A 42-year-old woman from rural Maharashtra presents with progressive fatigue, dyspnea on exertion, and palpitations over 6 months. On examination, she has pallor, glossitis, and a stocking-glove paresthesia. Her hemoglobin is 7.2 g/dL with MCV 78 fL. Peripheral blood smear shows hypochromic microcytic RBCs with occasional target cells. Serum vitamin B12 is 180 pg/mL (normal 200), and serum folate is 2.1 ng/mL (normal 5.4). Iron studies are normal. What is the most likely diagnosis?

Question

A 42-year-old woman from rural Maharashtra presents with progressive fatigue, dyspnea on exertion, and palpitations over 6 months. On examination, she has pallor, glossitis, and a stocking-glove paresthesia. Her hemoglobin is 7.2 g/dL with MCV 78 fL. Peripheral blood smear shows hypochromic microcytic RBCs with occasional target cells. Serum vitamin B12 is 180 pg/mL (normal >200), and serum folate is 2.1 ng/mL (normal >5.4). Iron studies are normal. What is the most likely diagnosis?

Accepted Answer

B. Combined vitamin B12 and folate deficiency. ## Clinical Presentation Analysis

This patient presents with a constellation of findings pointing to **combined B12 and folate deficiency**:

### Key Clinical Features

**Neurological signs:**
  - Glossitis (inflamed tongue)
  - Stocking-glove paresthesia (peripheral neuropathy)
  - These are hallmarks of B12 deficiency; folate deficiency does NOT cause neurological manifestations

**Hematologic findings:**
  - Microcytic anemia (MCV 78 fL)
  - Hypochromic RBCs
  - Normal iron studies (rules out iron deficiency as primary cause)

**Laboratory confirmation:**
  - Both B12 (180 pg/mL) and folate (2.1 ng/mL) are LOW
  - The combination explains both the neurological AND hematologic picture

### Why Combined Deficiency?

In India, **nutritional deficiencies** are common in rural populations due to:
  - Vegetarian diet (low B12 sources)
  - Poor folate intake (leafy greens, legumes)
  - Malabsorption (chronic diarrhea, celiac disease)
  - Alcohol use disorder

**High-Yield:** When you see BOTH neurological signs (paresthesia, glossitis) AND microcytic anemia with LOW B12 and LOW folate, the answer is combined deficiency.

### Differential Diagnosis Table

| Feature | B12 Deficiency | Folate Deficiency | Iron Deficiency | Combined B12+Folate |
|---------|---|---|---|---|
| Neurological signs | Yes | **No** | No | Yes |
| Glossitis | Yes | Yes | No | Yes |
| MCV | Macro | Macro | Micro | Micro* |
| B12 level | Low | Normal | Normal | Low |
| Folate level | Normal | Low | Normal | Low |
| Iron studies | Normal | Normal | Abnormal | Normal |

*In combined deficiency, iron depletion can lower MCV despite B12/folate deficiency.

**Key Point:** The presence of neurological manifestations (paresthesia, glossitis) is the clinching finding that distinguishes this from isolated folate deficiency, which causes only hematologic changes.

**Clinical Pearl:** In India, combined nutritional deficiencies are more common than isolated deficiencies in rural populations. Always check both B12 and folate when one is low.

![Anemias Overview diagram](https://mmcphlazjonnzmdysowq.supabase.co/storage/v1/object/public/blog-images/explanation/2614.webp)

Answer

A. Thalassemia trait

Answer

C. Anemia of chronic disease

Answer

D. Iron deficiency anemia

Explanation

Clinical Presentation Analysis

Key Clinical Features

Why Combined Deficiency?

Differential Diagnosis Table

Practice similar questions

Join our NEET PG community

Feature	B12 Deficiency	Folate Deficiency	Iron Deficiency	Combined B12+Folate
Neurological signs	Yes	No	No	Yes
Glossitis	Yes	Yes	No	Yes
MCV	Macro	Macro	Micro	Micro*
B12 level	Low	Normal	Normal	Low
Folate level	Normal	Low	Normal	Low
Iron studies	Normal	Normal	Abnormal	Normal