How to approach AKI?

AKI  臨床三角：T-notes

History taking

• Previous lab data of renal function?
• Change in amount/color of urine?
• Newly developed symptoms?
• Underlying disorders?
• Medication?
• Procedures? 

PE

評估 Fluid status

• Vital sign: BP, HR, postural hypotension
• PE: 

腎衰竭相關的PE

• Consciousness: drowsy?
• Skin:
• Conjunctiva:
• Abdomen:
• Abdomen bruits
• DGE:BPH? Tarry stool?

AKI or CKD?

	AKI	CKD
Serum Cr level	Rapidly variable	Stationary
Anemia	Absence	Presence
Kidney	Normal size & variable echogenicity	Small size or increased echogenicity (Except: DM, myeloma, amyloidosis, PCKD)

Classification of AKI: T-notes

Step1. Post-renal AKI

Step2. 分辨Pre-renal AKI及Intrinsic AKI

Step3. 若為Intrinsic AKI,區分：

• Vascular
• Tubular
• Interstitial
• Glomerular

AKI後續安排的檢查與鑑別診斷

Step1. Post-renal AKI:

locations:Ureter, bladder neck, urethra(stone, striction)

PE: Distended low abd, CV angle knocking tenderness

Confirm: low abdomen sonograghy

Management: Release obstruction

• Urinary catheterization(single or Foley)記錄餘尿量！
• PCN

Step2. 區分Pre-renal AKI及Intrinsic AKI(PE+Lab)

Diagnostic Index	Prerenal	Intrinsic Renal
Fractional excretion of Na	<1%	>2%
UNa concentration(mmol/L)	<10(20)	>20
U /P of Creatinine	>40	<20
U/P of Urea nitrogen	>8	<3
Urine specific gravity	>1.020	~1.010
Urine Osmolality	>500	~300
Plasma BUN/creatinine	>20	<10-15
Renal failure index	<1	>1
Urinary sediment	Hyaline casts	Muddy brown granular casts

Cause of Pre-renal AKI:
1.Hypovolemia
2.Low cardio output
3.Altered renal systemic vascular resistance ratio
4.Renal hypoperfusion with impairment or renal autoregulatory responses
5.Hyperviscosity syndrome(rare) 

Step3. Cause of Intrinsic AKI：

1.Renovascular obstruction

2.Disease of glomeruli or renal microvasculature

3.ATN

Ischemia

Toxins

-Exogenous

-Endogenous

4.Interstitial nephritis

A.Allergic

B.Infections

C.Infiltration

D.Idiopathic

5.Intratubular deposition and obstruction

6.Renal allograft rejection

治療：

1. 去除造成急性腎衰竭的原因
2. 判定是否需要緊急透析治療
3. 維持電解質及水分平衡，避免併發症
4. 避免給予有腎毒性的藥物
5. 針對特定的腎炎給予治療

何時該緊急透析治療？

1. 藥物無法控制的高血鉀併心電圖變化
2. 藥物無法控制的急性肺水腫
3. 藥物無法控制的代謝性酸中毒
4. 尿毒性心包膜積水
5. 尿毒性腦病變

Reference

VGHKS腎臟科教學內容