Water-soluble vitamins - B complex US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Water-soluble vitamins - B complex. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Water-soluble vitamins - B complex US Medical PG Question 1: A 48-year-old woman is brought to the emergency department by police because of confusion and agitation. Her medical record indicates that she has peptic ulcer disease that is treated with omeprazole. The patient's brother arrives shortly after. He reports that she drinks around 17 oz. of vodka daily. Neurological examination shows horizontal nystagmus. Her gait is wide-based with small steps. Her hemoglobin concentration is 9.1 g/dL. A peripheral blood smear shows hypersegmented neutrophils. Homocysteine levels are elevated. Methylmalonic acid levels are within normal limits. Which of the following is the most likely direct cause of this patient's anemia?
- A. Vitamin E deficiency
- B. Vitamin B1 deficiency
- C. Folate deficiency (Correct Answer)
- D. Vitamin B12 deficiency
- E. Alcohol toxicity
Water-soluble vitamins - B complex Explanation: ***Folate deficiency***
- The combination of **anemia**, **hypersegmented neutrophils**, elevated **homocysteine**, and *normal methylmalonic acid* levels strongly points to folate deficiency.
- **Alcoholism** is a significant risk factor for folate deficiency due to poor nutritional intake and impaired folate absorption and metabolism.
*Vitamin E deficiency*
- This deficiency typically causes **neurological dysfunction** and **hemolytic anemia**, but it does not lead to hypersegmented neutrophils or elevated homocysteine.
- It is often seen in conditions causing **fat malabsorption**, which is not explicitly indicated as the primary driver here.
*Vitamin B1 deficiency*
- **Thiamine (B1) deficiency** is associated with **Wernicke-Korsakoff syndrome**, characterized by confusion, nystagmus, and ataxia, which are present in this patient.
- Although alcohol abuse causes thiamine deficiency, it does not explain the **megaloblastic anemia** with hypersegmented neutrophils evident in the peripheral blood smear.
*Vitamin B12 deficiency*
- Vitamin B12 deficiency also causes **megaloblastic anemia** and elevated **homocysteine** levels, but it would also present with **elevated methylmalonic acid (MMA)** levels, which are explicitly stated as normal here.
- The patient's use of omeprazole (a proton pump inhibitor) can contribute to B12 deficiency over time by reducing gastric acid necessary for B12 release from food proteins, but the MMA levels rule it out as the *direct cause* of anemia in this specific instance.
*Alcohol toxicity*
- While chronic alcohol abuse can lead to **anemia** through various mechanisms, including **bone marrow suppression** or **gastrointestinal bleeding**, it does not directly explain the specific findings of **hypersegmented neutrophils** and the particular pattern of homocysteine and methylmalonic acid levels.
- Alcohol toxicity is an underlying cause for other deficiencies, but not the direct cause of this specific type of anemia.
Water-soluble vitamins - B complex US Medical PG Question 2: A 34-year-old man presents with dysphagia. The patient says that he has pain on swallowing which gradually onset 2 weeks ago and has not improved. He denies any change in diet but does say that he recently returned from a prolonged work trip to the Caribbean. No significant past medical history or current medications. On physical examination, the patient looks pale. His tongue is swollen and has a beefy, red appearance. Angular stomatitis is present. Laboratory findings are significant for macrocytic, megaloblastic anemia, decreased serum folate, increased serum homocysteine, and normal methylmalonic acid levels. Which of the following conditions most likely caused this patient’s symptoms?
- A. Diphyllobothrium latum infection
- B. Autoimmune destruction of parietal cells
- C. Tropical sprue (Correct Answer)
- D. Poor diet
- E. Celiac disease
Water-soluble vitamins - B complex Explanation: ***Tropical sprue***
- The combination of **dysphagia**, **glossitis** (beefy, red, swollen tongue, angular stomatitis), **macrocytic megaloblastic anemia**, **decreased serum folate**, and a history of travel to the **Caribbean** strongly suggests tropical sprue.
