THALASSAEMIA
This is another inherited disorder of haemoglobin synthesis and may occur as a
heterozygous trait or homozygous thalassaemia major. It occurs particularly in
Mediterranean countries and in the Middle-Eastern Arab countries. It results, like
sickle-cell anaemia, in a severe progressive haemolytic anaemia. Regular blood
transfusions are necessary to maintain the haemoglobin level above 10 g/dl. If
treatment is inadequate then hypertrophy of erythropoietic tissue occurs and this
results in massive expansion of the marrow of the facial and skull bones producing
maxillary hyperplasia and protrusion of the middle third of the face.
Dental management of anaemia
All anaemic children have a greater tendency to bleed after invasive dental
procedures.
Therefore, any signs or symptoms suggestive of anaemia should be investigated. The
haemoglobin level and haematocrit are simple tests used for screening, and a white
blood cell and platelet count should also be obtained. If these reveal any abnormalities
then further, more complex, tests may need to be undertaken. Ideally, the underlying
defect should be corrected before embarking on a course of routine dental care.
A family history of conditions such as sickle-cell anaemia and thalassaemia is
significant and all Black patients should be tested routinely for sickle-cell disease
prior to a general anaesthetic. Sickle-cell crises occur due to inadequate oxygenation
and, if possible, general anaesthetics should be avoided in preference to the use of
local anaesthesia.
Key Points
Sickle-cell disease:
- All Black patients should be screened prior to general anaesthesia.
White blood cell disorders: leukaemia
Leukaemia is a malignant proliferation of white blood cells. It is the most common
form of childhood cancer, accounting for about one-third of new cases of cancer
diagnosed each year. Acute lymphocytic leukaemia accounts for 75% of cases with a
peak incidence at 4 years of age. The general clinical features of all types of
leukaemia are similar as all involve a severe disruption of bone marrow functions.
Specific clinical and laboratory features differ, however, and there are considerable
differences in response to therapy and long-term prognosis.
Acute leukaemia has a sudden onset but the initial symptoms are usually non-specific
with anorexia, irritability, and lethargy. Progressive failure of the bone marrow leads
to pallor, bleeding, and fever, which are usually the symptoms that lead to diagnostic
investigation. The bleeding tendency is often shown in the oral mucosa (1097HFig. 16.4)
and there may also be infective lesions of the mouth and throat. The dental
practitioner may, therefore, be the first to diagnose the condition (1098HFig. 16.5). Bone
pain and arthralgia are also important presenting complaints in about one-quarter of
children. On initial haematological examination most patients will have anaemia and