Page 483 - Medicine and Surgery

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Chapter 12: Haemoglobin disorders and anaemia 479

Table 12.6 Autoimmune haemolytic anaemia
Disorder Aetiology Pathophysiology Management
Warm antibodies Primary or secondary to IgG antibodies often specific for Corticosteroids produce a
autoimmune disorders, rhesus antigens. remission in ∼80%.
lymphomas, chronic Complement fixation is unusual. Splenectomy may be indicated if
lymphatic leukaemia, haemolysis is severe and
carcinoma and drugs such refractory. Immunosuppressants
as methyldopa such as azathioprine may be of
value.
Cold haemagglutinin May be primary or secondary IgM antibodies agglutinate best Treat any underlying cause and
◦
disease to Mycoplasma at 4 C, often against minor avoid extremes of temperature.
pneumoniae, infectious red cell antigens. Steroids or chlorambucil may be
mononucleosis and rarely Complement fixing. tried.
other viral infections
Paroxysmal cold Usually secondary to Polyclonal IgG antibodies with The haemolysis is usually
haemoglobinuria childhood viral exanthems specificity for the P red cell self-limiting; however,
or syphilis antigen. Complement fixing. transfusions may be required.

Aplastic anaemia Recurrent infections due to leucopenia.
Bruising and purpura due to thrombocytopenia.

Definition
A pancytopenia due to a loss of haematopoetic precur- Investigations
sors from the bone marrow. Full blood count and blood film will demonstrate a pan-
cytopenia with absence of reticulocytes. A bone marrow
Aetiology/pathophysiology aspirate and trephine shows a hypocellular marrow with
Aplastic anaemia can be either congenital or much more no increased reticulin (fibrosis).
commonly acquired:
Management
There are several forms of congenital aplastic anaemia

Treatment should include withdrawal of any causative
themostcommonofwhichisFanconi’sanaemia.This
agents, supportive care (blood and platelet transfusions)
is an autosomal recessive aplastic anaemia with limb
and some form of definitive therapy. Blood and platelet
deformities.
transfusions should be used selectively in patients who
Idiopathic acquired aplastic anaemia is the most com-

are candidates for stem cell transplantation to avoid sen-
mon form. It is thought to be due to an immune
sitisation.
mechanism.
Stem cell transplantation is the treatment of choice
Secondary acquired aplastic anaemia may result from

in young patients with acquired severe aplastic anaemia
direct injury to stem cells by external radiation or cy-
whohaveanHLA identical sibling.
totoxicdrugs.Otherdrugsmaycauseaplasticanaemia
Immunosuppressive therapy is used as first line treat-
through dose dependent (e.g. gold) or idiosyncratic
ment in patients over 35–45 years, younger patients
(e.g. nonsteroidal anti-inflammatory drugs) reac-
without an HLA identical sibling or those with less se-
tions, or by both mechanisms (e.g. chlorampheni-
vere aplastic anaemia. Regimens include anti-thymocyte
col). Other causes include solvents, pesticides, in-
globulin and cyclosporine. Androgens may be used as
dustrial chemicals and insecticides and viruses (e.g.
additional therapy.
parvovirus B19 and HIV).
Prognosis
Clinical features The course is dependent on the severity of the dis-
Patients present with the features of pancytopenia: ease and the age of the patient. In young patients who
Symptoms and signs of anaemia (see page 468). undergostemcelltransplantationthe3-yearsurvivalrate