1. The Renal System:
History-Taking &
Urine Analysis
Clinical Skills
2013

2. Anatomy
 Gross structure – 2 adult kidneys approximately
150g each, lying retroperitoneally in the
abdominal cavity on either side of the vertebral
column at level of T12 – L3
 Renal vasculature – renal artery and vein
 Urine drains via pelvis of kidney into the ureters,
which cross over the pelvic brim to drain into
the bladder (NB pelvi-ureteric and vesico-
ureteric junctions – note VUR associated with a
congenital defect)
 Bladder, trigone, urethra, sphincter

3. Functions of the Kidney
 Controls volume, osmolarity and acid-
base balance of plasma and EC fluid, as
well as the level of electrolytes
 Recovers small molecules filtered by the
nephron, such as amino acids and
sugars
 Excretes nitrogenous waste from protein
metabolism, mainly urea, uric acid and
creatinine

4. Functions of the Kidney (cont)
 Excretes toxic metabolites and excess
electrolytes and water
 Maintains red cell production by the
secretion of erythropoietin
 Maintains calcium balance by production
of the active form of Vitamin D
 Controls blood pressure

5. SPECTRUM OF DISEASE
 Congenital abnormalities
 Interstitial nephritis
 Glomerulonephritis
 Cystic kidney disease
 Renal vascular disease
 Nephrotic syndrome
 Renal failure
 Infections of the urinary tract
 Obstruction of the urinary tract
 Urinary tract calculi and nephrocalcinosis
 Malignancy of the urinary tract eg CA bladder
 Incontinence

6. History-Taking
 Gathering of information
 Patient narrative
 Biomedical perspective
 Psychosocial perspective
 Context

7. Cardinal symptoms of diseases of the
urinary tract – presenting complaint/s
 Abnormalities of micturition
 Pain presentations
 Alteration in the appearance of urine
 Alteration in the amount of urine
 General symptoms of abnormal renal function

8. ABNORMALITIES OF
MICTURITION
 Dysuria
 Frequency and nocturia
 Urgency
 Hesitancy, decreased stream and
dribbling
 Retention
 Incontinence

9. Dysuria
 Dysuria = pain / discomfort during
micturition
 Often referred to as burning on
micturition
 Associated with cystitis or urethritis

10. Frequency and nocturia
 Frequency = the need to pass small
amounts of urine frequently
 Due to bladder irritation – may be
caused by infection, stone, tumour
 Nocturia = waking up to pass urine at
night (pregnancy - pressure, diabetes –
associated with polyuria)

11. Urgency
 Urgency = a sudden compelling need to
urinate
 Caused by local irritation or inflammation

12. Hesitancy, decreased stream
and dribbling
 Hesitancy = delay /difficulty in initiating
micturition
 Poor stream
 Dribbling = terminal dribbling after
passage of urine
 Associated with urinary obstruction –
often associated with prostatism or
bladder outflow obstruction in elderly
men

13. Retention
 Retention of urine - due to obstructive
lesions such as stricture, benign
prostatic hypertrophy or BPH, tumour
 May be heralded by the phase of
hesitancy

14. Incontinence
 Incontinence is the inability to hold urine in the bladder
voluntarily
 Spinal cord lesions are associated with retention and
overflow neurogenic incontinence
 Prostatic enlargement is associated with overflow
incontinence – dribbling incontinence after incomplete
urination
 Stress incontinence – more common in women – leakage
of urine after sudden increase in intra-abdominal
pressure eg due to coughing or sneezing, and associated
with bladder prolapse
 Urgency incontinence – associated with urgency and
caused by local irritation or inflammation

15. PAIN PRESENTATIONS
- renal, ureteric, vesical, urethral
 Renal angle pain - dull ache between 12th
rib
and erector spinae muscle on the side of the
affected kidney – pyelonephritis. (Refer renal
angle tenderness)
 Renal colic – due to ureteric obstruction – a
severe pain – lumbar region; radiates to
abdomen, groin, testes, thigh – due to stone or
tumour
 Ureteric colic – spasmodic, severe pain during
the passage of a renal calculus; radiation path
of renal colic; may be associated with vomiting,
sweating.
 Suprapubic pain from bladder / urethra is
referred to lower abdomen, perineum and glans
penis in males

