Renal/Urology Flashcards
what are the 3 classical locations for renal stones to get stuck?
- pelviureteric junction (PUJ)
- pelvic brim
- vesicoureteric junction (VUJ)
(the three places the ureters are narrowest)
what are most renal stones made up of? what are the other three substances?
- calcium oxalate.
- calcium phosphate
- urate
- struvite
give 3 predisposing factors for renal stones
hypercalcaemia, sarcoidosis, hyperparathyroidism, high uric acid, UTI, PKD, loop diuretics, antacids
why do renal stones form?
form when normally soluble material supersaturates the urine.
must also overcome the inhibitors of crystal formation present in normal urine.
what causes calcium renal stones?
hypercalciuria, due to hypercalcaemia - due to e.g. hyperparathyroidism, excess dietary clacium, excessive bone resorption (prolonged immobilisation)
who’s particularly at risk of uric acid stones?
those with clinical gout - hyperuricaemia.
those with ileostomies - loss of bicarbonate from GI secretions leads to acid urine, reducing solubility of uric acid.
how might frequent UTIs put you at risk of renal stones?
some infecting organisms produce urease
how do ureteric/renal calculi present? how does the pattern of pain relate to innervation of ureters?
renal colic - excruciating spasms, ‘loin to groin’.
restlessness, dysuria, desire but inability to void. not normally actually colicky pain.
might get macroscopic haematuria. if N&V, fever - worry about secondary pyelonephritis/pyonephrosis.
loin to groin pain as innervated by ilioinguinal and genitofemoral nerves.
what is the best investigation to visualise renal stones with?
KUB/abdo XR (kidney, ureter + bladder) - 50% of stones are radio-opaque. if they do turn up it’s helpful cos it’s easy to do follow up abdo XRs in clinic.
CT-KUB - for radio-lucent stones
what other investigations might you perform in renal colic (apart from imaging)?
urine dipstick - 90% +ve for blood, also white cells for secondary infection (MSU for MC&S if present)
calcium and urate levels - 24h urine.
how would you treat a patient with renal stones?
depends on size and material of stone. <7mm leave to pass naturally with LOTS OF ANALGESIA (diclofenac)
if >7mm:
- lithotripsy
- lithoplapaxy
- percutaneous nephrolithotomy
give some examples of steps to be taken to prevent recurrence of renal stones
drink plenty, normal dietary calcium intake, reduce salt intake
allopurinol for urate stones, pyridoxine for oxalate stones.
define hydronephrosis. what can it lead to?
dilatation of renal pelvis - compression and thinning of renal parenchyma - decrease in kidney size.
what happens to the urinary tract proximal to a point of obstruction?
dilates
give 3 possible causes of urinary tract obstruction
prostatic obstruction - hypertrophy or tumour. gynaecological cancers (but also other gynae stuff like ovarian cysts/endometriosis - most common kind of cause in young women) hypercalcaemia. caliculi (stones). renal tubular acidosis. primary hyperoxaluria. medullary sponge kidney. TB.
how would acute upper urinary tract obstruction present?
loin to groin pain.
superimposed infection ± loin tenderness.
enlarged kidney.
how would chronic upper urinary tract obstruction present?
flank pain, renal failure, superimposed infection, polyuria (due to impaired urine concentration).
how would acute lower urinary tract obstruction present?
severe suprapubic pain.
symptoms of bladder outflow obstruction.
distended, palpable bladder, dull to percussion.
how would chronic lower urinary tract obstruction present?
urinary frequency, hesitancy, poor stream, terminal dribbling, overflow incontinence.
distended palpable bladder.
how would you treat upper urinary tract obstruction?
nephrostomy or ureteric stent.
alpha blockers - decrease ureteric spasm, help with stent pain.
how would you treat lower urinary tract obstruction?
urethral/suprapubic catheter.
treat underlying cause.
possible large diuresis on relief of obstruction - watch for salt loss!
give 2 pre-renal causes of AKI
renal hypoperfusion, sepsis, CCF, cirrhosis, renal artery stenosis, NSAIDs, ACE inhibitors
give 2 renal causes of AKI
acute tubular necrosis, PKD, SLE, renal cell carcinoma, myeloma, diabetic nephropathy, drugs, vasculitis, thrombus, HUS, TTP, infections.
