise
- Nausea
- Urinary symptoms
- Swollen/tender prostate on PR
What is sterile pyuria?
Sterile pyuria
- mid-stream urine specimen has 10 or more white blood cells per cubic millimeter or +ve leukocytes on dip stick
- with negetive urinary culture
What are some infective causes of sterile pyuria?
Sterile pyuria (infective causes)
- TB (persistant)
- Recently treated UTI
- Inadequately treated UTI
- Appendicitis
- Prostatitis
- Chlamydia
What are some non infective causes of sterile pyuria?
Sterile pyuria (non-infective causes)
- Calculi
- Renal tract tumour
- Papillary necrosis
- Tubulointerstitial nephritis
- Polycystic kidneys
- Pregnancy
- SLE
- Steroids
How do you treat asymptomatic bacteria in pregnancy?
Asx Bacteriuria
- should be confirmed on 2nd sample
- ALWYS TREAT PREGNANT PEOPLE WITH ASX BACT
- Nitrofurantoin (avoid at term)
Complicated vs uncomplicated UTI?
Uncomplicated = normal urinary tract structure, function; normal immune system; non-pregnant
Complicated = structural/functional abnormality of genitourinary tract e.g. obstruction, catheter, stones, renal transplant, neurogenic bladder; pregnancy; immunocompromised
Main risk factors for UTI?
Bacterial inoculation
- Sexual activity
- Urinary incontinence
- Faecal incontinence
- Constipation
Binding of uropathogenic bacteria
- Spermicide use
- Decreased oestrogen
- Menopause
Decreased urine flow
- Dehydration
- Obstruction
Increased bacterial growth
- Diabetes
- Immunosuppression
- Obstruction
- Stones
- Catheter
- Pregnancy
Commonest causes of AKI?
- Sepsis
- Major surgery
- Cardiogenic shock
- Other hypovolaemia
- Drugs - NSAIDs, ACE inhibitors
- Hepatorenal syndrome (renal deterioration secondary to cirrhosis)
- Obstruction - BPH, tumours, stones, strictures
What from urninalysis would suggest intra renal?
- Blood/protien in urine suggests intra renal cause (↑renal damage, infection, vasculitis/ SLE rhabdomyolysis)
- Also recent throat infection
What other symptoms would make you think of vasculitis?
Vascilitis
-achy joints/ skin rashes/ AKI is classic vascilitis
What are some symptoms and signs of advanced uraemia?
- Reduced mental state, reduced GCS, seizures
- Myoclonic twitching
- Anorexia, nausea, vomiting
- Increased photosensitive pigmentation – which may make the patient appear misleadingly healthy
- Brown discolouration of the nails
- Excoriations from pruritis
- Signs of fluid overload – peripheral oedema, pulmonary oedema (crackles at the lung bases on auscultation)
- Pericardial friction rub
- Glove and stocking sensory loss – rare
What are some indications for dialysis/renal replacement therapy after AKI?
Dialysis indications (AEIOU)
A-Acidosis (pH <7.1)
E-Electrolytes (refractory hyperkalemia> 6.5mEq/L
I-Intoxications (SLIME neumonic-salicylates, lithium, isopropanol, methanol, ethylene glycol
O-Overload/pulmonary oedema despite diuretics
U-Ureamia >45 (elevated BUN with signs of uraemia (encephalopathy, seizures, coma, pericarditis)
For AKI, apart from a Creatinine rise of 26 in 48hrs, what else can indicate AKI?
Diagnosiing AKI
- Serum creatinine rises by >26 umol/L from baseline value within 48 hours
- Serum creatinine rises > 1.5 times from the baseline value within one week
- Urine output is less than 0.5ml/kg/hr for >6 consecutive hours
What ECG changes would you see in hyperkalaemia in order of severity?
- Tall tented T-waves
- Flattened P-waves
- Prolonged PR interval
- Widened QRS complexes
- Idioventricular rhythms (slow regular ventricular rhythm, typically with a rate of less than 50, absence of P waves, and a prolonged QRS interval)
- Sine wave patterns
- VF/asystole
Urine output for stage 1,2,3 AKI?
Urine output
stage 1 -<0.5ml/kg/hr for 6hours
stage 2 <0.5ml/kg/hr for 12hours
stage 3 <0.3ml/kg/hr for 24 hours
What do the following suggest in the context of AKI free light chains RBC casts Granular casts Eosinophils
- Bence-jones protein (Free light chains) – myeloma (75%)
- RBC casts (RBC from glomerulus) – Glomerulonephritis
- Granular casts – Acute tubular necrosis
- Eosinophils – Acute interstitial nephritis (drugs)
How can you tell the difference between pre renal AKI and intra renal AKI using urine osmolality?
Differentiate between pre-renal and renal
- Pre-renal e.g. hypovolaemia
- Kidneys aim to retain Na+/water → concentrated urine
- ↑Urine osmolality, ↓Na+
Renal e.g. ATN
- kidney damaged → loses filtration ability to concentrate urine
- ↓Urine Osmolality ↑Na+
When do you treat hyperkaleamia?
Treat when potassium > 6.5 OR >6 with ECG changes!