16. ALTERATION IN URINE
APPEARANCE
 Change in colour eg
Orange -
Rifampicin
Red -
blood
Black -
malaria

17. ALTERATION IN AMOUNT
OF URINE
 Polyuria
 Oliguria
 Anuria

18. Polyuria
 Passage of > 3 litres of urine per day
 Physiological – ingestion of large quantities of
fluid or substances containing diuretics
 Pathological
- Chronic renal failure or CRF – associated
polydipsia
- Diabetes mellitus – associated polydipsia
- Diabetes insipidus – neurohypophyseal or
nephrogenic
- Oedematous states – after administration of
diuretics

19. Oliguria
 Passage of < 500ml of urine per day
 Physiological - under conditions of
water deprivation
 Prerenal conditions – shock,
dehydration, haemorrhage
 Renal – Acute renal failure or ARF

20. Anuria
 Passage of <50 mls of urine in a day
 Some causes:
Renal infarct
Dissecting aneurysm
Complete ureteric obstruction

21. Notes re Renal Failure
 Occurs when glomerular filtration is
compromised
 May also be the consequence of abnormal
tubular function
 Prerenal – due to decreased renal perfusion eg
hypotension due to massive blood loss or
cardiac failure
 Renal – due to disease of nephron, glomeruli,
microvasculature (cf DM) or tubules (cf acute
tubular necrosis)
 Postrenal – due to obstruction to outflow or
recurrent ascending infections

22. Renal Failure (cont)
 Acute renal failure – sudden
deterioration of renal function, usually
reversible
 Chronic renal failure – longstanding and
progressive impairment of renal
excretory function – may be insidious in
onset

23. Clinical consequences of renal
failure
 Hypertension – renin secreted in response to impaired
perfusion – activates ACE to convert angiotensin I – II
– vasoconstriction – aldosterone secretion – sodium
and water retention (renin- angiotensin-aldosterone
system)
 Anaemia – erythropoietin deficiency
 Hypoproteinaemia due to protein loss – wasting and
malnutrition
 Renal osteodystrophy from failure of hydroxylation of
Vitamin D to active form (2º hyperparathyroidism)
 Other metabolic complications eg gout (defective
excretion of uric acid), endocrine and neurological
complications

24. GENERAL CLINICAL
FEATURES OF RENAL
DISEASE
 Renal oedema
 Increased BP - see previous slides on
renal failure

25. GENERAL FEATURES (cont)
 Other symptoms and signs of renal failure:
Anaemia
Purpura plus GIT bleeding
Urogenital symptoms – polyuria, polydipsia etc
Cardiovascular symptoms
GIT symptoms – anorexia, nausea & vomiting, loss
of weight, ammonia smell on the breath
Skeletal abnormalities – metabolic bone disease
Growth retardation in children and other endocrine
problems including gynaecomastia in men
Neurological symptoms such as depressed cerebral
function and convulsions in severe uraemia

26. HISTORY-TAKING (cont)
 History of presenting complaint to be in
detail – chronology is important,
especially in chronic conditions
 Don’t forget the systems enquiry – to
cover specific relevant aspects

27. HISTORY-TAKING - Context
 Past History
Preceding throat or skin infection - Strep
Recurrent UTI
Renal stone
HT, DM, hyperuricaemia (gout)
Childhood enuresis > 3 years of age (may be
associated with vesico-ureteric reflux and renal
scarring)
HIV status, TB and Hepatitis B, C
Past surgery or biopsy

28. HISTORY-TAKING - Context
 Medications
(Remember to ask about OTC drugs and herbal
medications as well)
Steroids
Immunosuppressants
Antibiotics
Anti-hypertensives
(know which drugs to avoid eg tetracyclines,
NSAIDs)
 Diet – protein, fluid, salt restriction

29. HISTORY-TAKING - Context
 Family History
DM, hypertension
Inherited forms of renal disease eg adult
polycystic kidney disease - inherited as
an autosomal dominant; Alport’s
Syndrome - inherited as an X-linked
recessive

30. HISTORY-TAKING - Context
 Social History
Employment – occupational exposures
eg heavy metals such as Cadmium
Home circumstances, family support
Impact of chronic illness, dialysis
Smoking and alcohol use

31. Urine Volume & Composition
 In health, the kidneys form approx 1500-
2000mls of urine/24hrs
 Urine is normally pale yellow in colour
(becomes paler with decrease in
osmolarity when large volumes of water
are ingested, and vice versa)
 pH is about 6 – slightly acidic