give 2 post-renal causes of AKI
urinary tract obstruction by stones/clots, blocked catheter, retroperitoneal fibrosis, benign prostatic hypertrophy/prostatic carcinoma
what would be the most worrying investigation result in AKI?
hyperkalaemia
what is used as a way to estimate kidney function? why is it good for this?
serum creatinine, used to calculate eGFR.
produced by body at pretty steady rate and is excreted by kidneys through glomerular filtration - no reabsorption.
if filtration is impaired, this is shown by high serum creatinine.
serum urea also rises in AKI.
give 3 risk factors for AKI
age >75yrs, CKD, cardiac failure, peripheral vascular disease, chronic liver disease, diabetes, drugs, sepsis, poor fluid intake/increased losses
explain the staging of CKD
1 - GFR >90, other renal damage 2 - 60-89, other renal damage 3a - 45-59 ± renal damage 3b - 30-44 ± renal damage 4 - 15-29 ± renal damage 5 - less than 15 - established renal failure
give 3 causes of CKD
diabetes (type 2»type 1).
glomerulonephritis (IgA nephropathy, SLE, vasculitis).
idiopathic, hypertension, renovascular disease, pyelonephritis, reflux nephropathy, PKD.
give 3 risk factors for CKD
diabetes, hypertension, heart disease, smoking, obesity, age >65yrs, FHx
give 3 symptoms of CKD
fatigue, weakness, anorexia, vomiting, metallic taste, pruritus, restless legs, bone pain, impotence
give 3 signs of CKD you might find on examination
uraemic flab, leuconychia, scratch marks, raised JVP, anaemia, ascites, peripheral neuropathy, AV fistula
usually presents as incidental finding in hypertensive diabetic >50yrs
what lifestyle measures would you ask a CKD patient to take?
stop smoking, lose weight, exercise, sodium restriction, increase fluid intake
explain how haemodialysis works
blood is passed over a semi-permeable membrane against dialysis fluid flowing in the opposite direction - small solutes diffuse down this concentration gradient into the dialysis fluid.
access required via AV fistula, CVC or synthetic graft.
3x hosp trips per week, 4hrs at a time - or at home 5x/week for 2-3hrs.
good for - live alone/frail/elderly or unsuitable for PD e.g. surgery
how can haemodialysis be used to clear excess fluid?
ultrafiltration, to create a negative transmembrane pressure, clearing fluid from the blood
give 2 problems with haemodialysis
risk of *disequilibration syndrome, hypotension, time consuming.
access problems - need AV fistula or tunnelled venous access line.
complications:
- *access - infection, thrombosis, aneurysm, endocarditis, stenosis
- *hypotension (common), cardiac arrhythmias, air emboli
- N&V, headache, cramps
- *anaphylaxis to sterilising agents
- *disequilibration synd.
explain how haemofiltration works
blood is filtered across a highly permeable membrane, allowing movement of small and large solutes by convection.
ultrafiltrate is replaced with an equal volume of fluid.
what is the main problem with haemofiltration?
takes a lot longer than haemodialysis - useful in critically ill patients, but impractical long term
explain how peritoneal dialysis works
uses the peritoneum as a semi-permeable membrane - catheter is inserted into the peritoneal cavity and fluid infused. sits in the cavity, allowing solutes to diffuse across.
what are the main positives and negatives of peritoneal dialysis?
positives - can be carried out at home, ‘ambulatory’ PD can be used, or overnight, so patient leads normal life.
negatives - peritonitis, exit site infection, loss of membrane function over time, herniation at exit site.
give 2 contraindications to renal transplantation
active infection, cancer, severe comorbidity
give 2 possible complications of renal transplantation
surgical - bleed, thrombosis, infection, hernia.
delayed graft function, drug toxicity, infection, malignancy, rejection.
how would you manage acute rejection of a kidney transplant?
high dose IV methylprednisolone + intensify immunosuppression regime.
what 2 genes are associated with ADPKD and what is the difference between them?
PKD1 and PKD2.
