Name	Definition	Example
Nephrotic	Massive proteinuria	Minimal change disease
Nephritic	Haematuria, renal failure	Post-streptococcal glomerulonephritis
Tubulointerstitial nephropathy	Renal failure, mild proteinuria	Analgesic nephropathy
Acute renal failure^*	Sudden fall in function, rise in creatinine	Acute tubular necrosis
Rapidly progressive renal failure	Fall in renal function, over weeks	Malignant hypertension or ‘crescentic’ glomerulonephritis
Asymptomatic urinary abnormality	Isolated haematuria, or mild proteinuria	Immunoglobulin A nephropathy

^* Newly defined as acute kidney injury, AKI; Levin A, Warnock D, Mehta R, Kellum J, Shah S, Melitoris B, Ronco C. Improving outcome for AKI. Am J Kidney Dis 2007; 50(1):1–4.

Examination anatomy

Figure 7.1 shows an outline of the anatomy of the urinary tract. Figure 7.2 shows the arterial supply of the kidneys as demonstrated on a CT renal angiogram and Figure 7.3 shows the outline of the renal collecting system. Problems with function can arise in any part, from the arterial blood supply of the kidneys, the renal parenchyma, the ureters and bladder (including their innervation), to the urethra.

Figure 7.1 The anatomy of the kidneys and urinary tract

Figure 7.2 CT angiogram showing the origins and course of the renal arteries (large arrows) from the abdominal aorta; the left and right inferior phrenic arteries are visible arising superiorly

Figure 7.3 Outline of the renal collecting system

This intravenous pyelogram shows the outline of the kidneys (1), the renal pelves (2) and the calyces (3) and ureters (4).

Basic male and female reproductive anatomy is shown in Figures 7.9 (page 216) and 7.13 (page 218).

Change in appearance of the urine

Some patients present with discoloured urine. A red discoloration suggests haematuria (blood in the urine).¹ Urethral inflammation or trauma, or prostatic disease, can cause haematuria at the beginning of micturition which then clears, or haematuria only at the end of micturition (Table 7.3). Patients with porphyria can have urine that changes colour on standing. Consumption of certain drugs (e.g. rifampicin) or of large amounts of beetroot and, rarely, haemoglobinuria (due to destruction of red blood cells and release of free haemoglobin) can cause red discoloration of the urine (page 212). Patients with severe muscle trauma may have myoglobinuria as a result of muscle breakdown. This can also cause red discoloration. Foamy, tea-coloured or brown urine may be a presenting sign of nephrosis or kidney failure. It is worth noting that the colour of the urine is not a reliable guide to its concentration.

Table 7.3 Haematuria

1 Favours urinary tract infection

Dysuria

Fever (prostatitis, pyelonephritis)

Suprapubic pain (cystitis)

Moderate flank or back pain (pyelonephritis)

2 Favours renal calculi

Severe loin pain

3 Favours source not glomerular

Clots in urine

4 Favours blood not in urine

Menstruation

5 Favours immunoglobulin A nephropathy

Multiple episodes over months

6 Favours trauma

Recent indwelling urinary catheter or procedure

Recent back or abdominal injury

7 Favours bleeding disorder

Use of anticoagulant drugs

Urinary tract infection (UTI)

This condition includes both upper urinary tract (renal) infection and lower UTI (mostly the bladder—cystitis). Possibly as many as 50% of lower UTIs also involve the kidneys. Renal infection may be difficult to distinguish clinically from lower UTIs but is a more serious condition and more likely to involve systemic complications such as septicaemia.

Urinary tract infection is much more common in women than in men, but there are a number of risk factors for the disease (Table 7.4). It can be strongly suspected on the basis of the patient’s symptoms.² These include: dysuria (pain or stinging during urination), frequency (need to pass small amounts of urine frequently), haematuria, and loin (more suggestive of upper UTI) or back pain. Physical examination may reveal fevers, rigors, lower abdominal discomfort and loin pain when the renal angle is balloted posteriorly. The latter findings are more suggestive of complicated UTI or pyelonephritis. The presence of a vaginal discharge is against the diagnosis. Elderly patients with a urinary tract infection often present with confusion and few other symptoms or signs. A UTI in a male or frequent, relapsing or recurrent UTI in a female suggests an anatomical abnormality and requires urological evaluation.

