Nephrology Flashcards
Within ADPKD, what are the two different types, which chromosomes cause the mutations and when do they usually reach ESRF?
PKD1 (85%) - Chr16, ESRF by 50s
PKD2 (15%) - Chr4, ESRF by 70s
T1 = most common (1st), Chr (1)6, reaches ESRF 1st
In patients with a positive FH, what is the USS criteria for diagnosing PKD?
two cysts, unilateral or bilateral, if aged < 30 years
two cysts in both kidneys if aged 30-59 years
four cysts in both kidneys if aged > 60 years
What are the main symptoms of PKD and what complications may occur in the kidney?
Abdo pain +/- haematuria
Cyst infection
Renal calculi
Increased BP
Progressive kidney failure
What are the extra-renal manifestations of PKD?
Liver cysts -> hepatomegaly
Intra-cranial aneurysm -> SAH
Cysts: pancreas, ovaries, testes, liver
Mitral valve prolapse (systolic apical murmur) and diverticular disease
- essentially all cystic/out-pouching structures
Management of PKD?
HIGH BP SHOULD BE TREATED AGGRESSIVELY (aim <130/80mmHg)
Strict criteria, but some patients may be offered tolvaptan (vasopressin receptor 2 antagonist) to slow cyst development
No other regular treatment
Treat infections + monitor U&Es
To help pain -> cyst removal/nephrectomy
Increased water intake, decreased sodium intake and avoid caffeine may also help
If a patient develops a SAH with a history of PKD, what might you offer their family members?
Magnetic resonance angiography screening may be done in 1st degree relatives of those with SAH + ADPKD
Which Ab is idiopathic membranous glomerulonephritis related to?
Anti-phospholipase A2 antibodies
What are the three defining features of nephrotic syndrome? + extra finding
Proteinuria (>3g/24hrs)
Hypoalbuminaemia (<30g/L)
Oedema
- also severe hyperlipidaemia
What are the three primary causes of nephrotic syndrome?
Minimal change disease
Membranous nephropathy
Focal segmental glomerulosclerosis
What can cause secondary nephrotic syndrome?
infections: hepatitis B, malaria, syphilis
malignancy (in 5-20%): prostate, lung, lymphoma, leukaemia
drugs: gold, penicillamine, NSAIDs
autoimmune diseases: systemic lupus erythematosus (class V disease), thyroiditis, rheumatoid
What is minimal change disease, causes, how is it Ix and Tx?
fusion of foot processes, more common in children
Can see loss of foot processes on electron microscopy (light microscopy normal)
80% idiopathic, but can be caused by:
drugs: NSAIDs, rifampicin
Hodgkin’s lymphoma, thymoma
infectious mononucleosis
Tx = steroids Prognosis = 1/3 one episode, 1/3 infreq relapses 1/3 freq relapses (stop before adulthood)
What is membranous nephropathy, how is it Ix and Tx?
thickened glomerular BM, more common in adults, usually idiopathic – may be assoc with AI disease e.g. SLE
Tx = ACEi, immunosuppression (steroids + another agent) if severe/progressive
Prognosis = , 1/3 remission, 1/3 remain proteinuric, 1/3 renal failure
What is the pathophysiology of nephrotic syndrome?
Injury to the podocytes appears to be the main cause – usually they wrap around the glomerular capillaries and maintain the filtration barrier, preventing large protein molecules from getting through. Damage can cause a large protein loss.
What are good prognostic indicated of membranous nephropathy?
Female
Young age
Asymptomatic proteinuria at the time of presentation
What is focal segmental glomerulosclerosis, how is it Tx?
Segments of glomeruli develop sclerosis, 50% will get better, 50% develop ESRF, Tx = steroids
What is the presentation of nephritic syndrome?
Haematuria (micro/macro), HTN, drop in GFR
Also - fluid retention + oedema, and proteinuria
Causes of nephritic syndrome?
Post-strep infection
IgA nephropathy
Rapidly progressive GN
Membranoproliferative GN
Goodpastures disease
What is post infectious (post-strep) GN?
Post-infection with Group A B-haemolytic streptococcus (pyogenes)
• Causes inflammation in the glomeruli + defective filtration, causing blood to leak through
• Typically occurs in children
ASSOCIATED WITH LOW COMPLEMENT
- Occurs 1-2 weeks after throat/skin infection
- Tx = supportive, potentially Tx oedema with furosemide, >95% recover renal function
What is IgA nephropathy?
- Commonest GN in HICs in adults - typical: young man with haematuria that recovers rapidly after attacks
- Usually present with macroscopic haematuria, may present 1-2 days after a viral infection
- Renal biopsy – IgA deposits seen in the matrix
- Tx – BP control with ACEi, immunosuppression may slow the decline of renal function
- 20% of adults develop ESRF over 20 years
What is rapidly progressive GN?
- The most aggressive GN
- Different causes – all have crescents (fibrin thickening) in the glomeruli seen on biopsy
- Examples: Goodpasture’s, granulomatosis with polyangiitis, microscopic polyangiitis
What is Goodpasture’s disease?
• Also known as anti-glomerular BM disease
• Caused by auto-Abs to T4 collagen (an essential component of the GBM)
o Features
–> pulmonary haemorrhage
–> rapidly progressive glomerulonephritis (rapid AKI)
• Tx – plasma exchange, steroids +/- cyclophosphamide, if started early full recovery is possible
What are some common causes of polyuria?
diuretics, caffeine & alcohol
diabetes mellitus
lithium
heart failure
What is the mechanism by which alcohol intake causes polyuria?
Alcohol acts to inhibit ADH. This causes reduce aquaporin insertion in the collecting tubules
What is diabetes insipidus?
Either a deficiency of ADH (cranial) or an insensitivity to ADH (nephrogenic)