PKD2 renal cysts develop more slowly - ESRF comes later.
give 3 signs of ADPKD
renal enlargement with cysts.
abdo pain ± haematuria (haemorrhaging cyst).
cyst infection, renal caliculi, hypertension, progressive renal failure.
name 2 extra-renal features of ADPKD
liver cysts, intra-cranial aneurysm leading to subarachnoid haemorrhage, mitral valve prolapse, ovarian cysts, diverticular disease
how would you treat a patient with ADPKD?
aggressive BP management (less than 130/80)
how would you diagnose ADPKD?
renal USS.
screen family members using USS too.
what is the difference between ADPKD and ARPKD?
autosomal recessive is an infancy disease with renal cysts and congenital hepatic fibrosis
define glomerulonephritis
group of disorders where damage to the glomerular filtrating apparatus causes leaking of protein/blood into the urine.
3rd most common cause of ESRF (in adults usually FSGN in nephrotic synd)
changes most likely immune mediated.
give 3 causes of glomerulonephritis
SLE, infections (strep throat, HIV), vasculitis, gold, penicillamine, malignancy of breast/bone/myeloma, diabetes, hypertension
what investigation would you perform in glomerulonephritis?
renal biopsy
what lung disease is associated with a type of glomerulonephritis?
Goodpasture’s syndrome aka anti-glomerular basement membrane disease
explain the pathology of IgA nephropathy
patient starts with sore throat/UTI due to streptococcus - triggers an immune reaction, leading to deposition of IgA complexes in the glomeruli
what would a biopsy show with rapidly progressive glomerulonephritis?
crescents
how does IgA nephropathy usually present?
with macroscopic/microscopic haematuria (occasionally with nephritic syndrome)
what are the features of nephrotic syndrome?
normal/mildly high BP. urine = proteinuria. GFR = normal to mildly low. peripheral oedema hypoalbuminaemia hyperlipidaemia.
what are the features of nephritic syndrome?
BP = moderately/severe high. urine = haematuria. GFR = moderate to severely low.
oliguria/AKI
HTN
haematuria - active urinary sediment
it’s an AKI with rapid deterioration in function.
what is seen on renal biopsy in IgA nephropathy?
mesangial proliferation, IgA and C3 deposits
what is Henoch-Schonlein purpura? how does it present?
systemic variant of IgA nephropathy - causes small vessel vasculitis.
purpuric rash on extensor surfaces, flitting polyarthritis, abdo pain, nephritis.
how would you diagnose Henoch-Schonlein purpura?
IgA and C3 deposits seen in renal or skin biopsy
what parts of the kidney are damaged in SLE?
vascular, glomerular and tubulointerstitial components
how would you diagnose anti-GBM disease (Goodpasture’s)?
serum anti-GBM - autoantibodies to type IV collagen (in GBM)
give some different causes of rapidly progressive glomerulonephritis. what do they all have in common?
all show crescents affecting most glomeruli at biopsy.
immune complex disease e.g. post infection, SLE, IgA/HSP.
Pauci-immune disease (ANCA+ve) - granulomatosis with polyangitis (Wegener’s), microscopic polyangitis.
Goodpasture’s.
what specific features would you see on inspecting the urine in acute tubular necrosis?
muddy brown casts
what are the 2 most common causes of acute tubular necrosis?
renal tubular cell death by ischaemia (renal hypoperfusion) or by nephrotoxins (drugs - tetracycline)
what is the classical triad of clinical features of nephrotic syndrome? explain each one
hypoalbuminaemia - due to increased catabolism of reabsorbed albumin in proximal tubules.
proteinuria - due to injury to podocytes - filtration barrier no longer maintained, proteins leak into urine.
oedema - due to lowered plasma oncotic pressure and sodium retention.
name 2 primary causes of nephrotic syndrome
minimal change disease, membranous nephropathy, focal segmental glomerulosclerosis (FSGS), mesangiocapillary GN (MCGN)
name 2 secondary causes of nephrotic syndrome
hepatitis B/C, SLE, diabetic nephropathy, amyloidosis, paraneoplastic or drug related
how might nephrotic syndrome present?
pitting oedema.
urine dipstick massive +ve for protein.