- **Normal methylmalonic acid** levels rule out B12 deficiency, leaving folate deficiency as the primary cause of macrocytic anemia, consistent with tropical sprue's malabsorption.
*Diphyllobothrium latum infection*
- This infection causes **vitamin B12 deficiency** due to the parasite absorbing B12, leading to **macrocytic megaloblastic anemia**.
- However, B12 deficiency would present with **elevated methylmalonic acid** (MMA) levels, which are normal in this patient.
*Autoimmune destruction of parietal cells*
- This condition (pernicious anemia) leads to a **lack of intrinsic factor**, causing **vitamin B12 malabsorption** and subsequent B12 deficiency.
- Like *Diphyllobothrium latum* infection, it would also present with **elevated methylmalonic acid** levels.
*Poor diet*
- While a severely poor diet can lead to nutritional deficiencies, the patient denies any change in diet, and the specific constellation of symptoms (especially a history of travel to the Caribbean and **normal MMA**) points more directly to a malabsorption syndrome like tropical sprue.
- While a poor diet could cause folate deficiency, it wouldn't explain the rapid onset of severe symptoms or the specific malabsorptive context without further history.
*Celiac disease*
- Celiac disease typically causes **malabsorption** leading to iron deficiency anemia (microcytic) or, less commonly, folate deficiency (macrocytic).
- However, celiac disease is an immune reaction to **gluten** and is not specifically associated with travel to the Caribbean or the classic oral findings described.
Water-soluble vitamins - B complex US Medical PG Question 3: A 35-year-old alcoholic patient presents with high-output cardiac failure, tachycardia, a bounding pulse, and warm extremities. Blood work reveals vitamin deficiency. Which of the following vitamin deficiencies is most likely associated with such a clinical presentation?
- A. Thiamine (Correct Answer)
- B. Riboflavin
- C. Vitamin B12
- D. Vitamin D
- E. Niacin
Water-soluble vitamins - B complex Explanation: ***Thiamine***
- **Thiamine deficiency**, particularly in alcoholics, can lead to **wet beriberi**, characterized by **high-output cardiac failure** due to peripheral vasodilation, resulting in symptoms like tachycardia, bounding pulse, and warm extremities.
- Thiamine (vitamin B1) is a crucial cofactor in carbohydrate metabolism, and its deficiency impairs myocardial energy production and causes systemic vasodilation.
*Riboflavin*
- **Riboflavin deficiency** (ariboflavinosis) typically presents with **cheilosis**, glossitis, angular stomatitis, and seborrheic dermatitis, and is not directly associated with high-output cardiac failure.
- While it can occur in alcoholics, cardiac failure is not a prominent feature.
*Vitamin B12*
- **Vitamin B12 deficiency** primarily causes **megaloblastic anemia** and neurological symptoms such as **peripheral neuropathy**, ataxia, and cognitive impairment, rather than high-output cardiac failure.
- Cardiac manifestations are usually due to severe anemia leading to compensatory high output, but not the primary cause as seen in thiamine deficiency.
*Vitamin D*
- **Vitamin D deficiency** is associated with **osteomalacia** in adults and rickets in children, leading to bone pain, muscle weakness, and increased fracture risk.
- It does not cause high-output cardiac failure or related cardiovascular symptoms.
*Niacin*
- **Niacin deficiency** (pellagra) is characterized by the "3 Ds": **dermatitis**, **diarrhea**, and **dementia**, along with glossitis and stomatitis.
- While cardiovascular symptoms can occur in severe cases, high-output cardiac failure with a bounding pulse is not a typical hallmark of pellagra.