Table 7.4 Risk factors for urinary tract infection (UTI)

Female sex

Coitus

Pregnancy

Diabetes

Indwelling urinary catheter

Previous UTI

Lower urinary tract symptoms of obstruction

Urinary obstruction

Urinary obstruction is a common symptom in elderly men and is most often due to prostatism (now called lower urinary tract symptoms—LUTS) or bladder outflow obstruction. The patient may have noticed hesitancy (difficulty starting micturition—urination), followed by a decrease in the size of the stream of urine and terminal dribbling of urine. Strangury (recurrently, a small volume of bloody urine is passed with a painful desire to urinate each time) and pis-en-deux/double-voiding (the desire to urinate despite having just done so) may occur.³ When obstruction is complete, overflow incontinence of urine can occur. Obstruction is associated with an increased risk of urinary infection.

Renal calculi can cause ureteric obstruction (Figure 7.4). The presenting symptom here, however, is usually severe colicky or constant loin or lower quadrant pain which may radiate down towards the symphysis pubis or perineum or testis (renal colic). Urinary obstruction can be a cause of acute renal failure (kidney injury) (Table 7.5).

Figure 7.4 Renal calculus

Phleboliths (calcifications related to blood vessels) are rounded opacities seen in the pelvis below the level of the ischial spines, whereas ureteric calculi lie above this level, in the line of the ureters. The large staghorn calculus shown here is occupying the calyces of the left renal pelvis. This type of calculus is almost always radio-opaque. An abdominal ultrasound examination (IVPs are almost never performed in this context today) is necessary to check whether there is an obstruction at the pelviureteric junction. In general, 90% of renal calculi are radio-opaque and visible on plain X-ray films. A significant proportion of patients presenting with renal colic due to calcium calculi have hyperparathyroidism.

Table 7.5 Causes of acute renal failure (acute kidney injury, AKI ^*)

a. Onset over days

This is defined as a rapid deterioration in renal function severe enough to cause accumulation of waste products, especially nitrogenous wastes, in the body. Usually the urine flow rate is less than 20 mL/hour or 400 mL/day, but occasionally it is normal or increased (high-output renal failure).

Prerenal

Fluid loss: blood (haemorrhage), plasma or water and electrolytes (diarrhoea and vomiting, fluid volume depletion)

Hypotension: myocardial infarction, septicaemic shock, drugs

Renovascular disease: embolus, dissection or atheroma

Increased renal vascular resistance: hepatorenal syndrome

Renal

Acute-on-chronic renal failure (precipitated by infection, fluid volume depletion, obstruction or nephrotoxic drugs)—see Table 7.7

Acute renal disease:

• e.g. primary or secondary glomerulonephritis, connective tissue diseases

Acute tubular necrosis secondary to:

• ischaemia (hypovolaemia)

• toxins and drugs (such as aminoglycoside, antibiotics, radiocontrast material, heavy metals)

• rhabdomyolysis, haemoglobinuria

Tubulointerstitial disease:

• e.g. drugs (such as proton pump inhibitors, sulfonamides, cyclosporin A), urate or calcium deposits, phosphate, oxalate, crystal nephropathy

Vascular disease:

• e.g. vasculitis, scleroderma

Myeloma Acute pyelonephritis (rare) Postrenal (complete urinary tract obstruction) Urethral obstruction:

• e.g. calculus or blood clot, sloughed papillae, trauma, phimosis or paraphimosis

At the bladder neck:

• e.g. calculus or blood clot, prostatic hypertrophy or cancer

Bilateral ureteric obstruction:

• intraureteric, e.g. blood clot, pyogenic debris, calculi

• extra-ureteric, e.g. retroperitoneal fibrosis (due to radiation, methysergide or idiopathic), retroperitoneal/pelvic tumour or surgery, uterine prolapse

b. Causes of rapidly progressive renal failure (onset over weeks to months) Urinary tract obstruction Rapidly progressive glomerulonephritis Bilateral renal artery stenosis (may be precipitated by angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use) Multiple myeloma Scleroderma renal crisis Malignant hypertension Haemolytic uraemic syndrome

Note: Anuria may be due to urinary obstruction, bilateral renal artery occlusion, rapidly progressive (crescentic) glomerulonephritis, renal cortical necrosis or a renal stone in a solitary kidney.

