What is the appropriate intravenous antibiotic treatment for a patient with mild bibasilar atelectasis, possible small pleural effusion, leukocytosis (elevated White Blood Cell count), and a history of allergy to penicillin and cephalexin (Keflex)?

From the Guidelines

For this patient with chest x-ray findings of bibasilar atelectasis, possible small pleural effusion, and elevated white blood cell count with neutrophilia, I recommend intravenous levofloxacin 750 mg daily as appropriate antibiotic therapy in the emergency department. Given the patient's allergies to penicillin and Keflex (cephalexin), fluoroquinolones are a safer choice. The chest x-ray findings suggest a possible lower respiratory infection with atelectasis (collapsed lung tissue) and potential small fluid collection. The elevated white blood cell count (13.6) with increased neutrophils (11.7) indicates an active bacterial infection. According to the guidelines for hospital-acquired pneumonia, levofloxacin is a recommended initial empiric antibiotic therapy for patients not at high risk of mortality and without factors increasing the likelihood of MRSA 1.

Some key points to consider in the management of this patient include:

• The patient's allergy to penicillin and Keflex, which makes beta-lactam antibiotics a less suitable option
• The need for adequate hydration and incentive spirometry to prevent further atelectasis
• The importance of follow-up within 2-3 days to assess clinical response to treatment
• The potential need to transition to oral antibiotics after initial IV therapy, depending on the patient's clinical condition and response to treatment. Given the patient's presentation and the guidelines, levofloxacin 750 mg IV daily is a suitable choice for initial empiric antibiotic therapy 1.

From the FDA Drug Label

The recommended dose of Azithromycin for Injection for the treatment of adult patients with community-acquired pneumonia due to the indicated organisms is: 500 mg as a single daily dose by the intravenous route for at least two days If anaerobic microorganisms are suspected of contributing to the infection, an antimicrobial agent with anaerobic activity should be administered in combination with Azithromycin for Injection

The patient has a community-acquired pneumonia with a WBC count of 13.6 and is allergic to penicillin and keflex. The recommended treatment is azithromycin 500 mg IV daily for at least 2 days. However, since the patient is allergic to penicillin and keflex, and azithromycin does not cover anaerobic microorganisms, the treatment should be considered with caution and potentially in combination with another antimicrobial agent with anaerobic activity, if anaerobic microorganisms are suspected. 2

From the Research

Patient Assessment

• The patient has a chest x-ray showing shallow inspiration with mild bibasilar atelectasis and blunting of the costophrenic angle, which may represent a small pleural effusion or atelectasis.
• The patient's CBC results show an elevated WBC count of 13.6, hemoglobin of 13.4, and segmental neutrophil abs of 11.7, with lymphocytes at 0.7.
• The patient is allergic to penicillin and Keflex.

Antibiotic Allergy Management

• According to 3, up to 30% of patients report at least one antibiotic allergy, but many of these allergies are misdiagnosed.
• 4 states that approximately 10% of the US population reports allergies to β-lactam agents like penicillin, but clinically significant IgE-mediated or T lymphocyte-mediated penicillin hypersensitivity is uncommon (<5%).
• The study 4 also notes that cross-reactivity between penicillin and cephalosporin drugs occurs in about 2% of cases.

Treatment Options

• Given the patient's allergy to penicillin and Keflex, alternative antibiotics should be considered.
• 3 emphasizes the importance of evaluating antibiotic allergies to provide optimal patient care and avoid the use of broad-spectrum antibiotics.
• The patient's treatment in the emergency department should involve IV antibiotics, taking into account their allergy history and the potential for cross-reactivity with other antibiotics.

Anaphylaxis and Allergic Reactions

• 5, 6, and 7 discuss the management of anaphylaxis and allergic reactions in the emergency department, emphasizing the importance of prompt recognition and treatment.
• However, these studies do not directly address the patient's current situation, as there is no indication of anaphylaxis or a severe allergic reaction at this time.