Consolidation is an old term for lobar pneumonia, which describes the appearance of the lung in autopsy studies. Consolidation denotes pneumonia so serious that William Osler (an early American physician) called it in 1901, "the captain of the men of death." The outlook for severe pneumonia has improved since then with vaccinations, antibiotics and early detection with X-rays. According to the CDC, there were 55,477 deaths from pneumonia in the United States in 2006.
When the body reacts to infection or other process in the lung, inflammation causes fluid, pus or debris to leak into the lung tissue and change its density, consolidating it and making it thicker and heavier. This pathological process originally described the appearance of affected lungs at autopsy. Before stethoscopes or X-rays were invented, doctors searched for ways to correlate these postmortem findings with those in living patients.
History of the Physical Examination
Leopold Auenbrugger, an early Austrian physician, learnt that tapping on the chest with the finger (percussion) allows detection of fluid or solid structures, a technique he reportedly learnt from tapping on kegs in his father's hotel wine cellar. Consolidation produces a duller note than a normal lung when the chest is tapped.
Physicians learnt to suspect consolidation when they found certain other subtle clues while examining patients which are now of mainly historical interest. The chest may rise and fall less on the side that has consolidation, known as reduced expansion.
In the presence of consolidation, sounds from the larger airways near the voicebox are transmitted and heard more easily in the chest with a stethoscope, known as bronchial sounds. A whispered sound may be heard louder in the stethoscope, known as "whispered pectoriloquy" or vocal resonance. When the hand is held against the chest and a patient with consolidation says "bee," it sounds like "bay"; this change in pitch of the sound became to be known as increased tactile vocal fremitus or egophony.
Symptoms and Signs
A loose productive cough, difficulty breathing, chest pain, fever, night sweats and fatigue, and rust coloured or red sputum may all be signs of a lobar pneumonia. Patients who have severe pneumonia may breathe more rapidly (tachypnea), appear sweaty (diaphoretic), cough frequently, have difficulty speaking and appear pale.
Doctors now diagnose consolidation or pneumonia with X-rays. A lung that is consolidated absorbs more radiation and appears like an obvious white puffy cloud on an x-ray. A patient with a less severe atypical pneumonia may not have signs of consolidation on the x-ray. An x-ray picture is taken as if the person is standing in front of you, so the patient's right side is on the left side of the picture. Bones and structures like the heart and oesophagus appear white; a normal lung usually is filled with air and does not absorb radiation so it appears dark, or radiolucent.
Bacterial infections such as Streptococcus pneumoniae (pneumococcus) or klebsiella commonly cause lobar pneumonia or consolidation, both of which may cause a more typical or severe pneumonia. Other "atypical" bacteria such as mycoplasma or legionella are less likely to cause consolidation, athough this is not always the case. Viral infections such as influenza also cause pneumonia.
Because pneumonia is caused by bacteria, measures like hand washing and coughing into the arm can prevent its spread. A doctor will advise whether vaccination to prevent the most common bacteria responsible for severe pneumonia (pneumococcus) is appropriate.
A physician evaluates a patient to decide whether to use a breathing machine to help support the lung or to admit the patient to the hospital for oxygen, breathing treatments and intravenous antibiotics. Some patients with "walking pneumonia" or "atypical pneumonia" are treated with antibiotics at home; usually these patients do not have consolidation. The presence of signs of consolidation may predict a more severe pneumonia.