Renal Flashcards
Genetics of Alport’s syndrome?
X linked dominant
- defect in gene which codes for type IV collagen -> abnormal glomerular BM
- more severe disease in males
Cause (most common) of Alport’s patient with failing renal transplant?
Presence of anti-GBM antibodies leading to Goodpasture’s syndrome-like picture
Features of Alport’s syndrome?
- microscopic haematuria
- progressive renal failure
- bilateral sensorineural deafness
- lenticonus: protrusion of the lens surface into the anterior chamber
- retinitis pigmentosa
Renal biopsy features of Alport’s syndrome?
splitting of lamina densa seen on electron microscopy
Diagnosis of Alport’s syndrome?
- molecular genetic testing.
- renal biopsy: electron microscopy showing characteristic finding of longitudinal splitting of lamina dense of the glomerular BM, resulting in a “basket-weave” appearance
Management of cranial DI?
tx underlying cause. desmopressin
Management of nephrogenic DI?
thiazides , low salt/protein diet
what systemic conditions cause cranial DI?
- histiocytosis X
- DIDMOAD is the association of cranial Diabetes Insipidus, Diabetes Mellitus, Optic Atrophy and Deafness (also known as Wolfram’s syndrome)
- haemochromatosis
what antibodies are assoc with primary membranous nephropathy?
anti-phospholipase A2 receptor antibodies
common causes of secondary membranous nephropathy?
- malignancies: solid tumours (lung/ colon etc)
- infections: hep B/C, HiB, malaria, syphilis, schistosomiasis
- autoimmune diseases: SLE, sarcoid, IBD
- drugs: NSAIDs, captopril, gold, penicillamine, lithium, clopidogrel
Causes of renal artery stenosis?
90%: atherosclerosis
10%: fibromuscular dysplasia (‘string of beads’ appearance of renal arteries)
Features of fibromuscular dysplasia??
- HTN
- CKD/ AKI secondary to ACEi initiation
- flash pulmonary oedema
Causes of rapidly progressive GN?
aka crescentic glomerulonephritis
- Goodpastures, ANCA positive vasculitis
Common causes of polyuria?
diuretics, caffeine & alcohol
diabetes mellitus
lithium
heart failure
What antibody could be used in treatment of haemolytic uraemic syndrome?
Eculizumab (C5 inhibitor monoclonal antibody)
MOA of tolvaptan?
vasopressin receptor 2 antagonist
- reduces water absorption and increases water loss without sodium loss
CKD: if albumin: creatinine ratio is between 3-70mg/mmol, what to do?
repeat sample with a subsequent early morning sample.
- > 3 is considered clinically important proteinuria
CKD: if albumin: creatinine ratio is >70mg/mmol, what to do?
refer to nephrologist
Management of proteinuria in CKD?
1st line: ACEi (ARB)
features of rhabdomyolysis?
- AKI with disproportionately raised Cr
- High CK
- Myoglobinuria
- HypoCa (Myoglobin binds calcium)
- High phosphate (released from mycocytes)
- HyperK
- met acidosis
Fractional urea excretion in urine in pre-renal uraemia vs ATN?
pre-renal: <35% fractional urea excretion
acute tubular necrosis: >35%
**fractional urea excretion = (urine urea /blood urea ) / (urine creatinine/plasma creatinine) x 100
Reason for hyper acute organ rejection?
presence of pre formed antibody e.g. HLA mismatch/ ABO incompatibility
tx: removal of graft, if left in situ -> abscess
Reason for acute organ rejection? usually during first 6 months
usually T cell mediated
- tissue infiltrates and vascular lesions
tx: medical management
Main reason for chronic organ rejection? occurs after first 6 months
vascular changes predominate
Most common and severe from of glomerulonephritis secondary to SLE?
Class IV: Diffuse proliferative GN
what are stag horn calculi composed of?
struvite (ammonium, magnesium phosphate, triple phosphate)
What bacteria predispose to stag horn calculi?
ammonia producing bacteria.
e.g. ureaplasma urealyticum, proteus infections
what stones are radio-lucent?
urate stones, xanthine stones
*cystine stones are semi-opaque, with a ground glass appearance.
extra renal manifestations of PCKD?
