Renal - Presenting problems in renal and urinary disease

Question 1

What is dysuria?

Answer 1

Painful micturition, often with suprapubic pain, frequency and a feeling of incomplete bladder emptying. The cause is usually UTI, but sexually transmitted diseases and bladder stone may also present with dysuria.

Question 2

Differential diagnosis of loin pain

Answer 2

Dull ache in the loin is often musculoskeletal
May be caused by renal stone, renal tumour, acute pyelonephritis or obstruction of the renal pelvis. Acute loin pain referring to the groin (“renal colic”) + haematuria is typical of ureteric obstruction MC due to calculi

Question 3

What is oliguria and anuria?

Answer 3

Daily urine volumes of <300 ml are termed oliguria. Anuria is the (almost) total absence of urine (<50 ml/day). A low measured urine volume is an important finding and is a consequence of reduced production, obstruction to urine flow or both. Patients should be assessed for signs of dehydration or hypotension, and for signs of urinary obstruction. Catheterisation relieves distal obstruction and allows monitoring of urine flow rate. USS reveals site of obstruction

Question 4

Polyuria

Answer 4

Inappropriately high urine volume (>3 L/day)

Question 5

What can cause polyuria?

Answer 5

Excess fluid intake
Hyperglycaemia
Cranial diabetes insipidus
Nephrogenic diabetes inspidius: lithium, diuretics, interstitial nephritis, hypokalaemia, hypercalcaemia

Question 6

Nocturia

Answer 6

Waking up at night to void urine may be a consequence of polyuria but may also result from fluid intake or diuretic use in the late evening

Nocturia also occurs in CKD, and in prostatic enlargement where it is associated with poor stream, hesitancy, incomplete emptying, terminal dribbling and urinary frequency

Question 7

What is frequency?

Answer 7

Describes micturition more often than a patient’s expectations. It may be a consequence of polyuria, when urine volume is normal or high, but is also found in patients with dysuria or prostatic disease when urine volumes are low

Question 8

What is urinary incontinence?

Answer 8

Any involuntary leakage of urine
Can be secondary to pathology but also occur in the normal urinary tract, e.g. in association with dementia or poor mobility, or transiently during an acute illness or hospitalisation, especially in older people
Diuretics, caffeine and alcohol may worsen incontinence

Question 9

What is stress incontinence?

Answer 9

One of the incontinence syndromes
Leakage occurs because passive bladder pressure exceeds the urethral pressure, due to either poor pelvic floor support or a weak urethral sphincter, most often both
Very common in women, especially following childbirth. It is rare in men, where it usually follows prostate surgery
It presents with incontinence during coughing, sneezing, or exertion. In women, perineal inspection may reveal leakage of urine with coughs.

Question 10

Urge incontinence

Answer 10

Leakage occurs when detrusor over activity produces an increased bladder pressure that overcomes the urethral sphincter
Urgency with or without incontinence may also be driven by a hypersensitive bladder resulting from a UTI or bladder stone
Detrusor overactivity may be neurogenic (in spina bifida or multiple sclerosis) or idiopathic
Incidence of urge incontinence increases with age, and is also seen in men with lower urinary tract obstruction, it most often remits after the obstruction is relieved

Question 11

What does continual continence suggest the presence of?

Answer 11

Continual incontinence is suggestive of a vesicovaginal or ureterovaginal fistula, often complicating previous surgery or radiotherapy

Question 12

What is overflow incontinence?

Answer 12

This occurs when the bladder becomes chronically over distended. It is most common in men with benign prostatic hypertrophy or bladder neck obstruction, but may occur in either sex as a result of detrusor muscle failure (atonic bladder). This may be idiopathic but more commonly results from pelvic nerve damage from surgery (e.g. hysterectomy or rectal excision), trauma or infection or from compression of the cauda equina from disc prolapse, trauma or tumour

Question 13

Post micturition dribble

Answer 13

This is very common in men, even the relatively young. It is due to a small amount of urine becoming trapped in the U bend of the bulbar urethra, which leaks out when the patient moves. It is more pronounced if associated with a urethral diverticulum or urethral stricture. It may occur in females with a urethral diverticulum and may mimic stress incontinence

