General nephrology - COPIED Flashcards
What four signs makes up nephrotic syndrome?
proteinuria >> 4.5 g/ 24hr
dyslipidemia (hypercholesteraemia specifically)
hypoalbuminaemia
peripheral oedema
*** rem. haematuria is rare, and BP may be normal or slighly elevated ***
what usually prevents protein loss in the urine?
podocytes
fenestrated membrane
Do you get haematuria with nephrotic syndome?
Possibly. It depends on the damage to the glomerulus.
Why can you get sepsis with nephrotic syndrome?
Loss of immunoglobulins (proteins) in the urine will compromise the immune system.
Why do you get peripheral oedema with nephrotic syndrome?
Due to loss of protein in urine, therefore hypoalbuminemia.
Loss of proteins in the urine. The liver tries to compensate by….
producing more albumin
It also produces more cholesterol (hypercholesterolemia)
What is the consequence to the heart of the increase in peripheral oedema with nephrotic syndrome?
Reduction in venous return, therefore a reduction in stroke volume.
This reduction in blood flow reduces the GFR.
In addition there is inflammation in the Kidneys that also reduce GFR. THIS STIMULATES RENIN.
What is the consequene of an increase in RENIN production with nephrotic syndrome?
In response to low renal BP, Renin is released.
Renin-Angiotensin-aldersterone causes Na2+ to be retained and thus increase in BP.
This will result in more oedema because of the hypoalbuminuria.
What types of oedema can you get with nephrotic syndome?
periorbital oedema
ascites
peripheral oedema
Oedema in nephrotic syndrome also causes what problems in the thoracic region?
breathlessness
pulmonary oedema
pleural effusion
what does the urine look like in nephrotic syndrome?
frothy
What investigations?
urine dip stick
MSU, FBC
EUC, LFT, Calcium levels
serum (and urine) immunoglobulins to screen for autoimmune diseases.
CXR - pleural effusion/ oedema
ultrasound, biopsy.
What conditions can lead to nephrotic syndrome?
Glomerular disease (e.g. minimal change disease in childhood), focal segmental glomerulosclerosis, membranous nephropathy.
Diabetes
SLE
Amyloidosis
(Hep B and C, HIV) - check this
BUN
Bloode urea nitrogen; medical test.
NB. Liver produces urea as a waste product of protein digestion.
What benign things can increase urinary protein output?
Pyrexia
exercise
adoption of upright posture(postural proteinuria)
What do red cell casts always indicate?
renal disease
WC casts may indicate acute pyelonephritis
What are the three big causes of ESKD?
Diabetes (number ONE)
Hypertension
Glomerulopathy
What is Glomerulopathy?
immunologically mediated disorders with involvement of:
cellular immunity
humoral immunity
inflammatory mediators
Why do you get hypoalbuminemia with nephrotic syndrome?
Which protein is lost in the urine due to kidney damage
Why do you get lipiduria with nephrotic syndrome?
Passing of lipoproteins in the urine due to kidney damage (thus also hypoalbuminaemia)
What is acute glomerulonephritis?
– acute nephritic syndrome
Abrupt onset of glomerular haematuria (RBC casts or dysmorphic RBC),
non-nephrotic range proteinuria, oedema (periorbital, leg or sacral), hypertension and
transient renal impairment.
- OFTEN inflammation of glomeruli/ small b. vessels.
What is nephrotic syndrome?
Massive proteinuria (>3.5 g/day),
hypoalbuminaemia, oedema,
lipuria and hyperlipidaemia
NO RBCs in the urine
Why are ACE inhibitors used to treat nephrotic syndrome?
to reduce urinary albumin excretion when px ingests > protein.
How do you treat nephrotic syndrome?
Restrict sodium and use a thiazide diuretic.
(May have to be parenteral administration because of gut mucosal oedema)
Normal protein diet
Why is prophylactic anticoagulation desirable with nephrotic syndrome?
Due to loss of clotting factors (eg. antithrombin) in the urine and an increase in hepatic production of fibrinogen.
Avoid bed rest. Thromboembolism is very common in nephrotic syndrome.
Why use ACE inhibitors or ARBs for nephrotic syndrome?
reduce proteinuria by lowering pressure in glomerulus.
Loss of proteins with nephrotic syndrome predisposes patient to what?
Thromboembolisms (due to loss of clotting proteins)
Sepsis/ infections (due to loss of immunoglobulins)
Lipid abnormalities - can accelerate atheromas
Anaemia (loss of transferrin)
Oedema (lower limbs, sacrum) + can be periorbital & hands
What class of group for lowering nephrotic associated hyperlipidaemia?
