What is the appropriate management for a patient presenting with anemia (low hemoglobin)?

Review of Systems for Low Hemoglobin Presentation

A systematic review of systems for anemia must focus on identifying the underlying cause through targeted questioning about blood loss, hemolysis, nutritional deficiencies, chronic disease, and bone marrow dysfunction. 1

Constitutional Symptoms

• Fatigue and weakness: Assess severity, duration, and impact on daily activities, as these are the most common presenting symptoms of chronic anemia 2
• Dyspnea on exertion: Quantify exercise tolerance and whether symptoms occur at rest, indicating severity of tissue hypoxia 2
• Lightheadedness or syncope: Particularly important if hemoglobin <7-8 g/dL, suggesting cardiovascular instability 3
• Chest pain or palpitations: Critical red flag requiring immediate evaluation, especially in patients with cardiovascular disease 2
• Fever: May indicate infection, inflammatory conditions, or hemolysis 4
• Unintentional weight loss: Raises concern for malignancy or chronic inflammatory disease 3

Gastrointestinal System

• Melena or hematochezia: Direct evidence of GI bleeding requiring urgent endoscopic evaluation 3
• Dysphagia: Suggests upper GI pathology including esophageal or gastric malignancy 3
• Abdominal pain: Pattern and location may indicate peptic ulcer disease, inflammatory bowel disease, or malignancy 4, 3
• Diarrhea: Particularly chronic diarrhea with malabsorption in celiac disease or inflammatory bowel disease 4, 1
• NSAID or aspirin use: Common cause of occult GI bleeding and iron deficiency 1
• History of gastric or bowel surgery: Especially ileal resection causing B12 or folate deficiency 4

Hematologic System

• Easy bruising or bleeding: Suggests platelet dysfunction, coagulopathy, or bone marrow failure 5
• Petechiae or purpura: May indicate thrombocytopenia or vasculitis 5
• Dark urine: Classic sign of intravascular hemolysis 4
• Jaundice: Indicates hemolysis or liver disease 4
• Previous blood transfusions: Important for assessing chronicity and severity 4

Genitourinary System

• Menstrual history in women: Heavy or prolonged menses are the most common cause of iron deficiency in premenopausal women 1, 3
• Hematuria: May indicate renal pathology or urologic malignancy 4
• Urinary symptoms: Dysuria, frequency, or flank pain suggesting infection or renal disease 4
• Pregnancy status: Anemia defined as hemoglobin <11 g/dL in pregnancy 1

Renal System

• History of chronic kidney disease: Anemia of CKD typically develops when GFR <30 mL/min/1.73 m² 4, 1
• Dialysis status: Requires specific monitoring protocols with monthly hemoglobin checks 4
• Urine output changes: May indicate worsening renal function 4

Dietary and Nutritional History

• Dietary iron intake: Assess consumption of red meat, fortified cereals, and iron-rich foods 1
• Vegetarian or vegan diet: Increases risk of iron and B12 deficiency 4
• Alcohol consumption: Associated with folate deficiency and macrocytic anemia 4
• Pica or pagophagia: Ice chewing is highly specific for iron deficiency 3
• Blood donation history: Frequent donation depletes iron stores 1

Inflammatory and Autoimmune Conditions

• Inflammatory bowel disease: Causes both iron deficiency from blood loss and anemia of chronic disease 4
• Rheumatoid arthritis or other autoimmune diseases: Associated with anemia of chronic inflammation 4
• Chronic infections: Including HIV, tuberculosis, or endocarditis 4

Medications

• Azathioprine or 6-mercaptopurine: Can cause bone marrow suppression and hemolytic anemia 4
• Chemotherapy agents: Cause bone marrow suppression 4
• Anticoagulants: May unmask or exacerbate GI bleeding 1
• Proton pump inhibitors: Long-term use impairs iron absorption 3

Endocrine System

• Hypothyroidism symptoms: Cold intolerance, constipation, weight gain—TSH should be checked in unexplained anemia 4, 1
• Adrenal insufficiency: May present with normocytic anemia 4

Neurologic System

• Paresthesias or numbness: Particularly in hands and feet, suggesting B12 deficiency 4
• Gait disturbance or ataxia: Classic for B12 deficiency with subacute combined degeneration 4
• Cognitive changes: Memory impairment may occur with severe B12 or folate deficiency 4

Family History

• Hemoglobinopathies: Sickle cell disease, thalassemia, particularly in patients of Mediterranean, African, or Southeast Asian descent 6
• Hereditary spherocytosis or other congenital anemias: Family history of anemia, splenectomy, or gallstones 6
• Colon cancer or GI malignancies: Increases suspicion for hereditary cancer syndromes 3

Critical Red Flags Requiring Urgent Evaluation

• Hemoglobin <7 g/dL: Consider transfusion and immediate hospitalization 4, 3
• Hemodynamic instability: Tachycardia, hypotension, or altered mental status 3
• Men with hemoglobin <12 g/dL or postmenopausal women with hemoglobin <10 g/dL: Requires urgent GI evaluation for malignancy 1, 3
• Alarm symptoms: Weight loss, dysphagia, melena, hematochezia mandate expedited investigation 3