Renal 7.5 Flashcards
Options of renal replacement therapy
Tx: living/deceased; always has better outcomes than any dialysis, and more effective when pre-emptive
Haemodialysis
Haemofilltration
Haemodiafiltration (in a Rx centre more effective than HD in a Rx centre)
PD - continuous ambulatory, & automated PD
Indications for considering starting RRT?
- Sx of uraemia on ADLs
- biochemical measures
- uncontrollable fluid overload
- eGFR 5-7 if no Sx
When to start assessment for RRT/conservative Rx?
At least 1yr before therapy e.g. Tx/HD is likely to be needed, inc for those with a failing Tx
What are AV fistulas?
= Direct connections between arteries & veins, may occur pathologically but gene formed surgically to allow access for HD - now regarded as preferred method of access due to lower rates of complications
What are the potential complications of AV fistulas?
- infection
- thrombosis
- stenosis
- steal syndrome
How to calculate anion gap?
(Na + K) - (HCO3 + Cl)
normal 8-14
Causes of a normal anion gap or hyperchloraemic metabolic acidosis?
- GI bicarbonate loss: diarrhoea, fistula, ureterosigmoidostomy
- renal tubular acidosis
- drugs e.g. Acetazolamide
- Ammonium chloride injection
- Addison’s disease
Causes of a raised anion gap metabolic acidosis?
- lactate: shock, hypoxia, burns, metformin (type B)
- ketones: DKA, etoh
- urate: renal failure
- acid poisoning: salicylates, methanol
What is Alport’s syndrome? what is the inheritance?
X-linked dominant
- defect in the gene which codes for type IV collagen -> abnormal glomerular-basement membrane
- more severe in males (females rarely develop renal failure)
Pt with Alport’s syndrome has a renal Tx that starts to fail - what is the cause?
presence of anti-GBM antibodies, leading to a Goodpasture’s syndrome like picture
When does Alport's syndrome present? what are the features? renal ear eye
- microscopic haematuria
- progressive renal failure
- BL SNHL
- lenticonus: protrusion of the lens surface into the anterior chamber
- retinitis pigmentosa
What is on renal biopsy in Alport’s syndrome?
Splitting of lamina densa on electron microscopy
What is amyloidosis?
Extracellular deposition of an insoluble fibrillar protein amyloid
- accumulation of amyloid fibrils leads to tissue/organ dysfunction
What are the component of amyloid?
- many different precursor proteins
- fibrillar component, insoluble amyloid
- non-fibrillary components inc: amyloid-P (derived from acute phase protein serum amyloid P), apolipoprotein E & heparan sulphate proteoglycans
How to classify amyloidosis?
systemic vs localised
- further characterised by precursor protein e.g. AL in myeloma - A amyloid, L Light chain Ig fragments
3 ways to Dx amyloidosis?
- Congo red staining of tissue: apple-green birefringence
- SAP: serum amyloid precursor scan
- Biopsy of rectal tissue
What are the 3 main types of amyloidosis?
- AL amyloid (Light chain Ig fragment)
- AA amyloid (precursor serum amyloid A protein, acute phase reactant)
- Beta-2 microglobulin amyloidosis (precursor protein, part of the major histocompatibility complex)
AL amyloid
- what are the causes?
- what are the features?
- myeloma, MGUS, Waldenstom’s
- cardiac & neuro involvement, macroglossia, periorbital eccymoses
AA amyloid
- when is it seen?
- what are the features?
- chronic infection/inflammation eg TB, RA, bronchiectasis
- fenal involvement is most common feature
Beta-2 microglobulin amyloidosis (precursor that is a part of the MHC) - what is it associated with?
pts on renal dialysis
ARPKD: what is the genetic defect?
- defect in gene on chr 6 which encodes fibrocystin (protein important for normal renal tubular development)
How to Dx ARPKD?
What are the features?
- prenatal US or in early inference with abdo masses & renal failure
- newborns may have features consistent with Potter’s syndrome 2ry to oligohydramnios
- ESRF develops in childhood
- pts also typically have liver involvement e.g. portal & interlobular fibrosis
What is on renal biopsy in ARPKD?
multiple cylindrical lesions at right angles to the cortical surface
What is the genetics of ADPKD type 1?
PKD1 loci, which codes for polycystin-1
chr 16
85% of cases, presents with renal failure earlier
What is the genetics of ADPKD type 2?
PKD2 loci, which codes for polycystin-2
chr 4
15% of cases
What is the screening Ix for relatives of ADPKD?
Abdo US/S
ADPKD: what is the Ultrasound Dx criteria (in pts with +ve FHx)?
