15.  Haematologic diseases

Q. 2. Describe the laboratory investigations for bleeding and clotting disorders.

Ans. Various laboratory diagnostic tests for bleeding and clotting disorders are as follows:

Investigation of disordered vascular haemostasis

Disorders of vascular haemostasis may be due to vascular permeability, reduced capillary strength and failure to contact after injury.

Bleeding time

This simplest test is based on the principle of formation of haemostatic plug following standard incision on volar surface of forearm and the time the incision takes to stop bleeding is measured the test is dependent upon capillary function as well as on platelet number and ability of platelets to adhere to form aggregates.

Normal range is 3–8 minutes.

A prolonged bleeding time may be seen due to

thrombocytopenia;

disorder of platelet function, for example von Willebrand disease;

vascular abnormalities, for example Ehlers–Danlos syndrome; and

severe deficiency of factor V and II.

Hess capillary resistance test (Tourniquet test)

This test is done by placing sphygmomanometer cuff to the upper arm and raising the pressure in it between diastolic and systolic for 5 min.

After deflation, the number of petechia appearing in the next 5 min in 3 cm area over the cubital fossa is counted.

Presence of more than 20 petechiae is considered a positive test. The test is positive in increased capillary fragility as well as in thrombocytopenia.

Investigation of platelet and platelet function

Haemostatic disorder is most commonly due to abnormalities is platelet number, morphology or function.

Screening tests carried out for assessing peripheral blood platelet count is skin bleeding time.

Examination of fresh blood film to see the morphologic abnormalities of platelets.

Special tests

If these screening tests suggest a disorder of platelet function, the following platelet function tests may be carried out.

i. Platelet adhesion test: such as retention in a glass bead column, and other sophisticated techniques.

ii. Aggregation test: which are turbidimetric techniques using ADP, collagen or ristocetin.

iii. Granular content of platelets and their release can be assessed by electron microscopy.

Tests for coagulative defect

Clotting time

Thrombin time

Prothrombin time

Thromboplastin generation time

Partial thromboplastin time.


Q. 3. What are the aetiological factors for the spontaneous bleeding from gingiva? Describe the oral manifestations of myelogenous leukaemia.

Or

How do you manage a case of myeloid leukaemia patient visiting dental hospital.

Ans.

The various causes of bleeding in the oral cavity are as follows:

Local causes

Postextraction, postsurgical, posttraumatic.

Infections—viral, bacterial fungal, parasitic and spirochete.

Oral ulcerative lesions—stomatitis, glossitis, etc.

Oral exophytic soft tissue lesions—pyogenic granuloma, pregnancy tumour.

Local irritants leading to gingivitis and periodontitis.

Rupture of blood containing bulla.

Congenital hamartomas—haemangioma, hereditary haemorrhagic telangiectasia.

Arteriovenous malformation.

Haemorrhage due to platelet disorders

Thrombocytopenia

Thrombocytosis

Thrombasthenia

Glanzmann’s disease

Aldrich syndrome.

Haemorrhage due to coagulation diseases

Haemophilia

Christmas disease

von Willebrand disease

Deficiency of Stuart factor

Multiple myeloma

Systemic lupus erythematosus

Diffuse intravascular coagulation

Macroglobulinaemia.

Haemorrhage due to systemic diseases

Scurvy

Diabetes mellitus

Septic embolism in bacterial endocarditis

Meningococcemia

Systemic viral infection

Anticoagulant therapy

Graft versus host reaction

Sturge–Weber syndrome.

Leukaemia

Leukaemia is a disease characterized by the progressive over production of white blood cells, which usually appear in the circulating blood in an immature form.

Classification

Depending on the onset and the course of the leukaemia it is classified as:

a. Acute leukaemia

b. Chronic leukaemia

Depending on the type of cell of origin leukaemia is also classified into:

a. Myeloid (myelogenous) leukaemia and

b. Lymphoid (lymphoblastic, lymphocytic) leukaemia.

Acute and chronic leukaemias are broadly classified as:

i. Acute lymphoblastic leukaemia (ALL)

ii. Acute myeloblastic leukaemia (AML)

iii. Chronic lymphocytic leukaemia (CLL)

iv. Chronic myelocytic leukaemia (CML).

Aetiology

Unknown

However, some are associated with ionizing radiation, cytotoxic drugs, chemical carcinogens and infectious origin of unknown organism.

Other predisposing factors may be chromosomal abnormalities, genetics, age, hormones, immune competence and stress.

Clinical features

Acute leukaemia

Acute lymphoblastic leukaemia is common in children while acute myeloid leukaemia is common in adults.

Sudden onset.

Characterized by weakness, fever, headache, petechial or ecchymotic haemorrhages in the skin and mucous membranes.

Lymphadenopathy is often the first sign of the disease.

Gingival bleeding, epistaxis, haemorrhage may occur due to thrombocytopenia.

Bleeding may occur due to disseminated intravascular coagulation (DIC), which is mainly in patients with acute promyelocytic leukaemia.

Hepatomegaly, splenomegaly, gum hyperplasia, stomatitis, sternal tenderness, enlargement and infiltration of skin may be seen.

Chronic leukaemia

Disease is present before the symptoms are seen.

Patient may appear with excellent health or exhibit emaciation suggestive of a chronic debilitating disease.

Lymph node enlargement common in CLL but uncommon in CML.

Splenomegaly and hepatomegaly are fully developed due to protracted course of the disease.

Enlargement of salivary glands and tonsils leading to leukaemic infiltration and xerostomia.

