An approach to anaemia

James talks to Dr Shafqat Inam about an approach to anaemia. Anaemia is a reduction in the number of red blood cells and haemoglobin in the blood, and it’s common in hospitalised patients.

Summary Writer:  Elizabeth Campbell

Editor:  James Edwards

Interviewee: Shafqat Inam

About Dr Shafqat Inam

Shafqat Inam is currently a Haematology Registrar at Royal Prince Alfred Hospital and Concord Hospital and Associate Lecturer at the University of Sydney. He studied medicine at the University of New South Wales and completed his junior medical officer and Basic Physician Training at Royal Prince Alfred Hospital. He has a particular interest in research and medical education.

An Approach to Anaemia

With Dr Shafqat Inam, Haematology Registrar at Concord Hospital and Royal Prince Alfred Hospital, New South Wales, Australia

Introduction

Anaemia is common in hospitalised patients. Anaemia is a reduction in the number of red blood cells and haemoglobin in the blood. This is clinically important as haemoglobin is the main carrier of oxygen in the blood. The normal range of haemoglobin differs for men, women and children. Anaemia is a manifestation of an underlying disorder, not a diagnosis in itself.

Case

You are the junior doctor admitting a surgical patient, who you note has a haemoglobin of 92. Your team would like to optimise this before surgery.

  • As with any blood test, it’s important to confirm the blood test is correct. Could there be haemodilution?
  • Comprehensive history and examination is indicated. Any symptoms of anaemia?
  • Review other blood tests.
  • Classification by Mean Corpuscular Volume (MCV). MCV normal range is 80-100 femtolitres
    • Low MCV: iron deficiency anaemia, thalassaemia
    • High MCV: Vitamin B12 deficiency, or folate deficiency
    • Normal MCV: acute bleeding, haemolysis, anaemia of chronic disease
  • Classification by acuity
    • Acute
    • Chronic
  • History:
    • Symptoms of anaemia: dizziness, shortness of breath, palpitations. Symptoms are more common in acute anaemia.
    • Past medical history: potential causes of anaemia, such as chronic kidney disease, liver disease, thalassaemia.
    • Enquire about cardiac disease – this may lower threshold for transfusion.
    • Has the patient had any previous investigations for anaemia?
  • Examination:
    • Look for hypotension that may suggest an acute cause of bleeding.
    • Signs of anaemia: palmar crease or conjunctival pallor, signs of heart failure (in severe anaemia, or in patients with limited reserve).
    • Potential causes: koilonychias, angular stomatitis, peripheral stigmata of liver disease, bruising.
  • Multifactorial (especially in the elderly, or patients with multiple comorbidities)
  • Acute blood loss
  • Anaemia of chronic disease
  • Post-operative
  • Chemotherapy
  • Further testing is guided by clinical assessment.
  • If there is acute bleeding, ensure the patient has a valid group and hold.
  • Electrolytes, urea, creatinine – a raised urea:creatinine ratio is quite specific for upper GI bleeding.
  • Liver function testing.
  • Iron studies.
  • Thalassaemia screen.
  • Vitamin B12 and folate.
  • Electrophoretogram (EPG) to assess for multiple myeloma.
  • Haemolysis screen (diagnoses haemolysis):
    • Reticulocyte count (increased in haemolysis), lactate dehydrogenase (increased), total bilirubin (increased), haptoglobin (low), direct antiglobulin test (DAT = Coomb’s test; assesses whether the haemolysis is immune in origin).
  • Red-cell distribution width (RDW).
  • Consider occult blood loss, e.g. from a bowel cancer. Colonoscopy and endoscopy are required in an adult patient. Document this clearly in the discharge letter, so the patient’s GP can arrange this.
  • Microcytic anaemia
  • High RDW
  • Low ferritin. Remember, ferritin is an acute phase reactant, so may be raised in inflammatory states, therefore also look for an increased transferrin level, and low transferrin saturation.
  • Diagnose the cause of the deficiency.
  • Iron replacement is the mainstay of treatment: oral supplementation replaces iron stores over weeks to months. If the patient requires more rapid replacement, or cannot tolerate oral iron, an iron infusion can be performed.  Modern iron infusions are safe.
  • Blood transfusion should be avoided in stable patients if possible.
  • There is no absolute threshold for PRBC transfusion. The haemoglobin must be considered in the context of the patient’s comorbidities and the clinical scenario. For example, in ischaemic heart disease, we would aim for a haemoglobin above 90.
  • Acute bleeding (this may not be apparent on initial investigations).
  • In a stable patient with iron deficiency anaemia, correct the underlying cause first. Consider replacing iron and other measures such as erythropoietin in chronic kidney disease patients.
  • If you decide to transfuse a stable patient with packed red blood cells, give one unit of PRBC, then re-assess the need for any further transfusion.
  • With history, examination and judicious further testing, you will be able to diagnose and manage most patients with anaemia.
  • If there is a primary haematological problem such as leukaemia, myelodysplastic syndrome, or haemolytic anaemia, these patients are often known to a haematologist.
  • If there are other blood count abnormalities, such as thrombocytopenia, or leucopenia, there may be an underlying bone marrow problem.
  • If you require assistance in interpreting results, or advice on further testing, the Haematology team can assist.
  • Anaemia is not a diagnosis in itself. It has varied causes and in hospitalised patients, it is often multifactorial.
  • A careful history and examination is vitally important.
  • Think very carefully before transfusing a patient with packed red blood cells.

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Tags: #acute bleeding,#acute pain management,#anaemia,#B12 deficiency,#blood test,#ferritin,#haematology,#haemodilution,#Haemoglobin,#haemolysis,#iron deficiency,#occult blood loss,#PRBC,#RDW,#red blood cells

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