^* Levin A, Warnock D, Mehta R, Kellum J, Shah S, Melitoris B, Ronco C. Improving outcome for AKI. Am J Kidney Dis 2007; 50(1):1–4.

Urinary incontinence

This is the inability to hold urine in the bladder voluntarily. It is not a consequence of normal ageing alone. The problem can occur transiently with urinary tract infections, delirium, excess urine output (e.g. from the use of diuretics), immobility (because patients are unable to reach the toilet), urethritis or vaginitis, or stool impaction.

Causes of established urinary incontinence include: (i) stress incontinence (instantaneous leakage after the stress of coughing or after a sudden rise in intra-abdominal pressure of any cause)—this problem is more common in women due to vaginal deliveries or an atrophic vaginal wall postmenopause causing a hypermobile urethra; (ii) urge incontinence (overactivity of the detrusor muscle) which is characterised by an intense urge to urinate and then leakage of urine in the absence of cough or other stressors—this occurs in men and women; (iii) detrusor underactivity—this is rare and is characterised by urinary frequency, nocturia and the frequent leaking of small amounts of urine from neurological disease; (iv) overflow incontinence (urethral obstruction)—this occurs typically in men with disease of the prostate, and is characterised by dribbling incontinence after incomplete urination; and (v) a vesico/urethral fistula—a complication of obstructed labour.

Chronic renal failure (chronic kidney disease)

The clinical features of chronic renal failure can be deduced in part by considering the normal functions of the kidneys.

1. Failure of excretory function leads to accumulation of numerous ‘uraemic’ toxins, hence the widely used term ‘uraemia’. This frequently leads to malaise, lethargy, anorexia, malnutrition and hiccups.

2. Urinary concentrating ability may be lost early, leading to the risk of dehydration; nocturia can be an early symptom.

3. Various factors such as the failure to excrete sodium may lead to hypertension.

4. Damage to the renal tubules may lead to sodium loss and hypotension.

5. Excretion of potassium depends in part on urine volume. Hyperkalaemia usually becomes a problem when a patient is oliguric (passes less than 400 mL urine/day) and may occur when taking potassium-sparing diuretics or agents that promote potassium retention (ACE inhibitors, angiotensin receptor blockers, non-steroidal anti-inflammatory drugs).

6. Failure of acid excretion leads to metabolic acidosis.

7. Disordered mineral and bone metabolism (abnormal levels of calcium, phosphorus, parathyroid hormone [PTH] and vitamin D) may lead to abnormalities in bone and vascular or soft-tissue calcification.⁴

8. Failure to secrete erythropoietin leads to normochromic normocytic anaemia.

9. Alterations in the metabolism of those medications which are excreted by the kidneys.

Adequacy of renal function is defined by the glomerular filtration rate (GFR). This is the volume of blood filtered by the kidneys per unit of time. The normal range is 90–120 mL/min. The GFR is estimated by calculating the clearance of creatinine (a normal breakdown product of muscle) from the blood. The serum creatinine and urea levels also provide a measure of accumulation of uraemic toxins and therefore of renal function. Most laboratories now provide an estimated GFR (eGFR) measurement calculated from the serum creatinine and the patient’s age and sex.

A new definition and classification of chronic kidney disease (CKD) has been introduced. CKD is defined as kidney damage or GFR <60 mL/min/1.73 m² for 3 months or more, irrespective of cause.⁵ Further kidney disease has been divided into 6 groups according to GFR (Table 7.6). These allow planning of investigations and treatment that might slow progression of the disease.

