Page 103 - Medicine and Surgery
P. 103

P1: FAW
         BLUK007-03  BLUK007-Kendall  May 25, 2005  17:29  Char Count= 0








                                                                           Chapter 3: Respiratory infections 99


                  Table 3.9 Histological stages of pneumococcal lobar pneumonia
                  Stage             Microscopy
                  Congestion & oedema  Engorgement of the alveolar walls, air spaces filled with oedematous fluid.
                  Red hepatisation  Organisation of the fluid into a fibrin mesh containing red cells, neutrophils and bacteria.
                  Grey hepatisation  Clearance of the red blood cells and neutrophils and predomination of macrophages in an attempt
                                     to clear the remaining bacteria.
                  Resolution        The fibrin meshwork is broken down, neutrophil debris is ingested by macrophages which are
                                     cleared through the lymphatics.


                                                                 scopy and bronchial lavage may be considered, as this
                  Macroscopy/microscopy
                                                                 is more likely to give microbiological results.
                    Bronchopneumonia: The affected areas of the lung are     Patients should have a follow-up chest X-ray after

                    consolidated. The air spaces are filled with an acute
                                                                 6weeks to ensure resolution, and to exclude any un-
                    inflammatory exudate causing the lung to be firm and
                                                                 derlyinglesionsuchascarcinomacausingobstruction.
                    a dark red or grey colour. The bronchi are inflamed
                    and pleural involvement is common.
                    Lobar pneumonia: The affected lobe is consolidated  Management

                    with the acute inflammatory exudate being contained  1 Non-pharmacological: Fluids, physiotherapy to clear
                    in a single segment, lobe or lung. Several identifiable  secretions,analgesiaforpleuriticpainwherenecessary
                    stages are seen in a pneumococcal lobar pneumonia  andoxygenifthereishypoxia(guidedbyarterialblood
                    (see Table 3.9):                             gases).
                                                                2 Empirical antibiotic treatment should be commenced
                                                                 immediately based on knowledge of the likely organ-
                  Complications                                  isms, modified where necessary by local microbiol-
                  Development of lung abscesses and pleural effusion  ogy guidelines and on the basis of culture results (see
                  (which may be reactive or infected, i.e. an empyema),  Table 3.10, p. 102).
                  pleural infection (pleurisy) and septicaemia.  3 Patients with sickle cell disease, asplenia or severe
                                                                 dysfunction of the spleen, chronic renal disease or
                                                                 nephrotic syndrome, coeliac disease, immunodefi-
                  Investigations                                 ciency or immunosuppression, haematological malig-
                    Achest X-ray will demonstrate areas of consolidation,  nancy, cardiovascular disease, chronic pulmonary dis-

                    any abscesses, effusions and masses (such as under-  ease, chronic liver disease or diabetes mellitus should
                    lying bronchial carcinoma). X-ray changes generally  receivepneumovax prophylaxis.
                    lag behind clinical features so the X-ray may occa-
                    sionally be normal at presentation, and may remain
                    abnormal for several weeks after the pneumonia has  Prognosis
                    resolved.                                   Outcome depends greatly on the age of the patient and
                    The white cell count will normally demonstrate a neu-  concurrent disease (including diabetes mellitus, chronic

                    trophilia. If patients require admission, sputum and  renal failure, congestive heart failure and underlying res-
                    blood cultures should be taken and specific serologi-  piratory disease such as chronic obstructive pulmonary
                    cal tests are available for Legionella and other atypical  disease). Mortality for community-acquired pneumonia
                    pneumonias.                                 is about 14% (about 20% for those requiring hospital
                    Urea and electrolytes are measured for hydration and  admission and up to 35% for those requiring intensive

                    to detect any co-existing renal disease.    care).
                    Blood gases may be required to monitor oxygenation
                                                                 British Thoracic Society guideline for identifying pa-
                    and to assess for respiratory failure.      tients with severe community acquired pneumonia:
                    In severe cases, immunosuppressed individuals and  Core features (score 1 for each): Confusion, urea ≥

                    those unresponsive to standard therapy, broncho-  7 mmol/L, respiratory rate ≥ 30 breaths per minute,
   98   99   100   101   102   103   104   105   106   107   108