Causes of Anemia in Men

Introduction to Anemia Causes

• The American Gastroenterological Association suggests that in men presenting with anemia without obvious bleeding, the primary non-bleeding causes are celiac disease, chronic NSAID use, nutritional deficiencies, chronic kidney disease, and chronic inflammatory conditions 1, 2

Malabsorption Disorders

• Celiac disease is found in 3-5% of all iron deficiency anemia cases and must be screened for in every patient with unexplained anemia, according to the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition 1, 2
• Upper endoscopy with duodenal biopsies is recommended if serology is positive or clinical suspicion remains high 1, 2

Medication-Induced Blood Loss

• NSAIDs are common and frequently unreported causes of occult gastrointestinal blood loss, even without overt bleeding symptoms, as stated by the American College of Gastroenterology 3
• Anticoagulants and antiplatelet agents can unmask underlying vascular lesions like angiodysplasia, according to the American Cancer Society 4
• Explicitly asking about all NSAID use is essential, as patients often don't consider over-the-counter medications worth mentioning, as recommended by the American College of Gastroenterology 3

Nutritional Deficiencies

• Poor dietary iron intake is a common cause of anemia, particularly in men of lower socioeconomic status with limited access to iron-rich foods, as reported by the World Health Organization 5

Chronic Disease States

• Androgen deprivation therapy in prostate cancer survivors causes normochromic normocytic anemia through suppression of erythropoiesis, according to the American Cancer Society 4

Non-Gastrointestinal Blood Loss

• Urinalysis should be performed in all cases to exclude urinary tract bleeding, as recommended by the American Urological Association 5, 2
• Frequent blood donation can cause anemia, as stated by the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition 1, 2

Critical Diagnostic Approach

• Screen for celiac disease with tissue transglutaminase antibody, as recommended by the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition 1
• Obtain comprehensive medication history focusing on NSAIDs and anticoagulants, as recommended by the American College of Gastroenterology 3

Common Pitfalls

• Assuming all anemia in men must be from gastrointestinal bleeding misses treatable malabsorption and nutritional causes, as stated by the American College of Gastroenterology 2
• Failing to ask specifically about over-the-counter NSAID use can lead to missed diagnoses, as recommended by the American College of Gastroenterology 3
• Not screening for celiac disease can result in missed diagnoses, as recommended by the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition 1, 2

Iron Deficiency Anemia Diagnosis and Management

Primary Mechanism in Young Men

• In a 20-year-old male with iron deficiency anemia, gastrointestinal blood loss is the most likely cause and requires comprehensive investigation with bidirectional endoscopy, regardless of the absence of GI symptoms 6
• The most common GI sources in this age group include NSAID-induced mucosal damage and inflammatory bowel disease, such as Crohn's disease and ulcerative colitis 6, 7
• Peptic ulcer disease and Meckel's diverticulum are also potential causes of iron deficiency anemia in young men 6

Critical Malabsorption Causes

• Celiac disease must be screened in every patient with unexplained iron deficiency anemia, as it accounts for 2-5% of cases and is easily missed 6
• Small bowel biopsies should be obtained during upper endoscopy even without positive serology if clinical suspicion exists 6
• Other malabsorption causes include bacterial overgrowth, Whipple's disease, and intestinal lymphangiectasia 6

Diagnostic Approach Algorithm

• Serum ferritin <12 μg/dL is diagnostic of iron deficiency, while ferritin >100 μg/dL essentially excludes iron deficiency 6, 7
• Upper GI endoscopy with small bowel biopsies reveals the cause in 30-50% of patients, and colonoscopy or barium enema should also be performed to rule out dual pathology 6, 7

Common Pitfalls to Avoid

• Do not stop investigating after finding one cause, as multiple etiologies coexist in 10-15% of patients 6
• Do not accept minor findings as the sole cause without completing lower GI investigation 6, 7
• Do not assume dietary deficiency is the cause even with a positive dietary history; full GI investigation is still required 6, 7

Iron Deficiency Anaemia Causes and Management

Population-Specific Causes

• The American Gastroenterological Association recommends that gastrointestinal blood loss be considered the predominant mechanism in men and postmenopausal women, requiring urgent investigation to exclude malignancy 8, 9, 10, 11
• In premenopausal women, menstrual blood loss is the most common cause of iron deficiency anaemia, but gastrointestinal pathology should still be considered, particularly in those over 40 years or with alarm symptoms 8, 9, 10, 11, 12, 13
• The American College of Gastroenterology suggests that coeliac disease must be screened for in every patient with unexplained anaemia, regardless of menstrual history 13

Recurrent IDA After Initial Treatment

• The European Society for Gastrointestinal Endoscopy recommends that small bowel pathology, including angiodysplasia and tumours, be considered when bidirectional endoscopy is negative 8, 9, 12, 14
• In patients with inflammatory bowel disease, recurrent iron deficiency anaemia may indicate ongoing inflammatory activity, even with clinical remission and normal biomarkers 15
• The American Gastroenterological Association suggests that post-surgical states, such as gastric resection or bypass, can predispose to recurrent iron deficiency anaemia through multiple mechanisms 15, 16

Monitoring for Recurrence

• The Crohn's and Colitis Foundation recommends that patients with inflammatory bowel disease and iron deficiency anaemia require structured monitoring, with follow-up every 3 months for at least one year after correction of iron deficiency anaemia 15
• The American Society for Metabolic and Bariatric Surgery suggests that post-bariatric surgery patients require lifelong monitoring given their 25% risk of developing iron deficiency anaemia 15, 16