Petechiae, ecchymosis of skin. Papules, pustules, bullae, areas of pigmentation, herpes zoster, itching and burning sensations are also seen.

Oral manifestations

Oral lesions occur in both acute and chronic forms.

Gingivitis, gingival hyperplasia, haemorrhage, petechiae and ulceration of the mucosa.

Rapid loosening of the teeth due to necrosis of PDL.

Alterations in the developing tooth crypts.

Osseous changes in jaws.

Diagnosis

a. Peripheral blood examination reveals the presence of blast cells with high, low or normal total leukocyte count.

b. There is also the evidence of anaemia and thrombocytopenia.

c. The bone marrow examination shows hypercellularity along with the presence of >20 % leukaemic blast cells.

d. Cytochemical staining, cytogenetics and immune-phenotyping of the cells help in differentiating different types of leukaemia.

Treatment

The management of acute leukaemia consists of supportive and specific treatment.

Supportive treatment

Anaemia is managed with infusion of red cell concentrate. Platelet transfusion is needed to treat bleeding manifestations and to maintain platelet count above 10,000–20,000/mm3.

Specific treatment

The objective of specific treatment is to eliminate leukaemic cells without affecting the normal cells. However, the therapy may be associated with high morbidity and mortality. Hence, the decision to administer a specific therapy to a particular patient is based on the age, type of leukaemia and the presence of other associated illnesses.

Chemotherapy

In chemotherapy, a combination of various cytotoxic drugs is given under a standard protocol. The first step is to achieve remission (normal blood counts, normal bone marrow, and normal clinical status). The initial induction phase is followed by the consolidation phase and the maintenance phase.

Radiotherapy

Cranial irradiation along with intrathecal methotrexate is given in ALL patients for CNS prophylaxis.

Bone marrow transplantation

If a patient relapses after chemotherapy, remission is difficult to induce, then bone marrow transplantation is advised in such cases.


Q. 4. Classify anaemias. Discuss in detail the oral manifestations, diagnosis and management of pernicious anaemia.

Or

Define and classify anaemias. Discuss in detail about iron deficiency anaemia.

Or

Classify anaemias. Describe clinical features and laboratory diagnosis of iron deficiency anaemia.

Ans. Anaemia is defined as an abnormal reduction in the number of circulating red blood cells, the quantity of haemoglobin and the volume of packed red cells in a given unit of blood. The normal haemoglobin level varies from 14 to 16 g/dl in the adult male and 12 to 14 g/dl in the female.

Classification

Anaemia has been traditionally classified into:

Dyshematopoietic

Haemorrhagic and

Haemolytic anaemia.

According to the morphology (MCV, MCH and MCHC) into the following types:

Normocytic

Microcytic

Macrocytic

Normochromic

Hypochromic.

However, the recent classification is based on reticulocyte index, which is a measure of RBC production:

The reticulocyte index is increased (>2.5) due to increase in erythropoiesis in haemolytic and haemorrhagic anaemias.

A low reticulocyte index <2% shows decreased marrow production or maturation defects during erythropoiesis.

Aetiologic classification of the anaemias

I. Blood loss

Acute posthaemorrhagic blood loss

Chronic posthaemorrhagic blood loss

II. Deficiency of haemopoietic factors

Iron deficiency

Folate and vitamin B12 deficiency

Protein deficiency, i.e. diarrhoea, malabsorption

III. Bone marrow aplasia

Aplastic anaemia

Pure red cell aplasia

IV. Anaemia due to systemic infections or systemic disorders

Anaemia due to chronic infection

Anaemia due to chronic renal disease

Anaemia due to chronic liver disease

Disseminated malignancy

Endocrinal diseases

V. Anaemia due to bone marrow infiltration

Leukaemias

Lymphomas

Myelofibrosis/myelosclerosis

Congenital sideroblastic anaemia

VI. Anaemia due to increased red cell destruction (haemolytic anaemia)

Intracorpuscular defect (hereditary or acquired)

Extracorpuscular defect (acquired).

Pernicious anaemia

(Vitamin B12 deficiency, Addisonian anaemia)

Pernicious anaemia is a type of a chronic progressive, megaloblastic anaemia of adults and is caused by deficiency of intrinsic factors in stomach.

It is probably an autoimmune disorder with a genetic predisposition and the disease is associated with human leukocyte antigen (HLA) types A2,A3,B7 and A blood group.

Clinical features

Occurs rarely before 30 years of age and increases in frequency with advancing age.

No racial predilection, in other countries except in US females are more commonly affected.

The four major cardinal features of pernicious anaemia are:

a. Abnormally large RBCs

b. Hypochlorhydria

c. Neurologic and gastrointestinal symptoms

d. A fatal outcome unless the patient receives life-long injections of vitamin B12.

Generalized weakness, fatigue, headache, palpitation, nausea, vomiting, anorexia and diarrhoea.

Shortness of breath, dyspnoea, loss of weight, pallor and abdominal pain.

Patients have smooth, dry and yellow skin.

Neurological manifestations include tingling sensation in hands and feet, paraesthesia of extremities due to peripheral nerve degeneration.

Oral manifestations

Glossitis, glossodynia (painful tongue) and glossopyrosis (itching and burning tongue).

Tongue appears beefy red in colour.

Sometimes loss of papilla produces a bald appearance of tongue which is referred to as Hunter glossitis or Moeller glossitis.

Sometimes hyper pigmentation occurs in mucosa.

Histopathology

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Apr 11, 2016 | Posted by in Orthodontics | Comments Off on 15.  Haematologic diseases
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