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Clinical assessment of renal disease

Acute renal failure (ARF)

Acute renal failure is the failure of renal function over a period of hours or days and is

defined by increasing serum creatinine and urea. It is a life-threatening disorder caused

by the retention of nitrogenous waste products and salts such as sodium and potassium.

The rise in potassium may cause ECG changes and a risk of cardiac arrest. Acute renal

failure may be classified into pre-renal, renal and post-renal. Prompt identification of

pre- or post-renal factors and appropriate treatment action may allow correction before

damage to the kidneys occurs. Pre-renal failure occurs due to a lack of renal perfusion.

This can occur in volume loss in haemorrhage, gastrointestinal fluid loss and burns or

because of a decrease in cardiac output caused by cardiogenic shock, massive pulmonary

embolus or cardiac tamponade (application of pressure) or other causes of hypertension

such as sepsis. Post-renal causes include bilateral uretic obstruction because of calculi

or tumours or by decreased bladder outflow/urethral obstruction e.g. urethral stricture or

prostate enlargement through hypertrophy of carcinoma. Correction of the underlying

problem can avoid any kidney damage. Renal causes of acute renal failure include glom-

erular nephritis, vascular disease, severe hypertension, hypercalcaemia, invasive disorders

such as sarcoidosis or lymphoma and nephrotoxins including animal and plant toxins,

heavy metals, aminoglycosides, antibiotics and non-steroidal anti-inflammatory drugs.

Chronic kidney disease (CKD)

CKD is a progressive condition characterised by a decliningeGFR (Table 16.6). All CKD

patients are subject to regular clinical and laboratory assessment and once Stage 3 has

been reached to additional clinical management. This is aimed at attempting to

reverse or arrest the disease by drug therapy saving the patient the inconvenience

and the paying authority the cost of dialysis or transplantation.

16.3.5 Endocrine disorders

Endocrine hormones are synthesised in the brain, adrenal, pancreas, testes and ovary,

and most importantly in the hypothalamus and pituitary, but they act elsewhere in

Table 16.6Stages of chronic kidney disease (CKD)

CKD stage

eGFR (cm^3 min^1

1.73 m^2 ) Clinical relevance

1 > 90 Regard as normal unless other symptoms presenta

2 60–89 Regard as normal unless other symptoms presenta

3 30–59 Moderate renal impairment

4 15–29 Severe renal impairment

5 < 15 Advanced renal failure

Note:aSymptoms include persistent proteinuria, haematuria, weight loss, hypertension.

649 16.3 Examples of biochemical aids to clinical diagnosis