The platelet count should be at least 50× 109 /l before surgery is attempted and
continuous infusion of platelets may be required. In children with the idiopathic form
of this condition, prednisolone (4 mg/kg per day for 1 week, given orally) will
increase the platelet count to over 50× 109 /l within 48 h in about 90% of cases. The
necessary treatment can then be carried out.
16.3.3 Blood dyscrasias
There are several relatively common disorders of the red and white blood cells that
may influence dental care in the child. Many of these conditions also give rise to
abnormal bleeding but, in addition, may lead to delayed healing, infection, or mucosal
ulceration. An outline classification is given in 1096HTable 16.7.
Red blood cell disorders: anaemia
When there is a reduction in the red blood cell volume or haemoglobin concentration,
the oxygen carrying capacity of the blood is lowered. Anaemia is not a specific
disease but a symptom of an underlying disorder. Children with anaemia may be very
pale (examine the nail-beds, conjunctiva, and oral mucous membranes). They may
also be tired, listless, and breathless.
IRON-DEFICIENCY ANAEMIA
This may result from chronic blood loss, possibly as a result of haemorrhagic
disorders, but in children it is more commonly due to dietary deficiency or
malabsorption. Vitamin B12 and folic acid are also needed for the maturation of red
blood cells in the bone marrow.
GLUCOSE 6-PHOSPHATE DEHYDROGENASE (G-6-PD) DEFICIENCY
This enzyme is needed in the hexose monophosphate shunt pathway. In deficiency the
accumulation of oxidants in the red blood cells causes their haemolysis and may result
in jaundice, palpitations, dyspnoea, and dizziness. Drugs such as aspirin, phenacetin,
and ascorbic acid, as well as infections, may precipitate haemolysis. As the gene for
G-6-PD is located on the X-chromosome it is inherited as a sex-linked condition.
There are many variants of the condition and it is common in certain ethnic groups;
for example, type A is found in 11% of American black people and G-6-PD MED is
relatively common in ethnic groups of Mediterranean origin.
SICKLE-CELL ANAEMIA
This is an inherited autosomal-recessive disorder that results in the substitution of a
single amino acid in the haemoglobin chain. Sickle-cell trait is the heterozygous state
in which the affected individual carries one gene for haemoglobin S. Approximately,
10% of American Black children and up to 25% of Central African Black children
carry the trait. Sickle-cell anaemia is the homozygous state, with affected genes from
both parents. The red blood cells containing haemoglobin S have a life of only 30-60
days and become clumped together under certain conditions, thus blocking small
blood vessels and leading to pain and necrosis. Affected children may be pale, tired,
weak, and breathless. They may complain of painful joints and swelling of the hands
and feet. There tends to be a failure to thrive and growth retardation with an increased
susceptibility to infection. Later problems include renal function impairment and
retinal and conjunctival damage.