- liver cysts (70% - the commonest extra-renal manifestation): may cause hepatomegaly
- berry aneurysms (8%): -> subarachnoid haemorrhage
- CVS: mitral valve prolapse, mitral/tricuspid incompetence, aortic root dilation, aortic dissection
- cysts in other organs: pancreas, spleen; very rarely: thyroid, oesophagus, ovary
Triad of features in haemolytic uraemic syndrome?
AKI, MAHA, Thrombocytopenia
Causes of transient or spurious non-visible haematuria?
urinary tract infection
menstruation
vigorous exercise (this normally settles after around 3 days)
sexual intercourse
most common histological sybtype or renal cell cancer?
clear cell (75-85%)
Paraneoplastic hepatic dysfunction syndrome?
seen in renal cell carcinoma
- aka Stauffer syndrome
- presents as cholestasis/ hepatosplenomegaly
- secondary to increased IL-6
management of renal cell carcinoma?
- partial/ total nephrectomy
- IFN-alpha, IL-2 can reduce tumour size
- tyrosine kinase inhibitors! e.g. sorafenib, sunitinib
causes of nephrogenic DI?
- genetic: more common- defective ADH receptor, less common- defective aquaporin 2 channel
- electrolytes: hypercalcaemia, hypokalaemia
- lithium: desensitizes the kidney’s ability to respond to ADH in the collecting ducts
- demeclocycline
- tubulo-interstitial disease: obstruction, sickle-cell, pyelonephritis
Genetics of ADPKD type 1 vs ADPKD type 2?
type 1 : chr 16
type 2: chr 4
what antibodies are used in immunosuppression post renal transplant?
selective inhibitors of IL-2 receptor: daclizumab, basilximib
commonest cause of glomerulonephritis worldwide?
IgA nephropathy aka Berger’s disease
Assoc conditions of IgA nephropathy?
alcoholic cirrhosis,
coeliac disease,
henoch-schonlein purpura
Mx of IgA nephropathy?
steroids/ immunosuppressants
Poor prognostic markers of IgA nephropathy?
male, proteinuria (esp >2g/day), HTN, hyperlipidaemia smoking, ACE genotype DD
Good prognostic markers of IgA nephropathy?
frank haematuria
histology of renal biopsy in IgA nephropathy?
mesangial hypercellularity, positive immunofluorescence for IgA & C3
renal biopsy findings in Goodpasture’s syndrome?
Linear IgG deposits along the basement membrane
Mx of Minimal change glomerulonephritis?
majority 80% are steroid-responsive.
2nd line- cyclophosphamide
reasons why patients may fail to respond to erythropoietin therapy?
- iron deficiency
- inadequate dose
- concurrent infection/inflammation
- hyperparathyroid bone disease
- aluminium toxicity
How long may finasteride take to work for BPH?
6 months
SE of erythropoietin injections?
- accelerated hypertension potentially leading to encephalopathy and seizures (blood pressure increases in 25% of patients)
- bone aches
- flu-like symptoms
- skin rashes, urticaria
- pure red cell aplasia* (antibodies against EPO)
- raised PCV increases risk of thrombosis (e.g. Fistula)
- iron deficiency 2nd to increased erythropoiesis
Ix of renal vascular disease/ renal artery stenosis?
MR angio
Management of renal artery stenosis?
balloon angioplasty
most common cause of peritonitis secondary to peritoneal dialysis?
Coagulase negative staph e.g. staph epidermidis
Complications of nephrotic syndrome?
- increased risk of clots (loss of antithrombin III and plasminogen in the urine)
- hyperlipidaemia
- CKD
- increased risk of infection due to immunoglobulin loss in urine
- hypocalcaemia (vitamin D and binding protein lost in urine)
Causes of type 1 membranoproliferative glomerulonephritis?
- 90% of cases are type 1
causes: cryoglobulinaemia, Hep C
electron microscopy showing: subendothelial and mesangium immune deposits of electron-dense material resulting in a ‘tram-track’ appearance
type I membranoproliferative glomerulonephritis
Causes of type 2 membranoproliferative disease?
partial lipodystrophy (classically patients have loss of subcut tissue from their face), factor H deficiency
pathophysiology of type 2 membranoproliferative disease?
- persistent activation of alternative complement pathway
- low circulating levels of C3
- C3b nephritic factor found in 70%
electron microscopy showing: intramembranous immune complex deposits with ‘dense deposits’
type 2 membranoproliferative glomerulonephritis aka ‘dense deposit disease’
causes of type 3 membranoproliferative glomerulonephritis?
hep B and C
Management of membranoproliferative glomerulonephritis?
steroids
Which HLA matching is most important for renal transplant?
