Renal/Genitourinary Flashcards
Functions of the kidney
AWETBED
Acid-base homeostasis
Water balance
Electrolyte balance
Toxin/waste product removal
Blood pressure control
Ertyhropoietin
D (vitamin D activation)
Define Acute Kidney Injury
A sudden decline in kidney function leading to a rise in serum creatinine and fall in urine output.
What can renal dysfunction cause
Dysregulation of
- Fluid balance
- Acid-base homeostasis
- Electrolyte imbalance
Drugs to stop in acute kidney injury
DAAMN
D - Diuretics
A - ACEi/ARB
A - Aminoglycosides
M - Metformin
N - NSAIDs
ACEi/ARB protective in Chronic
6 pre renal causes of AKI
Hypoperfusion
- Hypovolaemia (bleeding, reduced cardiac output (CHF), cardiogenic shock)
- Liver failure (hypoalbuminaemia)
- Renal artery blockage/stenosis
- ACEi & NSAID
- Sepsis causing systemic vasodilation
- Dehydration
4 intrarenal causes of AKI
Intrinsic disease of kidney
- Acute tubular necrosis
- Acute interstitial nephritis (these 2 can be drug induced)
- Glomerulonephritis
- Small vessel vasculitis
4 post renal causes of AKI
Obstruction to urinary outflow, causing back pressure into kidney. (Obstructive uropathy)
- BPH
- Urolithiasis
- Cervical and prostate cancer
- Bladder neck stricture
Risk factors of AKI
- Age >65
- Heart failure
- Diabetes
- Poor fluid intake
- Hypovolaemia
- Nephrotoxic meds (NSAID, ACEi)
- Contrast medium usage in imaging
- Prostate cancer
- BPH
- Sepsis
- Liver disease
Electrolyte consequences of AKI
Hyperkalaemia and azotaemia (increased blood creatinine and urea)
Metabolic acidosis
Symptoms of pre renal AKI
Hypotension
Reduced capillary refill
Dry mucus membranes
Reduced skin turgor
Cool extremities
Intra renal AKI symptoms
Infection/ signs of underlying disease (vasculitis, glomerulonephritis etc)
Post renal AKI symptoms
Loin to groin pain
Haematuria
Palpable bladder/prostate
Prostatic urinary issues (dysuria, terminal dribbling, hesitancy)
Causes of Acute tubular necrosis
Ischaemia - Pre renal disease
Nephrotoxicity - (aminoglycosides, chemotherapy), contrast in CT, myoglobin, multiple myeloma
Pathophysiology of acute tubular necrosis
Nephrotoxins (aminoglycosides, NSAIDs, uric acid) can kill epithelial cells. When cells die, they block tubules increasing pressure. Less filtration occurs, causing azotaemia, hyperkalaemia and metabolic acidosis.
Pathophysiology of prerenal AKI
Less blood into kidney usually due to hypovolaemia causes activation of RAAS system
Na+ and urea reabsorbed, leading to oliguria
Causes less urine output which is more concentrated
Diagnostic criteria for AKI (stage 1)
- Rise in creatinine > 26μmol/L within 48 hours
- Rise in creatinine >1.5 x baseline (i.e. before the AKI) within 7 days.
- Urine output <0.5ml/kg/hour for >6 consecutive days.
Investigations in AKI
Check for hypo/hypervolaemia and urine output
FBC, U&E, ABG, Creatinine Kinase, Urine output should all be checked.