HMG-CoA reductase inhibitor
Diagram of mesengial cells between arterioles and bowman’s capsule.
What is amyloidosis?
group of diseases in which abnormal protein, known as amyloid fibrils (insoluble), is deposited extracellularly. Acquired or inherited disorder of protein folding.
In the kidneys the amyloid deposition reduces the kidney’s ability to filter and hold on to proteins (nephrotic syndrome). Heart also affected (and Liver).
What is azotemia?
azot = “nitrogen”, -emia=”blood”
>> nitrogen-rich compounds in the blood (urea, creatinine), due to << kidney filtering.
Can cause uremia and AKI
ATI - acute tubular injury (acute tubular necrosis ATN) is most common cause of intrinsic renal azotemia
What are marked histological changes with diabetic renal disease?
glomerular basement membrane thickening
mesangial expansion
progressive depletion of podocytes
later … glomerulosclerosis
IMP> renal injury in diabetes is clinically silent.
What lifestyle would you give a diabetic px to reduce risk of developing ESKD?
Stop smoking, do exercise, control BP, address hyperlipidaemia.
If microalbuminuria then start ACE inhibitors or ARBs regardless of BP elevation.
What’s the relationship of SLE and renal disease?
Renal disease occurs in 1/3 of SLE patients,
25% of these reach end-stage CKD within 10 years.
SLE is an autoimmune disorder creating immune deposits in the glomeruli and mesangium.
Systemic lupus erythematosus (SLE) that affects the kidneys is called lupus nephritis.
acute glomerulonephritis – acute nephritic syndrome.
Abrupt onset of glomerular haematuria (RBC casts or dysmorphic RBC),
non-nephrotic range proteinuria,
oedema,
hypertension and
transient renal impairment (temporarily oliguria and uraemia)
PSGN stands for?
Post streptococcal GlomeruloNephritis
Why is there a delay between Streptococcal infection (maybe throat) and onset of nephritic disorders?
And what’s the outcome? Lifestyle advice?
it takes time for immune complex formation & deposition,
and for glomerular injury to occur.
Usually spontaneously resolves.
Strongly limit Sodium and Potassium.
Restrict protein
Loop diuretics usually very useful.
What does RPGN stand for?
Rapidly Progressive GlomeruloNephritis
RPGN features
focal necrosis with or without crescents and rapidly progressive renal failure over weeks.
NB> crescents are aggregations of macrophages and epithelial cells in Bowman’s space.
What are the main features of Pre-renal AKI?
A decrease in blood perfusion and thus << GFR.
Both Kidneys need to be affected (why? remember?)
common causes; hypovolemia, hypotension, <
What drugs impair kidney autoregulation?
ACE inhibitors
NSAIDs
What other things can cause >> creatinine?
>> muscle mass
>> red meat ingestion
muscle damage (rhabdomyolysis)
decreased tubular secretion (eg. cimetidine, trimethoprim tx)
What must you check when giving hypovolaemic px fluids?
BP
signs of jugular venous pressure >>
signs of pulmonary oedema
Why do you often see scratch marks with CKD?
Uremic pruritus
What do red cell casts suggest?
glomerulonephritis
What is acute tubular necrosis (ATN)? - acute tubular injury (ATI)
Lesser known functions of the kidneys
- activation of Vit D
- metabolism of insulin
*
What are the causes of CKD?
could be systemic; diabetes mellitus, hypertension, hyperlipidaemia
chronic damage following renal diseases
autoimmune, e.g. SLE, Goodpasture’s
genetic; polycystic kidney disease
What is the goal of CKD care?
- prevent cardiovascular problems
- prevent ESKD
- prevent complications of CKD
- prevent dialysis
When to refer to a specialist? Re GFR
if GFR <30ml/min/1.73 m2
Sustained decrease of GFR of 25% or more
What does the Cockcroft-Gault formula measure, and when is it used?
- Preferred method for estimating renal function or calculating drug dosages in patients with renal impairment e.g. elderly or extremes of muscle mass.
- Estimate of CrCl
(NB> use ideal weights for obese px)
Name some potentially damaging Kidney drug groups
- ACEIs, ARBs,
- PPIs
- diuretics
- antibiotics
- NSAIDs
- Lithium
What’s the relationship between Metformin and CKD?
Metformin should be
avoided if eGFR
below
30ml/min/1.73m2
Which drugs might need dose reduced with CKD?
