Genitourinary Flashcards
(246 cards)
Define nephrolithiasis
Renal stones/renal calculi. Stones form in the renal pelvis of the kidney and can travel down the ureters. Majority (80-90%) are calcium oxalate stones (radio-opaque). Other types: calcium phosphate, uric acid (radio-lucent: not seen on x-ray), struvite (produced by bacteria), cystine.
Describe the epidemiology of nephrolithiasis
Very common. More in men (testosterone > increased oxalate)
Describe the aetiology of nephrolithiasis
Chronic dehydration, obesity, high protein/salt diet, recurrent UTIs, low urine output, hyperparathyroidism/hypercalcaemia
Describe the pathophysiology of nephrolithiasis
Excess solute in chronic dehydration causes supersaturated urine which favours crystallisation. Stones cause regular outflow obstruction (hydronephrosis). This leads to dilation and obstruction of renal pelvis. Stones commonly get stuck at pelvo-ureteric junction, vesico-ureteric junction and pelvic brim.
What are the key presentations for nephrolithiasis
Renal colic = severe colicky unilateral pain originating in loin and radiating to groin. Patient can’t lie still. Haematuria, nausea and vomiting, reduced urine output
What is the gold standard investigation for nephrolithiasis
Non-contrast CT KUB (kidney, ureter, bladder) – presence of stones. Can only see radio-opaque stones in USS
Describe the first line investigations for nephrolithiasis
Urine dipstick: haematuria, leukocytes, nitrates. FBC, CRP (infection), U&Es (hypercalcaemia). Abdominal x-ray (will show calcium stones but not uric acid stones as they are radiolucent)
Describe the differential diagnosis for nephrolithiasis
Peritonitis, appendicitis, UTI
Describe the management for nephrolithiasis
Symptomatic relief – hydration, NSAIDs (diclofenac). Antiemetics, antibiotics. Watchful waiting – stones under 5mm should pass spontaneously without infection
Elective treatment if too big – Extracorporeal Shock Wave Lithotripsy ESWL (break stone into smaller fragments using shockwaves), ureteroscopy and laser lithotripsy, PCNL (percutaneous nephrolithotomy, use nephoscope to remove stone)
Lifestyle: decrease sodium and protein intake, increase citrus fruit, adequate fluid intake
Describe the complications for nephrolithiasis
Obstruction (leading to AKI), infection (leading to pyelonephritis)
Define acute kidney injury
Sudden decline in kidney function determined by increased serum creatinine and decreased urine output. NICE criteria for AKI (KDIGO classification):
Rise in creatinine of >26 micromol/L in 48 hours
Rise in creatinine of >50% from baseline in 7 days
Urine output of <0.5ml/kg/hr for >6 hours
Describe the aetiology of acute kidney injury
Pre-renal: inadequate blood supply to kidneys – dehydration, hypotension (shock), heart failure
Intra-renal: intrinsic disease in kidney leads to reduced filtration – glomerulonephritis, interstitial nephritis, acute tubular necrosis
Post-renal: obstruction to outflow of urine in kidney causing back pressure and reduced function – obstructive uropathy: kidney stones, cancerous masses, ureter/urethra strictures, enlarged prostate or prostate cancer
What are the risk factors for AKI
Hypotension, volume depletion, CKD, heart failure, diabetes, cirrhosis, nephrotoxic meds (NSAIDs, ACEi), cancer, trauma
Describe the pathophysiology of AKI
Pre-renal: low blood volume > decreased perfusion > decreased GFR and creatinine clearance
Intra-renal: kidney damage > decreased oncotic and hydrostatic pressure > decreased GFR
Post-renal: obstruction > back pressure into kidney > decreased hydrostatic pressure > decreased GFR
Decreased GFR leads to build up of normally excreted substances: creatinine, K+ (arrhythmias), urea (confusion, uraemia), fluid (oedema), H+ (acidosis)
Describe the key presentations for AKI
Reduced urine output, high creatinine, hyperkalaemia (arrhythmias, muscle weakness), uraemia (pericarditis, N+V, encephalopathy), fluid overload (pulmonary and peripheral oedema, hypovolemic shock, orthopnoea), hypotension, sepsis/acute illness
Describe the clinical manifestations for AKI
Signs: Pre-renal: hypotension, syncope, D+V
Intra-renal: infection, signs of underlying disease
Post-renal: lower urinary tract symptoms (LUTS) – low urine output
Symptoms: Vomiting, nausea, fever, dizziness, altered mental status
What is the gold standard investigation for AKI
Metabolic profile: U&E (GFR) and creatinine – raised serum creatinine, reduced urine output
Describe the first line investigations for AKI
NICE criteria for AKI (KDIGO classification):
Rise in creatinine of >26 micromol/L in 48 hours
Rise in creatinine of >50% from baseline in 7 days
Urine output of <0.5ml/kg/hr for >6 hours
Determine cause: urea:creatinine ratio – pre-renal (>100:1), intrarenal (<40:1), post-renal (40-100:1)
Metabolic panel and urine output monitoring: raised serum creatinine, low urine output, raised potassium, metabolic acidosis (raised H+)
Urinalysis: leucocytes and nitrates (infection), proteinuria and haematuria (acute nephritis)
Other: FBC, CRP, renal ultrasound, ECG (hyperkalaemia)
Describe the differential diagnosis for AKI
Chronic kidney disease, renal stones, tubular necrosis
Describe the management for AKI
1st line - Treat underlying cause (hypotension, stones, infection). Stop nephrotoxic drugs (NSAIDs, ACEi). Treat complications (electrolyte imbalances).
Severe – renal replacement therapy: haemodialysis (indicated in AFUK: acidosis, fluid overload, uraemia + complications, K+ >6.5)
Describe the complications for AKI
End-stage renal failure, chronic kidney disease, metabolic acidosis, uraemia > encephalopathy, pericarditis
Define bladder cancer
Cancer in bladder arising from urothelium. Most common subtype = transitional cell carcinoma. Others = squamous cell carcinoma (schistosomiasis increases likelihood), adenocarcinoma
Describe the epidemiology of bladder cancer
Old men, people who work in rubber/dye industry
Describe the aetiology of bladder cancer
Mutation