Core problems Flashcards
What are the 3 commonest sites for a renal calculi?
Ureteropelvic junction, ureters crossing over iliac arteries, uretero-vesical junction
Give 4 compositions of renal calculi. What is the commonest?
CALCIUM OXALATE, uric acid, struvate (infected stones w/ magnesium, calcium + ammonium), cysteine
What are struvate stones made from?
Bacteria, magnesium,
What are the risk factors for developing renal calculi?
Anatomical deformities (trauma, hoarseshoe kidney…etc), urinary factors (increased concentration of substances)….etc
What are the causes of calcium oxalate stones?
Hypercalcuria, hyperoxaluria, low dietary calcium
How does low dietary calcium cause struvate stones to form?
There is decreased intestinal binding of oxalate and calcium –> ^ oxalate absorption –> ^ urinary oxalate excretion
What diseases are hyperuricaemia associated with?
Gout and uric acid stones
What are the symptoms of a kidney stone?
Asymptomatic, renal colic (loin pain), recurrent UTIs (LOTS), haematuria
What might a person also have if they suffer from a uric acid stone?
Gout
Describe the pain caused by a kidney stone
Loin pain, radiates to groin (E.g. testes), rapid onset, VERY severe, unilateral, colicky, worse on fluid loading, associated nausea
Why is the pain colicky (comes and goes) for renal calculi?
Due to peristalsis of the ureters
How does renal colic pain differ from appendicitis pain?
Appendicitis pain is associated with a fever? It starts of generalised in the abdomen and then localises to the RIF (renal colic is in the loin and radiates to the groin)
What is the DDx for renal colic?
AAA, appendicitis, diverticulitis, ectopic pregnancy, testicular torsion…
What urine investigations would you carry out to investigate renal colic?
urinalysis/dipstick, 24hr urine collection (cysteine, oxalate…), MSSU/MC&S
What blood tests might you order to investigate renal colic?
FBC, U+Es (Ca2+ and urate)
EXAM: what is the gold standard investigation to diagnose/look for kidney stones? What else can you use?
NCCT-KUB (non-contrast CT of kidney, ureters and bladder) - can use KUB XR
Why is non-contrast used when investigating renal colic?
Toxicity - can make things worse?
What might USS show in renal colic?
Hydronephrosis
Give 2 complications of kidney stones
UTIs and sepsis
Why is an MRI not used to investigate stones?
You can’t see the stones
What is the treatment for small kidney stones?
fluids, analgesia, anti-emetic, observe (as most stones pass spontaneously)
What is the management for a larger kidney stone that isn’t passing spontaneously?
Admit, IV fluids, analgesia, anti-emetic, observe for sepsis, ESWL –> ureteroscopy w/ laser –> PCNL
give an example of an anti-emetic - how does it work?
Serotonin 5-HT3 receptor antagonist (e.g. granisetron)
Why can ACE-I be used in CKD but not AKI?
It is nephrotoxic (reduces renal perfusion by vasodilating the efferent arteriole) it causes AKI - but in CKD the cause is hypertension therefore using ACE-I is helpful
What is the commonest cause of AKI?
Pre-renal causes
In AKI why do you get SOB/hypoxia?
Because reduced GFR means you go into fluid overload causing pulmonary oedema
What is used to to stage AKI?
KDIGO: using serum creatinine + urine output
What do the investigations in AKI look for?
Staging of severity, causes and complications
Why is contrast imaging avoided in AKI?
Nephrotoxic - makes AKI worse
Give examples of nephrotoxic drugs?
Gentamicin, ACE-i, NSAIDs,
Give some pre-renal causes of AKI
Hypovolaemia (burns, haemorhage), HF (hypotension), infection, NSAIDs, ACE-i, Renal artery stenosis, diarrhoea, thrombosis
Give some renal causes of AKI
Vasculitits, HUP, TTP, infection, SLE, glomerulonephritis, acute tubular necrosis
What is the commonest renal cause of AKI?
Acute tubular necrosis
Give some post-renal causes of AKI
Urinary tract obstruction (stone, tumour [bladder, ureter, prostate], BPH, strictures)
What is AKI? What is it characterised by?