Urinalysis
Imaging
- Ultrasound - urinary tract to look for obstruction
- CXR - Signs of volume overload (cardiomegaly, pulmonary oedema)
- ECG - Hyperkalaemic changes
- CTKUB check obstruction
What urinalysis is conducted in AKI
Urine osmolality and electrolytes checked
Dipsticks - Leucocytes and nitrites = infection
Protein/ blood = acute nephritis
Glucose suggests diabetes
Treatment of AKI
Prerenal: IV fluids and treatment of sepsis
Intrarenal: Stop nephrotoxic drugs, treatment specific to condition
Post renal: Catheter in BPH
Treatment of AKI complications
Hyperkalaemia
- Calcium gluconate (protect myocardium)
- Insulin/dextrose (drive K+ into cells)
- Stop K+ sparing medication
Acidosis
- Sodium bicarbonate
Pulmonary oedema/hypervolaemia
- Diuretics
Complications of AKI
- Hyperkalaemia
- Fluid overload from treatment
- Metabolic acidosis
- Uraemia (encephalopathy/pericarditis)
- CKD
Classification systems in AKI
KDIGO (Kidney Disease: Improving Global Outcomes)
RIFLE (Risk Injury Failure Loss Endstage renal disease)
Staging of AKI
KDIGO criteria
Stage 1
- Creatinine >26 or 1.5-1.9x baseline in <48hr
- Urine output <0.5ml/kg/hr for 6-12 hours
Stage 2
- >2-2.9x baseline creatinine
- Urine output <0.5ml/kg/hr for >12 hours
Stage 3
>353 or 3x reference creatinine
<0.3ml/kg/hr for >24 hours or anuria for >12
Define CKD
Progressive deterioration in renal function over at least 3 months characterised by eGFR of <60ml/min/1.73m²
What 2 tests are considered in CKD classification
eGFR and albumin:creatinine ratio
How is eGFR used to stage CKD
Stage 1 - >90 (normal)
Stage 2 - 60-89 (mild reduction, only CKD if symptoms)
Stage 3a - 45-59 (mild-moderate reduction)
Stage 3b - 30-44 (moderate-severe reduction)
Stage 4 - 15-29 (severe reduction)
Stage 5 <15 (End stage kidney failure)
How is albumin:creatinine ratio used to stage CKD
Checks proteinuria to give A score
A1 - <3mg/mmol
A2 - 3-30mg/mmol
A3 - >30mg/mmol
What can be used as evidence of renal damage?
- Albuminuria (ACR>3)
- Electrolyte abnormalities
- Histological abnormalities
- Structural abnormalities on imaging
- Kidney transplant history
- Urine sediment abnormalities
At what eGFR is metformin contraindicated
<30ml/min/1.73² (stage 3b)
Causes of CKD
Most common: Diabetes and HTN
Nephrotoxic drugs
Glomerulonephritis
Systemic disease e.g. rheumatoid arthritis/SLE
How does CKD lead to its complications
low eGFR = azotaemia (which can cause encephalopathy and pericarditis)
Urea affects platelet function (bleeding)
Uremic frost (urea crystals in skin)
Kidneys normally activate vit D. No activation = hypocalcaemia = PTH secretion = bone resorption (renal osteodystrophy)
Low fluid to kidney = RAAS activation = HTN
HTN causing increased intraglomerular pressure - causing shearing and loss of selective permeability (protein/haematuria)
Kidneys produce less EPO = Anaemia
Signs/symptoms of CKD
Asymptomatic at first
Uraemic frost (tiny yellow white urea crystals on skin)
Uraemia swallow (pale/brown colour on skin)
Pallor
Fatigue
Lethargy
Frothy urine
Swollen ankles/oedema
Increased bleeding
What does anaemia, with low calcium and low phosphate imply
CKD
Investigations in CKD
Urine dipstick
- Haematuria, glycosuria
eGFR and urine albumin:creatinine ratio
U&E
FBC
- Normocytic normochromic anaemia
Bone profile/PTH
- Ca2+ low, phosphate high, PTH high, ALP high
Renal ultrasound
Bilateral kidney atrophy (small kidneys)
Complications of CKD
Anaemia (EPO reduced)
Osteodystrophy (decreased vit D activation)
Neuropathy/encephalopathy
Pericarditis
Treatment of CKD
No cure except transplant, can only treat symptoms
Anaemia - EPO + Iron
Osteodystrophy - Vit D supplementation
CVD - ACEi + statins
Oedema - Diuretics
(ACEi help in CKD but harm in AKI)
What is RRT and what are its indications
Renal replacement therapy - Persistent severe complications (electrolyte, oedema, uraemia) or Stage 5 CKD
AEIOU
Acidosis > 7.2 - Acidosis not helped by sodium bicarbonate
Electrolytes K+>7mmol/L
Intoxication - Stage 5 CKD
Oedema
Uraemic pathology - Encephalopathy, pericarditis etc
What are the types of RRT
Haemodialysis (most common)
- Blood taken from artery, filtered and returned into vein at AV fistula.
