1. Assessment of a Patient with Renal Disease
Dr Andrew Stein
Consultant in Renal and General Medicine, UHCW

3. Aims Anatomy Function Definitions History Examination Investigation
eGFR, CKD, Creatinine
History
Examination
Investigation
Likely Cases

4. Theme of Lecture: Basic Renal Principles
Assessment of a renal patient is not that complicated, need to be methodical ..
History, esp DRUGS
Examination, esp fluid state
Careful analysis of data
Exclusion of non-renal causes of symptoms
Re-assess patients daily (fluid state)
Some technical knowledge of dialysis/Tx etc

5. 7 Renal Syndromes AKI/AKI-CKD CKD-ESKD Nephrotic Syndrome
Nephritic Syndrome
Macroscopic haematuria
Microscopic haematuria
Hypertension

6. Anatomy

7. Surface Anatomy of Kidney

8. Nephron

9. Normal (Basics) Normal bladder size Normal urine output 300-400 mls
2L/day (urinate 8x in day, 1x/night ≈ 200 mls)
Oliguria < 400 ml/day
Oligo-anuria < 200ml/day
Anuria = zero ml/day

10. Kidney Size 12 (10-14) x 6 x 3 cm, 150g, retroperitoneal
How does that affect palpation?

11. Kidney Palpation Normal kidneys are not usually palpable
However, in some slim women, lower pole of the right kidney can occasionally be felt during deep inspiration
Large kidneys or masses can sometimes be felt

12. Function

13. Functions of Kidney Execretory (3) Metabolic/endocrine (4)
Excretion of waste products
Regulation of fluid state and electrolytes
Acid-base balance
Metabolic/endocrine (4)
Erythropoitein
Renin
Prostagladins
Activation of vitamin D
Consequences?

14. How Hard do 2 Kidneys Work?
25% cardiac output
GFR 120 mls/min =
~ 170 L /day
Ie blood volume passes through kidneys 35x/day

15. What is GFR? Why Measure it?
Glomerular filtration rate (GFR) is the rate (volume per unit of time) at which ultrafiltrate is formed by the glomerulus. Approximately 120 mL are formed per minute
We use GFR to estimate renal function
GFR α 1/creatinine, ie mathematically linked
Whats wrong with creatinine?
A normal creatinine concentration can occur even when the GFR has dropped by 50%
So creatinine is a fairly insensitive indicator of early renal impairement
Creatinine clearance and the assessment of renal function Nankivell, BJ. Aust Prescr 2001; 24: 15-7

16. CKD: GFR α 1/creatinine
Why GFR? Creatinine is rel specific but not very sensitive
120 mls/min
Creatinine
Creat GFR/% Do
Prepare Think
GFR
Creat <120 mcmol/L

17. Factors Affecting Serum Creatinine
GFR 60 mls/min
Age
Sex
Race
Muscle mass, useage
Diet
Drugs (eg?)
Creat 200
GFR 15 mls/min
Needs dialysis

18. Other Problems with Creatinine
Creatinine is an imperfect filtration marker, because it is secreted by the tubular cells into the tubular lumen, especially if renal function is impaired
The amount excreted exceeds the amount filtered by 10-20%
Fortunately this is balanced by a similar error in the chemical assay used which overestimates serum creatinine
So. Above 40 mls/min, the serum creatinine is accurate and good reflection of GFR. Under this level, it tends to overestimate GFR
Note: some drugs (such as cimetidine or trimethoprim) have the effect of reducing tubular secretion of creatinine. This increases the serum creatinine. These drugs are not often used now

19. Can Urea Be Used?
Measuring the blood urea concentration has limitations because, as well as renal impairment, it is increased by:
Increased protein metabolism (raised in catabolic states, and high protein diet)
Dehydration
Heart failure
RVD
Steroids
And, conversely, patients with renal impairment can have relatively normal blood urea concentrations if they are grossly malnourished and not eating

