Lower Respiratory Infections

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These are infections of the lower respiratory tract system. They include the Lower Obstructive Airway Diseases, Chronic Obstructive Pulmonary Disease (COPD), Pneumonia, Aspiration Pneumonia, Atypical Pneumonia and COVID 19.

Exacerbation of Chronic Obstructive Pulmonary Disease (COPD)

Description

This is an acute deterioration of the respiratory symptoms of patients with underlying COPD results in additional therapy.

Common causes include:

  • Infections
    • Bacteria-H. influenzae, S. pneumoniae, M. catarrhalis
    • Viruses-Community Acquired Pneumonia
  • Bullae-Pneumothorax

Treatment

  • Treat causes of exacerbations of the conditions
  • Hydrocortisone 200mg intravenously 4 hourly for 24 hours and maintain on oral Prednisolone 30mg on alternate days (duration required)
  • Suction of the fluid from the airway
  • Give an appropriate antibiotic: Erythromycin 500mg QID (frequency) daily for 10 days
  • Smoking cessation
  • Give oxygen.

Prevention

  • Reduce industrial exposure
  • Wear gas masks

Pneumonia

Description

This is an inflammation of the lungs usually caused by Streptococcus pneumoniae, Mycoplasma pneumoniae and Staphylococcus aureus Haemophilus Influenzae type B and atypical organisms such as Jiroveci pneumonia.

Clinical features

These are usually of sudden onset.

Signs and Symptoms

  • Fever
  • Dry or productive cough
  • Chest pain
  • Chills
  • Breathlessness
  • Children may be unable to drink or breastfeed
  • Bronchial breathing
  • Drowsiness
  • Increased respiration rate
  • Cyanosis may be present
  • Flaring of nostrils
  • Chest indrawing
  • Increased pulse rate
  • Crepitations
  • Breath sounds may be reduced
  • Sputum may be “rusty”.

Complications

  • Septicaemia
  • Lung abscess
  • Emphysema
  • Heart failure
  • Meningitis

Investigations

This is based on clinical findings but may be supported by radiological examinations which show lobar and bronchial pneumonia.

Treatment

Some patients will need admission particularly if there is cyanosis or complications.

  • Benzylpenicillin 1-2MU intravenously 6 hourly for 5 days adults, children 25,000-50,000 units/kg intravenously/intramuscularly in 4 divided doses for 7 days (as soon as the symptoms and respiratory rates are controlled change to oral medication i.e. Amoxycillin 250mg for adults and 125 mg/5ml in children) or
  • Ceftriaxone 1g - 2g daily adults, children 20-50mg/kg daily intravenously/intramuscularly for 7 days. if allergic to penicillin or
  • Erythromycin 500mg adults, orally 6 hourly for 7 days, children 20-30mg/kg in 4 divided doses for 7 days
  • Oxygen is indicated if respiratory distress or cyanosis is present
  • Non-opiate analgesics; Paracetamol 500mg - 1g orally 3 - 4 times daily adults, children 10-20mg/kg orally 3 - 4 times daily.

Refer early to a specialist if the patient is not rapidly improving with antibiotic treatment

Aspiration Pneumonia

Description

A pulmonary infection resulting from inhalation of bacteria-rich fluids into the lower respiratory tract.

This is frequently found in:

  • Older adults
  • CVA & post-stroke pneumonia
  • Alcohol Use Disorder (AUD)
  • Seizures
  • Drug overdose
  • Use of sedatives
  • CNS disorders
  • Muscular disorders

Signs and Symptoms

Commonly present with features of CAP, including cough, fever and malaise

Investigations

A comprehensive history regarding current or previous dysphagia, previous stroke, instances of aspiration, coughing during eating or drinking, and other medical conditions predisposing to overt or silent aspiration aids in diagnosing aspiration pneumonia.

  • CxR
  • CT Scan
  • Septic screen
  • FBC
  • Urea & Creatinine
  • Videofluoroscopy swallowing study (VFSS) (a modified barium swallow

Treatment

Supportive

  • Nurse in lateral decubitus or propped-up
  • NG tube insertion where necessary
  • Chest physiotherapy

Pharmacological
Local facility outpatient

  • Amoxicillin 500mg eight hourly 5-7 days
  • Doxycycline 100mg twelve hourly 5-7 days
  • Azithromycin 500mg stat then 250 mg once daily for 4 days

Patients with co-morbidities who are not admitted may be given

  • Amoxicillin/clavulanate 500mg/125mg 8 hourly
  • A combination of a cephalosporin and a macrolide
  • Also, a respiratory quinolones (levofloxacin or moxifloxacin)

Hospitalized patients with non-severe CAP, without risk factors for methicillin-resistant Staphylococcus aureus (MRSA) infection or Pseudomonas aeruginosa

  • Ampicillin/sulbactam 1.5g to 3 g 6 hourly
  • Cefotaxime 1g to 2g -8 hourly or ceftriaxone 1g to 2g daily
  • Ceftaroline 600 mg 12hourly plus a macrolide
  • Also, a respiratory quinolones

In patients with confirmed risk factors for MRSA or P-aeruginosa or a prior history of infections secondary to these organisms

  • Piperacillin/tazobactam
  • Cefepime imipenem, or meropenem in combination with vancomycin or linezolid

Atypical Pneumonia

Signs and symptoms of pneumonia plus extra- pulmonary signs such as arthritis, splenomegaly caused by Mycoplasma, Chlamydia, PCP.

