Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Nephrology > Acute Kidney Injury > Flashcards

Acute Kidney Injury Flashcards

1
Q

What is the definition of ARF?

A

When renal function SUDDENLY decreases
That the patient can’t maintain fluid and electrolyte balance
And can’t excrete nitrogenous waste

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What lab abnormalities help diagnose ARF?

A

Acute increase in creatinine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the clinical manifestations of ARF?

A
  1. Oliguria & fluid overload
    • pulmonary oedema > dyspnoea
  2. Uremia
    • vomiting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the 3 main causes of ARF? Which are more common amongst these?

A
  1. Pre-renal
  2. Intrinsic
  3. Post-renal

Pre-renal and intrinsic causes make up 90% of all ARF, post-renal only 10%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the pre-renal causes of ARF?

A

Perfusion or volume depletion

  • Perfusion: CCF, malignant/uncontrolled HTN
  • Volume depletion: dehydration, vomiting, diarrhoea, overdiuresis, sepsis, other shocks, third spacing of fluid from severe pancreatitis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the intrinsic causes of ARF?

A

ATN
Glomerulonephritis
Interstitial nephritis - drugs e.g. antibiotics, analgesics & NSAIDs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What specific group of antibiotics can cause ARF?

A

Aminoglycosides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the post-renal causes of ARF?

A

Urinary obstruction can be a result of stones, BPH, strictures.
Infection - pyelonephritis from ascending urinary tract infection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What lab results suggest ARF?

A
  1. Electrolytes - hyperkalemia, hyper phosphatemia, hypocalcemia
  2. Increased urea and creatinine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Sepsis and ARF - how will the patient present?

A

Sepsis: fever, toxic-looking
ARF: acute rise in creatinine, rise in BUN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Dehydration and ARF - how will the patient present?

A

Dehydrated: thirsty, dry mucous membranes, altered mental status
Cap refill time increased, reduced skin turgor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Shock and ARF - how will the patient present?

A

Shock: hypotension and tachycardia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Acute glomerulonephritis results in increased urinary sodium. T/F?

A

True - acute GN affects concentrating ability > dilute urine > urinary Na high (Na goes where water goes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

ATN results in high urinary Na. T/F?

A

True - ATN, like acute GN affects concentrating ability > dilute urine > high urinary Na

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Urinary Na is normal, <20mmol/L, differentials are narrowed down to which:

  1. Acute tubular necrosis
  2. Acute GN
  3. AIN
  4. Pre-renal azotemia
  5. Urinary tract obstruction
A

If urine Na is normal, concentrating ability is unimpaired, options 3 - 5 are possible differentials.
Only ATN and acute GN will affect concentrating ability resulting in dilute urine with high urinary Na concentration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Urinary tract obstruction definitely results in normal urinary Na as concentrating ability is not affected. T/F?

A

False: urinary Na in the setting of urinary tract obstruction is variable. Concentrating ability may or may not be affected.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Urine osmolality >500mOsm/kg, differentials narrowed down to which:

  1. ATN
  2. Acute GN
  3. AIN
  4. Pre-renal azotemia
  5. Urinary tract obstruction
A

Urine osmolality >500mOsm/kg means urine is concentrated and concentrating ability is NOT affected, leaving options 3 and 4 possible.

  1. ATN 2. Acute GN affect concentrating ability, resulting in dilute urine > urine osmolality becomes <350.
  2. Urinary tract obstructed body will try to get rid of obstruction by peeing out more dilute urine frequently > low osmolality > less than 350mOsm/kg.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the causes of urinary tract obstruction within the lumen?

A

Stones
Crystalluria
Tumour
Papillary necrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the causes of urinary tract obstruction WITHIN the wall?

A

Neurogenic bladder (spasm)
Urethral stricture
Bladder neck stenosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the causes of urinary tract obstruction outside the wall?

A

Cancer of surrounding structures i.e. colon, cervix, uterus, prostate
Constipation
BPH
Retroperitoneal fibrosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Hx/Ex/Ix suggest post-renal cause of ARF > where might the urinary tract obstruction be? 3 places.

A

Within the lumen e.g. calculi
Within the wall e.g. neurogenic bladder
Outside the wall e.g. cancer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the clinical history and examination signs and symptoms that are relevant for ruling in post-renal cause of ARF?

A
  1. Haematuria - cancer
  2. Distended bladder - urinary tract obstruction
  3. Enlarged prostate on PR exam - obstruction
  4. LUTS - obstruction
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are LUTS?

A

Storage and voiding problems

  • Urgency, incontinence
  • Frequency, hesitancy. straining, dribbling
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Urine microscopy shows muddy brown casts - what is your diagnosis for the patient’s cause of ARF?

