7.2 Pediatric, Obstetric, and Geriatric Clinical Nutritional Assessment

Clinical nutritional assessment requires specialized diagnostic criteria calibrated to distinct physiological stages of the human life cycle. In pediatric populations, assessment focuses on cellular growth velocity, skeletal maturation, and early identification of malnutrition syndromes. In maternal and obstetric care, assessment guides fetal organogenesis, placental expansion, and gestational weight tracking. In geriatric populations, assessment emphasizes functional muscle preservation, sensory deficits, altered gastrointestinal physiology, and polypharmacy interactions.

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Pediatric Nutritional Assessment: Growth Standards & Anthropometric Z-Scores

Pediatric growth assessment relies on the World Health Organization (WHO) Child Growth Standards (birth to 59 months) and the WHO Growth Reference (5 to 19 years), officially adopted by the Philippine Department of Health and National Nutrition Council (NNC).

Statistical Foundation: Anthropometric Z-Scores

Because body dimensions change rapidly during childhood, raw measurements are converted to Z-scores (standard deviations from the median) based on an international reference population: $Z = \frac{\text{Observed Measurement} - \text{Median Reference Value}}{\text{Standard Deviation of Reference Population}}$

Core Pediatric Growth Indicators

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Differentiating Severe Acute Malnutrition: Marasmus vs. Kwashiorkor

In children aged 6 to 59 months, Severe Acute Malnutrition (SAM) is clinically diagnosed by the presence of any one of three independent criteria:

1. Weight-for-Height (WFH) $< -3\text{ SD}$, OR
2. Mid-Upper Arm Circumference (MUAC) $< 115\text{ mm}$ ($< 11.5\text{ cm}$), OR
3. Presence of bilateral pitting edema.

SAM manifests as two distinct pathophysiological extremes: Marasmus and Kwashiorkor (or combined Marasmic Kwashiorkor):

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Maternal & Obstetric Assessment: Gestational Weight Tracking & Nutrient Targets

Obstetric nutrition assessment focuses on pre-pregnancy nutritional status, monitoring gestational weight gain (GWG) trajectories, and ensuring adequate micronutrient delivery for embryonic morphogenesis and placental development.

Pre-Pregnancy BMI Stratification & Weight Gain Targets

The Institute of Medicine (IOM, 2009) recommends total weight gain according to pre-pregnancy BMI, using WHO BMI categories:

• In twin pregnancies, recommended gain for normal-weight women is 37 to 54 lbs ($16.8 - 24.5\text{ kg}$).
• Risks of Inadequate Gain: Intrauterine growth restriction (IUGR), low birth weight ($< 2500\text{ g}$), preterm delivery, and neonatal mortality.
• Risks of Excessive Gain: Fetal macrosomia ($> 4000\text{ g}$), shoulder dystocia, primary cesarean delivery, gestational hypertension/preeclampsia, gestational diabetes mellitus, and long-term postpartum maternal obesity.

Nutritional Demands Across Trimesters and Lactation

• Energy Requirements:
  • 1st Trimester: $+0\text{ kcal/day}$ (no additional energy required above pre-pregnancy baseline).
  • 2nd Trimester: $+340\text{ kcal/day}$.
  • 3rd Trimester: $+452\text{ kcal/day}$ (commonly rounded to $+450\text{ kcal/day}$).
  • Lactation (0–6 months postpartum): $+500\text{ kcal/day}$ ($+330\text{ kcal/day}$ supplied by increased dietary intake, while $\sim 170\text{ kcal/day}$ is mobilized from subcutaneous fat stores accumulated during gestation).
  • Lactation (7–12 months postpartum): $+400\text{ kcal/day}$.
• Protein: Additional $+25\text{ g/day}$ throughout the second and third trimesters and during lactation (total $\sim 71\text{ g/day}$ or $1.1\text{ g/kg/day}$) to support fetal, uterine, and breast tissue protein accretion.
• PDRI 2015 (Philippine standard): +300 kcal/day in the second and third trimesters, +500 kcal/day during lactation, and +27 g protein/day in both pregnancy and lactation. Use these figures for Philippine meal plans.
• Critical Micronutrients:
  • Folate / Folic Acid: $600\,\mu\text{g DFE/day}$ ($400\,\mu\text{g/day}$ preconception). Crucial for neural tube closure between days 21 and 28 post-conception; prevents spina bifida and anencephaly.
  • Iron: The PDRI 2015 adds 10 mg/day to the 28 mg/day for women 19-49, a total that cannot be met by diet alone (IOM RDA: 27 mg/day). The DOH gives daily supplements of $60\text{ mg elemental iron} + 400\,\mu\text{g folic acid}$. Expands maternal red blood cell mass by $30 - 40\%$ and builds fetal hepatic iron stores to sustain the infant through the first 6 months of life.
  • Calcium: The PDRI 2015 recommends 750 mg/day for women 19-49, plus 50 mg/day in the third trimester (IOM RDA: 1,000 mg/day; 1,300 mg/day for pregnant adolescents). Supports fetal skeletal ossification; protects maternal trabecular bone; reduces risk of gestational hypertensive disorders.
  • Iodine: The PDRI 2015 adds 100 µg/day to the adult 150 µg/day in both pregnancy and lactation (IOM: 220 µg/day in pregnancy and 290 µg/day in lactation). Essential for fetal thyroid hormone synthesis and neurocognitive development; prevents congenital iodine deficiency syndrome (cretinism).
  • Fluid Intake: $3.8\text{ L/day}$ (approx. $16\text{ cups}$) during lactation to sustain breast milk production ($750 - 850\text{ mL/day}$).