20. What About Tubular Function?
Although glomeruli control the GFR, damage to the tubulointerstitium is also an important predictor of GFR and progression towards renal failure
Renal tubules make up 95% of the renal mass, do the bulk of the metabolic work and modify the ultrafiltrate into urine
They control a number of kidney functions including acid-base balance, sodium excretion, urine concentration or dilution, water balance, potassium excretion and small molecule metabolism (such as insulin clearance)
Measurement of tubular function is impractical for daily clinical use, so we usually use the GFR to assess renal function

21. Definitions

22. Definitions of Normal Renal Function, Renal Impairment and Failure in AKI/CKD (Creatinine + GFR)
AKI/AKI-CKD
Creat >120 mcmol/L (normal range )
RIFLE (research mainly)
CKD
GFR < 120 mls/min (not used in AKI)
Renal impairment = CKD <60 mls/min (CKD3a)
Renal failure = <15 mls/min (CKD4)
Simple Definition of Renal Impairment
= Creat > 120 mcmol/L (AKI, CKD, or AKI-CKD)

23. CKD, eGFR, Creatinine and Symptoms
CKD1 – creat N (<120)
CKD2 – creat N (<120)
CKD3a – creat N-150
CKD3b – creat
CKD4 – creat >200
CKD5 – creat >400
When do symptoms start?
Who to refer?

24. Another Way of Describing Renal Impairment

25. Classification of AKI: RIFLE
RIFLE (Bellomo, 2004) Creatinine
R isk x baseline
I injury x
F ailure >3x
L oss (>4 wks)
E SRD (>3 mths)
Later: AKIN, KDIGO, NICE (2013)

26. History

27. Presenting Complaint Asymptomatic (routine bloods)
Symptoms of fluid overload:
SOB = pulmonary oedema, pulmonary oedema and pulmonary oedema
Don’t forget pulmonary haemorrhage, acidosis (Kussmaul’s breathing)
SOA
Other: itching, nocturia, ‘uraemia’
Urinary symptoms
Frothy urine (nephrotic syndrome)
Macroscopic haematuria (IgA?)

28. HPC Length of symptoms Associated symptoms
Eg onset of SOA, frothy urine and red rash on face (Diagnosis ..?)

29. Urinary Symptoms (Surgical)
Ask patient to describe urination (prostate)
UTIs (reflux nephropathy)
Loin pain
“I cannot pass urine” (anuria)
Macroscopic haematuria

30. Anuria V rare Only 3 causes Obstruction Vascular catastrophe
Severe acute glomerulonephritis

31. Macroscopic Haematuria
Recurrent visible haematuria
Age > 40 years, presume neoplasia
Smoking
UTI/stones or other urological disorders
Occupational exposure to chemicals or dyes
Pelvic irradiation
Excessive analgesic use
Cyclophosphamide

32. PMH DM (esp DM2) Stones/UTIs Prostatic disease
Autoimmune disease (SLE)
Neoplasia (pelvic, myeloma)
Atheroma (RVD)
Previous AKI

33. SH Smoke (RVD) Alcohol (IgA)
IV drugs / sexual orientation (Hep B, Hep C, HIV)
Home set-up (dialysis etc)

34. FH
PCKD (first case?)
Rare (eg, Alports, other hereditary nephritis, thin basement membrane disease, nail-patella syndrome, cystinuria, hyperoxaluria)

35. Drugs + Allergies DRUGS DRUGS DRUGS NSAIDs (analgesic nephropathy)
ACEi-ARB
Lithium (chronic interstitial nephritis)
Chemotherapy
Prev drug allergies (eg .. ?)