Water-soluble vitamins - B complex US Medical PG Question 4: A 24-year-old man presents to the emergency department complaining of a prolonged course of diarrhea. He reports that he has had 3–4 large volume watery stools daily for the last several weeks. He has no pain with bowel movements, no abdominal pain, and no blood in his stools. He is homeless and uses recreational drugs. He also reports that he usually drinks a half-liter of whiskey, or whatever else he can find, every day and he has done this for several years. The physical exam is notable for a hyperpigmented rash across his face, neck, chest, and the backs of his hands and forearms. On mental status exam, he is oriented to person and place but not time; he scores a 23/30 on the Montreal Cognitive Assessment (MOCA). This patient's presentation is most likely related to which of the following micronutrients?
- A. Vitamin B2
- B. Vitamin B12
- C. Vitamin D
- D. Vitamin C
- E. Vitamin B3 (Correct Answer)
Water-soluble vitamins - B complex Explanation: ***Vitamin B3***
- The patient's symptoms—diarrhea, dermatitis (hyperpigmented rash), and dementia (disorientation to time, MOCA 23/30)—are the classic **3 Ds of pellagra**, which is caused by a **vitamin B3 (niacin) deficiency**.
- His chronic alcohol use and poor nutritional status (homelessness, recreational drug use) put him at high risk for such a deficiency, as alcohol impairs nutrient absorption and niacin is often lacking in the diets of those with limited food access.
*Vitamin B2*
- Deficiency in **vitamin B2 (riboflavin)** typically presents with cheilosis, angular stomatitis, glossitis, seborrheic dermatitis, and ocular symptoms like corneal vascularization, none of which are specifically mentioned here.
- While chronic alcohol use can also cause riboflavin deficiency, the patient's full symptom complex points more strongly to pellagra.
*Vitamin B12*
- **Vitamin B12 deficiency** often leads to **macrocytic anemia**, neurological symptoms including peripheral neuropathy, ataxia, and cognitive impairment, and glossitis, but it does not typically cause the characteristic dermatologic rash or diarrhea seen in this patient.
- While chronic alcohol use is a risk factor, the specific triad of diarrhea, dermatitis, and dementia is not consistent with B12 deficiency.
*Vitamin D*
- **Vitamin D deficiency** is associated with bone health issues (rickets in children, osteomalacia in adults), muscle weakness, and in severe cases, hypocalcemia.
- It does not present with the specific combination of diarrhea, hyperpigmented rash, and cognitive changes described in the patient.
*Vitamin C*
- **Vitamin C deficiency (scurvy)** typically manifests as perifollicular hyperkeratosis, bleeding gums, petechiae, impaired wound healing, and musculoskeletal pain.
- While malnourishment and alcohol abuse increase the risk of scurvy, the patient's symptoms do not align with the classic presentation of vitamin C deficiency.
Water-soluble vitamins - B complex US Medical PG Question 5: A 51-year-old gentleman presents with new onset bilateral paresthesias of his feet. He also admits that he has not been able to exercise as much as previously and his friends have commented that he looks pale. Upon physical exam you find that he has conjunctival pallor and mildly decreased sensation and proprioception on his feet bilaterally. Based on your suspicions you decide to obtain a blood smear where you see megaloblasts as well as hypersegmented neutrophils. Given these findings you decide to investigate the cause of his disorder by injecting an intramuscular vitamin, then feeding him a radiolabeled version of the same vitamin orally. After waiting 24 hours you see that no radiolabeled vitamin appears in the urine so you repeat the test with intrinsic factor added to the oral mixture, at which point 20% of the radiolabeled vitamin appears in the urine. Which of the following is the most likely etiology of this gentleman's symptoms?
- A. Bacterial overgrowth
- B. Pancreatic insufficiency
- C. Insufficient vitamin intake
- D. Pernicious anemia (Correct Answer)
- E. Folate deficiency
Water-soluble vitamins - B complex Explanation: ***Pernicious anemia***
- The combination of **neurological symptoms** (paresthesias, decreased proprioception), **anemia symptoms** (pallor, fatigue), **megaloblastic anemia** on blood smear (megaloblasts, hypersegmented neutrophils), and the specific Schilling test results (vitamin B12 malabsorption corrected by added **intrinsic factor**) is diagnostic for pernicious anemia.
