Anaemia, bruising and blood disorders

Anaemias, Inflammatory Arthropathies & Geriatric Comprehensive Assessment

Haematological disorders, systemic autoimmune conditions, and complex geriatric syndromes represent interconnected domains of general internal medicine. A methodical, analytical approach to mean cell volume (MCV), joint aspirate microscopy, vasculitis emergencies, and geriatric assessment algorithms ensures prompt diagnosis, joint preservation, and mitigation of hospital-acquired disability.

Diagnostic Approach to Anaemias by Mean Cell Volume (MCV)

Anaemia is defined by the World Health Organization as a haemoglobin concentration $< 130\text{ g/L}$ in adult men and $< 120\text{ g/L}$ in non-pregnant adult women. Initial diagnostic stratification relies on the Mean Cell Volume (MCV, reference range $80 - 100\text{ fL}$).

1. Microcytic Anaemias ($MCV < 80\text{ fL}$)

• Serum Ferritin: Iron Deficiency Anaemia (IDA): Low ($< 30\ \mu\text{g/L}$; $< 50-100$ in inflammation); $\beta$-Thalassaemia Trait (Minor): Normal or Elevated; Anaemia of Chronic Disease (ACD): Normal or Elevated ($> 100\ \mu\text{g/L}$); Sideroblastic Anaemia: Elevated
• Serum Iron: Iron Deficiency Anaemia (IDA): Low; $\beta$-Thalassaemia Trait (Minor): Normal; Anaemia of Chronic Disease (ACD): Low; Sideroblastic Anaemia: Elevated
• Total Iron Binding Capacity (TIBC): Iron Deficiency Anaemia (IDA): High ($> 70\ \mu\text{mol/L}$); $\beta$-Thalassaemia Trait (Minor): Normal; Anaemia of Chronic Disease (ACD): Low or Normal; Sideroblastic Anaemia: Normal or Low
• Transferrin Saturation: Iron Deficiency Anaemia (IDA): Low ($< 16-20\%$); $\beta$-Thalassaemia Trait (Minor): Normal; Anaemia of Chronic Disease (ACD): Normal or Mildly Low ($15-25\%$); Sideroblastic Anaemia: High ($> 50\%$)
• Red Blood Cell Count (RBC): Iron Deficiency Anaemia (IDA): Low; $\beta$-Thalassaemia Trait (Minor): Disproportionately High ($> 5.5 \times 10^{12}\text{/L}$); Anaemia of Chronic Disease (ACD): Normal or Low; Sideroblastic Anaemia: Low or Normal
• Mentzer Index ($\text{MCV} / \text{RBC}$): Iron Deficiency Anaemia (IDA): $> 13$; $\beta$-Thalassaemia Trait (Minor): $< 13$; Anaemia of Chronic Disease (ACD): $> 13$; Sideroblastic Anaemia: Variable
• Blood Film: Iron Deficiency Anaemia (IDA): Hypochromic, microcytic; pencil cells; $\beta$-Thalassaemia Trait (Minor): Target cells, basophilic stippling; Anaemia of Chronic Disease (ACD): Normocytic or mildly microcytic; Sideroblastic Anaemia: Ringed sideroblasts on Prussian blue bone marrow
• Diagnostic interpretation: Iron Deficiency Anaemia (IDA): Iron studies identify deficiency; assess its cause; $\beta$-Thalassaemia Trait (Minor): Raised HbA2 can support beta-thalassaemia, while alpha-thalassaemia may have normal electrophoresis; Anaemia of Chronic Disease (ACD): Clinical context and directed testing guide other causes

Australian AMC Rule for Iron Deficiency: In all adult men and postmenopausal women presenting with confirmed iron deficiency anaemia without obvious macroscopic blood loss, bidirectional endoscopy (gastroscopy and colonoscopy) is mandatory to exclude occult gastrointestinal malignancy (colorectal carcinoma or gastric adenocarcinoma).

