18 - Clinical problem solving: Renal Failure Flashcards
Diabetes…
Diabetes is the most common cause of nephrotic syndrome and these can be involved in both CKD and AKI
What is kidney failure?
- reduction in gfr and eleveated creatinine
50 years vomiting, unwell, diarrhoea diabetes HT > What should you ask?
Fever - hot, cold, shaky Reduced urine output? Infection? Cough, skin, tummy? Pain? Shortness of breath? Fluid overload
50 years vomiting, unwell, diarrhoea diabetes HT > acute or chronic?
Can’t tell
Suspicious of AKI; vomiting and diarrhoea (tend to be dehydrated)
> examination
What would an examination include?
- afebrile
- looks unwell
- BP 90/60 (Hypotensive)
- dry skin
- clear chest
- jvp 0cm
Other than jvp what else could you look at to give an indication of fluid levels?
- mucus membranes (mouth breathers will be dry)
- skin turgor (reduced in elderly)
What should JVP be?
+1/2cm
If 0 or less then they are intravascularly dry and dehydrated
Now knowing more info are they more likely to have AKI or CKD
Acute
- they are dehydrated
- hypotensive
Likely to be a pre-renal AKI
What lab tests would you do?
sodium k+ Cl glucose creatinine urea
What other blood tests might you do to help tell if it is acute or chronic?
- ESR (RBC sedentary rate - increases in ALL renal failure due to inflammation)
- HB!
- calcium (initially low)
- phosphate (increases due to PTH)
What does normal HB suggest?
ACUTE
Acute renal injury?
AKI is acute deterioration of kidney function over a short period of time. Is usually reversible. Often associated with other illnesses. Often oliguria.
Most causes of AKI are…
70% are pre renal
Pre-renal AKI
- hypoperfusion of kidneys often
> bleeding, sepsis, dehydration, heart failure
> some progress into intrinsic renal damage via Acute Tubular Necrosis
Renal AKI
- mostly ATN via pre-renal but also toxins and drugs (nephrotoxins, NSAIDs, contrast!!,
Besides ATN what are other causes of intrinsic AKI?
Rapidly Progressive Glomerulonepheritis (can also cause CKD)
Rapidly progressive glomerulonephritis?
Is where there is rapid inflammation of the glomeruli. Often results in both blood and protein in the urine, often HYPERTENSIVE, see crescents in the glomeruli on biopsy and red cell CASTS
- often caused by vasculitis or bacteria
What is the best test for post-renal AKI?
Renal us (blockage - hydronephrosis and kidney size) > most people who come in with kidney failure get a renal US
Will palpating the bladder be useful to diagnose post-renal AKI?
Only tells you if there is a blockage at the urethra as bladder will be dilated. Doesn’t tell you anything about anything more proximal to the bladder
Post renal biggest symptom?
Usually not peeing at all
Will urine volume be useful to diagnose post-renal AKI?
Will be reduced/oliguric in everyone with AKI so no
Will palpation of the kidneys be useful to diagnose post-renal AKI?
No not possible
Same diabetic patient but hypertensive
If hypertensive want to look to see if the patient is fluid overloaded - odema/pitting, JVP distension, water in the lungs and crackles on auscultation, rapid pulse as heart has to work harder, HT,
What does a pericardial rub suggest?
Odema
What do you expect to see on the blood tests?
- high urea and creatinine
- high phosphate
- LOW ALBUMIN (nephrotic syndrome?)
- low HB
- how RBC cound and haematocrit
- high mean cell HB
- high WBC
If creatinine is 600 what do you expect GFR to be?
More than 6x normal. Very low kidney function > 6-10 mL/min
What are signs of CKD?
- malnutrition (nauseus, unwell, off food)
- fluid overload (reduced urine, HT, odema, pul odema)
- rash/itching
- pericardial rub (extrafluid in the pericardial cavity)
Why may you get itching and a rash in CKD?
Increased urea and phosphate
What blood tests will help to work out AKI from CKD?
K+
urea
creatinine
phosphate
All high as kidney not functioning properly
Why is phosphate increased in renal failure?
We normally excrete phosphate through urine. Vit D also decreases as kidney produces the enz that produces active vitd > reduced Ca absorbed in the gut. Stimulate parathyroid to pull ca and phosphate out of the bones. Extra-osseous calcifications (hyperphosphataemia)
What other tests might be helpful to confirm the diagnosis?
- kidney size (shrunken in most but NOT in diabetes)
- presence of an obstruction
What is normal HB?
130-150
What is normal kidney size
10-11 cm
What is the most likely cause of CKD
- 2/3s are caused by diabetes
- the rest are caused by HT and glomerular disease like glomerularnephritis
What is the best treatment to prevent deterioration of CKD?
BP treatment (reduces glomerular damage, pressure and protein excretion)
What BP treatment works the best in CKD
ACE inhibitors
- aim to stabilise kidney function
- prevent ang 1 > ang 2
> vasodilation of the efferent arteriole and reduces pressure in the glomerulus
Teaching points
- Blood tests for kidney failure
- Differentiate AKI and CKD
- Different types of AKI
- CKD progression
