Red Blood Cell Disorders Flashcards
What kind of stem cell differentiates and matures to form different blood cell lines
Hematopoietic stem cells
What is erythropoiesis
The process that produces RBCs
Describe the structure of Hb
4 proteins chains, 2 alpha and 2 beta, each chain has a heme group
What stimuli are there to increase erythropoiesis
Low level of O2
High altitude
Increase in exercise
Loss of lung tissue in emphysema
Describe the feedback mechanism of erythropoiesis
Negative:
- reduced O2 levels in blood
- kidney releases erythropoietin
- erythropoietin stimulates red bone marrow
- enhanced erythropoiesis increases RBC count
- increases O2 carrying ability of blood and then yeh lol
What are the 2 types of red cell disorders
- Anaemia
- Polycythaemia
Describe features anaemic red cell disorders
- Defined as Hb below the normal for the age, gender and ethnic background
- ↓ red blood cells, ↓ Hb level or defective Hb
- ↓ oxygen carrying capacity of blood
Describe features polycythaemia red cell disorders
- Over-production of red blood cells
- ↑ Viscosity & BP, decrease flow rate of blood with ↓ O2 delivery
- Lead to embolism, stroke or heart failure
How does primary polycythaemia occur
Due to cancer of erythropoietic cell line in the red bone marrow
How does secondary polycythaemia occur
From dehydration, emphysema, high altitude
What causes reduced erythrocyte and Hb production
Deficiency States -
- Iron deficiency
- Folic acid deficiency
- Vitamin B12 deficiency
- Coeliac/Crohn’s disease (malabsorption or iron folic acid and B12)
- Bone marrow Aplasia
Name some etiological factors that cause anaemia
- Increased RBC destrcution
- Anaemia of chronic disease
- Acute blood loss
- Chronic renal failure associated anaemia
- malignancy related, bone marrow infiltration associated anaemia
what can cause increased destruction of RBCs and lead to anaemia
- Sickle cell anaemia
- Thalassemia major/minor
- Glucose-6-phosphate dehydrogenase deficiency
- Hereditary spherocytosis
What does microcytic mean
Smaller RBCs
What are hypo chromic RBCs
RBCs with less colour under microscope due to less Hb
What does microcytic mean
Larger RBCs
What do MCH and MCV mean
MCV = measure of average size of your RBCs MCH = measure of Hb and colour in RBCs
How are MCV and MCH affected with microcytic + hypochromic RBCs
MCV and MCH are lowered
How are MCV and MCH affected with macrocytic RBCs
MCV and MCH are raised
What is the most common anaemia and which population does it occur most often
Iron deficiency anaemia
Predominant in women of child bearing age
What are some of the causes of iron deficiency anaemia
Acute or chronic blood loss Menorrhagia GI bleeding Chronic intake of aspirin and NSAIDs Iron deficiency (vegans)
what arrest clinical features of iron deficiency anaemia
Early - none Late - - Tiredness - Dyspnoea - Palpitations - Tachycardia - Conjunctiva pallor - Cold intolerance, tingling and numbness of extremities - Koilonychia, Patterson-Brown-Kelly syndrome
What are the dental aspects of iron deficiency anaemia
- Sore tongue
- Atrophic glossitis
- Cadidiasis
- Angular stomatitis
- Apthous-like ulcerations
- Pallor of oral mucosa
What investigations and treatments are done for iron deficiency anaemia
Investigations = FBC and iron studies Treatment = oral iron supplements, treat underlying cause
Who commonly get B12 deficiency and what is the initial complaint they give
- Common in older women
- Burning of the tongue with no obvious abnormality on examination (psychosomatic)
What are the causes of B12 deficiency
- Pernicious anaemia (autoantibody to gastric parietal cells)
- Partial gastrectomy (low levels of intrinsic factors)
- Crohn’s/Coeliac disease (malabsorption of B12)
- Nitrous oxide abuse
What are the dental aspects of B12 deficiency
- Depapillated and beefy red tongue
- Angular chelitis
- Recurrent oral ulcers
- Circumoral and peripheral tingling, numbness
- LA is safe
- Conscious sedation can be given if Hb slightly low
What investigations and treatment are used for B12 deficiency
- Serum Vitamin B12 levels
- Intrinsic factor antibodies/ Gastric anti-parietal cell antibodies
Treatment - monthly IM injection of Vitamin B12
List the aetiology of folate deficiency
- Poor intake, poverty dietary ignorance, chronic alcoholism
- Malabsorption
- Drug induced