- Pernicious anemia is an autoimmune condition targeting **gastric parietal cells** or **intrinsic factor** itself, leading to **vitamin B12 deficiency** due to impaired absorption.
*Bacterial overgrowth*
- **Bacterial overgrowth in the small intestine** can consume vitamin B12, leading to deficiency, but the Schilling test would show improvement with **antibiotics**, not intrinsic factor.
- While it can cause B12 deficiency and megaloblastic anemia, improvement upon adding intrinsic factor points away from this diagnosis.
*Pancreatic insufficiency*
- **Pancreatic enzymes** are required to cleave vitamin B12 from its binding proteins, but the **Schilling test** would show improvement with **pancreatic enzyme supplements**, not intrinsic factor.
- While pancreatic insufficiency can lead to B12 malabsorption, the specific Schillings test results rule it out.
*Insufficient vitamin intake*
- **Insufficient dietary intake** of vitamin B12 would lead to B12 deficiency, but in such a case, the **Schilling test** would show normal absorption of radiolabeled B12 even without intrinsic factor in the second stage.
- The initial B12 malabsorption indicates an absorption problem, not solely a dietary lack.
*Folate deficiency*
- **Folate deficiency** also causes **megaloblastic anemia** and can present with fatigue and pallor, but it does **not cause neurological symptoms** like paresthesias or proprioception deficits.
- The Schilling test specifically evaluates **vitamin B12 absorption**, not folate levels, so it would be irrelevant for diagnosing pure folate deficiency.
Water-soluble vitamins - B complex US Medical PG Question 6: A homeless woman presents with shortness of breath on exertion and pedal edema. Cardiac workup performed shows evidence of dilated cardiomyopathy and increased cardiac output. She also has decreased sensation over both extremities bilaterally. Which vitamin deficiency most likely caused these symptoms?
- A. Vitamin B6
- B. Vitamin C
- C. Vitamin B1 (Correct Answer)
- D. Vitamin B3
- E. Vitamin A
Water-soluble vitamins - B complex Explanation: ***Vitamin B1***
- The combination of **dilated cardiomyopathy**, **high-output heart failure** (manifesting as shortness of breath and pedal edema), and **peripheral neuropathy** (decreased sensation) is classic for **wet beriberi**, caused by thiamine (Vitamin B1) deficiency.
- **Homelessness** is a significant risk factor for nutritional deficiencies, including thiamine deficiency, due to inadequate diet.
*Vitamin B6*
- Deficiency can cause **peripheral neuropathy**, but it does not typically lead to **dilated cardiomyopathy** or **high-output heart failure**.
- Other manifestations of B6 deficiency include **sideroblastic anemia** and **seizures**.
*Vitamin C*
- Deficiency causes **scurvy**, characterized by **gingivitis**, **poor wound healing**, **petechiae**, and joint pain.
- It does not present with **cardiomyopathy** or **neuropathy** as described.
*Vitamin B3*
- Deficiency causes **pellagra**, characterized by the "3 Ds": **dermatitis**, **diarrhea**, and **dementia**.
- While it can affect the nervous system (dementia), it does not typically cause **dilated cardiomyopathy** or **peripheral neuropathy**.
*Vitamin A*
- Deficiency primarily affects **vision** (e.g., **night blindness**, **xerophthalmia**) and immune function.
- It is not associated with **cardiac** or **neurological symptoms** like those described in the patient.
