What are the important negative symptoms to be aware of in patients with influenza (flu)?

Important Negative Symptoms in Influenza

The most important negative symptoms to be aware of in patients with influenza include signs of respiratory distress, altered mental status, severe dehydration, and persistent high fever, as these may indicate severe complications requiring immediate medical attention.

Clinical Presentation of Uncomplicated Influenza

Influenza typically presents with:

• Abrupt onset of fever (38-40°C)
• Myalgia (back and limbs)
• Headache
• Severe malaise
• Nonproductive cough (may become productive in 40% of cases)
• Sore throat
• Rhinitis 1, 2

The illness usually resolves within 7-10 days, though cough and malaise may persist for weeks 1.

Important Negative Symptoms to Monitor

Respiratory Complications

• Persistent high fever beyond 3-5 days
• Worsening cough or productive cough with purulent sputum (may indicate secondary bacterial pneumonia)
• Dyspnea or respiratory distress (rapid breathing, use of accessory muscles)
• Chest pain with breathing
• Cyanosis (bluish discoloration of lips or skin) 1, 2

Neurological Complications

• Altered mental status or confusion
• Seizures or convulsions (especially in children)
• Extreme irritability in children
• Neck stiffness
• Severe headache unresponsive to analgesics 1, 2

Cardiovascular Complications

• Chest pain unrelated to coughing
• Palpitations
• Syncope or near-syncope 1

Dehydration Signs

• Decreased urine output
• Dry mucous membranes
• Sunken eyes
• Decreased skin turgor
• Lethargy 1, 2

Other Important Warning Signs

• Inability to maintain oral hydration
• Persistent vomiting
• Signs of clinical deterioration after initial improvement (may indicate secondary bacterial infection)
• Severe myalgia with dark urine (may indicate myositis with myoglobinuria) 1, 2

Special Considerations by Age Group

Neonates and Infants

• May present with non-specific signs of sepsis
• Apneic episodes
• Poor feeding
• Lethargy or floppiness
• Fever may be the only presenting feature 1

Children

• Febrile seizures (particularly repeated seizures)
• Higher fevers than adults
• More prominent gastrointestinal symptoms (nausea, vomiting, diarrhea)
• Otitis media (common complication in children)
• Croup (more severe when caused by influenza) 1, 2

Elderly

• May present with less pronounced fever
• Confusion or altered mental status without other symptoms
• Worsening of underlying chronic conditions
• Exacerbation of heart failure 2

When to Seek Immediate Medical Attention

Patients should seek immediate medical attention if they develop:

1. Difficulty breathing or shortness of breath
2. Persistent pain or pressure in the chest or abdomen
3. Persistent dizziness, confusion, or inability to arouse
4. Seizures
5. Not urinating
6. Severe muscle pain
7. Severe weakness or unsteadiness
8. Fever or cough that improves but then returns or worsens
9. Worsening of chronic medical conditions 1, 2

High-Risk Patients Requiring Closer Monitoring

• Persons aged >65 years
• Very young children (especially <2 years)
• Pregnant women
• Persons with underlying medical conditions:
  • Chronic respiratory disease (including asthma)
  • Chronic cardiac disease
  • Chronic renal disease
  • Chronic liver disease
  • Immunosuppression
  • Diabetes mellitus
  • Non-ambulant individuals 1

Complications to Be Vigilant For

• Secondary bacterial pneumonia (typically occurs 4-5 days after onset of illness)
• Primary viral pneumonia (onset within 48 hours of start of fever)
• Encephalitis/encephalopathy (occurs within first week of illness)
• Myositis (occurs during early convalescence)
• Reye's syndrome (in children on aspirin therapy)
• Myocarditis/pericarditis
• Acute respiratory distress syndrome 1, 3

Early recognition of these negative symptoms and prompt medical attention can significantly reduce morbidity and mortality associated with influenza complications.