Fortnightly Review: Management of community acquired lower respiratory tract infection
Authors: H S R Hosker, G M Jones, P Hawkey
Journal: BMJ (1994)

Lower respiratory tract infection incorporates a spectrum of disease from acute bronchitis to pneumonia.The division between bronchitis and pneumonia is not always clear, but patients with focal signs on clinical examination should be regarded as suffering from clinical pneumonia even if the chest radiograph is normal.In otherwise healthy individuals, acute bronchitis is usually associated with a speedy recovery and few sequelae, but pneumonia remains a leading cause of death throughout the world.Infective exacerbations of chronic obstructive pulmonary disease lead to considerable morbidity, time off work, and days in hospital.This article reviews the diagnosis and management of community acquired lower respiratory tract infection.The management of patients with underlying diseases such as cystic fibrosis and bronchiectasis, and of immunocompromised patients, is not considered here. EpidemiologyInfections of the lower respiratory tract are respon- sible for 6% of all general practitioner consultations and form 4A4% of all hospital admissions.'They account for 3-5% of deaths in adults up to the age of 60.The best estimate from available data suggests that around 25 million prescriptions for antibiotics are written each year by general practitioners to treat respiratory infections.2As with most diseases, the less severe types pre- do-minate.Acute bronchitis is common and usually self limiting, although the associated cough and sleep disturbance can be distressing.Children who develop croup or stridor during a viral respiratory infection may need to be admitted to hospital.Community acquired pneumonia is potentially more serious, with elderly people and those with pre-existing illness at greatest risk of dying.Community acquired pneumonia is distinct from other types (box 1) in terms of epidemiology, causative organisms, management, and outcome.It occurs more commonly in those over 65, smokers, and those with other non-respiratory illnesses (particularly alcoholism), and the incidence doubles during the winter months.Most cases are managed by primary care teams-78-95% of adults with pneumonia are treated at home by general practitioners.'The remainder of patients with more severe illness will require hospital admission, including all those with adverse prognostic factors, severe pain, or breathlessness.* Patient with adverse prognostic signs * Patient with focal signs on examination * Failure to improve after a course of appropriate antibiotics * Clinical deterioration * Signs of effusion or empyema * Doubtful diagnosis * Persisting haemoptysis W * Age > 60 years * Respiratory rate -30/min* * Diastolic blood pressure S 60 mm Hg* * Confusion * Blood urea > 7 mmol/l* * Arterial oxygen tension < 8 kPa * Leucocyte count > 20 or < 4 x 109/1 * Serum albumin < 35 g/l * Multiple lobes seen to be affected on chest x ray *Presence oftwo or more ofthese factors is associated with a 21-fold increase in mortality Box 3-Common risk factors for tuberculosis * Poor social circumstances * Alcoholism * Diabetes mellitus * Immigrant population * Travel to developing countries * No previous BCG vaccination * HIV infection Box 5-Common underlying diseases predisposing to lower respiratory tract infection * Chronic obstructive pulmonary disease * Bronchiectasis * Bronchial carcinoma * Inhaled foreign body * Alcoholism *