What are the treatment options for Lower Respiratory Tract Infections (LRTI) and typhoid?

Treatment of Lower Respiratory Tract Infections (LRTI) and Typhoid

For lower respiratory tract infections, aminopenicillins like amoxicillin are first-line therapy, while typhoid fever should be treated with ciprofloxacin as the preferred agent. 1, 2

Lower Respiratory Tract Infections (LRTI) Treatment

Outpatient Management

• Aminopenicillins (e.g., amoxicillin 500-1000 mg every 8 hours) are the first-choice antibiotics for uncomplicated LRTI managed at home 1, 3
• Treatment duration should typically be 5-7 days for home-managed LRTI 1, 3
• For patients with risk factors for beta-lactamase producing organisms (chronic lung disease, recent antibiotic treatment, or failure of aminopenicillin), amoxicillin-clavulanate is recommended 1, 4
• Alternative options for penicillin-allergic patients include:
  • Macrolides (e.g., clarithromycin 250-500 mg twice daily) 3, 5
  • Tetracyclines (e.g., doxycycline 100 mg twice daily) 1, 3
  • Oral cephalosporins for non-anaphylactic penicillin allergy 1, 3
  • Third-generation quinolones for treatment failures or complicated cases 1, 3

Hospital Management

• For patients requiring hospitalization but not ICU care, options include:
  • Second-generation cephalosporins (e.g., IV cefuroxime 750-1500 mg every 8 hours) 1
  • Third-generation cephalosporins (e.g., IV cefotaxime 1 g every 8 hours or IV ceftriaxone 1 g daily) 1, 6
  • IV benzyl penicillin 1-4×10^6 units every 2-4 hours or IV amoxicillin 1 g every 6 hours 1
• For ICU patients with severe LRTI:
  • Combination therapy with a second or third-generation cephalosporin plus either a second-generation quinolone (ciprofloxacin) or a macrolide (IV erythromycin 1 g every 6 hours) 1

Special Considerations

• For suspected aspiration pneumonia or pulmonary abscess: IV amoxicillin-clavulanate 2 g every 6 hours 1
• Response to therapy should be assessed at day 2-3 for hospitalized patients (fever, progression of pulmonary infiltrates) and day 5-7 for outpatients (improvement of symptoms) 1
• Patients should be advised to return if fever does not resolve within 48 hours 1
• Cough may persist longer than the duration of antibiotic treatment 1

Typhoid Fever Treatment

• Ciprofloxacin is FDA-approved for typhoid fever caused by Salmonella typhi 2
• The typical adult dose is 500 mg orally twice daily 2
• Amoxicillin-clavulanate has also shown efficacy in treating typhoid fever and typhoid carriers 7
• Note that ciprofloxacin is not effective in eradicating the chronic typhoid carrier state 2

Risk Stratification for Hospital Referral

Clinical Criteria for Hospital Referral

• Signs of immediate severity:
  • Temperature <35°C or ≥40°C 1
  • Heart rate ≥125 beats/min 1
  • Respiratory rate ≥30 breaths/min 1
  • Cyanosis 1
  • Blood pressure <90/60 mmHg 1
• Other concerning features:
  • Confusion, drowsiness, altered mental status 1
  • Chest pain 1
  • Suspected complications (pleural effusion, cavitation, metastatic infection) 1
  • Failure of first-line antibiotic therapy 1

Laboratory and Radiological Criteria for Hospital Management

• Leukopenia (<4,000 WBC/mL) or severe leukocytosis (>20,000 WBC/mL) 1
• Anemia (hemoglobin <9 g/100 mL) 1
• Renal impairment (serum urea >7 mM, creatinine >1.2 mg/dL) 1
• Hypoxemia (PaO₂ <60 mmHg) or hypercapnia (PaCO₂ >50 mmHg) on room air 1
• Acidosis (pH <7.3) 1
• Coagulation abnormalities suggesting disseminated intravascular coagulation 1
• Multilobar involvement, pleural effusion, or cavitation on chest radiograph 1

Common Pitfalls and Caveats

• Many LRTIs are viral in origin and self-limiting; antibiotics should only be used when bacterial infection is suspected 1
• Overuse of fluoroquinolones can lead to resistance; reserve them for treatment failures or complicated cases 3, 2
• Streptococcus pneumoniae is the most common bacterial pathogen in LRTI, and antibiotic therapy should always be active against it 1
• Ciprofloxacin, while effective for typhoid, is not a drug of first choice for pneumonia caused by Streptococcus pneumoniae 2
• Patients should be informed that cough may persist longer than the duration of antibiotic treatment 1