Age<30: 2 cysts UL/BL
Age 30-59: 2 cysts in both kidneys
Age>50: 4 cysts in both kidneys
What are the features of ADPKD?
- hypertension
- recurrent UTIs
- abdo pain
- haematuria
- renal stones
- CKD
What are the extra-renal manifestations of ADPKD?
- liver cysts 70%
- berry aneurysms 8%
- CVS: MVP, mitral/tricuspid incompetence, aortic root dilation, aortic dissection
- cysts in other organs: pancreas, spleen (v rarely thyroid, oesophagus, ovary)
Prerenal causes of AKI?
think ischaemia
- hypovolaemia 2ry to diarrhoea/vomiting etc
- renal artery stenosis
Intrinsic causes of AKI?
think damage to glomeruli, renal tubules or interstitium, immune-mediated or dye to toxins/drugs/contrast
- glomerulonephritis
- acute tubular necrosis
- acute interstitial nephritis
- rhabdomyolysis
- tumour lysis syndrome
Postrenal causes of AKI?
think obstructive uropathy e.g. UL ureteric stone/BL hydronephrosis 2ry to acute urinary retention caused by BPH
- stone in ureter/bladder
- BPH
- external compression of ureter
RFs for AKI?
- age>65
- Hx of AKI
- CKD
- other organ failure.chronic disease e.g. heart failure, liver disease, diabetes
- nephrotoxics inc contrast within past wk
- emergency surgery
- intraperitoneal surgery
- oliguria of urine output <0.5ml/kg/h
- neuro or cognitive impairment or disability that may mean limited access to fluids due to reliance on someone else
Sx & signs of AKI?
- reduced urine output
- fluid overload eg peripheral, pulmonary
- rise in K, urea, Cr, change in acid-base balance which can lead to
- arrhythmias
- uraemic complications eg pericarditis, encephalopathy
Criteria for Dx of AKI?
- rise in Cr of >25 within 48h
- 50%+ rise in Cr within 7 days
- fall in urine output to <0.5ml/kg/h for >6hours
What drugs should be stopped in AKI as it may worsen renal function?
NSAIDs aminoglycosides ACE-I A2RBs diuretics
What drugs may have to be stopped in AKI as there is increased risk of toxicity (but don’t usually worsen AKI itself)
metformin
lithium
digoxin
What Ix to consider when you suspect AKI?
- bloods (U&Es)
- urinalysis
- ecg (hyperkalaemic change/arrhythmias)
- renal US with 24h if at risk/obstructive cause is suspect - +/- urology r/v
Rx of hyperkalaemia to stabilise the cardiac membrane?
IV calcium gluconate
Rx of hyperkalaemia for a short-term shift in K from extra to intracellular fluid compartment?
- combined insulin/dextrose infusion
- nebulised salbutamol
Rx of hyperkalaemia to remove K from the body?
Calcium resonium - oral/enema
loop diuretics
dialysis
In AKI NICE guidelines - when to refer to a nephrologist?
- renal Tx
- ITU pt with unknown cause of AKI
- vasculitis/glomerulonephritis/tubulointerstitial nephritis/myeloma
- AKI with no known cause
- inadequate response to Rx
- complications of AKI
- stage 3 AKI
- CKD stage 4/5
- any indication for renal replacement therapy e.g. refractory hyperkalaemia, metabolic acidosis, uraemic complications, refractory fluid overload
Prerenal Uraemia - kidneys hold onto sodium to preserve volume - what happens to: urine sodium? fractional Na excretion? fractional urea excretion? urine:plasma osmolality? urine:plasma urea? specific gravity? urine? response to fluid challenge?
urine sodium <20 fractional Na excretion <1% fractional urea excretion <35% urine:plasma osmolality >1.5 urine:plasma urea >10.1 specific gravity >1020 urine: bland sediment response to fluid challenge - Yes
Acute tubular necrosis - what happens to: urine sodium? fractional Na excretion? fractional urea excretion? urine:plasma osmolality? urine:plasma urea? specific gravity? urine? response to fluid challenge?
urine sodium >30 fractional Na excretion >1% fractional urea excretion >35% urine:plasma osmolality <1.1 urine:plasma urea <8.1 specific gravity <1010 urine: brown granular casts response to fluid challenge - No
BPH - what are the RFs?
what are the typical LUTS?
