Approach to pedal oedema

Question 1

What are 4 causes of bilateral pedal oedema?

Answer 1

1) CHF
2) AKI
3) Nephrotic syndrome (hypoalbuminemia)
4) Chronic kidney disease (advanced)
5) Chronic venous stasis

Question 2

What are 5 causes of unilateral pedal oedema?

Answer 2

1) Lymphoedema
2) Fracture
3) Haematoma
4) DVT
5) Infection (cellulitis, myositis)
6) Pretibial myxoedema

Question 3

What are the categories for the severity of oedema?

Answer 3

0+: no pitting oedema
1+: 2mm, disappears rapidly
2+: 4mm, disappears in 10-15s
3+: 6mm, >1min
4+: 8mm, >2min

Question 4

What are the 2 pathophysiological theories for fluid overload in nephrotic syndrome?

Answer 4

1) Underfill theory:
↓plasma albumin
→ ↓oncotic pressure for filtration
→ underfill activate neurohormonal system (ADH, RAAS, SNS, ANP, etc.)

2) Overfill theory:
Abnormal protein filtration → Na retention by ENaC
ENaC density controlled by aldosterone, ADH

Question 5

What are the clinical implications of the underfill theory of fluid overload in nephrotic syndrome?

Answer 5

Px with nephrotic syndrome are very sensitive to diuretics.
(give too much → AKI)

Question 6

What are the clinical implications of the overfill theory of fluid overload in nephrotic syndrome?

Answer 6

Nephrotic px respond better to amiloride (K+ sparing) + Frusemide (Loop) than just Frusemide monotherapy.

Question 7

What are the 2 aspects/parameters most important in assessing the prognosis of CKD?

Answer 7

GFR and Persistent albuminuria

Question 8

Why would px with CKD present with delayed fluid overload and thus have a delay in diagnosis?

Answer 8

Renal reserve
(eGFR remains stable for awhile as nephron number decreases because of reserves)

Question 9

What is the consequence of progressive loss of kidney function (estimated by eGFR)?

Answer 9

1) Reduced sodium filtration
2) Inappropriate suppression of tubular reabsorption

Question 10

What are the criteria for AKI?

Answer 10

1) Serum creatinine ↑ by ≥ 0.3mg/dL in 48hrs
2) Baseline serum creatinine ↑ by 50% in 7 days
3) Urine output < 0.5ml/kg/hr for ≥6hrs

Question 11

In severe AKI px, what is indicated when there is volume overload?

Answer 11

Dialysis support

Question 12

Does fluid overload manifest early or late in CKD?

Answer 12

Late

Question 13

True or false. Different diuretics are needed at different stages of a px with CKD.

Answer 13

True
Loop diuretics (GFR <30 ml/min)
Thiazide diuretics (GFR >30 ml/min)

Question 14

What are the stages in AKI?

Answer 14

3 stages:

1) SCr ↑ ≥26umol/L in 48hrs / ≥1.5-2 fold from baseline
+ <0.5ml/kg/hr for 6hrs

2) SCr ↑ ≥ 2-3 fold from baseline
+ <0.5ml/kg/hr for 12hrs

3) SCr ↑ ≥3 fold from baseline / ≥354umol/L / initiated on renal replacement therapy

+ <0.3ml/kg/hr for 24hrs / anuria for 12 hr

Question 15

What to ask in HPI for Hx taking in a px with pedal oedema?

Answer 15

1) Location
2) Urinary symptoms (poly/dys/oligo/hematuria)
3) Complications associated with excess fluid (eg. SOB, orthopnea, exertional dyspnoea, chest pain, palpitations)
4) Duration
5) Speed of onset
6) Intensity
7) Development pattern

Question 16

What are some systemic signs/symptoms to ask in Hx taking of a px with pedal oedema?

Answer 16

Facial: (Photosensitive) rash → SLE

Dermatological: Nails → autoimmune; Skin → Diabetic skin changes

Rheumatological: Joints and tendons

GI: Abdo pain → Henoch-Schonlein purpura

Neurological: Headache, seizure, cognition

Cardiac: Chest pain, palpitations

Question 17

What to ask in PMH for Hx taking in a px with pedal oedema?

Answer 17

1) Developmental Hx:
- solitary kidney? (FSGS)
- recurrent UTI? (reflux nephropathy)
- oedema? (minimal change, recurrent flares)

2) Pregnancy:
- Eclampsia
- Preclampsia
- De-novo GN

3) Accidents/Industrial mishaps:
- solitary functioning kidney

Question 18

What to ask in FH for Hx taking in a px with pedal oedema?

Answer 18

1) Any on CKD/dialysis
2) Any with autoimmune conditions

Question 19

What to ask for DH for Hx taking in a px with pedal oedema?

Answer 19

1) Any other chronic medications:
(eg. gold, penicillamine, hydroxychloroquine) (Minimal change disease)

2) Any OTC meds:
- actue interstitial nephritis
- nephrotoxicity

3) Any painkillers
- NSAIDS (nephrotoxic, Minimal change disease)

Question 20

What are the essential components of PE for a px with pedal oedema?

Answer 20

1) Lung: crepitations, reduced air entry
2) Heart: muffled heart sounds
3) Abdomen: ascites