HLA DR >B > A
Wilms tumour associations?
- Beckwith-Wiedemann syndrome
- part of WAGR syndrome with Aniridia, Genitourinary malformations, mental Retardation
- hemihypertrophy
- around 1/3 of cases are associated with a loss-of-function mutation in the WT1 gene on chromosome 11
Ix for vesicoureteric reflux?
micturating cystourethrogram
- after this, DMSA scan to look for renal scarring
endocrine effects of renal cell carcinoma?
erythropoietin, parathyroid hormone (HyperCa), renin, ACTH
How to calculate anion gap?
Na+ + K+ - (Bicarb + Cl-)
*normal anion gap is 8-14 mmol/L
How to calculate anion gap?
Na+ + K+ - (Bicarb + Cl-)
Causes of normal anion gap or hyperchloraemic metabolic acidosis?
- GI bicarbonate loss: diarrhoea, ureterosigmoidostomy, fistula
- renal tubular acidosis
- drugs: e.g. acetazolamide
- ammonium chloride injection
- Addison’s disease
Causes of high anion gap metabolic acidosis?
- lactate: shock, hypoxia
- ketones: diabetic ketoacidosis, alcohol
- urate: renal failure
- acid poisoning: salicylates, methanol
- 5-oxoproline: chronic paracetamol use
Which of the following types of renal stones are said to have a semi-opaque appearance on x-ray?
cystine stones
Management of oxalate stones?
- cholestyramine - reduces urinary oxalate secretion
- pyridoxine: same
Management of uric acid stones?
allopurinol
urinary arlkalinization e.g. oral bicarb
What is seen in stage 1 diabetic nephropathy?
hyperfiltration: increase in GFR
- may be reversible
What is seen in stage 2 diabetic nephropathy?
silent or latent phase
- GFR remains elevated
- most do not develop microalbuminuria for 10 years
What is seen in stage 3 diabetic nephropathy?
microalbuminuria
albumin excretion 30-300mg/day
What is seen in stage 4 diabetic nephropathy?
persistent proteinuria (dipstick +)
HTN
Histology shows diffuse and focal glomerulosclerosis (Kimmelstiel-Wilson nodules)
What is seen in stage 5 diabetic nephropathy?
end stage renal disease, GFR typically <10 mL/min
renal replacement therapy needed
Causes of acute interstitial nephritis?
- drugs: the most common cause, particularly antibiotics
penicillin, rifampicin, NSAIDs, allopurinol, furosemide - systemic disease: SLE, sarcoidosis, and Sjögren’s syndrome
- infection: Hanta virus , staphylococci
Features of acute interstitial nephritis?
- fever, rash, arthralgia
- eosinophilia
- mild renal impairment
- hypertension
Investigations of acute interstitial nephritis?
sterile pyuria, white cell casts
High B-HCG + testicular lump?
seminoma
Early features of TCA overdose?
anticholinergic symptoms: dry mouth, dilated pupils, agitation, sinus tachy, blurred vision
Features of severe TCA overdose?
arrhythmias, seizures, met acidosis, coma
ECG changes assoc w TCA overdose?
sinus tachy,
QRS widening,
QT prolongation
Management of TCA overdose?
1st line for hypotension or arrhythmias: IV bicarb
- IV lipid emulsion increasingly used to bind free drug and reduce toxicity
Dialysis in TCA overdose?
DIALYSIS INEFFECTIVE
Adverse effects of finasteride?
impotence
decreased libido
ejaculation disorders
gynaecomastia and breast tenderness
- also causes decreased levels of PSA
features of ethylene glycol toxicity?
- confusion, slurred speech
- High anion gap met acidosis
- AKI
Management of ethylene glycol toxicity?
- 1st Line: fomepizole (inhibitor of alc dehydrogenase)
- ethanol: works by competing with ethylene glycol for the enzyme alc dehydrogenase, limits formation of toxic metabolites.
- haemodialysis has a role in refractory cases
what antibiotics inhibit protein synthesis?
- 50S subunit: macrolides, chloramphenicol, clindamycin, linezolid, streptogrammins
- 30S subunit: aminoglycosides, tetracyclines