- ethnicity black >white >Asian
- age; 50% of 50y.o. men will have evidence of BPH, 30% will have Sx; 80% of 80y.o. men have evidence of BPH
- obstructive voiding Sx - weak/poor flow, straining, hesitancy, terminal dribbling, incomplete emptying
- storage irritative Sx - urgency, frequency, urgency incontinence, nocturia
- post-micturition Sx - dribbling
- complications - UTI, retention, obstructive uropathy
Rx options for BPH?
- watchful waiting
- medications: alpha-1 blockers, 5 alpha-reductase inhibitors
- surgery: TURP
How do alpha-1 blockers work in BPH?
what are examples?
what are the adverse effects?
- decrease smooth muscle tone (prostate & bladder)
- 1st line, improve Sx in 70% men
- tamsulosin, alfuzosin
- dry mouth, dizziness, depression, postural hypotension
How do 5 alpha-reductase inhibitors work in BPH?
how long does it take?
what are the adverse effects?
- e.g. finasteride
- block conversion of testosterone to DHT, which is known to induce BPH
- causes a reduction in rotate volume (unlike alpha blockers) and hence may slow disease progression
- may take 6months to improve Sx
- decreases PSA conc by unto 50%, erectile dysfunction, reduced libido, ejaculation problems, gynaecomastia
RFs for transitional cell carcinoma of the bladder?
- smoking
- aniline dyes eg 2-naphthylamine, benzidine
- rubber manufacture
- cyclophosphamide
RFs for squamous cell carcinoma of the bladder?
- schistosomiasis
- BCG Rx
- smoking
What is Cystinuria?
what is the genetic defect?
- autosomal recessive disorder characterised by recurrent renal stones formation
- defect in the membrane transport of cystine, ornithine, lysine & arginine (COLA)
- chr 2: SLC3A1 gene
- chr 19: SLC7A9 gene
Dx of Cystinuria?
cyanide-nitroprusside test
Features of cystinuria?
- recurrent renal stones
- classically yellow & crystalline, appearing semi-opaque on X-ray
Rx of cystinuria?
- hydration
- D-penicillamine
- urinary alkalinisation
What is diabetes insipidus?
- ADH deficiency or insensitivity
Causes of cranial diabetes insipidus?
- idiopathic
- posy-head injury
- pituitary surgery
- craniopharyngiomas
- histiocytosis X
- DIDMOAD: ass of cranial DI, DM, Optic Atrophy & Deafness = Wolframs syndrome
Causes of nephrogenic diabetes insipidus?
- genetic: vasopressin/ADH receptor (commoner) gene mutation, aquaporin 2 channel gene mutation
- electrolytes: hypercalcaemia, hypokalaemia
- drugs: demeclocycline, lithium
- tubulo-interstitial disease: obstruction, sickle-cell, pyelonephritis
Features of diabetes insipidus?
- polyuria, polydipsia
Ix of diabetes insipidus:
plasma & urine osmolality?
test?
- water deprivation test
- plasma osmolality high
- urine osmolality low (>700 excludes DI)
tubulo-interstitial disease causes of nephrogenic DI?
- obstruction
- sickle cell
- pyelonephritis
electrolyte causes of nephrogenic DI?
- hypercalcaemia
- hypokalaemia
drug causes of nephrogenic DI?
- lithium
- demeclocycline
What is stage 1 of T1 diabetic nephropathy?
- hyperfiltration: increase in GFR
- may be reversible
What is stage 2 of T1 diabetic nephropathy?
- (silent/latent phase)
- most pts don’t develop microalbuminuria for 10yrs
- GFR remains elevated
What is stage 3 of T1 diabetic nephropathy?
- incipient nephropathy
- microalbuminuria (albumin excretion of 30-300mg/day, dipstick negative)
What is stage 4 of T1 diabetic nephropathy?
- overt nephropathy
- persistent proteinuria (albumin excretion >300mg/day, dipstick positive)
- histology shows diffuse glomerulosclerosis & focal glomerulosclerosis (Kimmelstiel-Wilson nodules)
What is stage 5 of T1 diabetic nephropathy?
- ESRF, typically GFR<10
- RRT needed
What is epididymo-orchitis?
cause?
most important DDx?
Infection of the epididymis +/- testes, resulting in pain & swelling
- most commonly caused by local spread of infections from genital tract e.g. Chlamydia, gonorrhoea, Or the bladder
- ?Testicular torsion***
Features of epididymo-orchitis?
- UL testicular pain & swelling
- urethral discharge may be present, but urethritis is often aSx
- factors suggesting testicular torsion inc pts<20yrs, severe pain & acute onset
Rx of epididymo-orchitis?
- IM Ceftriaxone 500mg stat + Doxycycline 100mg BD PO for 10-14days if organism unknown
- further Ix after Rx to exclude any underlying structural abnormalities
What is erythropoietin?
what are the main uses?
