Dr Toni Hazell offers 10 practical tips exploring the best ways to investigate and manage anaemia in adults, and how to address patient concerns Show
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1. Know the definition and pathophysiology of anaemiaAnaemia is the most common haematological abnormality seen in general practice.1 NICE defines anaemia as a haemoglobin (Hb) level of:2,3
Red blood cells are made in the bone marrow by erythropoiesis, then released into the circulation as reticulocytes, developing into mature red blood cells 1 day later. These mature cells circulate for around 3 months and are then removed by macrophages. In a healthy patient, the rate of blood cell production and the rate of loss is balanced; in a patient with anaemia this balance is disrupted, for example due to reduced production or increased destruction of red blood cells, or because of significant blood loss.1 2. Be aware of the common causesManagement of anaemia depends on finding a cause, which usually requires further blood tests. The most common cause is iron deficiency.1 Anaemia is usually classified by the mean corpuscular volume (MCV) as follows:1
Table 1 includes suggestions for potential differential diagnoses. Table 1: Differential diagnoses for different types of anaemia1
3. Take a history and examine the patientThe tradition of following the ‘history, examination, investigations’ process often gets turned on its head—GPs may be sent the result of a full blood count (FBC) requested elsewhere and it is not always clear what the indication was. Private screening services also send their abnormal results to general practice, as do extended hours and hub doctors. If you did not request the test it is vital to take a history and examine the patient. Make sure the patient is haemodynamically stable—if they are not, or if there is recent bleeding, then you may need to arrange an emergency admission. Transfusion can be considered if the patient has a haemoglobin level of <70 g/l.4 Whether a transfusion is appropriate will depend partly on patient choice and the rate of decline of haemoglobin concentration if known; a woman with menorrhagia who has had a haemoglobin level of 65 g/l documented for the last year is less likely to need admitting than a patient with gastrointestinal (GI) symptoms whose haemoglobin level was normal 3 months ago. If the patient is not acutely unwell, explore the patient’s history to identify potential causes of their anaemia:
Physical examinations of patients with anaemia may include the following:
4. Remember the suspected cancer guidelinesNICE Guideline (NG) 12 on Suspected cancer: recognition and referral advises that referral or investigation is considered as follows for patients who:5
5. Request further investigations logicallyTailor any further investigations to the most likely differential diagnoses, the most common causes, and the patient’s MCV results and symptoms. Depending on the type of anaemia identified, appropriate tests may include:
The rest of this article will focus on the investigation and management of IDA—for more information, consider referring to guidance on other conditions that can cause or be related to anaemia, for example, NG8 on Chronic kidney disease: managing anaemia6 or the British Society of Gastroenterology guidelines on adult coeliac disease.7 6. Do not rule out IDA on ferritin aloneSerum ferritin is the biochemical test that most reliably correlates with relative total body iron stores,3 but ferritin is also an acute phase protein and will therefore be raised in the presence of infection, inflammation, or malignancy. Therefore, a normal ferritin level does not exclude IDA. If clinical suspicion of IDA is strong then consider checking for other iron indices; serum iron is highly variable as it is influenced by many factors (such as inflammation and infection) and is therefore not an ideal test. More useful tests include transferrin and total iron binding concentration (TIBC). Transferrin is an iron transport protein, which increases in iron deficiency so that the available iron can be fully utilised, while TIBC is a measure of the availability of iron binding sites on transferrin. Both transferrin and TIBC will be elevated in patients with IDA and these are therefore useful second-line tests. Some labs may also offer transferrin saturation; 30% is a normal value and it will fall in patients with iron deficiency.8 7. Consider whether further investigation of IDA is actually neededAccording to NICE, the following patients—if they have had a negative test for coeliac disease—usually need no further investigation after IDA has been diagnosed:3
For all patients who do not match the above criteria, the following investigations are recommended:3
8. Titrate the dose of iron to what the patient can tolerateThe aim of iron treatment is to restore haemoglobin levels and iron stores. The British National Formulary suggests that patients with anaemia should have 100–200 mg of elemental iron daily;9 the elemental iron content of various preparations is shown in Table 2. Table 2: Iron content of supplements by preparation9