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Geriatric Nutrition Assessment: Sarcopenia, MNA, and Physiological Decline

Older adults undergo physiological, mechanical, and neuroendocrine changes that increase vulnerability to malnutrition, functional dependence, and frailty.

Screening Tools: Mini Nutritional Assessment (MNA) & Sarcopenia

• Mini Nutritional Assessment Short-Form (MNA-SF): Validated specifically for geriatric individuals (age $\ge 65\text{ years}$). Evaluates 6 core parameters: decline in food intake over the past 3 months, unintentional weight loss, mobility status, psychological stress or acute disease, neuropsychological problems (dementia/depression), and BMI (or calf circumference if BMI is unavailable):
  • 12 to 14 points: Normal nutritional status
  • 8 to 11 points: At risk of malnutrition
  • 0 to 7 points: Malnourished
• Sarcopenia Diagnostic Framework (Asian Working Group for Sarcopenia - AWGS 2019):
  1. Muscle Strength: Measured by handgrip dynamometry: $< 28.0\text{ kg}$ for men; $< 18.0\text{ kg}$ for women.
  2. Muscle Mass: Evaluated via dual-energy X-ray absorptiometry (DXA) appendicular skeletal muscle mass index: $< 7.0\text{ kg/m}^2$ for men, $< 5.4\text{ kg/m}^2$ for women; or bioelectrical impedance analysis (BIA): $< 7.0\text{ kg/m}^2$ for men, $< 5.7\text{ kg/m}^2$ for women.
  3. Physical Performance: 6-meter walk gait speed $< 1.0\text{ m/s}$ or 5-time chair stand test $\ge 12\text{ seconds}$.
  • Sarcopenic Obesity: The concurrent presence of depleted skeletal muscle mass and high visceral adiposity. Often overlooked because an elevated BMI conceals progressive muscle atrophy.

Age-Related Physiological Factors

1. Altered Body Composition: Sarcopenia involves an involuntary loss of roughly $3 - 8\%$ of muscle mass per decade after age 30, accelerating after age 60. Visceral fat increases while total body water drops from $60\%$ to $\le 50\%$, significantly elevating dehydration risk.
2. Oral Cavity and Dentition: Edentulism (tooth loss), poorly fitting dentures, and xerostomia (dry mouth from salivary gland atrophy or anticholinergic drugs) cause seniors to avoid fibrous meats, raw fruits, and vegetables, resulting in micronutrient deficiencies.
3. Dysphagia Management: Neurological disorders (stroke, Parkinson's disease, dementia) frequently impair oropharyngeal swallowing. Diets must be modified using the International Dysphagia Diet Standardisation Initiative (IDDSI) framework (drinks Levels 0-4: thin, slightly thick, mildly thick, moderately thick, extremely thick; foods Levels 3-7: liquidised, pureed, minced and moist, soft and bite-sized, regular).
4. Gastrointestinal and Sensory Alterations:
   • Atrophic Gastritis & Hypochlorhydria: Age-related loss of gastric parietal cells decreases hydrochloric acid and intrinsic factor secretion. Achlorhydria impairs the cleavage of vitamin $B_{12}$ from food proteins and reduces the reduction of ferric ($Fe^{3+}$) to ferrous ($Fe^{2+}$) iron, precipitating megaloblastic and microcytic anemias.
   • Blunted Thirst Perception: Hypothalamic osmoreceptor sensitivity declines with age. Elderly patients do not experience thirst despite hyperosmolar dehydration.
   • Anorexia of Aging: Early satiety caused by elevated baseline cholecystokinin (CCK), blunted ghrelin, delayed gastric emptying, and hypogeusia/hyposmia (reduced taste and smell).
5. Polypharmacy Interactions: The concurrent use of $\ge 5$ medications induces frequent drug-nutrient interactions:
   • Loop Diuretics (e.g., Furosemide): Induce hypokalemia, hypomagnesemia, and zinc depletion.
   • Proton Pump Inhibitors (e.g., Omeprazole): Induce achlorhydria, impairing vitamin $B_{12}$, calcium, and magnesium absorption.
   • ACE Inhibitors (e.g., Enalapril): Risk of hyperkalemia; dysgeusia (metallic taste).
   • Metformin: Long-term therapy impairs ileal absorption of vitamin $B_{12}$, requiring routine serum monitoring.