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BDS2; CHHD > Haematology RBC Disorders > Flashcards

Haematology RBC Disorders Flashcards

1. Illustrate the haematopoietic system 2. Knowledge of red cell disorders 3. Categorise anaemia 4. Knowledge of signs and symptoms of RBC disorders 5. Interpret haematological data for RBC disorders 6. Knowledge of indices used to analyse RBC disorders 7. Elucidate dental aspects of common RBC disorders

1
Q

What is a haematopioetic stem cell

A

Cell that differentiates and matures to form different blood cell lines

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2
Q

What is erythropoiesis

A

Production of RBCs in bone marrow

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3
Q

What can reticulocyte count be used for

A

As an estimation of erythropoiesis rate

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4
Q

What are the requirements of erythropoiesis

A
  1. Healthy bone marrow to produce RBCs
  2. Healthy kidneys to produce erythropoietin
  3. Healthy liver for iron and B12 storage
  4. Healthy small intestine for vitamin absorption
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5
Q

What are the different Hb types in adults

A
  • HbA; 2 alpha and 2 beta chains
  • HbA2; 2 alpha 2 delta chains
  • HbF; 2 alpha and 2 gamma chains
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6
Q

What increases erythropoiesis

A

It is controlled by negative feedback so EPO production increases when;

  • altitude increases
  • hypoxia
  • exercise
  • cardiac/pulmonary disease
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7
Q

How long do RBCs circulate in the blood

A

120 days before kupffer cells (macrophages) engulf them

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8
Q

What is anaemia

A

When the Hb count is below the normal for a given age, gender and ethnicity

There are fewer RBCs which makes Hb low and so the blood carries less oxygen

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9
Q

Outline the four aetiological factors for anaemia

A
  1. Deficiency states; iron, folic acid, B12, coeliac/chrons (malabsorption)
  2. Bone marrow aplasia
  3. Increased destruction (haemolytic anaemia)
    - sickle cell = inherited
    - thalassemia = inherited
    - G6P dehydrogenase deficiency = inherited
    - hereditary spherocytosis = inherited
  4. Miscellaneous; chronic diseases, acute blood loss, real failure, malignancy thus bone marrow infiltration
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10
Q

What is polycythaemia

A

The opposite of anaemia; RBC overproduction

This causes increased viscosity and blood pressure and so reduces the blood flow rate - this decreases oxygen delivery = Hyper-viscosity syndrome which increases thrombosis risk

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11
Q

Outline the aetiological factors for polycythaemia

A

Primary = cancer of erythropoietic cell line

Secondary = dehydration, emphysema, altitude

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12
Q

What does polycythaemia lead to

A
  • embolism
  • heart failure
  • stroke
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13
Q

What are the morphological classifications of anaemia

A
  1. Microcytic
  2. Normocytic
  3. Macrocytic
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14
Q

What are the Hb concentration (colour) classifications for anaemia

A
  1. Hypochromic
  2. Normochromic
  3. Hyperchromic
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15
Q

What are the aetiological classifications for anaemia

A
  1. Impaired erythropoiesis
  2. RBC depletion/haemolysis
  3. Loss of RBCs due to chronic/acute bleeding
  4. Impaired RBC distribution causing hypersplenism
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16
Q

What are the causes of iron deficiency anaemia

A

This is the most common, and typically in women of childbearing age

  • acute/chronic blood loss
  • menorrhagia, GIT bleeding
  • aspirin and NSAIDS
  • vegans
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17
Q

Describe the clinical presentations of iron deficiency anaemia

A

Early stage = symptomless
Late = tiredness, dyspnoea (laboured breath)
- cold intolerance, tingling and numbness
- koilonychia (nail deformity)
- Patterson-Brown-Kelly syndrome making it hard to swallow

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18
Q

What is the relevance of iron deficiency anaemia for dentistry (SPACAA)

A
  1. Sore tongue
  2. Atrophic glossitis (dorsally); there are no filiform/fungiform papillae
  3. Angular stomatitis; maceration of skin by angle of mouth
  4. Candidiasis; creamy white lesions
  5. Aphthous ulcerations (round)
  6. Pallor of oral mucosa
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19
Q

What are the causes of B12 deficiency anaemia

A

Common in 55-60 year olds

  • pernicious anaemia = antibody to parietal cells (gastric)
  • partial gastrectomy = low levels of IF
  • crohn’s/coeliac disease = B12 malabsorption
  • nitrous oxide abuse
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20
Q

Describe the clinical presentations of B12 deficiency anaemia (same for folate deficiency)

A

Burning of the tongue

Patients are psychosomatic and can have neurological symptoms (pins + needles at extremities and visual disturbances)

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21
Q

What tests are used to diagnose B12 deficiency anaemia

A
  1. Schillings test; IM B12 given and urinary excretion is tested (no longer used)
  2. Serum B12 test
  3. Intrinsic factor antibodies = highly specific so there is rarely false positives
  4. Gastric anti-parietal cell antibody = low specificity
22
Q

How is B12 deficiency anaemia treated

A

Monthly IM B12 injections

23
Q

What is the relevance of B12 deficiency anaemia in dentistry (TUNAB)

A

Presents depapillated and beefy red tongue

Angular chelitis (inflamed corners of mouth)