Question 14

Clinical assessment of incontinence

Answer 14

Voiding diary - pattern of micturition, measured volume voided, frequency of voiding, precipitating factors, and associated features - e.g. urgency
Cognitive function and mobility
Neurological assessment - MS
Perineal sensation and anal sphincter tone - same sacral nerve roots also supply bladder and urethral sphincter
Lumbar spine inspected for features of spina bifida occulta
Rectal examination - prostate, exclude faecal impaction
Urinalysis and culture
Assess post micturition volume
Urine flow rates and urodynamics

Question 15

Causes of erectile dysfunction

Answer 15

MCC by psychological, vascular or neurological factors
With exception of diabetes, endocrine causes are uncommon and are characterised by loss of libido as well

If the patient has erections on waking in the morning, vascular and neuropathic causes are much less likely and a psychological issue should be suspected

Question 16

Haematuria

Answer 16

Indicates bleeding anywhere in the urinary tract, may be visible (macroscopic) or only detectable on urinalysis (microscopic)

Macroscopic haematuria most likely to be caused by tumours, severe infections, and renal infarction

Question 17

Findings associated with haematuria on dipstick analysis and suggested causes

Answer 17

Haematuria + white blood cells = infection
Haematuria + abnormal epithelial cells = tumour
Haematuria + red cell casts, dysmorphic RBCs = glomerular bleeding

Haemoglobinuria = intravascular haemolysis 
Myoglobinuria = rhabdomyolysis

Question 18

How should haematuria be investigated?

Answer 18

Repeated haematuria on dipstick —> exclude menstruation, infection, trauma —> image renal tract (cystoscopy, then CT or IVU and ultrasound)
- if anatomical lesions found –> full assessment and management
- if no anatomical lesion found –> features of significant renal disease present? (e.g. proteinuria, hypertension, abnormal renal function, family history of renal disease, signs of systemic disease)
Yes —> consider renal biopsy
No —> observation —> urinalysis, BP, creatinine every 12 months

Question 19

What is a normal urinary protein?

Answer 19

Moderate amounts of low molecular weight proteins DO pass through the glomerular basement membrane (GBM). These are normally reabsorbed by tubular cells so that <150 mg/day appears in the urine

Question 20

What are is a normal urinary to albumin creatinine ratio (ACR)?

Answer 20

< 3.5 female
< 2.5 male
3.5-15 is classed as microalbuminuria
- can identify very early glomerular disease, e.g. in diabetic nephropathy
- also associated with an increased risk of atherosclerosis and cardiovascular mortality

Question 21

ACR of 15-50

Answer 21

Dipstick results would also be positive

This is equivalent of 24 hr protein <0. 5 g

Question 22

ACR 50-200

Answer 22

Dipstick protein is more positive and indicates that glomerular disease is more likely, although it is not within the nephrotic range

ACR > 200 (PCR > 300) is nephrotic and always means glomerular disease. It is equivalent to a 24 hour protein excretion of >3 g

Question 23

How should repeated proteinuria be investigation?

Answer 23

First quantify the proteinuria:
- Substantial: total 24 hr protein > 1 g/day, PCR > 100 mg/mmol, ACR > 70 mg/mmol —> consider BIOPSY
- Moderate to low grade: total 24 hr protein < 1 g/day, PCR < 100 mg/mmol, ACR < 70 mg/mmol, features of other significant renal disease present? (e.g. haematuria, hypertension, abnormal renal function, FHx of renal disease, signs of systemic disease)
Yes —> BIOPSY
No —> Observation (urinalysis, BP, creatinine)

Question 24

What causes oedema?

Answer 24

1) Increased extracellular fluid - HF, renal failure, liver disease
2) High local venous pressure - DVT, pregnancy, pelvic tumour
3) Low plasma oncotic pressure - nephrotic syndrome, liver failure, malabsorption
4) Increased capillary permeability - infection, sepsis, calcium channel blocker
5) Lymphatic obstruction - infection (filariasis) malignancy, radiation injury

Question 25

Hypertension

Answer 25

Very common feature of renal parenchymal and vascular disease, and is an early feature of glomerular disorders. As GFR declines, hypertension becomes increasingly common, regardless of renal diagnosis. Controlling hypertension is important in patients with renal impairment because it is related to a decline in renal function and with adverse cardiovascular risk in renal disease