what do the glomeruli of a patient with minimal-change glomerulonephritis look like on light microscopy and electron microscopy?
look normal on light microscopy.
on EM - fusion of podocytes.
give 2 things associated with minimal-change glomerulonephritis
Hodgkin’s lymphoma, steroids, immunosuppressive drugs, asthma, eczema
how would you treat minimal change glomerulonephritis?
high dose prednisolone.
if relapse - ciclosporin/cyclophosphamide.
give 2 causes of membranous nephropathy
idiopathic, malignancy, hep B, gold, penicillamine, NSAIDs, autoimmunity.
what would you see on immunofluorescence of a renal biopsy in membranous nephropathy?
diffusely thickened GBM with IgG and C3 subepithelial deposits.
explain the difference between immune complex mediated and complement mediated mesangiocapillary GN
IC mediated - driven by circulating immune complexes, deposit in kidney and activate complement via classical pathway. SLE/hepC etc.
complement mediated - persistent activation of the alternative complement pathway e.g. due to C3 nephritic factor.
what would you seen on a renal biopsy of a patient with mesangiocapillary GN?
mesangial and endocapiallary proliferation.
thickened capillary BM.
tramline capillary walls.
immunofluorescence - Ig staining, complement staining or light chains.
how does focal segmental glomerulosclerosis (FSGS) present?
nephrotic syndrome or proteinuria
what would you see on renal biopsy of a patient with focal segmental glomerulosclerosis?
scarring of certain segments of some glomeruli.
immunofluorescence shows IgM and C3 deposits.
what is the main cause of urinary incontinence in men?
enlarged prostate - urge incontinence or dribbling resulting from partial retention of urine.
define functional incontinence
not really to do with physiology - patient is too slow in finding toilet due to immobility, unfamiliar surroundings etc
define stress incontinence
leakage from incompetent sphincter e.g. when intra-abdominal pressure rises (coughing, laughing)
who is commonly affected by stress incontinence?
pregnant women and following birth.
elderly women - weak pelvic floor.
define urge incontinence (aka overactive bladder syndrome)
urge to urinate is quickly followed by uncontrollable emptying of bladder as detrusor muscle contracts
what can precipitate urgency/leakage in urge incontinence?
arriving home (latchkey incontinence - conditioned reflex), cold, sound of runnning water, coffee/tea, obesity.
what can cause urge incontinence?
detrusor overactivity - malfunction of central inhibitory pathway, or a bladder muscle problem.
also - UTI, diabetes, diuretics, atrophic vaginitis, urethritis.
how could you manage stress incontinence?
pelvic floor exercises, surgery or duloxetine
how could you manage urge incontinence?
bladder training and weight loss. absorbent pads.
condom catheter for males.
tolterodine (antimuscarinic).
explain the physiology of erections
result from NO induced cGMP build up.
cGMP dependent protein kinase activates calcium/potassium channels, hyperpolarising and relaxing vascular and trabecular smooth muscle cells - allows engorgement
how would you identify that a case of erectile dysfunction was due to psychological causes alone?
morning erections still occur
name 3 (non-pharmacological) causes of erectile dysfunction
smoking, diabetes, alcohol.
hypogonadism, hyperthyroidism, cord lesions, MS, bladder neck/prostate surgery, radiotherapy, atheroma, renal or hepatic failure prostatic hyperplasia, post-priapism.
name 3 drugs that can cause erectile dysfunction
digoxin, beta blockers, diuretics, antipsychotics, antidepressants, oestrogens, finasteride, narcotics, alcohol.
what are the treatment options available for erectile dysfunction?
counselling. sildenafil - phosphodiesterase (PDE5) inhibitor - increases cGMP. vacuum aids. intracavernosal injections. transurethral pellets. prostheses - inflatable or malleable.
list some common side effects of phosphodiesterase inhibitors (e.g. sildenafil)
headache, flushing, dyspepsia, stuffy nose
in what layer of the scrotum does a hydrocele form in?
tunica vaginalis
give a primary and a secondary cause of hydroceles
primary - patent processus vaginalis, resolves in first year.
secondary - trauma, tumour, infection.
what causes a varicocele?
dilated veins of the pampiniform plexus