Renal Flashcards
UTI
Definitions (6)
Bacteriuria: bacteria in the urine, may be asymptomatic or symptomatic
UTI: presence of a pure growth of >10^5 organisms per ml of fresh MSU
Lower UTI: urethra (urethritis), bladder (cystitis), prostate (prostatitis)
Upper UTI: renal pelvis (pyelonephritis)
Pyuria: presence of pus cells in urine, inflammatory response
Sterile pyuria: -ve culture but +ve pus (eg. undeclared antibiotics, renal TB, GU infections, stones/malignancy)
UTI
Aetiology (3)
Mostly E.coli
Proteus mirabilis
Klebsiella pneumonia
UTI Risk factors (8)
Female: short urethra and close to rectum
Trauma to female urethra in sex/birth
Pregnancy: progesterone dilates ureters and pressure from fetus
Anatomical: VUR, pelvi-ureteric junction obstruction, chronic retention
Pre-existing renal conditions: renal cysts, parenchymal damage, stones
Spermicide activity
Immunosuppression
Foreign body: catheter, cystoscopy, stent
UTI
Uncomplicated (3)
Healthy, young, sexually active women
E.coli or Staph saprophyticus
Require no further investigation
UTI
Complicated (8)
In children In men In patients with abnormal renal tract In immunosuppressed In patients with foreign body in renal tract Bladder tumour Chronic retention Abnormal bladder outflow tract (BPH, urethral stricture, phimosis)
UTI
Symptoms (9)
Dysuria Frequency Urgency Haematuria Suprapubic pain Fever Hesitancy Nocturia Pyelonephritis: fever, rigors, N&V, back and flank pain
UTI
Signs (3)
Fever
Abdominal/loin tenderness
Foul-smelling urine
UTI
Investigations (5)
Urinalysis: no further investigation if +ve for nitrites and leucocytes (uncomplicated)
Urine MC&S of MSSU: bacteria, WBC, RBC (send immediately if male, child, immunosuppressed)- diagnostic >10^5
Culture for antibiotic sensitivity
Bloods: FBC, U&E, CRP, cultures if systemic unwell
Imaging: USS + referral to urology if child/man/no treatment response/recurrent/pyelonephritis
UTI Dipstick testing (6)
Nitrate (metabolic byproduct of bacteria)
Protein (sign of inflammation)
Leucocytes (marker of inflammation)
If all 3 are positive- empirical therapy
If leucocytes only positive- doesn’t diagnose or exclude, urine culture recommended
Blood/protein in absence of nitrate/leucocytes should be further investigated
UTI
Treatment in women (4)
Trimethoprim/nitrofurantoin for 3-6 days
2nd line amoxicillin or co-amoxiclav
If no response do urine culture
If upper UTI: co-amoxiclav IV then oral when afebrile
UTI
Treatment in pregnant women (2)
Any bacteriuria treat with antibiotic (nitrofurantoin safe)
Dipstick and culture repeated at each antenatal visit
UTI
Treatment in men (2)
If fail to respond to antibiotic must refer to urologist as is often due to anomaly in anatomy/function
Quinolone eg. ciprafloxacin
UTI
Treatment of acute pyelonephritis (2)
Ciprofloxacin for 7 days
Consider admission for IV co-amoxiclav and gentamicin in 1st 48h if vomiting or septic
AKI
Definition (2)
Rise in serum creatinine >26 in 48h or rise in creatinine >1.5x baseline or urine output <0.5ml/kg/h for >6h (consecutive hours)
Leads to a failure to maintain fluid, electrolyte and acid-base homeostasis
AKI
Pre-renal causes (3)
40-70% of cases, due to renal hypoperfusion Hypotension (due to hypovolaemia, sepsis, over diuresis) Renovascular disease (eg. renal artery stenosis)
AKI
Intrinsic renal causes (5)
10-50% of cases, due to direct parenchymal injury and may require renal biopsy for diagnosis
Acute tubular necrosis: commonest, often result of pre-renal damage or nephrotoxins eg. drugs (gentamicin, NSAIDs, ACE-i, lithium), contrast and myoglobinuria in rhabdomyolysis
Glomerular: primary glomerulonephhritis, SLE, drugs, infections
Interstitial: drugs, lymphoma infiltration, tumour lysis syndrome
Vascular: vasculitis, malignant hypertension, cholesterol emboli
AKI
Post-renal causes (4)
10-25% of cases, caused by obstruction
Luminal: stones, clots
Mural: malignancy (eg. ureteric, bladder, prostate), BPH, strictures
Extrinsic compression: malignancy, retroperitoneal fibrosis
AKI Risk factors (8)
>75 CKD Heart failure Peripheral vascular disease Diabetes Drugs/other nephrotoxins (especially recently started) Sepsis Poor fluid intake or increased losses
AKI
Signs + symptoms (10)
May be asymptomatic
Systemic: rash, arthralgia, fever
Haemoptysis (vasculitis/anti-GBM disease)
LUTS or anuria (obstruction)
Red-brown urine (rhabdomyolysis)
Fluid overload: hypertension, elevated JVP, lung crackles, peripheral oedema
Fluid deplete: reduced urine volume, non-visible JVP, poor turgor
Palpable percussible bladder or pelvic/abdominal mass (obstruction)
Palpable kidneys (polycystic)
Renal bruits (renovascular disease)
AKI
Investigations (9)
U&E + creatinine: assess severity
Urine: urinalysis (nitrites- infection, protein- intrinsic renal, leucocytes- acute interstitial nephritis, blood- glomerulonephritis), Na concentration (low if pre-renal, high in acute tubular necrosis), Bence Jones protein (exclude myeloma)