- haematopoietic growth factor that stimulates the production of erythrocytes
- Rx anaemia ass with CKD or cytotoxic therapy
Why may pts fail to respond to EPO therapy?
- iron deficiency
- inadequate dose
- concurrent infection/inflammation
- hyperparathyroid bone disease
- aluminium toxicity
Side-effects of EPO?
- accelerated hypertension, potentially leading to encephalopathy & seizures (BP increases in 25%)
- bone aches
- flu-like Sx
- skin rashes, urticaria
- pure red cell aplasia due to Abs against EPO (risk reduced with darbepoetin)
- raised PCV increases risk of thromboses e.g. of fistula
- iron deficiency 2ry to increased erythropoiesis
What is Fanconi syndrome?
What are the features?
Generalised disorder of renal tubular transport in the proximal convoluted tubule, resulting in:
- type 2 proximal renal tubular acidosis
- polyuria
- aminoaciduria
- glycosuria
- phosphaturia
- osteomalacia
- lots of urine with AA, sugar & phosphate
Causes of Fanconi syndrome?
- cystinosis (commonest cause in children)
- Sjogren’s syndrome
- multiple myeloma
- nephrotic syndrome
- Wilson’s disease
What are the maintenance fluid requirements for adults?
- 25-30ml/kg/day water
- 1mmol/kg/day of K, Na, Cl
- 50-100g/day of glucose to limit starvation ketosis
How many mmol of Na & Cl in 0.9% NaCl?
Na 154
Cl 154
How many mmol of Na & Cl in 0.18% saline with 4% glucose?
Na 30
Cl 30
glucose 40g
How much Na, Cl, K HCO3 in Hartmanns?
Na 131
Cl 111
K 5
HCO3 29
What type of renal impairment does focal segmental glomerulosclerosis lead to?
what happens with renal Tx?
NEPHROTIC syndrome
- CKD
- generally presents in young adults
- has a high recurrence rate in renal Tx
Causes of focal segmental glomerulosclerosis?
- idiopathic
- 2ry to other renal pathology e.g. IgA nephropathy, reflux nephropathy
- HIV
- heroin
- Alport’s syndrome
- sickle cell
What variables does th MDRD equation use to calculate eGFR?
What factors may affect the result?
- serum Cr
- age
- gender
- ethnicity
- pregnancy
- muscle mass
- eating red meat within 12h prior
CKD stages?
- GFR>90 with sign of kidney damage on other tests
- 60-90 with sign of kidney damage on other tests
3a. 45-59
3b. 30-44 - 15-29 (severe reduction)
- <15, established kidney failure - RRT may be needed
Common causes of CKD?
- HTN
- diabetic nephropathy
- chronic glomerulonephritis
- chronic pyelonephritis
- ADPKD
What type of anaemia is seen in CKD?
What does it predispose pts to - increasing mortality 3x in renal pts?
- normochromic, normocytic - becomes apparent when GFR <35
- mainly due to reduced EPO
- LV hypertrophy
Causes of anaemia in renal failure?
- reduced EPO levels (most significant)
- reduced erythropoiesis due to toxic effects of uraemia on bone marrow
- reduced iron absorption
- anorexia/nausea due to uraemia
- reduced red cell survival (esp in haemodialysis)
- blood loss due to capillary fragility & poor platelet function
- stress ulceration leading to chronic blood loss
Rx of anaemia in CKD?
- what is target Hb?
- target Hb 10-12
- optimise iron status before starting ESAs: erythropoiesis-stimulating agents - many pts esp on HD need IV iron
- ESAs eg EPO & darbepoetin should be used in those who are likely to benefit in terms of QoL & physical function
How is proteinuria identified in CKD?
ACR: albumin:creatinine ratio (more sensitive than PCR)
- proteinuria is an esp important marker of CKD for diabetic nephropathy
How is an ACR albumin:creatinine ration sample collected?
- spot sample (avoids 24h collection)
- 1st pass morning
- if initial ACR is 3-70, this should be confirmed by a subsequent early morning sample
- if initial ACR>70, repeat sample not needed
What level of urine ACR: albumin creatinine ratio is clinical significant for proteinuria?
3mg/mmol +
When to refer to a nephrologist with regards to urine ACR?
- urine ACR 70+ (unless known to be diabetes & appropriately treated)
- urine ACR 30+ with persistent haematuria, after excluding UTI
- consider referral to nephrologist if urine ACR 3029 with persistent haematuria and other RFs e.g. declining eGFR or CVD
1st line anti-hypertensive in proteinuria renal disease?
