Differential Diagnosis
The patient presents with a complex set of symptoms including cough, nasal congestion, decreased appetite, diarrhea, fever, and pain behind the right calf. Considering the combination and progression of these symptoms, the following differential diagnoses are proposed:
- Single Most Likely Diagnosis
- Influenza: The patient's symptoms of cough, nasal congestion, fever, and body aches, along with the recent similar illness in the mother, suggest a viral etiology. Influenza is a common cause of such symptoms, especially during peak seasons, and the patient's persistent fever despite antipyretics supports this diagnosis.
- Other Likely Diagnoses
- Viral gastroenteritis: The presence of nausea, vomiting, and diarrhea could indicate a gastrointestinal infection, possibly due to a virus. This, combined with systemic symptoms like fever and fatigue, makes viral gastroenteritis a plausible diagnosis.
- Sinusitis: The patient's nasal congestion with green mucus and cough suggests an upper respiratory infection, which could have progressed to sinusitis, especially given the duration of symptoms.
- Viral pharyngitis: Although not explicitly mentioned, the combination of fever, cough, and systemic symptoms could also suggest a viral pharyngitis, which often presents with sore throat, a symptom not denied by the patient.
- Do Not Miss Diagnoses
- Deep vein thrombosis (DVT): The pain behind the right calf is a red flag for DVT, especially in the context of recent or ongoing infection and immobilization due to illness. Although less common in pediatric patients, it is crucial not to miss this diagnosis due to its potential for severe complications.
- Bacterial sepsis: The patient's persistent high fever despite antipyretics and the presence of systemic symptoms like dizziness upon movement and immense fatigue could indicate a bacterial infection leading to sepsis, a life-threatening condition that requires immediate attention.
- Osteomyelitis or septic arthritis: The localized pain in the right calf could also suggest osteomyelitis or septic arthritis, particularly if the patient has been immobile or has a history of recent trauma to the area. These conditions are medical emergencies.
- Rare Diagnoses
- Kawasaki disease: Although rare, Kawasaki disease can present with fever, systemic symptoms, and sometimes gastrointestinal symptoms. It's known for its potential to cause coronary artery aneurysms if not treated promptly.
- Lyme disease: If the patient has been exposed to ticks, Lyme disease could be considered, especially with symptoms like fever, fatigue, and localized pain, although the absence of a characteristic rash (erythema migrans) makes this less likely.
- Inflammatory bowel disease (IBD): The gastrointestinal symptoms could, in rare cases, be the initial presentation of IBD, such as Crohn's disease or ulcerative colitis, especially if the symptoms persist or worsen over time despite treatment for infectious causes.