A

Acute tubular necrosis

Muddy brown casts are characteristic of ATN and are a type of granular casts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Intrinsic renal causes of ARF

A

By anatomy

  1. Glomerular - Acute GN
  2. Tubules - ATN
  3. Interstitium - AIN
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Acute interstitial nephritis is caused by?

A

Mostly nephrotoxic drugs e.g. antibiotics penicillin, aminoglycosides; analgesics, NSAIDs, PPIs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Urine osmolality is high >500mOsm/kg, what are the possible causes of ARF?

A

Things that don’t involve glomerulus:

  1. Pre-renal causes
  2. AIN (instrinsic)
28
Q

Urinary Na is high >20mmol/L, what are the possible causes of ARF?

A

Urine is diluted > concentrating ability affected >

  1. Not pre-renal cause
  2. Intrinsic - ATN and acute GN
  3. Post-renal - obstruction may or may not affect urinary Na levels
29
Q

What are the causes of acute GN?

A

Post-strep GN

IgA nephropathy - immune attack on glomerulus

30
Q

Urine microscopy shows WBC casts and eosinophilia what is the cause of ARF?

A

WBC casts + eosinophilia > immunological reaction going on > attack kidneys > IgA nephropathy (intrinsic cause); immune reaction to strep antigens > post strep GN

31
Q

Urinary sodium is >20, what are the causes of ARF?

A

> 20 abnormal > unable to concentrate urine > ATN and acute GN

32
Q

Components of urinalysis and what they mean

A 
pH
Specific gravity - concentration
Glucose - diabetes
Haemoglobin
Myoglobin - rhabdomyolysis
33
Q

A patient with ARF/AKI has a normal urinalysis with minimal cells and blood and no casts, what are the causes of ARF?

A

Pre-renal causes - volume depletion

Post-renal causes - obstruction

34
Q

What do the different cells seen under urine microscopy suggest about the cause of ARF?

  1. Granular casts + epithelial cells
  2. RBC casts
  3. WBC casts + eosinophils
A
  1. Granular + epithelial cells - ATN
  2. Acute GN
  3. AIN - caused by IgA nephropathy, post-strep GN
35
Q

What urine investigations to do for ARF?

A
  1. UFEME - urine full examination microscopy elements

2. Urine Na and osmolality

36
Q
  1. Urinary Na+ low and osmolality high - cause of AKI?

2. Urinary Na+ high and osmolality low - cause of AKI?

A
  1. concentrated urine - pre-renal causes of AKI

2. tubular injury - ATN

37
Q

How to differentiate ARF from CRF in FBC Ix?

A

CRF - will have anaemia > low Hb count
ARF - no anaemia > normal Hb count
Patients with CRF often have anaemia due to reduced erythropoietin synthesis by kidneys

38
Q

Eosinophilia on FBC in a patient with ARF.

A

Eosinophilia > immune > AIN caused by IgA nephropathy etc.

39
Q

Diagnosing AKI > did a FBC > what parameters are impt?

A

FBC

  1. Anaemia - CRF instead of ARF
  2. Eosinophilia - AIN (immune)
40
Q

What is the basic physiologic basis of using BUN:creatinine ratio to determine the cause of ARF?

A
  1. Urea is reabsorbed by tubules
  2. Creatinine is NOT reabsorbed
  3. In pre-renal causes the tubules are working so urea will be reabsorbed a lot, resulting in high urea content in the blood and high BUN:creatinine ratio of >100:1.
  4. When the tubules are affected, such as in intrinsic renal damage, urea is not reabsorbed and the ratio falls to <40:1.
  5. Ratio between 40:1 and 100:1, it can be normal renal function or post-renal cause of ARF.
41
Q

What bloods to do for ARF?

A
  1. FBC
    • Hb (anaemia - CRF)
    • Eosinophilia (Acute IN)
  2. CKMM (rhabdomyolysis)
  3. Electrolytes/urea/creatinine
    • Urea > crea
42
Q

Diagnosing AKI > did a FBC > what parameters are impt?

A

FBC

  1. Anaemia - CRF instead of ARF
  2. Eosinophilia - AIN (immune)
43
Q

What are the 3 KDIGO (indigo) criteria for diagnosing AKI?

A
  1. Rise in serum creatinine by more than 50% in the last 7 days
  2. Increase in serum creatinine by >0.3mg/dL or >26.5umol/L for 48 hours
  3. Oliguria <0.5mL/kg/hr for more than 6 hours
44
Q

What are the 3 stages of AKI defined by the KDIGO criteria?

