This document provides an overview of acute kidney injury (AKI), including definitions, causes, presentations, investigations, and management. It discusses the most common causes of AKI as being acute tubular necrosis, prerenal disease, and acute injury superimposed on chronic kidney disease. It also reviews peritoneal dialysis peritonitis and includes summaries of 6 case examples involving AKI, peritonitis, myeloma, vasculitis, and renal artery stenosis. Key points for managing renal patients are highlighted such as the importance of a baseline creatinine and treating peritonitis in a time-critical manner.

2. Nephrology!!

3. Objectives
 Basics of AKI
 Renal causes of AKI
 PD peritonitis
 A few interesting cases
 Things to consider for a renal patient

4. Acute Kidney Injury
 Increase in SCr by 26.5 umol/l within 48 hours (or)
 Increase in SCr to X1.5 times baseline, which is known or
presumed to have occurred within the prior 7 days; (or)
 Urine volume of <0.5 ml/kg/h for 6 hours
Discretion is required to determine the clinical significance of a
diagnosis of AKI
Clinical utility is not great, have greatest utility in epidemiologic
studies / clinical studies

5. Effect of AKI on odds of death
Chertow GM et al J Am Soc Nephrol 2005

6. Things that don’t diagnose
AKI
 Urea – not specific
 eGFR – used in Chronic Kidney disease
 Electrolytes disturbance
 A result of AKI, but not specific

8. Frequent causes
 ATN — 45 percent
 Prerenal disease — 21 percent
 Acute superimposed on chronic kidney disease (CKD) — 13
percent (mostly due to ATN and prerenal disease)
 Urinary tract obstruction — 10 percent (most often older men
with prostatic disease)
 Glomerulonephritis or vasculitis — 4 percent
 Acute interstitial nephritis — 2 percent
 Atheroemboli — 1 percent

9. Presenting Symptoms
• Diminished kidney function
– Edema, hypertension and reduced urine output
• Prolonged renal failure/ uremia
– Weakness, fatigability, anorexia, vomiting, change in mental status and
seizures
• Associated systemic symptoms and signs help with diagnosis
– Eg: fever, arthralgia, pulmonary lesions suggest systemic disease such as
vasculitis or lupus
• Flank pain
– Obstruction, infarction or infection
• Anuria
– Severe shock, bilateral obstruction

10. Investigations
 FBC/ UEC/ Calcium/ Phosphate/ CRP/ LFT/ cultures/ CK
 Urinalysis, Urine PCR, casts/ dysmorphic RBCs
 C3, C4
 Autoimmune screen: ANCA, anti- GBM antibody, ds- DNA, ASLO titres, Anti-PLA2R
 Myeloma screen: Free light chains, QUEPP, urine for BJ proteins
 Hepatitis/ HIV serology
 Renal tract ultrasound + Dopplers
 Renal biopsy

11. Urinalysis

12. Management
 Volume depletion- (pre-renal)
 IV fluids
 CSL theoretically preferred in acidosis
 Consider IV bicarbonate if severely acidotic but not
overloaded
 Volume overload
 Can occur from aggressive correction of dehydration
 Use diuretics dialysis if no response

13. Management
 Post renal cause: obstruction needs to be relieved
asap the more the delay, the greater the chance of
poor recovery
 Intrinsic renal cause: Rx is complex; largely depends
on underlying causes which is usually determined on
renal biopsy

14. Management: Indications for urgent
dialysis
Life threatening fluid and electrolyte abnormalities:
 Refractory hyperkalemia (ECG)
 Refractory acidosis
 Acute pulmonary edema
 Uremic encephalopathy
 Uremic pericarditis

15. Acute Tubular Necrosis
 Most common form of intra- renal AKI in hospitalized patients
 Sustained period of ischemia/exposure to nephrotoxics
 May resolve over 1-4 weeks or may result in permanent ESKD
depending on duration and severity of insult
 U/A: muddy brown casts
 Aim MAP of 65mmHg
 No benefit of low dose dopamine
 Diuretics do not improve outcome
 ATN + multi- organ failure 50- 80% mortality rate!

16. Contrast Induced
Nephropathy
 Rise in creatinine 24-48 hours post contrast
 Usually non- oliguric AKI
 Renal recovery occurs in 1-2 weeks
 GFR <60 at high risk
 Prevention better than cure: IV hydration, withhold
nephrotoxics (metformin, NSAIDS, ACE), NAC controversial
 Use of low osmolar/ iso-osmolar/ non ionic contrast
 MRI: gadolinium contrast NSF if GFR <40

17. Nephrotic Syndrome
 Proteinuria (3.5gm/day), hypoalbuminemia, edema,
dyslipidemia
 Types: MCD, FSGS, membranous
 Important secondary causes: DM, myeloma, SLE, drugs like
NSAIDS/ palmidronate, malignancie, amyloidosis, HIV
 Renal function may be normal
 Urine dipstick: protein +++, NO blood check urine PCR/ACR
 Usually commenced on diuretics and ACEI with O/P follow up +
renal biopsy to determine cause
 Idiopathic causes are usually treated with immunosupression

