10.2 MNT for Fevers, Infections, Diarrheal Disease, and Respiratory Disorders
Key Takeaways
Each 1 °C rise in body temperature increases the metabolic rate by about 13% (about 7% per 1 °F), so fever raises energy and fluid needs.
The general diet in fever is high in energy, protein, and fluids, given as small frequent feedings that progress from liquid to soft to regular as appetite returns.
WHO recommends low-osmolarity oral rehydration solution and 10-14 days of zinc (20 mg/day for children over 6 months, 10 mg/day for younger infants) for childhood diarrhea, with continued feeding and breastfeeding.
Patients with tuberculosis often have weight loss and higher energy and protein needs, and those on isoniazid need vitamin B6.
In COPD, small frequent nutrient-dense meals help counter weight loss, and overfeeding should be avoided because excess energy, especially carbohydrate, increases carbon dioxide production.
The table of specifications lists fevers, infections, respiratory disorders, and underweight among the medical conditions whose nutrition management examinees must explain. Infectious disease remains common in the Philippines, so these items connect clinical and community nutrition.
Metabolic Effects of Fever and Infection
- Higher metabolic rate: about 13% for each 1 °C (about 7% per 1 °F) rise in body temperature.
- Protein breakdown: cytokines and stress hormones increase muscle catabolism and nitrogen loss.
- Fluid and electrolyte loss: sweating, rapid breathing, vomiting, and diarrhea increase losses.
- Lower intake: anorexia, nausea, and fatigue reduce eating.
- Micronutrient demands: vitamin A, vitamin C, zinc, and other nutrients are used up faster.
The Diet in Fever
| Principle | Practice |
|---|---|
| High energy | Raise intake to cover the higher metabolic rate; use energy-dense liquids and soft foods |
| High protein | Eggs, milk, fish, chicken, tofu, and legumes in easy-to-eat forms |
| Generous fluids | Water, soups, juices, oral rehydration solution; about 2-3 L/day or more in adults unless restricted |
| Small, frequent feedings | 5-6 feedings a day when appetite is poor |
| Progressive consistency | Full liquid or soft foods during high fever, advancing as tolerated |
| Electrolytes | Broths and fruit juices help replace sodium and potassium |
Fevers are often grouped as short-duration (acute), such as influenza and dengue; prolonged or continued, such as typhoid fever and tuberculosis; and recurrent, such as malaria. Prolonged fevers cause more weight loss and need sustained high-energy, high-protein feeding.
Specific Infections
Typhoid fever. Caused by Salmonella Typhi, it causes prolonged fever and can ulcerate the small intestine. The classic diet is high in energy and protein, with a soft, low-residue diet during the acute phase to avoid irritating the bowel, plus generous fluids. Progress to a regular diet during recovery. Food and water safety is the main prevention.
Dengue. The key nutrition intervention is adequate oral fluids, including oral rehydration solution, to prevent dehydration and support circulation during the febrile and critical phases, with soft, easy-to-eat foods as tolerated. No specific food or herbal juice has been proven to raise platelet counts, so do not replace medical monitoring with home remedies.
Tuberculosis. The Philippines has a high tuberculosis burden. Patients commonly have weight loss and wasting from hypermetabolism and poor appetite.
- Provide a high-energy, high-protein diet in small, frequent meals.
- Give vitamin B6 with isoniazid to prevent neuropathy.
- Food support can improve treatment adherence, especially in food-insecure households.
- Screen household contacts and address food insecurity through social protection programs.
Pneumonia and other acute respiratory infections. Maintain fluids and energy, use soft foods during breathlessness, and continue breastfeeding sick infants.
Acute Diarrheal Disease
Diarrhea remains a major cause of child illness, and it worsens malnutrition.
| Intervention | Recommendation |
|---|---|
| Oral rehydration solution (ORS) | WHO low-osmolarity ORS (sodium 75 mmol/L, glucose 75 mmol/L, total osmolarity 245 mOsm/L) to prevent and treat dehydration |
| Zinc | 10-14 days: 20 mg/day for children over 6 months, 10 mg/day for infants under 6 months; shortens diarrhea and reduces recurrence |
| Continued feeding | Keep breastfeeding; continue age-appropriate foods during and after diarrhea; give an extra meal daily during recovery |
| Avoid | Sugary soft drinks and undiluted juices, which are hyperosmolar and can worsen diarrhea |
ORS works because sodium-glucose cotransport (SGLT1) in the intestine continues during most diarrheal illnesses, pulling water into the body with the absorbed sodium and glucose.
Chronic Obstructive Pulmonary Disease (COPD)
COPD (emphysema and chronic bronchitis) increases the energy cost of breathing, and many patients lose weight and muscle (pulmonary cachexia), which weakens the respiratory muscles.
- Energy and protein: enough energy to stop weight loss; protein about 1.2-1.5 g/kg to preserve muscle.
- Meal pattern: small, frequent, energy-dense meals; rest before meals; use prescribed oxygen during meals; avoid gas-forming foods that cause bloating and press on the diaphragm.
- Avoid overfeeding: excess energy, especially carbohydrate, increases carbon dioxide production and the work of breathing. A moderately higher fat proportion may help some patients, but avoiding total overfeeding matters more.
- Bone health: long-term corticosteroids increase osteoporosis risk, so ensure calcium and vitamin D.
- Fluids: adequate fluids help thin secretions unless restricted for heart failure.
Asthma
- Some people have food or additive triggers, such as sulfites in dried fruits and wine, or specific food allergies.
- Obesity worsens asthma control, so weight management helps.
- Long-term oral corticosteroids require attention to calcium, vitamin D, and glucose.
Cystic Fibrosis
This inherited disease causes thick secretions in the lungs and pancreas. Nutrition care includes a high-energy diet (often well above normal needs), pancreatic enzyme replacement with meals and snacks, fat-soluble vitamin supplements (A, D, E, K), and extra salt, especially in hot weather. It is uncommon in Filipinos but is a classic examination example of combined lung and pancreatic disease.
A patient's temperature rises from 37 °C to 39 °C during an infection. By about how much does the basal metabolic rate increase?
About 7%
About 26%
About 50%
About 2%
A 2-year-old has had watery diarrhea for one day with some dehydration. Besides low-osmolarity ORS and continued feeding, what does WHO recommend?
Zinc 20 mg daily for 10-14 days
Stopping milk and solid foods for 24 hours
Sweetened soft drinks to replace lost sugar
Iron drops 30 mg daily for 7 days
A man with COPD on a mechanical ventilator is fed far above his measured energy needs with a high-dextrose regimen. What problem does this most directly cause?
Lower carbon dioxide output and faster weaning
Hypoglycemia with ketosis from rapid fat burning
Extra carbon dioxide that slows weaning
Respiratory alkalosis from reduced breathing effort
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