Key takeaway
Iron deficiency anaemia in adults = always think GI cause first.
Anaemia is a sign, not a diagnosis. Treat the gut, not just the numbers.

zerotofinals.com/medicine/hae...

Management principles
Correct underlying cause
Replace iron, B12, folate as needed
Treat GI pathology: ulcers, IBD, malignancy
Monitor response (Hb + ferritin)

Imaging / Endoscopy
Upper GI: OGD → ulcers, cancer, angiodysplasia
Lower GI: Colonoscopy → polyps, cancer, IBD
Consider capsule endoscopy if small bowel suspected

www.youtube.com/watch?v=Ibzq...

Investigations flow
Hb and CBC → classify by MCV
Iron studies (ferritin, iron, TIBC)
B12/folate if macrocytic
Reticulocyte count
GI investigations if IDA in adults

Red flag symptoms in anaemia = urgent GI investigation
Weight loss, change in bowel habits
Melena
Dysphagia
Postmenopausal bleeding
Anaemia + red flags = rule out malignancy

Anaemia in liver disease
Often normocytic or macrocytic
Mechanisms: hypersplenism, chronic inflammation, nutritional deficiencies

Anaemia in IBD
Multifactorial: chronic inflammation, blood loss, malabsorption
Lab features: mixed microcytic + normocytic
Treat underlying IBD + replace iron/B12/folate

Macrocytic anaemia = malabsorption or B12/folate deficiency
GI causes: coeliac disease, chronic pancreatitis, post-gastrectomy
B12 deficiency → neuropathy, ataxia
Folate deficiency → usually diet-related

Normocytic anaemia = chronic disease or acute loss
Often seen in IBD, liver disease, chronic infection
Reticulocyte count helps differentiate:
High → haemolysis or acute bleeding
Low → impaired production

Adult IDA = always search for GI malignancy
Men and postmenopausal women must have endoscopy/colonoscopy
IDA may be the first presentation of colorectal cancer

Iron deficiency clues
Fatigue, pallor, SOB
Glossitis, koilonychia, pica
Lab pattern: ↓ ferritin, ↓ iron, ↑ TIBC

Microcytic anaemia = often GI blood loss in adults
Think iron deficiency anaemia (IDA)
Common GI causes:
Peptic ulcer disease
Gastric cancer
Colorectal cancer
IBD

Classification is key –
Use MCV to guide your investigations:
Microcytic (<80)
Normocytic (80-100)
Macrocytic (>100)