Differential Diagnosis for 12 y.o. boy with decreased appetite, HR 127, cough/headache, nausea, and fatigue
- Single most likely diagnosis
- Viral syndrome (e.g., viral pharyngitis, viral gastroenteritis): The patient's symptoms of decreased appetite, cough, headache, nausea, and fatigue, along with the negative point-of-care testing for strep-a pharyngitis, COVID-19, and influenza A and B, suggest a viral etiology. The fact that symptoms have been present for weeks but worsened 3 days ago also supports this diagnosis.
- Other Likely diagnoses
- Pneumonia: The patient's cough, headache, and fatigue, along with an elevated heart rate (HR 127), could indicate pneumonia, especially since the symptoms worsened 3 days ago. The recent history of bronchitis treated with azithromycin 3 months prior also increases the likelihood of a respiratory infection.
- Mononucleosis (infectious mononucleosis): Although the patient was recently treated for scarlet fever, the prolonged duration of symptoms (weeks) and the presence of fatigue, headache, and poor appetite could suggest mononucleosis, especially if the patient was exposed to someone with the illness.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
- Meningitis: Although the patient does not have the classic symptoms of meningitis (e.g., stiff neck, photophobia), the presence of headache, fever (inferred from the elevated heart rate), and fatigue necessitates consideration of this diagnosis to avoid missing a potentially life-threatening condition.
- Sepsis: The patient's elevated heart rate, fatigue, and poor appetite could indicate sepsis, particularly if the patient has a bacterial infection that is not responding to treatment. The recent history of azithromycin treatment for bronchitis increases the risk of antibiotic-resistant bacteria.
- Appendicitis: Although the patient denies vomiting and diarrhea, the presence of nausea, fatigue, and abdominal pain (not explicitly mentioned but possible given the nausea) requires consideration of appendicitis to avoid missing this surgical emergency.
- Rare diagnoses
- Kawasaki disease: This rare condition, which primarily affects children, can present with fever, fatigue, and headache, along with other symptoms such as rash and lymphadenopathy. Although the patient's symptoms do not perfectly align with Kawasaki disease, it is essential to consider this diagnosis due to its potential for serious cardiac complications if left untreated.
- Leukemia: The patient's prolonged fatigue, headache, and poor appetite could suggest a hematologic malignancy such as leukemia. Although this diagnosis is rare, it is crucial to consider it to avoid missing a potentially life-threatening condition that requires prompt treatment.