Circumoral and peripheral tingling numbness

Recurrent oral ulcers

Neurological symptoms

LA is safe and conscious sedation can be given if Hb is slightly low

24
Q

What is folate needed for

A

DNA/RNA synthesis; the body cannot store folate

25
Q

What does folate deficiency cause during pregnancy

A

Cleft palate in the child

26
Q

What are the causes of folate deficiency

A

Poor intake, chronic alcoholism, malabsorption and it can be drug induced (phenytoin, cytotoxic drugs, HIV/AIDS drugs)

27
Q

What treatments are given for folate deficiency anaemia

A

Daily oral intake of folic acid tablets

28
Q

What causes haemolytic anaemia

A

Abnormalities in…

  1. Hb formation
    - sickle cell disease where 2 abnormal HbS copies inherited (most common presentation)
    - thalassemia; no alpha/beta globulin chain
  2. Erythrocyte structure (presenting as sickle cell anaemia)
    - spherocytosis = broken down
    - elliptocytosis = oval shaped
    - G6P dehydrogenase deficiency causes premature RBC metabolism
    - RBC damage by malaria and drugs
29
Q

What causes sickle cell anaemia

A

Abnormal HbS + HbC which is common in African + Afro-caribbeans

This reduces oxygen tension causing sickling; this leads to haemolysis and so haemolytic anaemia

30
Q

SS

A

Sickle cell anaemia

31
Q

AS

A

Sickle cell trait = carrier

32
Q

SC

A

Sickle Hb disease (milder SS)

33
Q

Describe the clinical presentation of sickle cell anaemia

A
  1. Obstruction of small capillaries so restricted BF to organs causing ischaemia, necrosis and damage
  2. Painful crises due to infracts of bone, CNS, spleen + lungs as small vessels are occluded
  3. Haematological crisis (aplastic); paravirus - cessation of erythropoiesis causes severe anaemia
  4. Chronic anaemia (reticulocytosis where the body compensated and overproduces stale immature RBC reticulocytes)
  5. Chronic hyperbilirubinaemia; due to heam breakdown giving bilirubin which circulates in the body causing jaundice and gall stones
  6. Increased susceptibility to infections; meningitis and pneumonia = treated with penicillin
  7. Sequestration syndrome; chest and septicaemia (spleen)
34
Q

What is the relevance of sickle cell anaemia in dentistry

A

Orofacial manifestations present:

  • painful infarcts in jaw/osteomyelitis
  • hypercementosis
  • XS overjet/overbite due to enlarged haematopoietic maxilla
  • hypo mineralised teeth

Patients with SS should always be investigated before GA and given early infection management

  1. Prevent infections, hypoxia, acidosis and dehydration and these precipitate crisis
  2. Manage infection early
35
Q

Give examples of safe analgesics to use for someone with sickle cell anaemia

A
  • paracetamol

- codeine

36
Q

What is aplastic anaemia

A

A rare condition where the bone marrow is non-functional; Pancytopenia (leukopenia, thrombocytopenia and anaemia)

37
Q

What causes aplastic anaemia

A

Pancytopenia; leukopenia, thrombocytopenia + anaemia

Ideopathic causes; benzene, irradiation, hepatitis

Autoimmune disorders

Drugs = NSAIDs, allopurinol, anticonvulsants, cytotoxic drugs

38
Q

Describe the clinical presentation of aplastic anaemia

A

Anaemia, bleeding, increases susceptibility to infection, purpura is the first manifestation

39
Q

How is aplastic anaemia treated

A

Similar treatment to that of leukaemia

40
Q

Who is more at risk of thalassaemia and what is this

A

Asians, meditaranians and middle easterns - this is a disorder in globing chain reduction = autosomal recessive

41
Q

What does G6P dehydrogenase deficiency cause

A

RBC metabolic disorder causing Hb to denature by haemolysis and this is X-linked recessive

42
Q

What does hereditary spherocytosis cause

A

Spherical RBCs which undergo haemolysis; this is autosomal dominant

43
Q

What is polycythaemia vera

A

Where blood viscosity is increased which increases risk of thrombosis

44
Q

What key investigations are taken for patients queried anaemia

A
  1. FBC pf Hb, MCV, MCH, red cell distribution width
  2. Blood film which shows RBC shape
  3. Sickledex
  4. Hb electrophoresis which measures different Hb types
  5. Serum B12/folate/iron studies
45
Q

Outline management for RBC disorders

A
  • eliminate underlying disease
  • replacement therapy; folate, IM B12, ferrous sulphate/ fumerate
  • blood transfusion
  • erythropoietin
46
Q

What is erythropoietin

A

EPO hormone; stimulates bone marrow to release RBCs

47
Q

How is erythropoiesis increased

A

Reduced O2 is detected in the kidneys (and liver) to release erythropoietin which stimulates red bone marrow to increase the RBC count

48
Q

What are the special investigations and treatments for iron deficiency anaemia

A
  • FBC
  • Iron studies

Oral iron supplements and treatment of the underlying cause

49
Q

List the dental aspects of folate deficiency

A
  1. Soreness of the tongue without depapilation/colour change
  2. Atrophic glossitis
  3. Angular stomatitis
50
Q

Describe oral manifestations of aplastic anaemia (PUBS)

A

Similar to leukaemia :

  • ulcerative lesions of oral mucosa
  • oral petechiae
  • spontaneous gingival bleeding
  • gingival swelling if cyclosporin given

BDS2; CHHD (32 decks)

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