18. Nephritic syndrome
 Hypertension, edema, oliguria +/- hematuria
 Urine: RBC +++, protein +/-,
 Entity of RPGN (urgent evaluation and treatment)
 ANCA vasculitis
 Anti GBM antibody (Renal failure with pulmonary
hemorrhage)
 Other causes
 SLE, Post Strep GN, IgA nephropathy, HUS/TTP

19. Multiple myeloma
 Elderly age group
 Anemia, hypercalcemia, renal failure, bone pains/ susceptibility
to fractures usually vertebral
 LFTs may show raised globulins
 Discrepancy between urine PCR and ACR
 Cast nephropathy most common: from deposition of light
chains in the tubules
 Bone marrow biopsy + renal biopsy
 Rx: Chemotherapy, dialysis

20. PD Peritonitis
 Leading complication of PD; each episode damages the
membrane
 Morbidity and sometimes mortality
 Usually due to technique failure
 Cloudy effluent +/- abdominal pain +/- systemic symptoms
 Send PD fluid for MCS and gram stain (important for yeast
detection  anti fungal)
 Swab exit site as needed
 WCC >100 with >50% PMN is diagnostic

21. PD peritonitis
 Treatment is time critical
 Empirical IP antibiotics: Vancomycin 2gm + Gentamicin
80mg
 Further Abx therapy depends on organism cultured
 Most common: coag negative Staphylococcus
 S.aureus and P. aeroginosa: severe peritonitis
 Single gram negative rods: due to contamination/ exit site
infection/ transmural migration from constipation/ colitis

22. PD catheter removal
 Refractory peritonitis: failure to respond to therapy
within 5 days
 Fungal peritonitis
 Multi- organism peritonitis indicates bowel
perforation  urgent surgical review

23. Case 1
 76 year old man with h/o DM/ HTN
 Presented to ED with epigastric painCT abdomen
NAD
 Baseline creatinine 80
 Cardiogenic shockAMIsalvage angioplasty
 A week later creatinine up to 750

24. Xray

25. Case 2
 54 yo man, ESKD secondary to oxalate nephropathy,
Crohn’s disease- 2 prior abdominal surgeries
 On PD- 3 years
 Presented with cloudy bags and abdominal pain
 PD fluid grew: Initially Coagulase negative Staph
 Empirical IP abx
 Subsequent PD culture report: Serratia + Pseudomonas

26. Xray

27. Case 3
 44 yo man, sent in by GP with creatinine of 1100
 No prior blood tests to compare
 Catheter sample ++ protein, + blood
 Referred to renal from peripheral centre
 Initial thoughts?
 On arrival gross hematuria

28. USG

29. Case 4
 68 yo man, referred by GP for raised creatinine of 256
 B/g of DM-2 on insulin
 Self medicating with prednisolone for the past 3 weeks
for ‘headaches’. No features of sepsis.
 Vague h/o ?GCA several years ago; no biopsy; Rx with
prednisolone for 2 years
 Within 4 days, creatinine rose to 412
 Clinically euvolemic

30. Case 4
 Urine dipstick: blood +++
 Urine microscopy: RBC >100, PCR: 65 (<13)
 Complements: normal
 QUEPP: negative
 ANCA: 7 (<4 units)
 P- ANCA +ve , ELISA: Myeloperoxidase +Ve
 Renal biopsy: Pauci immune cresenteric GN
 Rx with steroids and cyclophosphamide with good
effect. Creatinine now stable at 200.

31. Case 5
 72 yo lady presented with N+V and 5 kg weight loss 10
days post endoscopy for investigation of anemia
 Creatinine 474 (baseline 5 months ago- 110)
 Initially Rx with IV hydration, anti-emetics fluid
overloaded creatinine increased to ~600
 Urine: ++ protein, ++ blood
 PCR: 500
 Complements: Normal

32. Case 5
 Renal biopsy: Cast nephropathy
 Positive serum and urine paraproteins
 Bone marrow biopsy confirmed myeloma
 Currently on hemo- dialysis and chemo therapy
 Poor recovery of renal function

33. Case 6
 68 yo man with known b/l renal artery stenosis
 Chronically atrophic left kidney
 Stent to right renal artery 6 years ago
 Presented with acute onset anuria for 18 hours
 Creatinine- baseline of 200  588
 What next?

34. The renal patient
 No IVCs in the cubital fossa
 In AKI; dipstick urine
 A baseline creatinine is always very useful
 Sudden onset anuria usually implies a post renal cause scan
and usually call urology. Get a non contrast CT KUB if no USG
available
 PD peritonitis: treatment is time critical, usually don’t need
admission
 Dialysis and transplant patients can get unwell pretty quickly-
low threshold to call HDU/ICU
 Initial Rx for most conditions in dialysis patients works as for
anyone else; just watch for fluid overload

35. Nuances
 No need to worry about contrast if patient already
established on dialysis
 ESKD usually used to refer to patient already on
RRT
 Renal dose medications; bear in mind interactions
with tacrolimus/ cyclosporine
 We rarely withhold immunosuppressant medications
for Tx patients

36. Thank you!