32. Urine composition vs that of
plasma
 Much higher levels of nitrogenous waste
products such as urea and ammonia
 Much lower concentrations of glucose,
protein and amino acids
 Solutes such as salts eg NaCl, KCl and
NaHCO3, and urea are excreted at a
fairly constant rate, independent of the
volume of urine
 Plasma has a constant osmolarity
whereas that of urine varies widely

33. URINE EXAMINATION
 Inspection
- colour and appearance (? foamy)
- deposits - cloudiness of the urine may be due
to the presence of bacteria or crystals
(phosphates - white, urates – pink)
 Specific gravity (1.005 – 1.035 Naish) Note SG
of water is 1.000 and of plasma 1.010
- Decreased SG - CRF
- Increased SG - DM

34. URINE EXAMINATION
 Reaction
- usually acidic
 Smell
- mild smell of ammonia is normal
- smell of antibiotics, foodstuffs
- fishy odour associated with UTI
 Quantity
- (N) in 24hrs = 1500 - 2000ml

35. Chemical Analysis
•Chemical reagent strips eg Combur-9
“Dipstix”
•Strip is dipped in urine; colour changes are
measured after a set period and compared
with a colour chart
•Analysis of pH, protein, glucose, ketones,
nitrite, bilirubin, urobilinogen, blood and
leucocytes
•To be demonstrated in Skills Lab

36. Protein:
Dipstix measurement is semi-quantitative + -
++++
Causes of proteinuria– renal disease eg
diabetic nephropathy, fever, post-operative,
CCF, orthostatic proteinuria
Glucose:
Causes of glycosuria – usually diabetes
mellitus, also renal glycosuria (Note false
positive and negative results eg large doses
Vit C)
Ketones:
Causes of ketonuria – diabetic keto-
acidosis and starvation

37. Nitrite:
– positive due to infection with bacteria that
produce nitrite – correlates well with UTI
(inaccurate results with Vitamin C ingestion)
Pus (WBCs):
Causes of pyuria (pus in the urine)
Urinary tract infection UTI
Sterile pyuria in renal tuberculosis
Blood:
– positive dipstix is abnormal
(Causes of haematuria, haemoglobinuria, etc
– see next slide)

38. Causes of haematuria – examples:
Renal causes – glomerulonephritis, renal carcinoma,
analgesic nephropathy, bleeding disorders, trauma
Urinary tract – cystitis, calculi, tumour
Causes of haemoglobinuria – examples:
Intravascular haemolysis eg haemolytic anaemia, march
haemoglobinuria
Causes of myoglobinuria – examples:
Convulsions, viral myositis, toxins such as snake venom
(due to muscle destruction)

39. Microscopy – ref Talley
MSU - NB Method of collection – need a clean
uncontaminated specimen using a sterile urine jar
• Microscopic examination of a centrifuged specimen
Look for:
• RBCs – circular, without a nucleus – uniform if from the
urinary tract, dysmorphic if from the glomeruli , usually 0, < 5
per lpf in very concentrated urine
• WBCs – lobulated nuclei < 6 per hpf – up to 10 may be
present in very concentrated urine
• Epithelial cells
• Bacteria – infection or contamination
• Casts - cylindrical moulds formed in the lumen of renal
tubules or collecting ducts
- size determined by the dimension - they indicate damage
to the glomerular basement membrane or tubule

40. Types of casts
Hyaline casts - < 1 per lpf, consist of Tamm-Horsfall
mucoprotein secreted by renal tubules, may contain 1-2
RBCs or WBCs
Granular casts – consist of hyaline material containing
fragments of serum proteins
Red cell casts – always abnormal – indicate primary
glomerular disease, contain 10-50 RBCs – post-
Streptococcal GN, SBE etc
White cell casts – WBCs adhere to inside of cast –
usually indicate bacterial pyelonephritis
Fatty casts – these suggest nephrotic syndrome

41. Culture and Sensitivity
To identify organism in infections
To assess sensitivity to anti-microbials

42. References
• Past protocols
• Medical Science, Jeannette Naish et al
Chapter 14 The Renal System
• Clinical Examination, Talley and o’Connor
Chapter 6 The Genitourinary System
• Principles and Practice of Medicine,
Davidson