ACE-I
- tend to reduce filtration pressure and a small fall in GFR & rise in Cr can be expected
- decrease in eGFR upto 25% or rise in Cr upto 30% is acceptable
- if more than this, may suggest underlying renovascular disease
Furosemide for hypertension in CKD?
- useful if GFR<45
- also lowers potassium
- high doses usually required
- may need withholding during periods of risk of dehydration
What basic problems lead to bone disease in CKD?
- low vitamin D (1-alpha hydroxylation normally occurs in the kidneys)
- high phosphate
- low calcium: due to lack of vitamin D, high phosphate
- 2ry hyperparathyroidism: due to low calcium, high phosphate, low it D
What clinical manifestations of bone disease occur in CKD?
- osteitis fibrosa cystica = hyperparathyroid bone disease
- osteosclerosis
- osteoporosis
- osteomalacia = low vit D
- adynamic = reduction in cellular activity (both blasts & clasts) - may be due to over Rx with it D
What are the aims of bone disease Rx in CKD?
what are the options?
- reduce high phosphate
- reduce PTH level
- phosphate binders
- vitamin D i.e. alfacalcidol (doesn’t require activation in kidneys)
what are the phosphate binders used in CKD?
what is the main problem with them?
- calcium-based binders
- vascular calcification
Causes of transient or spurious non-visible haematuria?
- UTI
- menses
- vigorous exercise
- sex
Causes of persistent non-visible haematuria?
- cancer: bladder, kidney, prostate
- stones
- BPH
- prostatitis
- urethritis eg Chlamydia
- renal causes: IgA nephropathy, thin basement membrane disease
Spurious causes of ?haematuria of red/orange urine where blood isn’t present on dipstick?
- foods: beetroot, rhubarb
- drug: rifampicin, doxorubicin
When to do an urgent 2WW referral for haematuria?
Age 45+ with:
- unexplained persistent visible haematuria after ruling out or treating a UTI
Age 60+ with:
- unexplained non-visible haematuria with dysuria/raised WCC
When to do a non-urgent referral for haematuria?
Age 60+ with:
- recurrent/persistent unexplained UTI
What is Henoch-Schonlein purpora?
IgA-mediated small vessel vasculitis
- overlap with IgA nephropathy
- usually seen in children after an infection
What are the features of HSP?
- palpable purpuric rash over buttocks & extensors with localised oedema
- abdo pain
- polyarthritis
- features of IgA nephropathy may occur e.g. haematuria, renal failure
Rx of HSP?
- analgesia for arthralgia
- Rx of nephropathy is generally supportive
- self-limiting (esp in children without renal involvement) so there’s good prognosis
- 1/3 relapse
Renal involvement in HIV - what drugs can precipitate intratubular crystal obstruction?
protease inhibitors eg Indinavir
HIVAN = HIV ass nephropathy
- what alters the course of the disease
- what are the 5 key features?
- **Antiretroviral therapy
1. normotension
2. elevated urea & creatinine
3. massive proteinuria
4. normal/large kidneys
5. FSGS with focal/global capillary collapse on renal biopsy
What is the triad in haemolytic uraemia syndrome?
- acute renal failure
- thrombocytopenia
- MAHA
What are the causes of HUS?
- post-dysentery classically E. coli
- tumours
- pregnancy
- ciclosporin, the pill
- SLE
- HIV
Ix in HUS?
- anaemia, thrombocytopenia, fragmented blood film
- U&E AKI
- stool culture
Rx in HUS?
- supportive: fluids, blood transfusion, dialysis if required
- plasma exchange in specific severe cases
Which diseases typically present with nephritic syndrome i.e. haematuria & hypertension?
- Rapidly progressive GN = crescenteric glomerulonephritis
- IgA nephropathy aka mesangioproliferative GN, Berger’s disease
Rapid onset nephritic syndrome (haematuria & HTN), often presenting as AKI - what is the cause?
Rapidly progressive glomerulonephritis = crescenteric GN
Causes of rapidly progressive GN aka crescenteric GN?
- Goodpasture’s
- ANCA +ve vasculitis
Glomerulonephritides which typically present with nephrotic syndrome (proteinuria, oedema)?
- Minimal change disease (child)
- Membranous glomerulonephritis (adult)
- Focal segmental glomerulosclerosis (young adult)
- Membranoproliferative
A child presents with nephrotic syndrome - what is the most likely disease?
Causes?
Minimal change disease
- Hodgkin’s, NSAIDs
- good response to steroids