Common Radiological Abnormalities in Diseases of the Respiratory System

Common Radiological Abnormalities in Diseases of the Respiratory System

Consolidation, collapse, fibrosis, pleural effusion, pneumothorax, cavities and Opacities in the lungs are all common radiological abnormalities. What are their significance?
Consolidation
The presence of homogenous opacities with well defined margins indicates pulmonary consolidation, since there is no change in the volume of the lung the trachea and mediastinum are not shifted.
Collapse
Pulmonary collapse throws a homogenous opacity with clear-cut concave margins. The trachea, mediastinum, and interlobar fissure are shifted towards the area of collapse. The dome of the diaphragm on the affected side is elevated. The unaffected portions of the lung show hyper-translucency due to compensatory emphysema.
Fibrosis
Presence of streaky linear or reticular shadows with shift of trachea and mediastinum to the same side and compensatory emphysema of the unaffected regions is suggestive of fibrosis.
Pleural effusion
The presence of small quantities of fluid (less than 300ml) in the pleura causes only obliteration of the costophrenic angle. As the quantity of fluid increases, more extensive homogenous opacity appears with obliteration of the costophrenic and cardiophrenic angles. The upper margin tends to be concave with its higher level towards the axilla and the lower level towards the mediastinum. Midline structures are shifted to the opposite side. The presence of fluid and air (hydropneumothorax) is diagnosed by the presence of a horizontal level of fluid below, with hypertranslucency (due to air) above. The lung markings are not visible since the lung is collapsed towards the helium.

Tuberculosis - The Lung Attacker

Tuberculosis - The Lung Attacker

(Latin tuber cuius, little bump). Infectious disease of world-wide incidence. As a disease of the lung it was known to the physicians of ancient Greece as a wasting disease; hence its other name, phthisis. The cause is a micro-organism called the tubercle bacillus, or the bacillus of Koch, the physician who discovered it. There are three known types of bacilli - human, bovine, and avian. The first two attack the human race, the human type producing infection by inhalation, the bovine by ingestion of the milk of tuberculous cows. Efficient pasteurisation, and proper handling, of milk protect man from bovine tuberculosis. The bovine bacillus can cause widespread disease in animals, especially cows and pigs.
No child is born with tuberculosis, the disease is the result of direct infection. It affects glands, bones, joints, and the genito-urinary system (bladder, testicle, and kidney), when it is often referred to as surgical tuberculosis. When present in the lungs it is called pulmonary tuberculosis. These forms of disease may be intercurrent, or one can result from the other, while both can lead to tuberculous meningitis.
Whatever be its route of entry to the body, the tubercle bacillus can always reach the lungs. Usually this takes place in childhood from minimal infection. It commonly produces but little clinical effect, leaving only a small hard nodule, called a Ghon's focus, in the lung substance, and calcified glands at the root of the lung. Occasionally the child develops vague symptoms of malaise and fever during the time it is over-coming this primary infection; this illness may last several months, but in the vast majority of cases the children recover completely. But if the child's resistance is poor, or it gets repeated infections, which do not allow it to develop immunity, it gets blood-borne extension (miliary tuberculosis), or a spread of infection through the air passages (pneumonic or broncho pneumonic tuberculosis). Such forms, formerly usually fatal, can nearly always be successfully treated with anti-tuberculous drugs.

Disease of the Pleura and Pulmonary Cysts

Disease of the Pleura and Pulmonary Cysts

Inflammation of the Pleura is called Pleurisy. In dry Pleurisy, the pleural surfaces are inflamed without fluid in between them. In many cases pleurisy is associated with effusion. Both dry pleurisy and pleural effusion may develop at different stages of the same disease process.
Dry or fibrinous pleurisy: The pleura gets involved from the disease of the underlying lung. Trauma to the chest may also lead to Pleurisy. The suggestive symptom is the catching pain felt acutely over the affected area by inspiratory movements brought about by deep breathing, coughing or sneezing. Its etiology are as follows: Pulmonary tuberculosis, Pneumonia, bronchogenic carcinoma, pulmonary infarction, connective tissue disorders (such as systemic lupus erythematosus, polyarteritis nodosa, and rheumatoid disease), rheumatic fever, viral infections (especially Coxsackie [Bornholm disease), hepatopulmonary amoebiasis, and uraemia.
The physical examination reveals diminution of movement on the affected side and the presence of pleural friction rub on auscultation. Pleural rub has a superficial grafting quality. The rub is heard better by gentle pressure of the chest piece of the stethoscope on the chest wall. Unlike rales, it is not altered by coughing. With the development of pleural effusion, the rub may disappear in most cases. Pleural rub has to be distinguished from crepitations and sounds arising from movements of the chest wall. Other painful conditions like Pneumonia, myocardial infarction, and herpes Zoster have to be differentiated from pleurisy.
Pleural effusion: In this condition, fluid accumulates between the two layers of the pleura. Normally, pleura contains only a small amount of fluid. The pleural fluid remains in dynamic equilibrium with blood. Movements of the lung favour the movement of the fluid in and out of the pleural space. In most of the disease states, absorption of the fluid is reduced. The fluid may be contained in the general pleural space or it may be loculated in the interlobar fissure, infrapulmonary space or may remain adjacent to the mediastinum. The fluid progressively compresses the subjacent lung which undergoes collapse.

Pneumonia - Diseases

Pneumonia - Diseases

Pneumonia is an acute lung inflammation in which the lungs fill with a fibrous material, impairing gas exchange. With poor gas exchange, the blood has too much carbon dioxide and too little oxygen.
People with normal lungs and adequate immune defenses usually recover fully. However, pneumonia is the sixth leading cause of death in the United States.
Classifying pneumonia
Pneumonia can be classified by location or type, as well as cause .
" Location: Bronchopneumonia involves the lungs and small airways of the respiratory tract. Lobular pneumonia involves part of a lobe of the lung. Lobar pneumonia involves an entire lobe .
" Type: Primary pneumonia occurs when a person inhales or aspirates a disease-producing microorganism; it includes pneumococcal and viral pneumonia. Secondary pneumonia may occur in someone who's suffered lung damage from a noxious chemical or other insult, or it may be caused by the blood-borne spread of bacteria from a distant site.
What causes it?
Pneumonia can be caused by a virus, bacterium, fungus, protozoa, mycobacterium, mycoplasma, or rickettsia.
Certain factors can predispose a person to bacterial and viral pneumonia-chronic illness and debilitation, cancer (especially lung cancer), abdominal or chest surgery, atelectasis (the collapse of air sacs in the lung), the flu, common colds or other viral respiratory infections, chronic respiratory disease (such a, emphysema, chronic bronchitis, asthma, bronchiectasis, or cystic fibrosis), smoking, malnutrition, alcoholism, sickle cell disease, tracheostomy, exposure to harmful gases, aspiration, and drugs that suppress the immune system.