Signs and tests of acute and chronic liver disease
Liver function
and tests
Adequate liver function is essential to
survival; humans will survive for only 24—48 hours in the an hepatic state
despite full supportive therapy. The main functions of the liver are shown in
Table 52.1. Routinely available tests of liver function are shown in Table
52.2. Bilirubin is synthesised in the liver and excreted in the bile. Increased
levels may be associated with increased haemoglobin breakdown, hepatocellular
dysfunction resulting in impaired bilirubin transport
Signs of
impaired liver function
The clinical signs associated with impaired
liver function depend on the severity of dysfunction and whether it
is acute or chronic.
Acute liver failure
The main causes of acute liver failure are
shown in Table 52.3. In the early stages there may be no objective signs, but
with severe dysfunction the onset of clinical jaundice may be
Chronic liver disease
Because of the many diverse functions of the
liver, patients with chronic liver disease may present in many different ways.
Lethargy and weakness are common features irrespective of the underlying
cause. Often this precedes clinical jaundice which indicates the liver’s
inability to metabolise bilirubin. The serum level reflects the severity of the
underlying liver disease. Progressive deterioration in liver function is
associated with a hyperdynamic circulation involving a high cardiac output,
large pulse volume, low blood pressure and flushed warm extremities. Fever is a
common feature which may be related to underlying inflammation and cytokine
release from the diseased liver or due to bacterial infection to which
patients with chronic liver disease are predisposed. Skin changes may be
evident, including spider naevi, cutaneous vascular abnormalities which blanch
on pressure, palmar erythema and white nails (leuconychia). Endocrine
abnormalities are responsible for hypogonadism and gynaecomastia. The mental
derangement associated with chronic liver disease is termed ‘hepatic
encephalopathy’. This is associated with memory impairment, confusion, personality
changes, altered sleep patterns and slow slurred speech. The most useful
clinical sign is the flapping tremor demonstrated by asking the patient to
extend his arms and hyperextend the wrist joint. Abdominal distension due to
ascites is a common late feature. This may be suggested clinically by the
demonstration of a fluid thrill or shifting dullness. Protein catabolism
produces loss of muscle bulk and wasting, and a coagulation defect is suggested
by the presence of skin bruising. A patient with the typical features of
end-stage chronic liver disease is shown in (Fig. 52.3.) The Child’s
classification allows an easy method of describing the severity of liver disease
and allows comparison of treatments for patients with chronic liver disease (Table 52.5).