NICE recommends iron supplementation with dried ferrous sulphate three times a day (or 200 mg twice daily until the clinical response is assessed after 2–4 weeks, increasing to three times daily if well tolerated or reducing to once daily if poorly tolerated), switching to ferrous gluconate if side-effects lead to poor tolerance.3 In the author’s experience, many CCGs prefer ferrous fumarate as first line due to cost issues, although NICE points out that ferrous fumarate has more elemental iron per tablet than ferrous sulphate and is therefore no more likely to be well tolerated.3 In practice, the main objective is to make sure that patients get as high a dose of elemental iron as they can tolerate. Constipation and associated abdominal pain are common when treating with iron; if patients are not warned about these symptoms in advance, they may simply stop taking the tablets. Many GPs will be familiar with cases where patients have claimed to be taking regular iron, but their last monthly prescription was issued over a year ago! In cases like these, it is important to determine whether the patient has poor adherence or if they are taking alternative over-the-counter preparations. If a patient is not taking their iron then it is important to ask why, switch preparation if necessary, and encourage them to take as much as possible—a low dose of iron is better than none.3 It is not uncommon for patients to buy liquid iron supplements over the counter if they do not want to take tablets. While patient choice must be respected, it is important that this choice is informed and therefore patients should be advised to check how much iron is in the preparation that they are buying. Some commonly advertised liquid iron supplements, used as suggested by the manufacturer, can provide as little as 5–15 mg of iron per day.10,11 Modified-release iron is not routinely recommended by NICE as these preparations are associated with lower absorption; they are also not available on the NHS. NICE also advises against the use of compound preparations with iron and vitamin B12/folic acid/vitamin C, unless the patient’s anaemia is related to very poor diet or malnutrition. Parenteral iron preparations, which are only needed in exceptional circumstances, are usually reserved as a secondary care treatment.3 9. Check iron absorption and encourage dietary intakeThe absorption of both dietary iron and supplements is reduced by the simultaneous intake of calcium, phytates (found in wholegrain cereals), polyphenols (found in tea and coffee) or by the use of a proton pump inhibitor or antacid. It is worth giving the patient information about dietary sources of iron12 as well as telling them whether they should stagger their medications so as not to take iron at the same time as calcium tablets. 10. Monitor the patient’s haemoglobin and keep referral in mindAccording to NICE, the following process should be observed for monitoring during treatment with iron:3
It is not necessary to keep checking ferritin levels, unless there is any concern that the diagnosis may not be correct.3 If there is no response to treatment with iron (and the patient is actually taking the tablets!), consider a different formulation or refer for specialist advice. If adherence is being affected by adverse effects, these should be addressed; for example, by offering co-prescription of a laxative for patients experiencing constipation or reassurance for patients concerned about black stools.3 Some patients who are at particular risk of recurrent IDA might benefit from a small prophylactic dose (e.g. one tablet daily of whichever formulation they prefer). This includes patients who have:
Dr Toni Hazell Part-time GP, Greater London References
Which condition would the nurse monitor for a patient who has a hemoglobin level of 20?An Hb value less than 5.0 g/dL (50 g/L) can lead to heart failure and death. A value greater than 20 g/dL (200 g/L) can lead to obstruction of the capillaries as a result of hemoconcentration.
What should I monitor for low hemoglobin?Complete blood count (CBC).
A CBC is used to count the number of blood cells in a sample of your blood. For anemia, your doctor will likely be interested in the levels of the red blood cells contained in your blood (hematocrit) and the hemoglobin in your blood.
What is the hemoglobin level of a patient with anemia?Anemia can be defined as a reduction in hemoglobin (less than 13.5 g/dL in men; less than 12.0 g/dL in women) or hematocrit (less than 41.0% in men; less than 36.0% in women) or red blood cell (RBC) count.
Which condition is the most common cause for Hematemesis quizlet?Conditions that most commonly cause hematemesis include: Bleeding ulcers. A peptic ulcer is an open sore in your stomach or duodenum. It's often caused by a bacterial infection, or by the regular use of NSAIDs or aspirin.
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