- 3x4 hours a week
- Complications: hypotension, nausea, chest pain, infected catheter (sepsis)
Peritoneal dialysis
- Peritoneal catheterisation, exchange of solutes across peritoneal membrane
- Done at home
- Complications: Peritonitis, abdominal wall hernia
Causes of CKD-mineral bone disease
Reduced 1-alpha hydroxylase activity (reduced vit D activation)
Reduced renal excretion of phosphate (phosphate stimulates bone resorption)
Treatment of CKD mineral bone disease
Reduced dietary phosphate (fish, meat, poultry)
Vit D replacement (calcitriol is already 1-alpha-hydroxylated)
Phosphate binders
Bisphosphonates
BP Targets in CKD
140/90 or 130/80 if coexisting diabetes
ACEi used (reduce filtration pressure, less proteinuria)
Define renal colic
AKA Nephrolithiasis
Formation of renal stones in urinary system
Pathophysiology of Nephrolithiasis
When solvent (water) too low, or solute too high, solutes can precipitate and crystallise, forming a nidus. More solutes precipitate around this, forming kidney stone.
Mg and Citrate inhibit crystal growth
What are the types of kidney stone, how do they form and how do they show?
Calcium oxalate (most common)
- Black/dark brown, radiopaque on X ray
- Form in acidic urine
Calcium phosphate stones
- Dirty white, Radiopaque
- Form in alkaline urine
Struvite stones (magnesium, ammonium. phosphate)
- Dirty white, radiopaque
- AKA infection stones, form during UTI (UTI organisms hydrolyse urea into CO2 and ammonia)
Uric acid stones
- Red-brown, radiolucent (transparent to X ray)
- High purine diet, dehydration, acidic urine
Cystine stones
- Yellow/light pink, radiopaque
- Cystinuria, autosomal recessive condition causing decreased cystine absorption
Renal stone appears dirty white and radiopaque, which 2 could it be?
Calcium phosphate
Struvite
(struvite forms during UTI)
Risk factors for renal stone development (7)
Dehydration
Low urine output
Hypercalcaemia, Hypercalciuria Hyperparathyroid
Previous kidney stones
Foods high in oxalate, phosphate or calcium (spinach, tea, rhubarb, chocolate)
Gout
Renal tubular acidosis
Signs/symptoms of nephrolithiasis
Severe, colicky loin to groin pain
- Lasts minutes to hours and fluctuates in severity
- Caused by peristalsis against stone (dilation, stretching and spasm due to obstruction of ureter)
Flank/renal-angle tenderness
Fever
Nausea/vomiting
Haematuria
(Hypotension and tachycardia if sepsis)
2 most common renal stone sites
- Ureteropelvic junction
- Renal pelvis (staghorn calculi form here)
Investigations in nephrolithiasis
Urine dipstick - haematuria (+ leucocytes and nitrites if infection)
Abdominal X ray - calcium based stones
USS KUB - Pregnant or under 16, only radiopaque
NCCT-KUB (Non Contrast CT of Kidney, Ureter, Bladder) - Stones seen in renal collecting system or ureter
Management of Nephrolithiasis
Hydration
IV diclofenac for renal colic
Antibiotics for UTI
Surgery if stones too big
- Extracorporeal shockwave lithotripsy (CI in pregnant)
- Percutaneous Nephrolithotomy (PCNL)
Kidney stone recurrence prevention
Citrus e.g. lemon juice (citric acid binds to urinary calcium)
Avoid cola drinks
Potassium citrate
Cystine binder if cystine stone
Thiazide diuretics (increase Ca2+ excretion)
What are the upper and lower UTIs
Upper - Pyelonephritis (renal parenchyma and renal pelvis)
Lower
- Urethritis (Urethral inflammation usually due to STI)
- Cystitis (Infection of bladder)
- Prostatitis (acute/chronic infection of prostate)
- Epididymis-Orchitis (epididymis, extends to testes, usually 2° to urethritis or cystitis)
How do you know if a UTI is complicated? (7)
If it affects:
a man
a pregnant lady
a baby
the immunocompromised
it is recurrent
people with abnormal urinary tracts (e.g. stones)
Catheterised
General UTI causing microbes
KEEPS
K- Klebsiella
E- E Coli (UPEC) (80% of cases)
E- Enterococci
P- Proteus spp
S- Staphylococcus
(Most common E Coli strain is UPEC (UroPathogenic E Coli))
Why are women more affected by UTIs
