Page 339 - Concise Pathology for Exam Preparation ( PDFDrive )

324 SECTION II Diseases of Organ Systems

Q. Define acute leukaemia. Outline its clinical features and laboratory
diagnosis.
Ans. Acute leukaemia is characterized by the replacement of normal marrow elements
by immature cells called leukaemic blasts, which ultimately spill over into the peripheral
blood.

Clinical Features
The clinical presentation of acute leukaemias is due to one or more of the following:
Anaemia
• Pallor, tiredness, malaise and effort intolerance
• Cardiorespiratory symptoms in severe anaemia

Granulocytopenia
Infections at various sites, eg, upper respiratory tract, skin, gingiva, lungs and urinary
tract. Superficial lymphadenopathy and fever are common.

Thrombocytopenia
• Causes bleeding from gum, nose (epistaxis), skin (purpura, ecchymoses, petechiae and
easy bruising), GIT, renal tract and uterus. Bleeding into eye and ear is also seen.
• Intracranial bleeding is a serious and fatal complication.

Myeloid Proliferation
Causes expansion of marrow leading to bone pains and sternal tenderness.
Leukaemic Infiltration Into Organs
• Common in liver, spleen and lymph nodes; results in hepatosplenomegaly and general-
ized lymphadenopathy
• Involvement of the central nervous system results in infiltration of brain parenchyma
and meninges (‘leukaemic meningitis’)
• Other areas of leukaemic infiltration include mouth, gums (causing gingival hypertro-
phy), skin, testes, ovaries, eyes and bone.
• Localized proliferation of myeloblasts outside marrow produces solid tumours called
chloromas.

Diagnosis

• Morphological examination of blood and bone marrow shows
• Severe anaemia of the normocytic normochromic type
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• A markedly raised TLC (range 1 3 10 /L to 500 3 10 /L)
• Numerous blast cells in the peripheral smear
• Markedly decreased platelet count
• Hypercellular bone marrow with replacement of normal elements by leukemic
blast cells
• Cytochemical stains in acute leukaemias
• Myeloperoxidase (MPO) is used for identification of primary or azurophilic granules
in myeloid precursors. Positive in AML-M1, -M2, -M3 and -M4.
• Staining with Sudan black B (SBB) and chloroacetate esterase (CAE) is mostly similar
to myeloperoxidase. These stain the phospholipids in the membrane of neutrophilic
granules.
• Nonspecific esterase (NSE) is present in large quantities in monocytic cells and is
positive in AML-M4 and -M5.

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