Respiratory Infections: Key Terms & Meds

• Key terms and medications for respiratory infections and related conditions are defined

Key Terms

• Cystic Fibrosis (CF) is an inherited disease affecting exocrine glands, impacting the pancreas, respiratory system, and apocrine glands
• CF symptoms typically start in infancy and involve increased sweat electrolytes, chronic respiratory infection, pancreatic insufficiency, and reduced fertility (females) or sterility (males)
• Pneumocystis Pneumonia (PCP) is an interstitial plasma cell pneumonia caused by Pneumocystis Jiroveci (PJP)
• PCP is common in patients with weakened immune systems
• Respiratory Syncytial Virus (RSV) causes the formation of syncytial masses in infected cell structures
• Virostatic refers to stopping a virus from replicating
• Virucidal refers to killing a virus
• Virus is an obligate intracellular parasite containing DNA or RNA that reproduces within a host cell, causing disease
• PCP commonly infects mammals at a young age and occurs with immune system suppression, also known as Pneumocystis Jiroveci

Pentamidine

• Pentamidine is an antifungal agent effective against Pneumocystis Jiroveci, the organism causing PCP, and can be administered parenterally or inhaled
• The brand name is NebuPent
• Dosage is 300 mg in 6 mL sterile water via DPI (Dry Powder Inhaler), administered once every 4 weeks
• Clinically used for PCP prophylaxis
• Administration via Respirgard 2 Nebulizer
• Precise mechanism of action is unknown
• Toxic effects on P. Jiroveci may result from multiple actions
• A flow rate of 5-7 L/min from a 50-psi gas source is required
• The mass median diameter is 1-2 um
• Clinically indicated for PCP prevention in HIV-infected patients with a history of PCP or a peripheral CD4+ (T Helper cell) lymphocyte count of 200/mm3 or less
• Aerosolized side effects include cough, bronchial irritation, shortness of breath, bad taste, bronchospasm, and wheezing
• Systemic side effects include conjunctivitis, rash, neutropenia, pancreatitis, and renal insufficiency
• Parenteral side effects include pain, swelling, abscess formation at the injection site, hypotension, leukopenia, and hepatic dysfunction

Environmental Contamination

• Precautions should be taken to prevent the spread of Tuberculosis (TB)
• Containment booths or isolation rooms should be used for patients with HIV to prevent the disease spreading
• Patients with a history of lung disease should not use this agent in aerosolized forms
• Use a nebulizer system with one-way valves and an expiratory filter
• Stop nebulization when the patient removes the mouthpiece
• Use nebulizers producing a Mass Median Diameter (MMD) of 1 to 2 um to enhance alveolar targeting and reduce large airway deposition and cough production
• Screen patients for a cough history and pretreat with a B agonist with sufficient lead time
• Administer aerosol in a negative-pressure room or isolation booth/hood
• Use barrier protection
• Do not allow patient interaction until coughing subsides
• Healthcare workers should screen themselves periodically for TB
• Pregnant women and nursing mothers should avoid exposure to the drug

Ribavirin

• Ribavirin is used to treat RSV infection in children and infants at risk for severe or complicated disease, herpes simplex virus, and influenza virus
• Ribavirin is virostatic, not virucidal, and inhibits DNA and RNA (retrovirus) viruses
• The brand name is Virazole
• Dosage is 20 mg/mL solution for 12-18 hours/day for a minimum of 3 days, and no more than 7 days
• Alternatively, 6 mg of powder in 300 mL of sterile water (20 mg/mL solution) can be used
• Delivery is via SPAG-2
• Concentration is 6g/300 mL
• Pulmonary side effects include deterioration of lung function and worsening of asthma or chronic obstructive disease, pneumothorax, apnea, and bacterial pneumonia
• Cardiovascular side effects include cardiovascular instability, including hypotension, cardiac arrest, and digitalis toxicity
• Hematological side effects on blood cells have been reported with oral or parenteral administration, but not with aerosol use
• Dermatological/topical side effects include rash, eyelid, erythema, and conjunctivitis
• Aerosolized Ribavirin can cause mutagenic and carcinogenic effects
• It's effects on fertility are uncertain
• It poses particular concerns for effects on pregnancy

Palivizumab

• Palivizumab (RSV infection) is an F protein inhibitor monoclonal antibody approved for preventing RSV in pediatric patients
• The brand name is Synagis
• Dosage is 15mg/kg given intramuscularly monthly during RSV season
• It involves Monoclonal antibodies
• Mechanism of action involves providing neutralizing and fusion-inhibiting activity, preventing viral replication
• Indicated for the prevention of serious lower respiratory tract disease caused by RSV in high-risk children and infants
• Safety and efficacy are established for infants with Bronchopulmonary Dysplasia (BPD), premature infants (