List I - Act Core Conditions Flashcards
What is anaemia?
- Low (Hb) due to either low RBC mass (low production/increased loss) or
- Increased plasma volume (e.g. pregnancy - haemodilution as increased plasma volume > increased RBC)
What are the normal values of Hb?
- Males - 13-18g/dL
- Females - 11.5-16g/dL
Higher in neonates, lower in younger children
How much iron is contained within the blood?
- 1mL blood contains 0.5mg iron
- Body stores are regulated by absorption (duodenum, jejunum)
- No active excretion occurs (small daily losses in the urine, faeces and sweat)
What are the daily requirements of iron?
- Adults
- Males - 1 mg
- Females - 2 mg if menstruating, 3 mg if pregnant
- Absorption
- Haem iron in meat readily absorbed, but in vegetables/cereals is part of amino/organic acid complex requiring release/reduction from Fe3+ to Fe2+ for absorption (promoted by gastric HCl acid and ascorbic acid in food)
What are the causes of iron deficiency anaemia?
- Chronic blood loss - menorrhagia, (occult) GI bleeds (PUD, colonic angiodysplasia, gastric/colorectal Ca)
- Increased requirements - childhood, pregnancy
- Poor diet (developing countries) - usually babies, children, special diets, poverty (rarely adults)
- Malabsorption (causes refractory IDA) - gastrectomy, coeliac disease
- Malnutrition, hookworm - most common in the tropics
How common is iron deficiency anaemia?
- Common (up to 14% of menstruating females)
- Most common cause of anaemia worldwide
- F>M
What is the pathophysiology of iron deficiency anaemia?
- Latent iron deficiency (initial depletion of iron stores is asymptomatic)
- Iron deficiency anaemia (when reticuloendothelial stores - haemosiderin/ferritin - are completely depleted)
- Symptomatic (only when Hb falls)
- Leads to tissue hypoxia (rate of development and commorbidity reflects severity)
- Acute IDA has worse severity as there is no time for the body to compensate for reduced O2 carrying capacity
What are the presenting clinical symptoms of IDA?
- Symptoms
- Acute IDA - SOB, faintness, palpitations, headache, tinnitus, anorexia, angina/claudication (if occult co-existent disease)
- Chronic IDA - fatigue, dysphagia (if post-cricoid mucous web), restless leg syndrome
- PMH - menorrhagia, GI bleeds, pregnancy, gastrectomy, coeliac disease
- SH - food diary
- DH - PPI (can also lead to IDA)
What are the presenting clinical signs of IDA?
- Signs
- Mild to moderate - may be absent (even in severe), palmar/conjunctival pallor
- Severe (signs of hyperdynamic circulation) - bounding pulse, tachycardia, ejection systolic flow murmur (loudest over apex), cardiac enlargement, retinal haemorrhage (rare), heart failure (later: rapid transfusion may be fatal)
- Chronic IDA - koilonychias, atrophic glossitis, angular chelitis (painful cracking at corners of mouth), oesophageal / post cricoid web (Plummer-Vinson Syndrome)
- Examination - always do GI examination and include PR
What is Plummer-Vinson Syndrome?
- Triad of the following:
- Dysphagia (secondary to oesophageal/cricoid webs)
- Glossitis
- Iron deficiency anaemia
- Associated with chronic IDA
- Treatment includes iron supplementation and dilation of the webs
What does FBC demonstrate typically in IDA?
- Hypochromic microcytic anaemia
What are the other blood pictures of IDA?
- Low MCV (microcytic)
- Low iron (hypochromic)
- High total iron-binding capacity (TIBC)/transferrin -reflects low iron stores
- Low transferrin saturation
- Low serum ferritin - correlates with iron stores
- Blood film - anisopoikilocytosis (RBC’s of different sizes and shapes), target cells, ‘penicil’ poikilocytes
What are the differential diagnoses of IDA?
- Anaemia of chronic disease (same but with high ferritin)
- Serum iron low <15
- TIBC High
- Ferritin High
- Chronic haemolysis
- Serum iron High
- TIBC Low
- Ferritin High
- Haemochromatosis
- Serum iron High
- TIBC Low / Normal
- Ferritin High
- Pregnancy
- Serum iron High
- TIBC High
- Ferritin Normal
- Sideroblastic anaemia
- Serum iron High
- TIBC Normal
- Ferritin High
What can cause ferritin to rise?
- Inflammation
- Infection
- Malignancy
What can cause variation in RBC size (anisocytosis)?
- IDA
- Thalassaemia
- Megaloblastic anaemia
What can cause variation in RBC shape (poikilocytosis)?
- IDA
- Thalassaemia
- Myelofibrosis
What is the clinical manifestation of haemolytic anaemia in blood?
- Jaundice
What is the clinical manifestation of B12 deficiency?
- Neurological symptoms/signs
What can cause a rise in platelets?
- Acute blood loss
* Anaemia of chronic disease (due to inflammatory process)
What can cause a fall in platelets?
- Bone marrow failure/megaloblastic anaemia (WCC fall)
What are the appropriate blood investigations of IDA?
- Bloods
- FBC (Hb low, MCV low, MCH low, MCHC low, normal WCC/platelets
- Ferritin low
- Serum iron low
- TIBC (total Fe-binding capacity) high
What imaging can be done for IDA?
- Barium enema
What special tests should be done to investigate IDA?
- PR examination
- Endoscopy
- Gastroscopy (OGD)
- Colonoscopy (or sigmoidoscopy)
- Stool for OC and P (ova: hookworm, cysts, parasites)
- Bone marrow aspiration - rare
What is the conservative approach to management of IDA?
- Conservative - management with dietary intake increase e.g. dark green leafy vegetables, meat, iron fortified bread