Table 7.6 Classification of chronic kidney disease by glomerular filtration rate (GFR)

Stage	Description	GFR (mL/min/1.73 m³)
–	Increased risk for chronic kidney disease (e.g. diabetes, hypertension)	>90
1	Kidney damage but normal GFR	>90
2	Kidney damage and mild GFR reduction	60–89
3	Moderate reduction in GFR	30–59
4	Severe reduction in GFR	15–29
5	Kidney failure	<15

A uraemic patient may present with anuria (defined as failure to pass more than 50 mL urine daily), oliguria (less than 400 mL urine daily), nocturia (the need to get up during the night to pass urine) or polyuria (the passing of abnormally large volumes of urine) (page 297). Nocturia may be an indication of failure of the kidneys to concentrate urine normally, and polyuria may indicate complete inability to concentrate the urine.

The more general symptoms of renal failure include anorexia, vomiting, fatigue, hiccups and insomnia. Pruritus (a general itchiness of the skin), easy bruising and oedema due to fluid retention may also be present. Other symptoms indicating complications include bone pain, fractures because of renal bone disease, and the symptoms of hypercalcaemia (including anorexia, nausea, vomiting, constipation, increased urination, mental confusion) because of tertiary (or primary) hyperparathyroidism.^a Patients may also present with the features of pericarditis, hypertension, cardiac failure, ischaemic heart disease, neuropathy or peptic ulceration.

Find out whether the patient is undergoing dialysis and whether this is haemodialysis or peritoneal dialysis. There are a number of important questions that must be asked of dialysis patients (Questions box 7.2).

Questions box 7.2

Questions to ask the dialysis patient

! denotes symptoms for the possible diagnosis of an urgent or dangerous problem.

1. What fluid restriction have you been recommended?

2. Have phosphate-binding drugs been prescribed? When do you take these relative to meals?

3. Do you use haemodialysis or peritoneal dialysis? Do you do this at home? How many times a week?

4. Have you had abdominal pain or fever recently?—Peritonitis related to peritoneal dialysis

5. Have there been any problems with haemodialysis, such as low blood pressure, or with the fistula used for haemodialysis? Have there been any problems with peritonitis with peritoneal dialysis?

6. How much weight do you gain between each haemodialysis?

7. Do you still pass any urine? If so, how much?

8. Are you on a renal transplant list or have previously had a transplant?

9. Do you follow recommended dietary restrictions?

10. What other medications do you take?

11. Have you had heart or blood vessel problems?

12. Have you had overactive parathyroid glands or parathyroid surgery?

Ask about any complications that have occurred, including recurrent peritonitis with peritoneal dialysis or problems with vascular access for haemodialysis.

A common form of treatment for renal failure is renal transplantation. A patient may know how well the graft is functioning, and what the most recent renal function tests have shown. Find out whether the patient knows of rejection episodes, how these were treated, and if there has been more than one renal transplant. It is necessary to ascertain if there have been any problems with recurrent infection, urine leaks or side-effects of treatment. Long-term problems with immunosuppression may have occurred, including the development of cancers, chronic nephrotoxicity (e.g. from cyclosporin or tacrolimus), obesity and hypertension from steroids, or recurrent infections. The patient should be aware of the need to avoid skin exposure to the sun and women should know that they need regular Papanicolaou ^b (Pap) smears for cancer surveillance.

Menstrual and sexual history

A menstrual history should always be obtained. The menarche or date of the first period is important (page 296). The regularity of the periods over the preceding months or years and the date of the last period are both relevant. The patient may complain of dysmenorrhoea (painful menstruation) or menorrhagia (an abnormally heavy period or series of periods).

Vaginal discharge can occur in patients with infections of the genital tract. Sometimes the type of discharge is an indication of the type of infection present. The history of the number of pregnancies and births is relevant: gravidity refers to the number of times a woman has conceived, while parity refers to the number of babies delivered (live births or stillbirths). One should also ask about any complications that occurred during pregnancy (e.g. hypertension).

The sexual history is also relevant.⁶ Ask about contraceptive methods and the possibility of pregnancy.⁷ Ask men about erectile dysfunction (impotence). Erectile dysfunction is defined as inability to achieve or maintain a satisfactory erection, for more than 3 months. Most causes are organic (neurogenic [e.g. diabetes] or vascular, or drug related [e.g. beta-blockers, thiazide diuretics]), with a slow onset and loss of morning erections in older men.