anemia of chronic disease Flashcards
define
Characterised by anaemia and evidence of immune system activation.
Anaemia chiefly due to decreased RBC production; may be aggravated by shortened RBC survival.
Commonly found in acute and chronic infections, autoimmune disorders, after major trauma and surgery, and in critical illness.
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This may be confused with iron deficiency anaemia.
However, unlike in iron deficiency anaemia,
- the total iron binding capacity is reduced and the
- serum ferritin is normal or increased.
nb:
TIBC is an indirect measure of the amount of iron that transferrin will bind.
Serum ferritin is an indirect yet quantitative and non-invasive measure of iron stores.
causes
Causes include:
- chronic inflammation:
- tuberculosis
- systemic lupus erythematosus
- malignancy
- rheumatoid arthritis
- endocrine disorders:
- hypothyroidism
- hypopituitarism
- Addison’s disease
- other causes:
- liver disease
- chronic renal failure
- malnutrition
hx + exam
presence of risk factors
Key risk factors include autoimmune disorders, malignancy, acute or chronic infection, and critical illness, major trauma, or major surgery with delayed recovery.
systemic symptoms of underlying condition
Symptoms such as fever, night sweats, anorexia, weight loss, weakness, myalgias, or arthralgias should prompt a search for an underlying condition.
absent hx of bleeding
It is important to determine if symptoms of bleeding are present (e.g., melaena, haematochezia, menorrhagia, metrorrhagia), as bleeding is not expected in ACD and should prompt a different workup.
physical finding suggesting infection
This might include stiff neck; tenderness of joints, shoulder girdle, abdomen, or bones; decreased breath sounds or sticky rales.
Any non-trivial infection may cause ACD.
physical finding suggesting neoplasm
Including the presence of a mass, adenopathy, hepatomegaly, splenomegaly.
Any active neoplasm may cause ACD.
physical finding suggesting autoimmune disorder
absent hx of high alcohol intake
Although a positive history may be present in people with ACD, it may prompt consideration of an alternative cause for the anaemia.
absent hx of exposure to chemicals and radiation
Although a positive history may be present in people with ACD, it may prompt consideration of an alternative cause for the anaemia.
absent hx of drugs known to be associated with risk of anaemia
Although a positive history may be present in people with ACD, development of anaemia shortly after commencing a new drug may warrant investigation as the drug may be the causative agent.
absent hx of poor nutrition
Although a positive history may be present in people with ACD, it may prompt consideration of poor nutrition as an alternative cause for the anaemia.
decreased exercise tolerance
It is often useful to determine what changes may have occurred in the patient’s level of activity, as patients often reduce exertion to avoid symptoms.
shortness of breath with exercise
A common symptom of moderate or severe anaemia of any cause.
fatigue
A common symptom of moderate or severe anaemia of any cause.
pallor
Conjunctival pallor and pallor of the palms, palmar creases and nail beds is a feature common to all types of anaemia.
strong risk factors
autoimmune disorders
malignancy
acute or chronic infection
critical illness, major trauma, or major surgery with delayed recovery
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1st investigations to order
Hb
The degree of anaemia in ACD is typically mild to moderate (8-11 g/dL)
Severe anaemia may indicate an alternative or co-existing cause (e.g., blood loss, iron deficiency anaemia, or a primary haematological disorder).
women < (12 g/dL); men (13 g/dL)
WBC and differential
Associated infection or other stimuli in ACD may cause the WBC, .
- count may be elevated
platelet count
Platelets may be mildly to moderately increased due to the underlying infection or inflammation.
- may be increased
MCV
Anaemia in ACD is normocytic or microcytic.
- normal or reduced
MCHC
Anaemia in ACD is normochromic or hypochromic.
- normal or reduced
peripheral blood smear
Spherocytes, RBC fragments, macro-ovalocytes, helmet cells, pencil-shaped forms, nucleated RBC suggest other diagnoses.
- normal
serum ferritin
Moderately helpful in distinguishing ACD and iron deficiency (ferritin rises in the former and falls in the latter).
Less helpful when the two conditions co-exist, as not infrequently occurs.
- increased
serum iron
Less useful than the transferrin saturation.
- reduced
TIBC
- normal or reduced
transferrin saturation
- reduced
absolute reticulocyte count
Indicative of underproduction by the marrow (typical in ACD).
- low for the degree of anaemia
serum creatinine
May be useful for ruling out anaemia associated with renal insufficiency, although ACD may complicate anaemia that is primarily due to renal disease.
- variable
LDH
Useful for ruling out haemolysis or another bone marrow disorder (elevated LDH).
- normal generally, though may at times be increased by the condition causing ACD
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CRP
Helps to confirm presence of inflammation, and therefore ACD, if cause of anaemia is uncertain.
elevated
ESR
Helps confirm presence of inflammation, and therefore ACD, if cause of anaemia uncertain.
- elevated
serum B12
Useful for ruling out B12 deficiency.
- normal
serum folate
Useful for ruling out folate deficiency.
- normal
TFTs
Useful as a test to exclude hypo- or hyperthyroidism that can lead to anaemia.
- normal
LFTs
Useful for ruling out liver disease as a cause of the anaemia.
- normal
indirect and direct bilirubin
Useful for ruling out haemolysis as the cause of the anaemia.
- normal
erythropoietin
- typically lower than expected for degree of anaemia
quantitative haemoglobin A2 analysis
May be used to exclude beta-thalassemia trait (microcytosis, significant poikilocytosis, MCHC relatively normal).
- normal
bone marrow biopsy
Usually performed if there is suspicion of a primary haematological disorder (e.g., myelodysplasia or a haematological malignancy).
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- Treat underlying cause.
- Erythropoietin - this is especially effective in the treatment of anaemia of chronic renal failure.
