Nephrology Flashcards
Visible haematuria following recent URTI?
IgA Nephropathy
Commonest causes of glomerulonephritis worldwide?
IgA Nephropathy (Berger’s disease)
IgA nephropathy associations?
- Alcoholic cirrhosis
- Coeliac disease/dermatitis herpetiformis
- Henoch-Schonlein puurpura
IgA nephropathy pathophysiology?
- Mesangial deposition of IgA immune complexes
- Considerable pathological overlap with Henoch-Schonlein purpura (HSP)
- Histology = mesangial hypercellularity, positive immunofluorescence for IgA & C3
IgA nephropathy presentation?
- Young male, recurrent episodes of macroscopic haematuria
- Typically associated with a recent respiratory tract infection
- Nephrotic range proteinuria is rare
- Renal failure unusual
Differentiating between IgA nepropathy and Post-streptococcal glomerulonephropathy?
PSG = low complement levels, proteinuria, interval between URTI and symptom onset
PSG vs. IgAN time after URTI?
- IgAN = 1-2 days
- PSG = 1-2 weeks
IgA nephropathy?
- No treatment, just renal function f/up = Isolated haematuria, no/minimal proteinuria, and normal GFR
- ACEi = persistent proteinuria >500, normal/slightly reduced GFR
- Steroids = active disease (falling GFR) or failure to respond to ACEi
IgA nephropathy prognosis?
- 25% ESRF
- Marker of good prognosis = frank haematuria
- Markers of poor prognosis = male, proteinuria >2, HTN, smoking, hyperlipidaemia, ACE genotype DD
CKD diet?
Low sodium, phosphate, potassium, protein (to reduce renal strain as is excreted by kidneys)
Prevention of contrast-induced nephropathy?
Volume expansion with 0.9% NaCl
Contrast media nephrotoxicity definition?
25% increase in creatinine occurring within 3 days of the intravascular administration of contrast media
When dose contrast-induced nephropathy occur?
2-5 days after administration
Contrast nephrotoxocity RFs?
- Known renal impairment
- Age > 70 years
- Dehydration
- Cardiac failure
- Nephrotoxics e.g. NSAIDs
High risk for contrast-induced nephropathy and metformin?
Hold metformin for 48 hours until renal function shown to be normal
Minimal change disease presentation?
Nearly always as nephrotic syndrome, accounting for 75% of cases in children and 25% in adults
Minimal change disease cause?
Majority are idiopathic, in 10-20% a cause is found:
1. Drugs: NSAIDs, rifampicin
2. Hodgkin’s lymphoma, thymoma
3. Infectious mononucelosis
Minimal change disease pathophysiology?
- T-cell and cytokine-mediated damage to the glomerular basement membrane → polyanion loss
- Resultant reduction of electrostatic charge → increased glomerular permeability to serum albumin
Minimal change disease features?
- Nephrotic syndrome
- Normotension (HTN is rare)
- High selective proteinuria = Only intermediate-sized proteins such as albumin and transferrin leak through the glomerulus
Minimal change disease biopsy?
- Normal glomeruli on light microscopy
- EM shows fusion of podocytes and effacement of foot processes
Minimal change disease Rx?
- Oral corticosteroids = 80% responsive
- Cyclophosphamide = if steroid resitant
Minimal change disease prognosis?
- 1/3 have one episode
- 1/3 have infrequent relapses
- 1/3 have frequent relapses which stop before adulthood
Most common inherited cause of kidney disease?
ADPKD
ADPKD Type 1?
- 85% cases
- Chromosome 16
- Presents with renal failure earlier
- Polycystin-1
ADPDK Type 2?
- 15% cases
- Chromosome 4
- Polycystin-2
Screening for ADPKD?
Abdominal US
US diagnostic criteria for ADPKD in pts with positive family history?
- 2 cysts, uni or bilateral, if < 30 y/o
- 2 cysts in both kidneys if 30-59 y/o
- 4 cysts in both kidneys if > 60 y/o
ADPKD Rx?
Tolvaptan (VP receptor 2 antagonist) if:
1. CKD 2/3 at start of treatment
2. Evidence of rapidly progressing disease
3. Company provides it with the discount agreed in the patient access scheme
Non-visible haematuria found in what % of population?
2.5%
Causes of transient non-visible haematuria?
- UTI
- Menstruation
- Vigorous exercise
- Sexual intercourse
Causes of persistent non-visible haematuria?
- Cancer (bladder, renal, prostate)
- Stones
- BPH
- Prostatitis
- Urethritis e.g. Chlamydia
- Renal causes = IgA nephropathy, thin basement membrane disease
Spurious causes of red/orange urine?
- Foods = beetroot, rhubarb
- Drugs = rifampicin, doxorubicin
Haematuria Ix?
- Urine dipstick
- Persistent non-visible haematuria is often defined as blood being present in 2 out of 3 samples tested 2-3 weeks apart
- Renal function, ACR, PCR and BP should be checked
- Urine microscopy may be used but time to analysis significantly affects the number of red blood cells detected
Haematuria 2ww criteria?
- > =45 y/o AND = Unexplained visible haematuria without UTI OR visible haematuria that persists or recurs after successful treatment of urinary tract infection
- Aged >/60 y/o AND have unexplained nonvisible haematuria and either dysuria or a raised white cell count on a blood test
Haematuria non-urgent referal criteria?
Aged >= 60 years with recurrent or persistent unexplained urinary tract infection
Hyperkalaemia classification?
- Mild = 5.5 - 5.9
- Moderate 6.0 - 6.4
- Severe = >=6.5
Hyperkalaemia ECG changes?
- Tented T waves (first)
- Loss of P waves
- Broad QRS complexes
- Sinusoidal wave pattern
Principles of hyperkalaemia treatment?
- Stabilisation of cardiac membrane = IV calcium gluconate
- Short term shift in potassium from ECF to ICF = combined insulin/dextrose and nebulised salbutamol
- Removal of potassium from body = calcium resonium (enema more effective than oral), loop diuretics, hyperkalaemia
Indication that kidney disease is chronic and not acute?
- US (CKD have bilateral small kidneys, except for ADPKD, DN early stages, amyloidosis and HIV-associated nephropathy)
- Hypocalcaemia (due to lack of Vitamin D)
MDRD equation for measuring GFR?
CAGE
1. Serum creatinine
2. Age
3. Gender
4. Ethnicity
Features which may affect GFR?
- Pregnancy
- Muscle mass (e.g. amputees, body-builders)
- Eating red meat 12 hours prior to sample being taken