A

Stage 1:

  1. rise in serum creatinine by 1.5-1.9-fold
  2. urine output < 0.5mL/kg/hr for 6-12 hrs

Stage 2:

  1. rise in serum creatinine by 2-to 2.9 fold
  2. urine output < 0.5mL/kg/hr for more than 12 hrs

Stage 3:

  1. rise in serum creatinine by 3-fold
  2. urine output < 0.5mL/kg/hr for more than 48 hrs
  3. Need replacement therapy
45
Q

What is the absolute increase in Cr considered as AKI?

A

> 44umol/L

46
Q

What can affect creatinine levels falsely?

A
  1. Muscle mass
  2. Rhabdomyolysis
  3. Starvation
  4. Nutrition & diet (protein intake)
  5. Patient on antibiotics Bactrim (increased serum creatinine levels)
47
Q

What is one type of AKI that has almost as high a mortality rate as ESRD?

A

Acute-on-chronic kidney disease

48
Q

What are the types of dialysis treatments for AKI?

A

PD
HD
CRRT: continuous renal replacement therapy (used more in ICU settings)

49
Q

Who is at risk of AKI?

A
  1. Polypharmacy - NSAIDs, aminoglycosides, ACE I, lithium, anti-fungals, diuretics
  2. Malignancy and chemotherapy
  3. Organ failure: liver failure, respiratory failure and heart failure
  4. Hypovolaemia and dehydration
50
Q

What is one serious infective cause of AKI?

A

Sepsis

51
Q

In the ED setting, someone’s come in with suspected AKI what are the most urgent things to know?

A
  1. Volume/fluid status - does this person need urgent resuscitation?
  2. What is their baseline renal function?
  3. Is it an acute kidney injury or acute-on-chronic picture?
  4. What medications are they taking?
  5. Urine sediment test
52
Q

Pre-renal causes of AKI: apart from volume depletion what’s the other major category?

A

Renovascular disease

  • Renal artery stenosis
  • Renal artery thrombosis
53
Q

UFEME shows haemoglobin in urine - what is this patient’s cause of AKI?

A

Rhabdomyolysis

54
Q

UFEME shows granular casts - what is the cause of AKI in this patient?

A

Granular > tubular > ATN

55
Q

UFEME shows red cell casts - what is the cause of AKI in this patient?

A

Acute GN

Glomerulus - vascular

56
Q

UFEME shows eosinophils and white cell casts - what is the cause of AKI in this patient?

A

AIN

Eosinophils - two-headed nucleus cell

57
Q

UFEME shows that urine osmolality is high and urine Na+ concentration is low > what is the cause of AKI in this patient?

A

Osmolality high > able to concentrate urine
Na+ low > tubular reabsorption okay
> 1. pre-renal 2. Acute GN

58
Q

UFEME shows that urine osmolality is low and urine Na+ concentration is high > what is the cause of AKI in this patient?

A

Osmolality low > unable to concentrate urine
Urine Na+ high > tubular reabsorption of water and Na+ impaired
> 1. post-renal 2. Acute IN 3. Acute TN

59
Q

When evaluating a patient with suspected AKI, the FBC shows eosinophilia > what is the cause of AKI?

A

Acute IN

60
Q

What test to order if you suspect the patient has AKI because of rhabdomyolysis?

A

CK-MM

61
Q

Patient with suspected AKI. Urea-creatinine ratio of 50:1 what is the cause of AKI?

A

Pre-renal, probably dehydration
Dehydration causes increased urea reabsorption resulting in increased serum urea levels. > 10:1 suggest dehydration as a cause.

62
Q

What are the things to screen for in an ‘autoimmune screen’ for a patient with suspected AKI to determine the cause?

A
  1. Anti-glomerularBM antibody
  2. ANCA
  3. ANA
  4. Complement levels
  5. Anti-dsDNA
63
Q

What imaging is useful to rule out/in urolithiasis as a cause of AKI?

A

Renal U/S
KUB (X-ray)
or CT KUB

64
Q

Other than visualising obstruction, why is a renal ultrasound useful in the setting of AKI?

A

If see small atrophied kidneys, suggests that patient also has chronic renal disease > acute-on-chronic picture.

65
Q

Renal ultrasound shows dilated calyces, ureters in a patient with AKI. What is the cause of his AKI?

A

Renal U/S shows hydronephrosis

Obstruction is the cause of his AKI

66
Q

Patient comes in with suspected AKI > after bladder catherization his condition improves. What was the cause of his AKI?

A

Urethral obstruction

Nephrology (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions