Management of Acute Febrile Illness with Negative Flu and COVID-19 Testing

Immediate Assessment and Symptomatic Treatment

The British Medical Journal recommends using paracetamol (acetaminophen) as first-line antipyretic for temperatures above 38.5°C, administered orally at 0.2 g per dose every 4-6 hours as needed (maximum 4 times in 24 hours) 1
Paracetamol is preferred over NSAIDs (like ibuprofen) when viral illness is suspected, even with negative testing, as suggested by the British Medical Journal 1
Target temperature reduction to below 38°C is acceptable; excessive temperature reduction is not necessary and may interfere with immune response, according to Military Medical Research 2
Regular fluid intake to prevent dehydration is advised, but limited to no more than 2 liters per day, as recommended by the British Medical Journal 1
The complaint of "thirst" suggests possible dehydration requiring active rehydration, as noted in the International Journal of Surgery 3
Monitor for signs of adequate hydration (urine output, mucous membrane moisture), as suggested by Clinical Gastroenterology and Hepatology 4

Other respiratory viruses (parainfluenza, adenovirus, respiratory syncytial virus, metapneumovirus) should be considered as alternative diagnoses, according to the International Journal of Surgery 3
Infectious mononucleosis (Epstein-Barr virus) is a key differential diagnosis, as noted in Military Medical Research 5
Acute viral gastroenteritis is another possible diagnosis, as suggested by Clinical Gastroenterology and Hepatology 4
Early bacterial infection (though less likely without localizing signs) should also be considered, according to Anaesthesia 6

The patient should seek immediate medical attention if she develops dyspnea or shortness of breath, as recommended by the International Journal of Surgery 3
Respiratory rate ≥30/min is a red flag symptom, according to the International Journal of Surgery 3
Persistent high fever despite antipyretics is a concern, as noted by the British Medical Journal 1
Altered mental status or severe headache are red flag symptoms, as suggested by World of Neurosurgery 8
Inability to maintain oral hydration is a sign of severe illness, according to Clinical Gastroenterology and Hepatology 4
Chest pain or pressure are red flag symptoms, as noted by World of Neurosurgery 8
Worsening symptoms after initial improvement are a concern, according to Anaesthesia 6

Bed rest with monitoring of vital signs (heart rate, oxygen saturation, respiratory rate, blood pressure) is recommended, as suggested by Military Medical Research 5
Avoid overexertion during acute illness, according to Military Medical Research 2
Ensure adequate energy intake with balanced nutrition, as recommended by Military Medical Research 2
Protein-rich foods (eggs, fish, lean meat, dairy) and carbohydrates are essential, according to Military Medical Research 2
Target energy intake of 25-30 kcal/kg/day, as suggested by Military Medical Research 2
Regular sleep schedule, avoidance of alcohol and smoking, and self-quarantine until symptoms resolve are recommended lifestyle modifications during illness, according to Military Medical Research 2 and Clinical Gastroenterology and Hepatology 4