Disease Correlation
Understanding the connections between specific disease states and abnormalities in vitamin and nutrient levels is critical for effective diagnosis and management
Vitamin and Mineral Deficiencies: General Considerations
- Etiology: Inadequate dietary intake, impaired absorption, increased nutrient requirements, and drug interactions are common causes of vitamin and mineral deficiencies
- Populations at Risk: Certain populations are at higher risk of nutrient deficiencies, including infants, children, pregnant women, elderly individuals, and those with chronic diseases or poor dietary habits
- Clinical Manifestations: Nutrient deficiencies can lead to a wide range of symptoms, including fatigue, weakness, neurological problems, skin changes, and impaired immune function
- Diagnosis: Diagnosis is based on dietary assessment, clinical evaluation, and laboratory testing
- Treatment: Treatment involves dietary modifications, supplementation, and addressing underlying causes
Water-Soluble Vitamin Deficiencies
Thiamin (Vitamin B1) Deficiency
- Disorder: Beriberi and Wernicke-Korsakoff Syndrome
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Etiology
- Alcohol abuse
- Malnutrition
- Malabsorption
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Laboratory Findings
- Decreased erythrocyte transketolase activity
- Elevated blood pyruvate and lactate levels
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Disease State Correlation
- Beriberi: Cardiovascular (wet beriberi) and neurological (dry beriberi) symptoms
- Wernicke-Korsakoff Syndrome: Confusion, ataxia, nystagmus, and memory impairment
Riboflavin (Vitamin B2) Deficiency
- Disorder: Ariboflavinosis
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Etiology
- Malnutrition
- Malabsorption
- Certain medications
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Laboratory Findings
- Decreased erythrocyte glutathione reductase activity
- Decreased urinary excretion of riboflavin
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Disease State Correlation
- Cheilosis (cracking at the corners of the mouth)
- Glossitis (inflammation of the tongue)
- Dermatitis
Niacin (Vitamin B3) Deficiency
- Disorder: Pellagra
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Etiology
- Inadequate dietary intake
- Malabsorption
- Certain medications
- Hartnup disease
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Laboratory Findings
- Decreased urinary excretion of niacin metabolites
- Decreased erythrocyte nicotinamide adenine dinucleotide (NAD) levels
-
Disease State Correlation
- Dermatitis (photosensitive)
- Diarrhea
- Dementia
Pyridoxine (Vitamin B6) Deficiency
- Disorder: Pyridoxine Deficiency
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Etiology
- Alcohol abuse
- Drug interactions (isoniazid, penicillamine)
- Malabsorption
-
Laboratory Findings
- Decreased plasma pyridoxal phosphate (PLP) levels
- Elevated urinary xanthurenic acid excretion after tryptophan load
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Disease State Correlation
- Neurological symptoms (seizures, depression, peripheral neuropathy)
- Dermatitis
- Anemia (microcytic)
Folate (Vitamin B9) Deficiency
- Disorder: Folate Deficiency
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Etiology
- Inadequate dietary intake
- Malabsorption
- Drug interactions (methotrexate)
- Pregnancy
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Laboratory Findings
- Decreased serum and red blood cell folate levels
- Elevated homocysteine levels
-
Disease State Correlation
- Megaloblastic anemia
- Neural tube defects in developing fetuses
- Increased risk of cardiovascular disease
Cobalamin (Vitamin B12) Deficiency
- Disorder: Cobalamin Deficiency
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Etiology
- Inadequate dietary intake (vegans)
- Pernicious anemia (lack of intrinsic factor)
- Malabsorption (Crohn’s disease, celiac disease)
- Gastrectomy
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Laboratory Findings
- Decreased serum vitamin B12 levels
- Elevated homocysteine and methylmalonic acid (MMA) levels
-
Disease State Correlation
- Megaloblastic anemia
- Neurological symptoms (peripheral neuropathy, cognitive impairment)
- Increased risk of cardiovascular disease
Fat-Soluble Vitamin Deficiencies
Vitamin A Deficiency
- Disorder: Vitamin A Deficiency
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Etiology
- Inadequate dietary intake
- Fat malabsorption
-
Laboratory Findings
- Decreased serum retinol levels
-
Disease State Correlation
- Night blindness
- Xerophthalmia (dry eyes)
- Impaired immune function
Vitamin D Deficiency
- Disorder: Vitamin D Deficiency
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Etiology
- Inadequate sunlight exposure
- Inadequate dietary intake
- Fat malabsorption
- Kidney and liver disorders
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Laboratory Findings
- Decreased serum 25-hydroxyvitamin D [25(OH)D] levels
- Elevated parathyroid hormone (PTH) levels
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Disease State Correlation
- Rickets (in children)
- Osteomalacia (in adults)
- Osteoporosis
- Increased risk of falls and fractures
General Notes on Interpretation
- Influence of Assay Methodology: Different analytical methods for measuring vitamins and nutrients can have varying sensitivities and specificities
- Patient Population: Consider age, sex, physiological state (e.g., pregnancy), and coexisting medical conditions
- Clinical Correlation: Always interpret test results in the context of the patient’s overall health and clinical presentation
Key Terms
- Vitamin: An organic compound that is essential for human health
- Deficiency: A condition in which the body does not have enough of a particular nutrient
- Toxicity: A condition in which the body has too much of a particular nutrient
- Malnutrition: A state of nutritional imbalance
- Megaloblastic Anemia: A type of anemia characterized by large, abnormal red blood cells
- Homocysteine: An amino acid that is elevated in folate and vitamin B12 deficiencies
- Clinical Correlation: Considering the patient’s clinical history, physical examination, and other test results when interpreting laboratory data