Haemotology + Oncology Flashcards
What are the (3) grouped causes of iron-deficiency anaemia?
- Insufficient intake → in infants, this may be due to prolonged breastfeeding without supplements + over-reliance on cow’s milk diet; in adolescents, the main cause is insufficient red meat, fish, chicken, greet vegetables or pulses
- Malabsorption → coeliac disease
- Chronic blood loss → eg. meckel’s diverticulum, H. Pylori gastritis or menorrhagia
What are the risk factors for iron-deficiency anaemia?
- prematurity
- low birth weight
- babies exclusively breastfed after six-months old
- older infants who drink cow’s milk exclusively
What is the clinical presentation of iron-deficiency anaemia?
- Normally asymptomatic till 6-7g/dl of Hb reached, often found incidentally when blood tests are done for other reasons
- Fatigue, irritability, anorexia
- Pallor of conjunctiva, tongue + palmar creases
- “Pica” → described inappropriate eating of non-food materials eg. soil, rubber
What are the investigations for iron-deficiency anaemia?
- FBC:
- MCV → microcytic
- MCH → hypochromic
- Low serum ferritin reflecting low iron store
- Blood film shows small hypochromic erythrocytes
- Diet history may reveal insufficient iron intake
What are preventative dietary modifications for iron-deficiency anaemia?
- eating daily iron requirements of 1mg/kg everyday by eating iron-rich foods (eg. red meat, liver, kidney + oily fish)
- vitamin C increases absorption of iron
- not drinking cow’s milk in preference to breast milk and not converting too early to cow’s milk
What is the treatment for iron-deficiency anaemia?
- Address underlying cause
- Dietary advice
- Iron replacement therapy
- Rarely, tranfusion in acute setting
- Oral iron supplements to be continued for at least 2-3 months after target iron levels are achieved to replenish iron stores
What is the aetiology of sickle cell disease?
- In sickle cell, there is substitution of amino acid valine for glutamic acid in the DNA coding for haemoglobin results in a functionally impaired beta-globin chain
- Such haemoglobin is known as HbS
- Condition causes red cells to deform when deoxygenated leading to so-called “sickling” of the RBC
- Severity of clinical course depends on the amount of HbS present
- Deformed RBC can get stuck in the small blood vessels of the body which results in hallmark “sickle-cell crisis”, a painful vasocclusive crisis
Microvascular occlusion results in ischaemia in an organ or bone, which is the cause of many of the clinical manifestations of sickle cell disease. They are very painful and can occur anywhere in the body.
What can a vaso-occlusive crisis be triggered by?
- Hypoxia
- Cold
- Infection
- Dehydration
- XS exercise or stress
What are the different types of sickle cell?
- Sickle-cell anaemia (HbSS) → person is homozygous for HbS and therefore produces no normal B-globin
- Sickle-cell B-thalassaemia → HbS is inherited from one parent, and B-thalassaemia from the other; the severity depends upon the amount of normal B-chain synthesis
- Sickle-cell haemoglobin C disease → HbS is inherited from one parent and HbC (another point mutation on B-globin gene) from other; milder form of sickle cell disease
- Sickle-cell trait → HbS inherited from one parent and normal Hb from other; only about 40% of Hb is HbS so they are generally asymptomatic apart from when in conditions of low oxygen tension eg. under anaesthesia or at high altitudes; they are described as carriers of HbS
What is the clinical presentation of sickle cell disease?
-
Anaemia presents at 6 months of age when HbF conc is greatly decreased, acute anaemia can develop due to:
- Haemolytic crises (associated w/ infection)
- Aplastic crises (often caused by parvovirus B19)
- Sequestration crises (enlargement of speel w/ abdo pain + circ collapse)
- Painful vaso-occlusive crises
- Infection → sepsis, osteomyelitis, pneumococci, haemphilus influenzae
- Priapism (painful erection) → needs urgent treatment as may lead to fibrosis w/ subsequent erectile dysfunction
- Splenomegaly (common in children)
What are the different types of ALL?
- Common ALL (75%), CD10 present, pre-B phenotype
- T-cell ALL (20%)
- B-cell ALL (5%)
What are long-term complications of sickle cell disease?
- Short stature and delayed puberty
- Cardiac enlargement and heart failure as a result of chronic anaemia
- Renal damage can result in an inability to concentrate urine causing enuresis and dehydration
- Adenotonsillar hypertrophy causing sleep apnoea syndrome leading to nocturnal hypoxaemia which may trigger vaso-occlusive crises
- Gallstones can develop due to excessive bilirubin production
- Cognitive problems not only due to strokes but also due to subtle cerebral damage that occurs
- Psychosocial problems
What is the prevention of sickle cell disease?
- Once daily folic acid supplements to meet the increased demand caused by increased haemolysis
- Prompt treatment of infection
- Presence of hyposplenism indicates the need for twice daily phenoxymethylpenicillin prophylaxis
- Avoiding exacerbating factors
What is the management for painful crises?
- Analgesia, opiates if severe + hydration
- Oxygen if decreased oxygen saturation + antibiotics if infection
- Blood transfusion if priapism, stroke or acute chest syndrome
For recurrent painful crises → hydroxyurea can be given to increase the production of HbF, if a suitable donor can be found then a bone marrow transplant can be done
Acute lymphoblastic leukaemia (ALL) is the most common malignancy affecting children and accounts for 80% of childhood leukaemias. The peak incidence is at around 2-5 years of age and boys are affected slightly more commonly than girls.
What are clinical features of ALL?
- anaemia → lethargy + pallor
- neutropaenia → frequent or severe infections
- thrombocytopenia → easy bruising, petechiae
- bone pain (secondary to bone marrow infiltration)
- splenomegaly
- hepatomegaly
- fever is present in up to 50% of new cases
- testicular swelling
Blood film may show evidence of circulating blast cells