They have a shorter urethra, which is closer to the anus, allowing for easier microbial colonisation
Investigations in uncomplicated UTI
Midstream urine dipstick (leukocytes, nitrites, may or may not have haematuria)
Midstream urinary culture (MC and S - Microscopy, culture and sensitivity)
Treatment of uncomplicated UTI
Nitrofurantoin and trimethoprim (teratogenic) 3 days, while waiting for culture
Do not treat >65 years if asymptomatic
Define Pyelonephritis with risk factors
Infection of renal parenchyma and upper ureter, which can be direct or haematogenous
- Vesico-ureteral reflux
- Unprotected sex
- Female
- Pregnancy
- Urinary tract obstruction
- Indwelling catheter
- Ascending lower UTI
Signs/symptoms of pyelonephritis
TRIAD:
Fever, loin/back pain, pyuria (WBC in urine)
Renal angle tenderness, nausea/vomiting, haematuria
Abdo exam and Investigations in pyelonephritis
Abdominal exam
- Tender loin
- Renal angle tenderness
Midstream urine disptick
- Blood, protein, leukocyte, nitrites, foul smell
CT scan first line imaging
GOLD: Midstream urine MC+S
Management of pyelonephritis
IV fluids and broad spectrum antibiotics (Co-amoxiclav 14 days)
Drain obstructed kidney and remove catheter
Complications of pyelonephritis
Renal abscess
Emphysematous pyelonephritis (gas accumulation in tissues, life threatening)
Chronic pyelonephritis
How should catheterised UTI be investigated
DONT use urine dipstick.
Culture should come from catheter
Define cystitis
Usually UPEC infection of bladder
Signs and symptoms of cystitis
Suprapubic pain/tenderness, Dysuria (pain/burning when urinating), frequency, urgency, cloudy/smelly urine
How to diagnose cystitis
Abdominal exam
Urine dipstick and MC+S
Define urethritis
Urethral infection and inflammation, usually sexually acquired
Causes of urethritis
Infective
- Gonococcal (Neisseria gonorrhoea)
- Non gonococcal (chlamydia tractomatis)
Non infective
Trauma
Reactive arthritis
Signs/symptoms of urethritis
Urethral discharge (blood/pus), itching, irritation
Dysuria, frequency, urgency
Investigations in urethritis
1st - NAAT (Nucleic acid amplification test)
Females - vulvovaginal swab
Males - First void urine (first in morning)
Urethral discharge gram stain (Gram negative diplococci = N gonorrhoeae)
Urine dipstick and culture
Treatment of urethritis
N gonorrhoea
- Single dose of IM Ceftriaxone (1g) or oral ciprofloxacin (500mg)
Chlamydia
- Doxycycline 2x a day for 7 days
What should be looked at after pharmacological treatment in urethritis
Sexual abstinence
Safeguarding issues in children
Contact tracing
Disseminated Gonococcal Infection most common complication (skin and joints affected)
Define Epididymo-Orchitis
Inflammation of epididymis, extending to testes, usually secondary to urethritis (STI pathology) or Cystitis (Mostly UPEC)
Signs/symptoms and treatment of Epididymo-Orchitis
Unilateral scrotal pain and swelling.
Pain relieved with elevation of testes
cremaster reflex intact
Treatment will be identical to cystitis or urethritis depending on cause.
Define prostatitis
Severe prostate infection usually due to KEEPS pathology
Signs/symptoms of prostatitis
Tender hot swollen prostate on DRE
Pelvic pain
LUTS (Dysuria, frequency, hesitancy, urgency etc)
Pain with bowel movements
Infection symptoms (Tachycardia, fever, nausea, rigors etc)
Investigations of prostatitis
Digital rectal exam (DRE)
Urine dipstick and MSU (midstream urine sample) with culture
Blood culture
STI screen (NAAT)
Differentials of prostatitis (5)
BPH
UTI
Prostate cancer
Bladder cancer
Epididymo-orchitis
Management of prostatitis
Acute
- 14 day ciprofloxacin
analgesia and laxatives if pain
Chronic
- Alpha blockers (tamsulosin)
- 4-6 week doxycycline or trimethoprim
Complications of prostatitis
Main: Prostate abscess (especially if indwelling catheter)
Sepsis
Progression to chronic
Define Benign Prostatic Hyperplasia
Non malignant growth of the prostate gland, causing compression of the prostatic urethra causing Lower Urinary Tract Symptoms (LUTS). Usually affects transitional zone