Aetiology, Symptoms, and Dietary Management of Fever, Typhoid, and Tuberculosis

PART 1 - FEVER (General)

Aetiology

• Infections - bacterial (most common), viral, fungal, parasitic
• Inflammatory conditions - autoimmune disease, rheumatoid arthritis, inflammatory bowel disease
• Malignancies - lymphoma, leukaemia ("fever of unknown origin")
• Drugs - drug fever, vaccine reactions
• Heat stroke - non-infectious hyperthermia

Metabolic Changes with Fever

• Basal metabolic rate (BMR) rises approximately 7% for every 1°F rise in temperature
• Increased protein catabolism and negative nitrogen balance
• Dehydration from sweating and increased insensible loss
• Glycogen stores depleted; gluconeogenesis increases
• Loss of electrolytes (sodium, potassium, chloride)

Symptoms

• Elevated temperature, chills, rigors
• Headache, malaise, fatigue
• Tachycardia, flushed skin
• Anorexia, nausea
• Sweating during defervescence

Dietary Management of Fever (General)

PART 2 - TYPHOID FEVER (Enteric Fever)

Aetiology

• Causative organism: Salmonella enterica serotype Typhi (S. Typhi) - a gram-negative, motile, non-spore-forming rod
• Paratyphoid fever is caused by S. Paratyphi serotypes A, B, and C
• Humans are the only known reservoir - there is no animal host
• Transmission: Feco-oral route - contaminated water and food; less commonly, sexual transmission between male partners
• Risk factors: Contaminated drinking water/ice, street food, raw fruit and vegetables grown in sewage-fertilized fields, lack of hand washing, prior Helicobacter pylori infection, travel to endemic areas
• Incubation period: Mean 10-14 days (range 5-21 days), depending on inoculum size and host immunity

Pathogenesis

Symptoms (Clinical Course)

• Step-ladder fever rising to 38.8-40.5°C (101.8-104.9°F)
• Headache (80% of cases), chills (35-45%), cough (30%)
• Myalgias, malaise, arthralgia
• Relative bradycardia (pulse-temperature dissociation, in <50%)

• Sustained continuous high fever
• Coated tongue (51-56%)
• Anorexia (55%), abdominal pain (30-40%)
• Nausea (18-24%), vomiting (18%), diarrhoea (22-28%) or constipation (13-16%)
• Rose spots - faint salmon-coloured, blanching, maculopapular rash on trunk and chest (~30% of patients)

• Splenomegaly (5-6%), hepatosplenomegaly (3-6%)
• Epistaxis

• Intestinal perforation (1%) and GI bleeding (6%) - life-threatening, require surgery
• Neurological: meningitis, Guillain-Barré syndrome, "muttering delirium" (2-40%)
• DIC, pancreatitis, hepatitis, myocarditis, orchitis, pneumonia

Dietary Management of Typhoid Fever

• Energy: High calorie - 2500-3500 kcal/day to offset increased BMR and protein catabolism
• Fluids: Liberal - 3-4 litres/day; ORS, coconut water, fruit juices, clear broths, barley water, rice water
• Diet texture: Liquid to semi-liquid; progress to soft diet as fever subsides
• Foods to include:
  • Cooked, easily digestible carbohydrates: white rice, khichdi, porridge (daliya), white bread, plain pasta, boiled potatoes, crackers
  • Soft proteins: eggs (boiled/poached), boiled chicken, fish, tofu, soft paneer
  • Ripe soft fruits: banana, melon, applesauce, canned fruit (no seeds or skins)
  • Cooked vegetables: carrots, potatoes, squash, beets, green beans
  • Dairy: low-fat milk, yoghurt, cheese (if tolerated)
  • Beverages: herbal tea, coconut water, oral rehydration solution, clear fruit juice, broth

• High-fibre foods: raw vegetables (broccoli, cauliflower, cabbage, kale, onions), whole grains (brown rice, barley, quinoa), nuts, seeds, legumes
• Spicy, fried, or fatty foods - increase GI irritation
• Raw or undercooked meats
• Dried fruits, berries with seeds, pineapple, kiwi
• Carbonated drinks, alcohol, caffeine

• Gradually transition to a normal balanced diet
• Continue high-protein foods to rebuild tissue
• Ensure adequate Vitamin C and Zinc for wound healing
• Small, frequent meals (5-6 per day) to reduce GI load

PART 3 - TUBERCULOSIS (TB)

Aetiology

• Causative organism: Mycobacterium tuberculosis - an obligate aerobe, acid-fast bacillus (AFB), non-motile, non-spore-forming
• Transmission: Airborne droplet nuclei (1-5 microns) containing viable bacilli, released when an infectious person coughs, sneezes, or speaks. A single cough can release thousands of droplet nuclei.
• Primary risk factors for infection:
  • Close contact with an infectious TB case
  • Overcrowding, poor ventilation
  • HIV infection (most important immunosuppressive risk factor)
  • Malnutrition and underweight
  • Diabetes mellitus, silicosis, chronic renal failure
  • Immunosuppressive therapy (steroids, TNF inhibitors)
  • Poverty, homelessness, prison environments
• Progression from infection to disease: Only ~5-10% of immunocompetent infected persons develop active TB in their lifetime. In HIV-infected persons, the risk rises to 10-16% per year without antiretroviral therapy (ART).

Types

1. Primary TB - initial infection, commonly in lower lobes; often asymptomatic
2. Reactivation (Post-primary) TB - upper lobe cavitary disease; most common clinical form
3. Latent TB Infection (LTBI) - positive tuberculin skin test or IGRA, no active disease
4. Miliary TB - haematogenous dissemination; millet-seed granulomas throughout lungs and other organs; more common in children and immunosuppressed
5. Extrapulmonary TB - occurs in 10-25% of patients; affects pleura (most common), lymph nodes, bones (Pott's disease), kidneys, meninges, pericardium, peritoneum

Symptoms

• Constitutional (B symptoms): Fever (low-grade, often afternoon), drenching night sweats, anorexia, significant weight loss, fatigue and malaise
• Respiratory: Chronic productive cough (>3 weeks) - initially dry, then mucopurulent; haemoptysis (blood-streaked or frank); dyspnoea; chest pain

• Insidious onset, often subtle
• High fever, severe malaise, weight loss
• Hepatosplenomegaly, lymphadenopathy
• Meningism if CNS involved

Dietary Management of Tuberculosis

• Energy: Increased caloric intake (2500-3500 kcal/day) to support tissue repair and recovery
• Protein: High protein (1.2-1.5 g/kg body weight/day) to rebuild muscle mass
  • Good sources: meat, fish, eggs, milk, yoghurt, dried peas, beans, lentils, soy
• Carbohydrates: 45-65% of total energy; focus on complex carbohydrates and whole grains (unlike typhoid, high fibre is not restricted in TB unless there is GI TB)
• Fats: 25-35% of total energy; include healthy fats (olive oil, nuts) for energy density

1. Eat more than usual - the body needs extra energy and protein for healing
2. Choose a variety of foods from all food groups
3. Eat small, frequent meals if appetite is poor
4. Increase caloric density by adding milk powder to soups, porridge, or smoothies
5. Avoid alcohol - strongly contraindicated as it is hepatotoxic and interacts with isoniazid (INH), pyrazinamide (PZA), and rifampin (RMP)
6. Take INH with food if nausea occurs, but avoid taking it with high-carbohydrate meals (reduces absorption)
7. Ensure adequate Vitamin B6 intake when on isoniazid therapy (supplements often prescribed concurrently)
8. Address food insecurity - food assistance programmes improve treatment adherence and outcomes

Summary Comparison Table