Water-soluble vitamins - B complex US Medical PG Question 7: A 17-year-old high school student presents to your office for recent mood and skin changes. The patient is a high school senior who is competing on the wrestling team and recently has lost weight to drop two weight classes over the past several months. He states he has dry, cracking, and irritated skin, as well as a sensation of tingling in his hands and feet. The patient also states that he has not been feeling himself lately. He finds himself more irritable and no longer enjoys many of the activities he once enjoyed. He finds that he often feels fatigued and has trouble concentrating. The patient does not have a significant past medical history and is not on any current medications. The patient admits to drinking alcohol and smoking marijuana on special occasions. He states that he uses supplements that his other team members use. Physical exam is significant for acne, dry, cracked skin around the patient's mouth in particular, and decreased sensation in his lower extremities. Laboratory values are as follows:
Serum:
Na+: 137 mEq/L
Cl-: 101 mEq/L
K+: 4.1 mEq/L
HCO3-: 24 mEq/L
BUN: 15 mg/dL
Glucose: 79 mg/dL
Creatinine: 0.9 mg/dL
Ca2+: 9.2 mg/dL
Mg2+: 1.5 mEq/L
Homocysteine: 11.2 µmol/L (normal: 4.6 to 8.1 µmol/L)
AST: 11 U/L
ALT: 11 U/L
Alkaline phosphatase: 27 U/L
Albumin: 4.5 g/dL
Total protein: 6.9 g/dL
Total bilirubin: 0.5 mg/dL
Direct bilirubin: 0.3 mg/dL
Which of the following is the most likely diagnosis?
- A. Depression secondary to dietary changes
- B. Anabolic steroid use
- C. Dermatologic fungal infection
- D. Viral infection
- E. Water soluble vitamin deficiency (Correct Answer)
Water-soluble vitamins - B complex Explanation: ***Water soluble vitamin deficiency***
- The patient's symptoms (irritability, fatigue, poor concentration, dry cracking skin around the mouth, tingling in hands and feet) coupled with a history of rapid weight loss for wrestling ("cutting weight") and elevated **homocysteine** levels are highly suggestive of a vitamin deficiency, specifically **B vitamins** (e.g., B6, B9, B12) which are water-soluble and easily depleted with poor dietary intake and increased metabolic demand.
- The elevated **homocysteine** is a key indicator, as vitamins B6, B9 (folate), and B12 are crucial cofactors in its metabolism. Deficiencies in these vitamins lead to hyperhomocysteinemia, which can cause neurological symptoms and skin manifestations.
*Depression secondary to dietary changes*
- While the patient exhibits mood changes (irritability, anhedonia, fatigue), these symptoms are better explained within the context of **nutritional deficiency**, which can directly impact neurotransmitter synthesis and overall neurological function.
- Depression alone would not typically account for the specific dermatological findings (**dry, cracking skin around the mouth**) or the **peripheral neuropathy** (tingling, decreased sensation) in conjunction with elevated homocysteine.
*Anabolic steroid use*
- Anabolic steroid use can cause **acne** and mood changes (irritability, aggression), but typically does not cause **dry, cracking skin around the mouth** or specific **tingling/numbness** in the extremities or elevated **homocysteine levels**.
- While the patient admits to using supplements, there's no direct evidence to suggest anabolic steroid use, and the constellation of symptoms points more strongly to a nutritional cause.
*Dermatologic fungal infection*
- A fungal infection might explain some skin changes, but it would not account for the systemic symptoms like **mood changes**, **fatigue**, **tingling in the hands and feet**, or the elevated **homocysteine**.
- The description of "dry, cracking skin around the patient's mouth" is more consistent with **cheilosis** or **angular stomatitis**, commonly associated with B vitamin deficiencies, rather than a typical fungal infection.
*Viral infection*
- A viral infection could cause **fatigue** and general malaise, but it would not explain the specific skin findings like **dry, cracking skin around the mouth**, **tingling in hands and feet**, or the elevated **homocysteine** levels, which are long-standing signs of nutritional deficiencies.
- The patient's symptoms have been ongoing for "several months," which is less typical for an acute viral illness.