The sudden decrease in renal function - reduced GFR, increased serum urea and creatinine, decreased urine output
Give 5 complications of AKI - explain how they occur
Metabolic acidosis (increased HCO3- excretion), ureamia (reduced excretion of nitrogenous waste - urea), fluid overload (Na+/H2O retention), hyperkalaemia (reduced potassium excretion), decreased urine output
Give 2 complications of uraemia
Uraemic pericarditis + encephalopathy
Give the symptoms of AKI and explain why they occur
- uraemia –> pruritis, anorexia, nausea, vomiting, drowsiness, confusion, coma
- SOB –> due to fluid overload causing pulmonary oedema
What signs are there for AKI
Fluid overload: pulmonary crackles + hypoxia (therefore ^ RR), ^ JVP, oedema, ascites
Pericardial rub
Skin rash
What might you ask in Hx when investigating AKI?
Any recent change in or start of new medications
What is normal eGFR?
100ml/min/1.73m2
How would you stage the severity of AKI?
KDIGO - serum creatinine + urine output
What might you see on a urine dipstick in AKI?
Infection (leucocytes + nitrates), blood + protein (glomerulonephritis)
What blood tests would you order for AKI?
U+E (K+, HCO3-, urea…etc), FBC, Serology
What might FBC show in AKI? Why?
Anaemia (reduced EPO production)
What might U+Es show in AKI?
Hyperkalaemia and metabolic acidosis
What imaging tests might you do in AKI?
USS and CXR
What is CXR likely to show in AKI?
Pulmonary oedema
If the cause is post-renal what will USS show in AKI?
Hydronephrosis due to urinary tract obstruction
Why would you carry out an ECG in AKI?
To look for evidence of hyperkalaemia and uraemic pericarditis
What ECG changes are seen in hyperkalaemia?
Tall tented T waves, absent P waves, wide QRS complex, prolonged PR interval
Why would you do a renal biopsy?
To exclude glomerulonephritis + vasculitis
How would you treat AKI?
- Identify + treat cause (e.g. stop nephrotoxins…) –> if pre-renal: IV fluid replacement
- renal referral if poor response to above
- RRT (dialysis)
- Rx complications: hyperkalaemia, pulmonary oedema, acidaemia, uraemia
Also: Low K+ diet
When is a renal referral indicated in AKI?
Unknown cause, hyperkalaemia, fluid overload, uraemia, glomerulonephritis suspected (blood + protein on dipstick)
How would you treat hyperkalaemia?
IV calcium gluconate, IV insulin + dextrose
How would you treat pulmonary oedema?
Diuretics (furosemide)
How would you treat uraemia?
Dialysis
How would you treat acidaemia?
Dialysis + IV/oral sodium bicarbonate
How does acute tubular necrosis present?
Initially oliguric and then polydipsia (diuresis)
What is the sympathetic and parasympathetic control to the bladder?
Parasympathetic: S2-4
Sympathetic: T11-L2
Who is at risk of developing AKI?
> 65, DM, CKD, HF, kidney stones (other urinary obstruction)
What is the diagnosis of AKI based on NICE guidelines?
- rise in serum creatinine of >26 mmol/L in 48h
Or 50%+ rise in serum creatinine in past 7 days - drop in urine output to 0.5ml/kg/h for 6h
If the cause of AKI was pre-renal, how would you treat it?
IV fluids
What are the two causes of ADPKD?
85% PKD1 mutation (chromosome 16)
15% PKD2 mutation (chromosome 14)
What is the commonest cause of PKD?
ADPKD
Which mutation in ADPKD has the slower course to ESRF (later in life)?
PKD2 mutation
Give some complications of ADPKD
SAH (due to berry aneurysm formation), ESRF, mitral valve prolapse, kidney stones, hypertension, ovarian cyst, UTI
What does urinalysis show in PKD?
Haematuria, UTI, proteinuria
How would you screen for PKD?
USS (shows cysts) and genetic testing
What must you do with all patients and 1st degree relatives of someone who has PKD?
MR angiography to screen for berry aneurysm
What system is used to classify cysts?
Bosniak classification
What symptoms might a person with ADPKD have?
Haematuria, loin pain, ^ UTIs, renal calculi
What signs might a person with ADPKD have?
Palpable enlarged kidney and hypertension
What is the treatment for ADPKD?
Monitor U+E, ACE-i (hypertension), Rx infections, pain (laparoscopic cyst removal)
What drug is in development for ADPKD?
V2 receptor antagonist (tolvaptan)
How would you treat ESRF in ADPKD patients?
RRT
