Renal Flashcards
Regarding urine PH, which of the following is correct?
A. It is a useful indicator of the acid base balance of blood
B. It is determined by the concentration of ammonium
C. It is lower than 5.5 in RTA
D. It rises on a vegetarian diet
E. Would be above 7.0 after prolonged, severe vomiting
Answer is D.
Urine PH is affected by diet, with vegetarians having more ALKALINE urine compared to omnivores.
Animal proteins found in meat, eggs and cheese are often converted into acidic products such as Amino acids –> daily increase in the body’s acid content –> acid excreted in kidneys.
Calcium PO4 stones are more likely to form in alkaline urine with pH >6.0, therefore need to give dietary advice.
Other answers:
- Urine pH is determined by the concentration of H+ ions
- bacterial infections often promote an ALKALINE urine due to the presence of bacterial enzymes converting Urea to ammonia
- In RTA, unable to lower the pH to less than 5.5 in Type1 RTA
- we do expect a pH of above 7.0 in severe vomiting to compensate for the loss of acid, but when there is hypovolaemia the retention of Na takes priority. Instead of HCO3 being excreted, it is reabsorbed in the proximal and distal nephron and this perpetuates the metabolic alkalosis until the fluid balance is restored.
What is the commonest cause of intrinsic AKI?
ATN
What is the benefit of measuring FGF-23 in dialysis patients?
FGF 23 in dialysis patients:
- a good marker of mortality
- the worse the GFR the higher the FGF 23
What is the most common cause of Acute Interstitial Nephritis?
How do you diagnose AIN?
PPI’s!
Diagnosis:
Eosinophilia on bloods
Urine may have eosinophilia and WCC casts
What is Hepatorenal Syndrome and what is the diagnostic criteria?
HRS is the development of renal failure with severe liver disease, in absence of any other renal pathology.
Diagnostic criteria (from BMJ):
- Cirrhosis with ascites
- Creat >133
- No improvement of serum creatinine despite 2 days of volume expansion and diuretic withdrawal
- Absence of shock
- No current / recent nephrotoxic drugs
- Absence of parenchymal kidney disease - need a normal renal US and No proteinuria / haematuria
What are the main drug causes of acute interstitial nephritis?
PPIs
Ciprifloxacin
NSAIDS
Beta lactam antibiotics
–> fever, rash, eosinophilia in urine/bloods, may have low grade proteinuria
What is the basic principle of management for PRIMARY Nephrotic Syndromes (Min change, Membranous, FSGS)?
1st line - Prednisone
2nd line - CTX
3rd line - CsA (but CsA nephrotoxic- tubulointerstitial nephritis)
The exception is Membranous Nephropathy where you give PRED and CTX TOGETHER for 6 months, ALTERNATING MONTHLY between the 2 drugs.
Also in Membranous, give WARFARIN if Albumin is low < 20 as there is a high risk of spontaneous DVT.
What is the management of Primary Membranous Nephropathy?
PREDNISONE and CTX TOGETHER for 6 months, ALTERNATING MONTHLY between the 2 drugs.
(steroid MONOTHERAPY does not work for Primary/Idiopathic Membranous Nephropathy)
WARFARIN if Albumin is low < 20 as there is a high risk of spontaneous DVT.
What is the antibody marker associated with Membranous Nephropathy?
PLA2R Antibody.
PLA2R Ab is present in 70% of Primary/Idiopathic MN.
It is NOT PRESENT in SECONDARY Membranous Nephropathy
What is the lab marker associated with FSGS?
SuPAR is a circulating Urokinase Receptor that is associated with FSGS.
(“Flash Gordon’S (FSGs) a “SuPAR-hero”)
What are the biopsy findings in Membranous Nephropathy?
LM/EM:
- SPIKES on silver staining
- Electron-dense deposits (= intramembranous deposits of Immunoglobulin)
- thickened GBM
- “granular” deposition
Late disease: interstitial fibrosis and less deposits
What are the secondary causes of Membranous Nephropathy?
*** HEP B!! - strongly associated!
Autoimmune diseases:
- Diabetes (DIABETIC NEPHROPATHY MOST COMMON CAUSE)
- SLE
- RA
Drugs - ACEI, NSAIDS
Infections
Cancers - CLL
(Need to rule out these secondary causes in any patient with Membranous Nephropathy)
What is the prognosis of FSGS after treatment with steroids?
Depends if PRIMARY or SECONDARY FSGS.
PRIMARY FSGS:
- good response to steroids
- BUT in renal transplant, there is a VERY HIGH RISK OF DISEASE RECURRENCE (suspect if there is heavy proteinuria after transplant)
SECONDARY FSGS:
- doesn’t respond to steroids or immunotherapy
- but responds very well to kidney transplant
(Note the secondary causes of FSGS:
Ischaemic/ Renovascular,
reflux Nephropathy
HIV)
What are the biopsy findings in FSGS?
What part of the nephron is involved first?
LM/EM:
- Sclerosis, FOCAL & SEGMENTAL (as the name implies)
- Juxtaglomerular nephrons involved first
- hyalinosis
- interstitial fibrosis
What are the clinical characteristics of a patient presenting with Messngioproliferative Glomerulonephritis?
Typically a young male, HTN and nephrotic picture, LOW C3.
(Can look at MPGN as being “half nephrotic/half nephritic”)
MOST cases are due to SECONDARY CAUSES, eg.
- SLE
- Hep-C Associated Cryoglobulinaemia
- -> Poor prognosis if nephrotic on presentation
- -> ESRF in 40%
What is the treatment for Mesangioproliferative GN?
ASPIRIN +/- Dipyrimadole
(No benefit with Immunosuppression)
Treat underlying cause eg. SLE, HepC Cryoglobulinaemia etc