Treatment

  • Erythromycin 500mg orally QID for 14 days for Chlamydia
  • Co-trimoxazole 960mg every 12 hours for 21 days in combination with a steroid i.e. Prednisolone for PCP starting with 40mg per day and reducing by 5mg every 3 days for adults
    • For children above 4 weeks to adults 120mg/Kg body weight in 2 to 4 divided doses for 21 days

COVID-19

Description

Corona virus disease 2019 (COVID-19) is a respiratory disease caused by the Severe Acute Respiratory Syndrome Corona-Virus 2 (SARS-CoV-2)

Signs and Symptoms

Non-severe

  • Fever
  • Cough
  • Myalgia
  • Fatigue
  • Evidence of lower respiratory tract infections by clinical assessment or imaging
  • Sp0₂ >93% on room air above sea level
  • Lung infiltrates < 50%

NB: Some patients may test positive for COVID-19 but are asymptomatic

Severe and/or Critical

  • Shortness of breath
  • Increased respiratory rate >30 bpm
  • Respiratory failure
  • Low oxygen saturations (SpO₂ ≤ 93% on room air above sea level)
  • Lung infiltrates > 50%
  • PaO₂/ FiO₂ > 300mmHg
  • Sepsis/ septic shock
  • Multi-organ failure

Investigations

  • SARS-CoV-2 Antigen RDT (rapid diagnostic test)
  • SARS-CoV-2 rt-PCR (Nucleic Acid Amplification Test - NAAT) test
  • Sp0₂
  • D-dimer
  • CRP
  • RBS/ FBS
  • BP
  • Chest x-ray or other imaging
  • LFTs
  • RFTs
  • Gene Xpert for TB
  • HIV
  • Malaria (RDT and MPS)

Treatment

Risk factors for hospitalization or progression to severe disease:

  • Age > 50 years
  • BMI <18 or >24
  • Co-morbidities such as HTN, DM
  • Immunosuppressive conditions such as HIV, cancer, long-standing steroid use
  • Chronic cardiopulmonary disease (asthma, CHF,CAD)
  • Chronic kidney disease
  • Pregnancy

Non-severe

  • Nirmatrelvir/ Ritonavir 300/ 100mg twice daily for 5 days (150mg/ 100mg for eGFR ≥30 ml/min and <60ml/min) OR
  • Remdesivir IV
    • Dosage (Adults and Children ≥ 40kg): 200mg on day 1 and 100mg on subsequent days. Duration 3-5 days
    • Dosage (Children ≥3kg to <40kg): 5mg/kg on day 1 and 2.5mg/kg on subsequent days. Duration 3-5 days
  • Molnupiravir 800mg twice daily for 5 days

Indications for Antivirals:

  • Positive COVID-19 test
  • Symptoms within 5 days of onset (for oral antivirals)
  • Symptoms within 7 days of onset (for IV antiviral)
  • At least 1 risk factor for progression to severe disease
  • ≥ 12 years and ≥ 40 kg body weight (Nirmatrelvir/Ritonavir)
  • ≥ 28 days and ≥ 3kg body weight (Remdesivir)
  • ≥ 18 years (Molnupiravir)

NB: Molnupiravir is contraindicated in Pregnancy

Multiple drug-drug interactions with Nirmatrelvir/Ritonavir. Check www.covid19-druginteractions.org/checker

Supportive treatment
Severe and Critical (hospitalized patients) need:

  • Oxygen therapy
    • Escalate to achieve target SPO2 above 94%
  • Immune modulating drugs
    • Dexamethasone IV 6mg once daily for up to 14 days OR
    • Hydrocortisone IV 50mg three times daily for up to 14 days
    • Prednisolone 40mg once daily for up to 14 days

NB: Steroids are only indicated in patients on O2

  • Baricitinib
    • Adults and children >9 years: 4mg od for up to 14 days
    • Children ≥2 to ≤9 years: 2mg od for up to 14 days

Given to:

Among hospitalized adults with severe COVID-19 having elevated inflammatory markers but not on invasive mechanical ventilation, or
Among hospitalized patients with severe COVID-19 who cannot receive a corticosteroid (which is standard of care) because of a contraindication (add Remdesivir)

Monitor ALC, ANC and renal function

  • Tocilizumab
    • Weight <30 kg: 12 mg/kg as a single IV infusion over 60 minutes. Weight ≥30 kg: 8 mg/kg as a single IV infusion over 60 minutes
    • Single dose administration. Second in 12-48 hrs depending on clinical response. Max 800mg per infusion
    • Should be given only in combination with dexamethasone (or another corticosteroid at an equivalent dose), age ≥ 2 years
    • Renal: adjustment currently not warranted
  • Antithrombotic
    • Enoxaparin 0.5mg/kg SC once daily for mild infection
    • Enoxaparin 1mg/kg SC twice daily for severe infection
  • Chest physiotherapy
  • Psycho-social counselling