Question explored with the scientific record
I now have productive cough with yellow sputum in addition to to sinusitis with post nasal drip and loose stools
The short version: your symptoms point to a viral or bacterial infection that has spread from the sinuses to the lower airways and also affected your gut, but the evidence here does not tell us which one.
The retrieved studies show that respiratory viruses are common in community-acquired pneumonia, with about 1 in 3 adult cases testing positive for a virus [4][5]. Influenza, respiratory syncytial virus, and coronaviruses are the most frequent [5]. A productive cough with yellow sputum fits a lower respiratory tract infection, and sinusitis with post-nasal drip is a classic upper respiratory source. The loose stools could be from the same virus (many respiratory viruses also cause diarrhea) or from a separate gastrointestinal infection. One review of infectious diarrhea found that children accounted for 63% of cases and that E. coli was the most common bacterial cause [3]. But the evidence here does not test whether your three symptoms share a single cause.
No study in this retrieval directly examines a patient with this exact combination of symptoms. The closest is a 2025 pediatric study of lower respiratory tract infections, which found viruses in 69% of cases and Mycoplasma pneumoniae as the dominant bacterial pathogen [6]. That study does not cover adults or the gut symptoms you describe. The sinusitis studies here compare antibiotic regimens [1][2], not the question of what is causing your illness.
My call: see a clinician for a focused exam, chest auscultation, and possibly a chest X-ray and stool culture to separate a single viral illness from a bacterial superinfection or a separate gut infection. Confidence: low — the evidence does not cover your specific presentation, so the answer rests on general clinical reasoning, not on studies that match your case.
Sources used 6
-
Evaluation of the clinical efficacy of local antibacterial therapy in the treatment of acute bacterial rhinosinusitis
In 100 patients with moderate acute bacterial rhinosinusitis, adding Polydexa with phenylephrine nasal spray to systemic amoxicillin/clavulanate versus control (oxymetazoline) accelerated improvement of subjective symptoms, rhinoscopic edema/discharge resolution, and radiographi…
DOI: 10.26442/00403660.2020.12.000834 -
A Multicenter, Investigator‐Blinded, Randomized Comparison of Oral Levofloxacin and Oral Clarithromycin in the Treatment of Acute Bacterial Sinusitis
In a multicenter, investigator-blinded randomized trial, oral levofloxacin 500 mg once daily for 14 days was as effective as oral clarithromycin 500 mg twice daily for 14 days in adult acute bacterial sinusitis, with similar overall safety but fewer taste disturbances and lower …
DOI: 10.1002/J.1875-9114.1998.TB03145.X -
Infectious Diarrhea, as a Valid Medical and Public, Worldwide Health Problematic
Infectious diarrhea cases in the surveillance territory (2017–2020) were most frequent in children (63%), with adults and elderly 17% each; cases declined by year (37%, 35.5%, 29.5%) and were mainly Enterobacteriaceae, including E coli 27%.
DOI: 10.31579/2690-8794/093 -
Respiratory virus is a real pathogen in immunocompetent community-acquired pneumonia: comparing to influenza like illness and volunteer controls
This study investigates the role of respiratory viruses as pathogens in community-acquired pneumonia (CAP) by comparing viral etiology in CAP patients, influenza-like illness patients, and healthy volunteers, revealing that respiratory viruses are significant contributors to CAP.
DOI: 10.1186/1471-2466-14-144 -
Respiratory Viruses in Adults With Community-Acquired Pneumonia
This study investigates the prevalence of respiratory viruses in adults with community-acquired pneumonia (CAP) compared to control subjects and patients with nonpneumonic lower respiratory tract infections (NPLRTI), revealing a higher proportion of viral involvement in CAP than…
DOI: 10.1378/chest.09-2717 -
Etiology and Clinical Prediction of Community-Acquired Lower Respiratory Tract Infection in Children
This study investigates the etiology and clinical predictors of community-acquired lower respiratory tract infections (LRTI) in children, revealing that viral infections are predominant, particularly respiratory syncytial virus, while identifying key clinical and laboratory fact…
DOI: 10.3346/jkms.2025.40.e5