Term
| Haemoglobin is made up of how many protein chains? |
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Definition
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Term
| What is haemoglobin and what is its main role? |
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Definition
| Haemoglobin is a metalloprotein tetramer found in red blood cells, its main role is in the transportation of oxygen around the body. |
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Term
| What is required for the synthesis of haemoglobin? |
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Definition
| Iron, protoporphyrin, haem and globins (alpha and beta). |
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Term
| What is the lifespan of a red blood cell? |
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Definition
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Term
| Describe Hereditary elliptocytosis |
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Definition
| A group of gentic disorders resulting in the malformation of ertyhrocytes reducing their potential oxygen capacity and theur life span. |
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Term
| What is the most common medical condition associated with glucose-6-phosphate dehydrongenase deficiency? |
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Definition
| Haemolytic anaemia, the deficiency i the enzyme causes the premature break down of RBC's this rate of hamolysis is faster than the rate of RBC production. |
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Term
| What symptoms would lead you to teh differential of haemolytic anameia? |
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Definition
| Palor, jaundice, dark urine, fatigue, SOB, and tachycardia. |
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Term
| Glucose-6-dehydrogenase deficiency contirbutes to what condition in newborns? |
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Definition
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Term
| Iron deficient anaemia would result in what change of RBC's? |
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Definition
Less iron +Hb > More divisions > smaller cells
Less Iron or globin chains results in a decrease of haemoglobin, cell divisions are controlled by the Hb concentration. |
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Term
| B12/Folate deficient anaemia would result in what change of RBC's? |
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Definition
Less DNA > Less divisions > Bigger cells.
B12/Folate deficiency interferes with DNA replication therefore resulting in a reduction of DNA. |
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Term
| Name two conditions caused by abnormal haemoglobin. |
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Definition
Sickle cell anaemia- Beta chain point mutation resulting in a conformational change.
Thalassaemia- Alph and/or Beta chain point mutations, deletions or translocations. |
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Term
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Definition
The inability or reduced ability to produce one of the globin chain required to make Hb.
Alph Thal- More common in mediterranean, middle east and south asian pops.
Beta thal- More common in west african pops. |
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Term
| Describe the genetic component of thalassaemia |
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Definition
| Autosomal recessive disorder, varying severity dependent on the number of affected alleles. Thalassaemia major/minor. |
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Term
| Describe Hydrops foetalis |
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Definition
| Excess fluid in neaonates resulting in heart failure, occurs in foetal alpha thlassaemia as foetal HB composed of alpha and gamma globins. |
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Term
| These signs/symptoms are indaicative of what? Anaemia, Jaundice, Splenomegaly/Hepatomegaly, Iron Overload, Frontal Bossing & Maxillary Prominence, Shortened Fingers & Limbs and Profound Microcytosis |
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Definition
Moderate Thalassaemia.
Anaemia
Profound Microcytosis - Often only slightly anaemic, but very microcytic
Jaundice, Splenomegaly/Hepatomegaly - Due to haemolysis & breakdown within organs
Frontal Bossing & Maxillary Prominence - Due to expansion of bone marrow‘Hair On End’ sign on X-Ray
Shortened Fingers & Limbs - Due to ischaemia & premature closure of epiphyseal plates (due to poor Hb carriage of O2)
Iron Overload - Can lead to complications e.g. cirrhosis |
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Term
| What investigations and results would allow for a diagnosis of thalassaemia? |
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Definition
Bloods- Microcytic, hypochromic RBC's with reticulocytes present.
Genetic testing
X-rays showing thickened 'hair on end' bone. |
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Term
| What are the management options for thalassaemia? |
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Definition
| Regular, long term trabsfusions, iron chelation (removal)e.g desferrioxamine. |
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Term
| Define Sickle cell anaemia |
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Definition
| Genetic condition resulting in the production of HbS, therefore casuing RBC sickling, haemolytic anaemia and vaso-occlusive events. |
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Term
| Where is sickle cell anameia most prevalent and what are the benefits of this? |
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Definition
| African populations, sickle trait is maalria resistant. |
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Term
| What genetic component is required for inheritence of sickle cell? |
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Definition
| Recessive allele caused by a single amino acid substitiution in the beta globin,producing HbS. Therefore 2 alleles needed for inheritence of symptoms. |
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Term
| Hypoxic stress, increase blood acidity, dehydration and anaethesia may cause a 'sickle attack' in sickle cell carriers, what pathological events might you expect? |
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Definition
| Vaso-occlusive events, haemolytic anameia. |
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Term
Explain the presentation of both these acute and chronic symptoms/signs of sickle cell anaemia.
Acute:
Pain
Fatigue
Organ Damage +/- Stroke
Acute Splenic Sequestration
Jaundice
Shortened limbs/digits
Chronic:
↑Infection
Dactylitis |
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Definition
Acute:
Pain - Due to occlusion/ischaemia
Fatigue - Due to anaemia
Organ Damage +/- Stroke - Esp. Lungs, Heart, Eyes
Acute Splenic Sequestration - Pooling of blood due to occlusion, producing hypovolaemia
Jaundice
Dactylitis - Swelling/inflammation of hands & feet due to occlusion
Chronic:
↑Infection - Due to infarction & ischaemia, esp. due to skin ulcers
Shortened limbs/digits - Due to infarction of epiphyseal plates during growth |
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Term
Describe the four potential crises in sickle cell:
Thrombotic Crises
Haemolytic Crises
Aplastic Crises
Sequestration Crises |
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Definition
Thrombotic (aka Vaso-Occlusive) Crises - Precipitated by infection/dehydration/↓O2
Infarcts occur in organs, incl. bones, lungs, spleen, brain, hands/feet
Sequestration Crises - Sickling in organs (esp spleen/lungs) leading to pooling of blood. May cause ARDS - Dyspnoea, Chest pain, Pul Infiltrates, ↓pO2
Aplastic Crises - Caused by Parvovirus Infection, Causes Anaemia with ↓Reticulocyte count
Haemolytic Crises - Rare
Sudden onset anaemia & ↑[unconj. bilirubin]serum, jaundice |
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Term
| What investigations and results would be required to confirm a diagnosis of sickle cell anaemia? |
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Definition
FBC
Blood film- sickle cells, howell-jolly bodies
Haemoglobin electrophoresis |
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Term
| How would you manage an acute sickle cell exacerbation? |
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Definition
O2
Analgesia - IV Morphine
Fluid Resuscitation & Keep Warm
Empirical ABX e.g. Cephalosporin - If T >38, or chest sx.
Monitor bloods, reticulocytes, & liver/spleen size
Blood Transfusion - If ↓Hb or ↓Reticulocyte count |
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Term
| How is sickle cell chronically managed? |
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Definition
| Genetic counselling, folic acid (zinc supplemantation?), treat hyposplenism (prophylactic ABX, vaccinations) |
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