ECG: exclude hyperkalaemia
VBG: exclude hyperkalaemia
FBC + film: exclude HUS
Anti-dsDNA and ANA: SLE
Urea:creatinine ratio (>100:1= pre renal, <40:1= intrinsic)
Renal USS: obstruction, hydronephrosis, cysts
ABG: acid-base balance
AKI
Classification (3)
Stage 1: creatinine increases >1.5x baseline, <0.5ml/kg/h urine output for >6 consecutive hours
Stage 2: serum creatinine rises 2-2.9x baseline, <0.5ml/kg/h urine for >12 hours
Stage 3: serum creatinine >3x baseline or commenced on RRT, <0.3ml/kg/h urine for >24 hours or anuria for 12h
AKI
Treatment (6)
Fluid therapy
Stop nephrotoxic drugs
Treat pre-renal causes: correct volume depletion, treat sepsis
Treat intrinsic causes: refer
Treat post-renal causes: catheterise if obstruction, consider retrograde stents or insertion of nephrostomy
RRT if complications or drug overdose
AKI
Indications for RRT (5)
Pulmonary oedema
Persistent hyperkalaemia
Severe metabolic acidosis
Uraemic complications eg. encephalopathy or pericarditis
Drug overdose- BLAST (Barbiturates, Lithium, Alcohol, Salicylates, Theophyline)
CKD
Definition (2)
Impaired renal function for >3 months based on abnormal structure/function or GFR <60 for >3 months without evidence of kidney damage
End-stage renal failure: GFR <15 or need for RRT
CKD
Aetiology (6)
Diabetes Glomerulonephritis: usually IgA Hypertension Renovascular disease Pyelonephritis Polycystic kidney disease
CKD
Pathology (2)
Renal injury causes kidney to adapt to nephron loss by increasing intraglomerular pressure to maintain filtration
Glomerulus becomes more permeable to molecules causing mesangial cell expansion, fibrosis and glomerular scarring
CKD
Pathology of complications (5)
Anaemia: low erythropoietin production by kidney interstitial fibroblasts leads to lack of RBC growth
Renal osteodystrophy: kidney is site of phosphate excretion and hydroxylation of vit D, low levels of 1,25 dihydroxyvitamin D occurs due to renal scarring and reduced phosphate levels leads to hyperphosphataemia, this causes hypocalcaemia and huge increase in PTH, promoting calcium resorption, changing bones
Cardiovascular risk: hypertension, high lipids, high phosphate
Hyperlipidaemia: reduced lipoprotein lipase and hepatic triglyceride lipase = less lipid uptake
Malnutrition: altered metabolism of protein, water, salt and potassium
CKD Risk factors (8)
Nephrotoxins Diabetes Hypertension Cardiovascular disease Structural renal disease, stones or BPH Recurrent UTI/childhood history of vesicoureteric reflux Multisystem disease such as SLE Family history of ESRF or known hereditary disease eg. PKD
CKD
Signs + symptoms (6)
Usually asymptomatic until stage 4/5 Uraemia: anorexia, vomiting, restless legs, fatigue, weakness, pruritus, bone pain Amenorrhoea/impotence Oliguria Dyspnoea Ankle swelling
CKD
Investigations (4)
Blood: Hb (normochromic normocytic anaemia), U&E, creatinine, glucose, Ca (low), phosphate (high), alk phos (high- renal osteodystrophy), PTH (high if >stage 3)
Urine: urinalysis (proteinuria, haematuria), MC&S (exclude UTI), albumin:creatinine ratio
Ultrasound: check size and anatomy, usually small (<9cm) in CKD but may be enlarged in amyloid, myeloma, APKD, DM
Renal biopsy if rapidly progressive or if unclear cause and normal sized kidneys
CKD
Staging (6)
Stage 1: GFR >90 (normal/high GFR but other evidence of renal damage)
Stage 2: GFR 60-89
Stage 3A: GFR 45-59
Stage 3B: GFR 30-44
Stage 4: GFR 15-29
Stage 5: GFR <15 (established renal failure)
CKD
Treatment of reversible causes (4)
Relieve obstruction
Stop nephrotoxins
Address cardiovascular risk factors
Tight glucose control in diabetes
CKD
Treatment to limit progression and complications (3)
BP: target <130/90 use ACE-i or ARB
Renal bone disease: check PTH and treat if raised (eg. calcitriol and alfacalcidol), restrict phosphate and give binders (eg. Calcichew)
Cardiovascular modification: statins and aspirin
CKD
Treatment to control symptoms (5)
Anaemia: replace iron/B12/folate if necessary, consider recombinant human erythropoietin if still anaemic
Acidosis: consider sodium bicarbonate supplements if low serum bicarbonate
Oedema: high dose loop diuretics and fluid and sodium restriction
Restless leg: clonazepam/gabapentin
RRT if GFR 8-10
Haemodialysis Mechanism (4)
Blood is passed over a semi-permeable membrane against dialysis fluid flowing in the opposite direction
Thus blood is always meeting a less concentrated solution and diffusion of small solutes occurs down the concentration gradient
Larger solutes don’t clear as effectively
Ultrafiltration creates a negative transmembrane pressure to clear excess fluid
Haemodialysis
Problems (4)
Disequilibration syndrome
Hypotension
Time consuming
Access problems (AV fistula: thrombosis/stenosis, tunnelled venous access line: infection/blockage/recirculation of blood)