What drugs can induce folate deficiency
Phenytoin, cytotoxic drugs, HIV/AIDs drugs
Describe the clinical features of folate deficiency
Same as B12 deficiency without neurological symptoms
What are the dental aspects of folate deficiency
- Soreness of the tongue without depapillation/colour change
- Atrophic glossitis
- Angular stomatitis
What investigations and treatment are used for folate deficiency
Investigations - Serum folate level
Treatment - daily oral intake of folic acid tablets
What are the abnormalities found in haemolytic anaemia
- Haemoglobin formation
- Erythrocyte structure/function
- RBC damage by external function (malaria, drugs)
What abnormalities of haemoglobin formation can cause haemolytic anaemia
Sickle cell disease
Thalassaemia’s
What abnormalities of erythrocyte structure/function can cause haemolytic anaemia
- Spherocytosis
- Glucose-6-phosphate dehydrogenase deficiency
What forms of Hb are present in people with SCA
HbS and HbC
What populations have this most commonly
African and afro-carribeans
What kind of inheritance gives SCA
Autosomal recessive
How does SCA work
Reduced oxygen tension causes sickling resulting in significant red blood cells breakdown (haemolysis)
What are the clinical features of SCA
- Painful crises due to infarcts of bone, CNS, spleen and lungs
- Haematological crises (aplastic)
- Susceptible to infections (meningococci, pneumococci)
- Chronic anaemia
- Chronic hyperbilirubinaemia (jaundice, gall stones)
- Sequestration syndrome (acute chest syndrome)
What are some orofacial manifestations of SCA
- Painful infarcts in jaw or osteomyelitis
- Hypercementosis
- Excessive overjet and overbite ~ enlarged haemopoietic maxilla
- Hypomineralised teeth
Besides orofacial manifestations what are the dental aspects of SCA
- Prevent infections, hypoxia, acidosis or dehydration ~ precipitate crisis
- Early management of infection
- Patient at risk must be investigated prior to GA
- Paracetamol and codeine ~ safe analgesics
What is aplastic anaemia
- Non-functioning bone marrow
- Rare
- Pancytopenia ~ leukopenia, thrombocytopenia and anaemia
What are the causes aplastic anaemia
- Idiopathic ~ exposure to benzene, irradiation, viral infections i.e hepatitis - Autoimmune disorders
- Drugs ~ NSAIDs, allopurinol, anticonvulsants, cytotoxic drugs
What are the clinical features
- Purpura is often the 1st manifestation
- Anaemia (normochromic, normocytic or macrocytic; fatigue, shortness of breath, pale skin)
- Susceptibility to infection
- Bleeding
What treatment modifications need to made in aplastic anaemic patients
- Anaemia (e.g. conscious sedation and GA should be avoided)
- Haemorrhagic tendencies
- Susceptibility to infections
What are the oral manifestations you can see in patients with aplastic anaemia
- Ulcerative lesions of oral mucosa, oral petechiae, spontaneous gingival bleeding etc.
- Gingival swelling if ciclosporin is used
What is thalassemia
Red cell disorder most common in patients of asian, mediterranean and middle east descent
What is Glucose-6-phosphate dehydrogenase deficiency
RBC metabolic disorder - Hb denaturation, haemolysis
What is hereditary spherocytosis
RBC disorder that causes spherical red blood cells - haemolysis
What is polycythaemia vera
Over production of RBCs, thrombosis is a complication
What are some of the key investigations for SCA
- FBC (Hb, MCV, MCH and RBC distribution width
- Blood film
- Sickledex
- Haemoglobin electrophoresis
- Serum B12
- Serum folate
- Serum iron studies (iron, ferritin, total iron biding capacity)
What are the symptoms of Microcytic anaemia + MCV<80fL
- Iron deficiency
- Thalassemia*
- Sideroblastic anaemia*
What are the symptoms of macrocytic anaemia + MCV>100fL
- Vitamin B12 deficiency
- Folate deficiency
- Alcoholism*
- reticulocytosis*
- hypothyroidism*
- Multiple myeloma*
- Myelodysplasia*
- Aplastic anaemia*
What are the symptoms of normocytic anaemia + MCV 80-100 fL
- chronic disease
- haemolytic anaemia
- acute blood loss*
marrow infiltration*
What can be done to manage anaemias
- Eliminate the underlying disease
- Replacement therapy
- Blood transfusion (acute haemolysis/blood loss)
- Erythropoietin (chronic renal failure and anaemia of chronic disease)
What replacement therapies can be used for anaemia
- Iron-ferrous sulphate, ferrous fumerate
- Folate
- IM B12