Water-soluble vitamins - B complex US Medical PG Question 8: A 66-year-old male with a history of deep venous thrombosis is admitted to the hospital with shortness of breath and pleuritic chest pain. He is treated with an anticoagulant, but he develops significant hematochezia. His BP is now 105/60 and HR is 117; both were within normal limits on admission. The effects of the anticoagulant are virtually completely reversed with the administration of protamine. Which of the following was the anticoagulant most likely administered to this patient?
- A. Enoxaparin
- B. Dabigatran
- C. Bivalirudin
- D. Warfarin
- E. Heparin (Correct Answer)
Water-soluble vitamins - B complex Explanation: ***Heparin***
- **Protamine sulfate** is the specific and virtually complete antidote for **unfractionated heparin (UFH)** and, to a lesser extent, low molecular weight heparins (LMWH).
- The patient's presentation with **shortness of breath** and **pleuritic chest pain** suggests a **pulmonary embolism (PE)**, a common indication for heparin.
*Enoxaparin*
- Enoxaparin is a **low molecular weight heparin (LMWH)**. While protamine can partially reverse LMWH effects, it is **not complete** (only 60-75% reversal) compared to UFH.
- LMWHs have a **longer half-life** and less predictable reversal with protamine than UFH.
*Dabigatran*
- Dabigatran is a **direct thrombin inhibitor** and its antidote is **idarucizumab**, not protamine.
- This drug is not reversible by protamine.
*Bivalirudin*
- Bivalirudin is a **direct thrombin inhibitor** used mainly during percutaneous coronary intervention and its effects are **not reversible with protamine**.
- Its short half-life often makes reversal agents unnecessary, but there is no specific antidote listed.
*Warfarin*
- Warfarin is a **vitamin K antagonist** and its effects are reversed by **vitamin K**, fresh frozen plasma (FFP), or prothrombin complex concentrates (PCCs), not protamine.
- Warfarin also has a **delayed onset of action**, making it less suitable for acute treatment of a suspected PE.
Water-soluble vitamins - B complex US Medical PG Question 9: A 42-year-old man presents to his primary care provider with recent swelling in his legs that has now spread to the lower part of his thighs. He sometimes has difficulty putting on his shoes and pants. He also noticed puffiness under his eyes over the last 3 weeks. A 24-hour urine collection confirms proteinuria of 5 g/day. Electron microscopy of a renal biopsy specimen reveals subepithelial deposits with a spike and dome pattern. Which of the following is associated with this patient’s condition?
- A. HIV infection
- B. Monoclonal protein spike
- C. High HbA1C
- D. Hepatitis B infection (Correct Answer)
- E. Hodgkin's lymphoma
Water-soluble vitamins - B complex Explanation: ***Hepatitis B infection***
- The patient presents with **nephrotic syndrome** (edema, proteinuria >3.5 g/day, periorbital puffiness), and renal biopsy shows **subepithelial deposits** with a **spike and dome pattern** characteristic of **membranous nephropathy**.
- **Hepatitis B infection** is a well-known and common secondary cause of **membranous nephropathy**, particularly in adults and in endemic areas. This is the classic association tested on USMLE.
*HIV infection*
- While **HIV infection** can cause nephrotic syndrome, it typically presents as **HIV-associated nephropathy (HIVAN)**, characterized by **focal segmental glomerulosclerosis (FSGS)**, not membranous nephropathy with subepithelial deposits.
- HIVAN is also often associated with rapidly progressive renal failure and collapsing glomerulopathy on biopsy.
*Monoclonal protein spike*
- A **monoclonal protein spike** (e.g., from multiple myeloma or monoclonal gammopathy of undetermined significance) most commonly causes renal disease manifesting as **amyloidosis** (fibrillar deposits) or **light chain deposition disease**, which show distinct findings on renal biopsy.
- While monoclonal immunoglobulins can rarely cause membranous nephropathy, this is uncommon and not the classic association. Given the spike and dome pattern, **Hepatitis B** is the better answer.