36. Examination
General
Limited cardiorespiratory
GI+

37. General Examination “Observation is 90% of Medicine” Prof Dan Hoyte
Walk into the room (DM?)
Face (eg SCCs (Tx-related), SLE)
Hands (radial/brachial fistula)
Skin (excoriation)
Uraemic frost = deposition of white/tan urea crystals on the skin after sweat evaporation (v rare)
Pulse (sign of LVF)

38. Cardiorespiratory = Limited cardiorespiratory BP BP BP JVP JVP JVP
Auscultation (pericardial rub)
Pulmonary oedema (± pleural rub)
Sacral oedema
Leg oedema

39. GI+ Observation (state the obvious, eg .. ) Light palpation
Deep palpation
Liver
Spleen
Kidneys + Bladder
Bruits (epigastric, femoral)

40. Technical Signs (relating to HD, PD and Tx)
Dialysis catheter
AVF (radial/brachial)
PD catheter
Urinary catheter/nephrostomy
Tx scars
Tx-related problems (eg NODAT, BCC/SCC)

41. Investigation
Urine
Blood
Radiology + invasive

42. Urine Tests

43. Urine - MSU <5 WC <25 RC No casts (esp red cell) No growth
“Mixed growth”?
.. which UTIs to investigate?

44. Dipstick – Blood, WC, Glucose
Haematuria 2+ (ie microscopic) = ?
80% sensitive, 65-99% specific
Need? ..
Leucocytes 1+ ≠ UTI (need? ..)
Nitrites - produced when bacteria reduce urinary nitrates derived from amino acid metabolism
Glucose - usually appears in urine when serum glucose increases to > 10 mmol/L) and renal function is normal
Useful screening test, not diagnostic

45. Microscopic Haematuria – Who to Investigate
If associated with:
Stage 4 or 5 CKD
Worsening CKD
Significant proteinuria (PCR ≥ 50, ACR ≥ 30 mg/mmol (≥ 0.5 g/24h))
Uncontrolled BP ≥ 140/90 mmHg (3+ drugs)
Or unexplained microhaematuria following urological assessment where no cause was found

46. Dipstick - Protein
Detects albumin but not other proteins, such as immunoglobulin light chains (consequence? ..)
Like creatinine, his test is specific(ish), but not very sensitive for the detection of proteinuria
Ie, it becomes positive (1+) only when protein excretion exceeds 0.5 g/L (upto 0.2g/L is normal). This is quite a lot
Hence, concept of microalbuminuria developed

47. Dipstick – Protein (Other Problems)
Semi-quantitative categories on the dipsticks should be used with caution (esp ‘proteinuria’ = albuminuria)
Only a rough guide since
Albumin conc varies with urine volume, ie
Dilute urine underestimates degree of proteinuria
Concentrated urine may show ‘3+ proteinuria’
Different products

48. Proteinuria (quantification)
Eat 80g /day
Heavy proteinuria is the hallmark of glomerular disease
Normal = <0.2 g/L, ie <0.4g/day, if 2L urine
Or PCR <15 mg/mmol (ACR <3 mg/mmol)
PCR/100 ≈ g/24h
ACR 3-30 mg/mmol = microalbuminuria
Dipstick specific but not very sensitive (like creatinine)
Dipstick g/L g/24h PCR (ACR) 0 <0.2 <0.4g <15 (<3) Trace (ACR 30)
(ACR 70) low
mod nephrotic range
high nephrotic
v high

49. CKD/Proteinuria Classification (Again!)

50. Blood Tests

51. Blood - Biochemistry Sodium (135-145 mmol/L)
Potassium ( mmol/L)
Severe hyperkalaemia > 6.4 mmol/L
Urea (3-7 mmol/L)
Severe level >50 mmol/L
Creatinine ( mcmol/L)
Severe level >400 mcmol/L

52. Hyperkalaemia

53. Blood – Bone Biochemistry
Calcium ( mmol/L)
Phosphate ( mmol/L)
Alk Phos ( iu/L)
PTH (<4.2 pcmol/L)
Renal osteodystrophy? ..

