What immediate action should be taken for treating orbital cellulitis before identifying the causative organism?

Administering beta-lactam antibiotics is crucial in the immediate management of orbital cellulitis because this condition is often caused by bacterial infections, which can lead to serious complications if not treated promptly. The urgency stems from the risk of vision loss or further complications such as cavernous sinus thrombosis, which can occur due to the proximity of the eyes and the brain.

Beta-lactam antibiotics are effective against many of the common bacteria responsible for this infection, including Streptococcus and Staphylococcus species. Starting antibiotic therapy promptly is essential while further diagnostic measures, such as identifying the causative organism through cultures, are being performed. This proactive approach ensures that the patient receives necessary treatment without delay, addressing the potential for worsening infection.

Other options such as starting non-invasive treatment, ordering a CT scan, or applying cold compresses are supportive or diagnostic actions but do not address the immediate need for antibiotic therapy in the face of a potentially severe, life-threatening infection like orbital cellulitis. The priority in treating this condition is to initiate appropriate antibiotic treatment as soon as possible.