*High HbA1C*
- A **high HbA1C** indicates **poorly controlled diabetes**, which is a leading cause of **diabetic nephropathy**.
- Diabetic nephropathy typically presents with **glomerular basement membrane thickening**, **mesangial expansion**, and **Kimmelstiel-Wilson lesions** (nodular glomerulosclerosis), not the spike and dome pattern seen in membranous nephropathy.
*Hodgkin's lymphoma*
- While lymphoma can be associated with kidney disease, **Hodgkin's lymphoma** is classically linked to **minimal change disease** in adults, which presents with effacement of podocyte foot processes on electron microscopy, without immune deposits.
- Membranous nephropathy, as seen here with subepithelial deposits, is not the typical renal manifestation of Hodgkin's lymphoma.
Water-soluble vitamins - B complex US Medical PG Question 10: A 3-year-old boy is brought to the physician for a follow-up examination. He has lactose intolerance. His family emigrated from Somalia 6 months ago. He is at the 30th percentile for height and 15th percentile for weight. Vital signs are within normal limits. Examination shows pale conjunctivae, an erythematous throat, and swollen tongue. There is inflammation of the perioral and labial mucosa, and peeling and cracking of the skin at the corners of the mouth. Cardiopulmonary examination shows no abnormalities. His hemoglobin concentration is 9.8 g/dL and mean corpuscular volume is 87 μm3. If left untreated, this child is also most likely to develop which of the following?
- A. Dilated cardiomyopathy
- B. Keratomalacia
- C. Ataxia
- D. Corneal vascularization (Correct Answer)
- E. Hypersegmented neutrophils
Water-soluble vitamins - B complex Explanation: ***Corneal vascularization***
- The clinical presentation of **angular cheilitis** (cracking/peeling at mouth corners), **glossitis** (swollen, erythematous tongue), **perioral and labial inflammation**, and **normocytic anemia** in a child with **lactose intolerance** (limiting dairy intake) strongly suggests **riboflavin (vitamin B2) deficiency**.
- If left untreated, riboflavin deficiency progresses to **corneal vascularization**, characterized by blood vessel invasion into the normally avascular cornea, often accompanied by photophobia and conjunctival injection.
- **Dairy products are the primary dietary source of riboflavin**, making lactose-intolerant individuals particularly vulnerable to deficiency.
*Hypersegmented neutrophils*
- This is the hallmark hematologic finding in **megaloblastic anemia** caused by **folate or vitamin B12 deficiency**.
- These deficiencies cause **macrocytic anemia** (MCV >100 μm³), but this patient has **normocytic anemia** (MCV 87 μm³), ruling out megaloblastic causes.
- The normal MCV excludes folate/B12 deficiency as the primary diagnosis.
*Dilated cardiomyopathy*
- This is the classic cardiac manifestation of **thiamine (vitamin B1) deficiency** (wet beriberi).
- While severe malnutrition can affect cardiac function, the specific clinical features presented (angular cheilitis, glossitis) are not characteristic of thiamine deficiency.
- Thiamine deficiency typically presents with peripheral neuropathy, muscle weakness, and cardiovascular collapse, not the oral/mucosal lesions seen here.
*Keratomalacia*
- This condition results from **severe vitamin A deficiency** and involves corneal softening, ulceration, and blindness.
- Vitamin A deficiency presents with **night blindness, xerophthalmia, and Bitot's spots**, not the oral mucosal lesions described.
- The clinical picture does not support vitamin A deficiency.
*Ataxia*
- **Ataxia** is associated with **vitamin B12 deficiency** (subacute combined degeneration affecting posterior columns and corticospinal tracts) or **vitamin E deficiency**.
- Again, the **normal MCV** rules out B12 deficiency as the primary diagnosis.
- The prominent oral and skin findings are not typical of neurological vitamin deficiencies.
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