Respiratory infections viral, treatment

Sinusitis, or inflammation of the paranasal sinuses, is better described as rhinosinusitis that also involves inflammation of contiguous nasal mucosa, which occurs in virtually all cases of viral respiratory infections. Acute rhinosinusitis is characterized by symptoms that resolve completely in less than 4 weeks, whereas chronic rhinosinusitis typically persists as cough, rhi-norrhea, or nasal obstruction for more than 90 days. Acute bacterial rhinosinusitis (ABRS) refers to an acute bacterial infection of the sinuses that can occur independently or be superimposed on chronic sinusitis. The focus of this section will be on ABRS and appropriate treatment. 

Acute HIV Infection Diagnosis of acute HIV infection is difficult, since many patients are asymptomatic, or have nonspecific clinical symptoms similar to other common respiratory infections. If acute HIV infection is suspected, HIV antibody tests and a plasma HIV RNA concentration should be obtained. A clear diagnosis is made when an HIV antibody test is negative and the plasma HIV RNA concentration is high. There are limited outcomes data for treating acutely infected patients. Treatment of acute infection can decrease the severity of acute disease and decrease the viral set point this may decrease progression rates and reduce the rate of viral transmission.18-22 Limitations include an increased risk of chronic drug-induced toxicides and the development of viral resistance. 

Hall CB, McBride JT, Walsh EE, Bell DM, Gala CL, Hildreth S, Ten Eyck LG, Hall WJ. Aerosolized ribavirin treatment of infants with respiratory syncytial viral infection. A randomized double-blind study. N Engl J Med 1983 308(24) 1443-7. 

Palivizumab Antibody to surface protein of RSV. Used for prophylaxis and treatment of respiratory syncytial viral infection... 

The adamantane moiety is of medicinal chemical interest because of its inertness, compactness relative to lipid solubilizing character, and symmetry. Considerable interest, therefore, was engendered by the finding that amantadine (78) was active for the chemoprophylaxis of influenza A in man. There are not many useful chemotherapeutic agents available for the treatment of communicable viral infections, so this finding led to considerable molecular manipulation. The recent abrupt end of the National Influenza Immunization program of 1976 prompted a new look at the nonvaccine means for prophylaxis or treatment of respiratory tract infections due to influenza A, especially in that the well-known antigenic shift or drift of the virus obviates usefulness of the vaccine but not amantadine. 

The drugs described next are used in the treatment in a variety of viral conditions, including HBV, hepatitis C virus (HCV), respiratory syncytial virus (RSV), human papilloma virus (HPV), and VZV. Some are also used in the therapy of HIV infection detailed information on the treatment of this disease is found in Chapter 51. 

St. John s wort has been used to treat a wide range of ailments for more than 2000 years, and is said to have been prescribed by Hippocrates himself. Apart from depression, St. John s wort is being promoted or used as a treatment for attention-deficit hyperactivity disorder (ADHD), anxiety, stress, obsessive-compulsive disorder, sleep problems, nocturnal enuresis, bacterial and viral infections such as HIV-AIDS, respiratory conditions, peptic ulceration, inflammatory arthritis, cancer, and skin wounds (Rey and Walter, 1998 Walter et ah, 2000). It is also said to increase libido, an application dating from the Middle Ages (Fletcher, 1996). No empirical evidence is currently available to support any of these uses. 

Neuraminidase is an essential viral glycoprotein for virus replication and release. The neuraminidase inhibitors zanamivir and oseltamivir have recently been approved for the treatment of acute uncomplicated influenza infection. When a 5-day course of therapy is initiated within 36-48 hours after the onset of symptoms, use of either agent shortens the severity and duration of illness and may decrease the incidence of respiratory complications in children and adults. Unlike amantadine and rimantidine, zanamivir and oseltamivir have activity against both influenza A and influenza B. Zanamivir is administered via oral inhaler. The compound displays poor oral bioavailability, limited plasma protein binding, rapid renal clearance, and absence of significant metabolism. Nasal and throat discomfort may occur—as well as bronchospasm in patients with reactive airway disease. 

Viral respiratory tract infections for which treatments exist include those of influenza types A and B, and respiratory syncytial virus (RSV). [Note Immunization against influenza A is the preferred approach. However, antiviral agents are employed when patients are allergic to the vaccine or when the outbreak is due to an immunologic variant of the virus not covered by vaccines, or when outbreaks occur among unvaccinated individuals at risk who are in closed settings, for example, in a nursing home.]... 

Pharmacokinetics Ribavirin is effective orally and intravenously. Its current use is as an aerosol in certain respiratory viral conditions, such as the treatment of RSV infection. Studies of drug distribution in primates showed retention in all tissues, except brain. The drug and its metabolites are eliminated in the urine. 

Amantadine is effective only against influenza A it acts by interfering with the uncoating and release of viral genome into the host cell. It is well absorbed from the gastrointestinal tract and is eliminated in the mine 3 h). Amantadine may be used orally for the prevention and treatment of infection with influenza A (but not influenza B) virus. Those most likely to benefit include the debilitated, persons with respiratory disability and people living in crowded conditions, especially during an influenza epidemic. 

TNFa is classically associated with septic shock and diverse infectious pathological conditions. It is involved in the development of a protective immune response in tuberculosis. Measurable serum TNFa levels have been detected in 10.5% of children with pulmonary tuberculosis, all of whom belonged to the group with active disease. Results suggest a protective role for TNFa in respiratory syncytial virus infection. In patients with chronic hepatitis C during treatment with IFNa, elevated production of TNFa by PBMCs may be due to host response to the virus. In HIV infection, TNFs and IL-6 stimulate viral replication. 

Acute cough is a common symptom associated with viral upper respiratory tract infections (URTIs) such as the common cold (see Chapter 21), and pharmacists are most frequently asked for advice and treatment for coughs from this cause. However, cough is a symptom of many conditions, most of which require referral to a doctor for further investigation. Pharmacists must be able to distinguish between a cough from a trivial condition and one from a potentially more serious cause and make appropriate referrals. 

Respiratory syncytial virus is the most common cause of acute bronchiolitis, an infection that mostly affects infants during their first year of life. In the well infant, bronchiolitis is usually a self-limiting viral illness, whereas in the child with underlying respiratory or cardiac disease or both, the child may develop severe respiratory compromise (failure) necessitating in-hospital treatment, such as rehydration, oxygen, and in select patients, bronchodilators, ribavirin aerosol, or both. 

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