2. Normocytic Anaemias ($MCV\ 80 - 100\text{ fL}$)

• High Reticulocyte Response (Reticulocyte Production Index $> 2.0$ / Reticulocytes $> 100 \times 10^9\text{/L}$):
  • Indicates active bone marrow response to accelerated red cell destruction (haemolysis) or acute haemorrhage.
  • Haemolytic Screen: Elevated indirect (unconjugated) bilirubin, elevated serum lactate dehydrogenase (LDH), and markedly reduced or undetectable haptoglobin (haptoglobin binds free haemoglobin dimers, cleared rapidly by the reticuloendothelial system).
  • Direct Antiglobulin Test (DAT / Coombs test):
    • Warm Autoimmune Haemolytic Anaemia (AIHA): IgG autoantibodies bind erythrocytes at $37^\circ\text{C}$; extravascular haemolysis in splenic sinusoids; spherocytes on blood film; responsive to oral corticosteroids.
    • Cold Agglutinin Disease: IgM autoantibodies bind at cooler temperatures ($< 37^\circ\text{C}$), fix complement, and cause intravascular haemolysis; acrocyanosis; managed by cold avoidance.
    • Microangiopathic Haemolytic Anaemia (MAHA): Mechanical shearing of RBCs by microthrombi producing schistocytes (helmet cells) on blood film (seen in Thrombotic Thrombocytopenic Purpura [TTP: ADAMTS13 deficiency], Haemolytic Uraemic Syndrome [HUS], and DIC).
• Low Reticulocyte Response: Hypoproliferative marrow failure: renal anaemia (erythropoietin deficiency), early nutritional deficiency, bone marrow infiltration (myeloma, leukaemia), or aplastic anaemia.

3. Macrocytic Anaemias ($MCV > 100\text{ fL}$)

• Megaloblastic anaemia: B12/folate-related DNA synthesis impairment can produce macrocytosis and hypersegmented neutrophils. Six-lobed cells, or an excess of five-lobed cells, support hypersegmentation; a single five-lobed cell is not diagnostic.
  • Vitamin B12 (Cobalamin) Deficiency: Due to pernicious anaemia (autoimmune destruction of gastric parietal cells causing intrinsic factor deficiency; anti-intrinsic factor antibodies $> 95\%$ specific), ileal disease/resection (Crohn's), or strict veganism. Causes Subacute Combined Degeneration of the Spinal Cord: demyelination of the posterior columns (loss of vibration and proprioception, sensory ataxia, positive Romberg test) and lateral corticospinal tracts (spastic quadriparesis, hyperreflexia, extensor plantar Babinski responses).
  • Folate Deficiency: Due to poor dietary intake, alcohol dependency, coeliac disease, or antifolate medications (methotrexate, trimethoprim). Neurological tract signs are absent.
  • B12 before folate alone: Exclude or treat B12 deficiency so correcting the anaemia does not mask ongoing neurological disease. Folate does not inevitably cause immediate irreversible deterioration in every deficient patient, but delayed B12 treatment can be harmful.
• Non-Megaloblastic Macrocytosis: Chronic alcohol misuse (most common cause in Australia), chronic liver disease, reticulocytosis (reticulocytes are larger than mature RBCs), hypothyroidism, or myelodysplastic syndrome (MDS).

Bruising and bleeding

Mucosal bleeding, petechiae and easy bruising suggest platelet/vascular problems, while deep muscle or joint bleeding raises coagulation disorders. Review medicines, alcohol/liver disease, family history and bleeding after procedures. FBC and film, PT/INR and aPTT guide further investigation; normal routine coagulation tests do not exclude von Willebrand disease or every platelet disorder. An unexpected low platelet result may be artefact from clumping and needs confirmation, but active bleeding or systemic illness requires urgent care without waiting for a routine repeat. Thrombocytopenia with haemolysis, renal or neurological findings raises a thrombotic microangiopathy; obtain urgent haematology advice. Bone pain with anaemia, kidney impairment or hypercalcaemia can raise myeloma and needs directed investigation rather than an iron prescription alone.

Primary references (checked 7 October 2026): RACGP thrombocytopenia assessment.