54. Blood – Haematology Hb – anaemia WC - N Platelets – thrombasthenia
MCV? ..
?EPO if HB < 100 g/L)
WC - N
Platelets – thrombasthenia
Clotting - N

55. Blood – Immunology (‘Renal Screen’)
Immunoglobulins (A, G, M) (IgA nephropathy, myeloma)
Protein electrophoresis (myeloma)
Serum free light chains (myeloma)
ANA and dsDNA (SLE)
Complement factors (C3 and C4) (SLE)
Anti-neutrophil cytoplasmic antibodies MPO and PR3 (ANCA) (vasculitis)
Anti-glomerular basement membrane antibodies (AGBM) (Goodpasture’s Syndrome)
Anti-streptolysin O titre (ASOT) (post-infectious glomerulonephritis)
Angiotensin converting enzyme (ACE) (raised in sarcoidosis)
Cryoglobulins (mesangiocapillary GN)
Hep B, Hep C, HIV (GNs and safety of patients and staff, esp HD)

56. Radiology + Invasive Tests

57. Radiology – Renal Ultrasound
2 kidneys?
Prepare for biopsy
Obstruction (treatable)
Appearance
Size (chronicity)
Disparity size (RVD)
Scars (reflux nephropathy)
Very bright (HIVAN)

58. Radiology - Other KUB (if known to have radio-opaque stones)
CT-KUB (stones) is better CT
MRI
(MRA/CTA)
Treatments (eg nephrostomy, antegrade or retrograde)

59. Causes of CKD Small kidneys / idiopathic 30% Glomerular Disease
Primary (GN)
Secondary (eg DM 20%)
Renovascular Disease
Atheroma
Fibromuscular Dysplasia
Obstructive Nephropathy
Prostate (man)
Pelvic cancer (woman)
Tubulo-interstitial Disease
Drugs eg Analgesic Nephropathy, Lithium
UTI eg Reflux Nephropathy
Autoimmune eg Sarcoidosis
Congenital eg PCKD

60. Investigation – Specialised (Renal Biopsy)
AKI, normal sized kidneys,
no obvious cause = biopsy
CKD, normal sized kidneys,
Proteinuria (>1g/L = 2g/24h = ‘nephrotic range’), no obvious cause
Transplant dysfunction

61. Investigation – Specialised (Renal Angiogram)
Rarely performed (now always with a review to intervention)
Hypertension (RVD)
with poor BP control on 4 drugs
‘Flash’ pulmonary oedema
AKI in single (or single effective kidney)
Fibromuscular dysplasia

62. Likely Cases

63. Case One 47y year old Asian male
Presents 2 wks SOB and SOA, O/E fluid overload
DM2 2 years
IHD/CCF
Serum albumin 40 g/L
Urinary protein 0.15 g/L
1. Other information?
2. Diagnosis?

64. Case Two 35y old female Investigated for BP Creat 68 mcmol/L
FH grandfather died of kidney problem
O/E large liver? 2 large kidneys? (both?)
1. Next investigation?
2. Diagnosis?

65. Case Three 23 year old female 2 weeks SOA O/E SOA Serum albumin 25 g/L
Urinary protein 4.3 g/L
Creat 87 mcmol/L
1. Renal syndrome?
2. Diagnosis?

66. Case Four 67 year old Asian male PMH DM2 (20y), TURP
C/O 6 mths SOB, O/E fluid overload, R fem bruit
Creat 465 mcmol/L (198 mcmol/L, 2012)
Urinary protein 0.1 g/L
1. Next investigation?
2. Diagnosis?

67. Case Five 87y old male C/O tiredness ESKF (2009)
On CAPD (4 x 2L bags a day)
Creat 877 mcmol/L and stable
1. Other information?
2. Diagnosis?

68. Summary
Assessment of a Renal Patient is not that complicated, need to be methodical ..
History, esp DRUGS
Examination, esp fluid state
Careful analysis of data
Exclusion of non-renal causes of symptoms
Re-assess patients daily (fluid state)
Some technical knowledge of dialysis/Tx etc

69. Questions
Renalmed.co.uk Acutemed.co.uk