- beta blockers
- digoxin
- allopurinol
- opioids
What are the first line antihypertensives for CKD?
ACEI, ARBs, and direct renin inhibitors
Managing BP with CKD
NICE BP targets
CKD + NO diabetes
120-139/ <90mmHg
CKD + diabetes and people with ACR >70mg/n/mmol
120-129<80mmHg
If uncontrolled hypertension in CKD then add:
non-dihydropyridine CCB
e.g. diltiazem
- If oedema consider loop diuretic
What diuretics can you use in severe CKD?
Loops
(Thiazides only effective to GFR 20-25 ml/min)
+ remember can be used with Kidney stones
Why do you get metabolic acidosis with CKD? And what’s the treatment?
Due to increasing inability of distal convoluted tubule to excrete hydrogen ions
Tx: Oral Sodium Bicarbonate
What do you get atherosclerosis with CKD?
Associated with
abnormal lipid and
carbohydrate
metabolism, especially
in diabetics.
tx: Consider statins,
antiplatelets/
anticoagulants
What is renal mineral bone disorder?
aka Renal Bone Disease
aka Renal Osteodystrophy
This involves softening of the bones due
to decalcification and deposition of
calcium at various sites around the body.
The mechanisms involved are complex.
What level of Hb is anaemia?
Hb < 11 g/dL
Symptoms of uraemia?
Dermatological – itching, skin pigmentation
Gastrointestinal – nausea, anorexia (ondansetron,
metoclopramide)
Neurological – peripheral neuropathy, restless
legs (clonazepam, pramipexole, gabapentin),
cramps (quinine).
(antihistamines, emollients, Eurax, ondansetron, etc)
Which coexisting illnesses increase risk of CKD?
Diabetes,
Hypertension
CVD,
structural renal tract disease
multisystem diseases that affect the kidneys, eg. SLE
Albuminuria; role in CKD diagnosis?
Persistent increased protein in the urine (two positive tests over 3 or more months) is the principal marker of kidney damage, acting as an early and sensitive marker in many types of kidney disease.
What is ACR?
albumin concentration (mg) / creatinine concentration (g)
Albumin-to-creatinine ratio (ACR) first method of preference to detect elevated protein
What ACR level would indicate CKD?
30-300 mg/g for >3 months
(relative to young adult level)
Tips for diagnosing CKD
- if GFR >60 ml/min/1.73m2, then not CKD unless evidence of kidney damage.
- features must be present on at least two occasions and for more than three months.
Investigations for CKD
U & E, glucose
24-hr creatinine clearance; determine level of renal failure
Casts; glomerulonephritis
Red Cells; can come from anywhere
Check < Calcium, phosphates
CKD definition (albumin level, GFR)
albumin excretion of > 30mg/ day
or
GFR <60 ml/min/1.73 m2
for >3 mtns
** damage needs to be >3mtn to distinguish CKD from acute kidney disease.
Definition of CKD
Abnormalities of kidney function or structure present for more than 3 months.
Includes all individuals with markers of kidney damage or those with an eGFR of less than 60 ml/min/1.73m2 on at least 2 occasions 90 days apart
(with or without markers of kidney damage).
What’s another name for Post streptococcal GlomeruloNephritis?
acute proliferative glomerulonephritis
Periorbital puffiness and difficulty in putting on rings is a sign of what?
nephrotic syndrome
What drugs commonly damage the kidneys?
NSAIDs,
lithium,
some antibiotics,
bisphophonates
Minimal Change Disease - what’s the story
podocytes damaged, most common cause of nephrotic syndrome with children.
Proteinura and oedema of MCD can develop very rapidly- almost overnight
Glomerulonephritis (GN) accounts for up to 1/3 of patients requiring dialysis.
What are the cardinal symptoms?
- proteinuria
- haematuria
- urinary casts
Diabetes; what is the initial sign of renal involvement?
microalbuminuria
.. progressing to >> proteinuria or even nephrotic syndrome.
*** Note: diabetic nephropathy usually suffer from diabetic retinopathy or neuropathy. Look for this! ***
Most important management of diabetes
very aggressively lower blood pressure (ACE inhibitors, ARBs)
Excellent glycaemic control
stop smoking
APKD - Adult polycystic kidney disease
General info
(picture needed)
Most common inherited condition to affect the kidneys, usually presenting in adult life.
Renal cysts can bleed, create haematuria, loin pain and become infected. Cysts enlarge and renal function declines.
Dx: FH, clinical features, CT, ultrasonography.
Tx:control BP, antibiotics, painkillers, dialysis, transplant
