Anaemia Flashcards
(26 cards)
What is anaemia defined as and what causes it?
Low Hb concentration
<135g/L in men and <115g/L in women
Due to ether a low red cell mass or increased plasma volume
-> reduced production or increased loss of RBCs
What are the symptoms of anaemia?
Fatigue, dyspnoea, faintness, palpitations, headache, tinnitus, anorexia, angina if there is pre-existing coronary artery disease
What are signs of anaemia?
Pallor (E.g. of the conjunctivae)
In severe anaemia (<80g/L) signs of hyperdynamic circulation (e.g. tachycardia, flow murmurs, cardiac enlargement, retinal haemorrhages
What are the types of anaemia?
Low mean cell volume - microcytic anaemia:
Iron deficiency anaemia
Thalassaemia
Sideroblastic anaemia
Normal MCV (normocytic anaemia)
Acute blood loss Anaemia of chronic disease Bone marrow failure (also low WCC or low platelets) Renal failure Hypothyroidism Haemolysis Pregnancy
High MCV (macrocytic anaemia)
B12 or folate deficiency Alcohol excess or liver disease Reticulocytosis Cytotoxics Myelodysplastic syndormes Marro infiltration Hypothyroidism Antifolate drugs (phenytoin)
What are causes of microcytic anaemia?
Iron deficiency anaemia
Thalassaemia - genetic diseases of unbalanced Hb synthesis with underproduction of one global chain.
Sideroblastic anaemia - think sideroblastic anaemia when microcytic anaemia is not responding to iron. - Ineffective erythropoiesis leading to increased iron absorption, iron loading in marrow and haemosiderosis (endocrine, liver and heart damage due to iron deposition)
.
MCV<76
What are causes of normocytic anaemia?
MCV 76-96
Acute blood loss Anaemia of chronic disease Bone marrow failure Renal failure Hypothyroidism Haemolysis Pregnancy
What causes macrocytic anaemia?
MCV > 96
B12 or folate deficiency Alcohol excess/liver disease Reticulocytosis - young larger RBCs signifying active erythropoiesis - increased in haemolytic, haemorrhage Cytotoxics Myelodysplastic syndromes Marrow infiltration Hypothyroidism Antifolate drugs (phenytoin)
When is blood transfusion indicated?
Hb > 70g/L acute anaemia
In severe anaemia with heart failure, t transfusion is vital but must be given slowly with furosemide - check for signs of worsening overload - rising JVP and basal crackles
What are causes of iron deficiency anaemia?
Blood loss e.g. menorrhagia or GI bleeding
Poor diet or poverty may cause IDA in babies or children
Malabsoprtion (coeliac’s disease) is a cause of refractory IDA
Hookworm (GI blood loss) in tropics
What are signs of chronic IDA?
Koilonichia (spooning of nails)
Atrophic glossitis
Angular cheilosis (stomatitis - ulceration at the side of mouth)
What tests for IDA?
Blood film: microcytic anaemia
Low ferritin
Check coeliac serology - if negative refer all males and females who are not mentruating for urgent gastroscopy and colonoscopy
How is IDA treated? SE?
Oral iron (ferrous sulphate) SE: nausea, abdo discomfort, diarrhoea or constipation, black stools.
Hb should rise by 10g/L a week with a modest reticulocytosis
Continue for 3 months after Hn normalises
IV iron only indicated if oral rout is impossible or ineffective (chronic renal failure where there is inadequate mobilisation of iron stores in response to Epo therapy)
What is anaemia of chronic disease?
Secondary anaemia
Arises from:
Poor use of iron in erythropoiesis
Cytokine induced shortening of RBC survival
Reduced production of and response to erythropoietin
Moild normocytic or microcytic anaemia
Check blood film, B12, folate, RSH and haemolytic
Treat underlying disease
IV iron if there is functional deficiency
Erythropoietin
What are side effects of erythroietin
Flu-like symtppoms
Hypertension
Mild raise in platelets
Thromboembolism
What is sideroblastic anaemia? When should you suspect it? Treatment?
When microcytic anaemia is not responding to iron, suspect sideroblastic anaemia.
Ineffective erythropoiesis leading to increased iron absorption, iron loading in marrow and haemosiderosis (endocrine, liver and heart damage due to iron deposition)
Raised ferritin
Treat cause
Pyridoxine ± repeated transfusions for severe anaemia
What are causes of macrocytosis?
MCV > 96
Megaloblastic - megaloblast is a cell in which nuclear maturation is delayed compared with the cytoplasm. Occurs in B12 and folate deficiency as these are required for DNA synthesis.
Non-megaloblastic: alcohol excess, reticulocytosis e.g. in haemolytic, liver disease, hypothyroidism, pregnancy
Other haematological disease
What tests for macrocytic anaemia?
B12 and folate levels
Blood films
LFT (GGT) , TFT, seum B12, serum folate
Bone marrow biopsy if the cause is not revealed by above
Where ifs folate found, where is is absorbed? What causes its deficiency?
Found in green vegetables, nuts, yeast, liver
Synthesised by gut bacteria
Absorbed by duodenum/proximal jejunum
Causes of deficiency:
Poor diet - poverty, alcoholic, elderly
Increased demand - pregnancy or increased cell turnover in haemolysis, malignancy
Malabsorption - coeliac disease
Alcohol
Drugs - anti-epileptics (valproate, phenytoin), methotrexate, trimethoprim
What does maternal folate deficiency cause?
Neural tube defects
How is folate deficiency treated?
Assess for underlying cause
Folic acid 5mg/day PO for 4 months
With vitamin B12
In pregnancy, prophylactic doses of folate are given from conception.
What is vitamin B12 for?
Water soluble vitamin - helps synthesise DNA so in deficiency, RBC production is slow.
What are causes of B12 deficiency?
Dietary e.g. vegans, B12 is found in meat fish and dairy
Malabsorption: during digestion, intrinsic factor in the stomach binds B12 enabling it to be absorbed in the terminal ileum - malabsorption can therefore arise in the stomach due to lack of intrinsic factors (pernicious anaemia, post- gastrectomy) or the terminal ileum (ideal resection, Crohn’s, bacterial overgrowth)
What are features of B12 deficiency?
Symptoms of anaemia
Lemon tinge to skin due to pallor and mild jaundice due to haemolysis
Glossitis
Angular stomatitis
Neuropsych: irritable, depression, psychosis, dementia
Neurological: Parasethesia, peripheral neuropathy
Subacute combined degeneration of the spinal cord - periphaer sensory neuropathy with UMN and LMN signs due to low B12. Classi triad of: Extensor plantar reflex UMN Absent knee jerks LMN Absent ankle jerks LMN
Insidious onset and signs are symmetrical
DCML loss causing sensory (joint position and vibration) and LMN signs and corticospinal tract loss causing motor and UMN signs. Spinothalamic tracts are preserved so pain and temperature remain in tact.
What is pernicious anaemia?
Autoimmune condition in which atrophic gastritis leads to a lack of intrinsic factors secretion from the parietal cells of the stomach.
Dietary B12 therefore remains unbound and cannot be absorbed by the terminal ileum.
