Respiratory System 09

Respiratory system 09 A.A. Stokhof and A.J. Venker-van Haagen already been done in the general examination. Then, to Chapter contents evaluate the respiratory sounds, we return to the description in the history, although abnormal respiratory 9.1 History63 sounds are sometimes clearly recognized during the 9.1.1 Symptoms63 examination. Then comes the external examination of 9.1.2 Living conditions65 the nose and sinuses, followed by examination of the 9.1.3 Past history65 larynx and trachea, and then finally the thorax. 9.2 Physical examination65 9.2.1 Respiratory movements and sounds65 9.1 History 9.2.2 Nose and frontal sinuses65 In focusing the history on the respiratory system, we use Introduction 65 the same approach as for the general history (Chapter 6). Nose 66 Further questions are asked about the symptoms Frontal sinuses67 reported by the owner. More detailed questions are Nasopharynx 67 then asked about other symptoms associated with Oropharynx 67 the respiratory system, such as nasal discharge, 9.2.3 Larynx and trachea67 sneezing, additional sounds, coughing, sputum, Technique 67 gagging or retching, and labored respiration. After this, additional specific questions are asked about the 9.2.4 Thorax68 situation in which the patient is living and any Thoracic wall69 previous illnesses in the patient or its relatives. We Technique 69 go into these aspects of the history as follows. Respiratory movements69 Bronchi, lungs, and pleura69 9.1.1 Symptoms Auscultation 69 Technique 71 Nasal discharge is often associated with one or more of Percussion 72 the other signs given above. The owner is asked Technique 72 whether the nasal discharge is from one or both nostrils and whether it is continuous or only occurs at 9.3 Notation73 certain times (e.g., mainly in the morning when the 9.4 Further examination74 dog awakens, or mainly when the dog goes outside), or only occurs when the dog sneezes. Questions about the description of the exudate must be asked in layman’s terms, such as watery, mucus, pus, or blood. If the screening examination has led to formulation of a A stridor is a respiratory sound that can be heard at problem and a diagnostic plan that includes examination some distance from the animal and keeps recurring; it is of the respiratory system, the first step is to further focus of fairly constant amplitude and frequency. A narrowing the history on this system. The second step is to observe (stenosis) in the upper airways can lead to such an the respiratory movements, although this has usually acceleration of the air stream that the Reynolds value 63 Chapter 9: RESPIRATORY SYSTEM (} 4.1.4) is exceeded and strong turbulence develops. 1 A cough that is started by stimulation of the The stridor is named after the location of the larynx usually occurs episodically, is often heavy, obstruction, such as a nasal stridor, pharyngeal stridor, and is sometimes associated with gagging or or laryngeal stridor. The location of the obstruction also retching, a tendency to vomit, and sometimes the determines the sound. For example, sniffing is coughing up of a little mucus or saliva. characteristic of nasal stridor, snoring is characteristic of 2 A cough that is due to a process in the trachea is a a pharyngeal stridor, and a soft ‘sawing’ sound typifies a loud, explosive cough that often has the laryngeal stridor. In a few breeds of dogs, selective characteristics of a bark. breeding for brachycephalic characteristics has led to 3 Stimulation of the bronchi can result in various various types of stridor. The tooting sound of a collapsed kinds of coughing. In the acute phase the pattern is trachea is expiratory, while the sounds mentioned above not easy to differentiate from a cough due to can be inspiratory or both inspiratory and expiratory, tracheitis. When much mucus and pus are depending on the severity of the obstruction. A stridor produced, the cough has a wet and rough character. of the nose or nasopharynx disappears as soon as the animal begins to breathe through the mouth. In very The tracheal cough—and even more so the bronchial severe nasal obstruction the animal does this cough—are above all dry and nonproductive in the spontaneously, but often keeps alternating with attempts acute phase and then associated with the coughing up to breathe through the nose. In a mild stenosis the of sputum in the chronic phase. In taking the history stridor is only heard during and shortly after exercise. an attempt is made to describe the cough in terms of Sneezing is one of the two reflexes that protect the frequency, duration, strength, whether it is painful, the respiratory system against injury. Stimulation of production of sputum, the probable localization of the subepithelial receptors in the nose triggers the sneezing cough stimuli, and the time of occurrence (excitement, reflex.1 The stimuli include inflammation or products of time of day, change of environment). inflammation, foreign bodies, and tumors. In addition Sputum is the substance in the airways that is to sneezing, which everyone recognizes, there is another transported by coughing. In the dog and the cat we sound that occurs in the dog and which is called are seldom well informed by the history about its ‘reverse sneezing’. This occurs as a result of stimulation character (serous ¼ watery, mucous, purulent ¼ pus, of the mucosa of the nasopharynx, leading to a spasm mucopurulent ¼ mucus and pus) or the amount, because of the pharyngeal muscles, which hinders the passage of the coughed-up material is usually swallowed air to the larynx. The dog (it occurs chiefly in the dog) immediately. In by far the majority of cases it is only on makes an inspiratory snoring sound and at the same the basis of the nature of the cough (productive or time shows all the signs of severe dyspnea. The nonproductive) that one can form an impression about pharyngeal spasm can be interrupted by reflex the presence or absence of sputum. Sputum is coughed swallowing, which can be brought about by massaging out only when coughing itself so stimulates the pharynx the throat or by obstructing the nostrils until the dog that the animal begins gagging or retching so severely swallows. Reverse sneezing occurs without warning in that swallowing does not occur. The owner can describe otherwise healthy animals and episodes can last from the nature of the sputum with the help of questions seconds to minutes. If there is irritation or inflammation about its color, stringiness, and odor. Account must be of the mucosa in the nose and nasopharynx, the taken of the frequent mixing with saliva and the possible frequency can increase to several times per day. addition of material from the digestive tract. In acute Coughing is the second important reflex by which the lung edema there may be not only coughing of serous respiratory system protects itself against injury. The sputum but also serous discharge via the nasal openings, reflex can occur via stimulation of the airways with the formation of air bubbles at the nostrils. The anywhere from the larynx to the larger bronchi.2 After discharge can have a pinkish-red color due to the a deep inspiration the intrathoracic pressure is presence of some blood. Damage to the blood vessels increased (sometimes to 20 kPa!) by closure of the can lead to the production of sputum that is blood-red. glottis and contraction of the thoracic and abdominal Dyspnea (labored or difficult breathing) is muscles. This is followed by an abrupt decompression, characterized by forced respiratory movements, by opening the glottis and driving out the respiratory whereby auxiliary respiratory muscles are activated. gas, together with any sputum that may be present.3 When the history is being taken it must first be The frequency, severity, and character of the stimulus is determined whether the dyspnea is acute and recurring determined by (1) the nature of the causative lesion, (2) or chronic and continuous. In cases of acute dyspnea it the presence of sputum, and (3) any complicating is certainly necessary to also ask about the conditions factors such as pain or reduced ventilation capacity. under which this difficult breathing recurs and whether The following types of cough can be distinguished, there are any accompanying signs (e.g., stridor). according to the site of the stimulation: Owners do not always find it easy to distinguish 64 Physical examination between panting (thermal or nervous polypnea) and nasal openings are often small (Fig. 9.1), which can dyspnea. Questions about the depth of the breathing cause respiratory difficulties. can help here. A chronic dyspnea is sometimes clearly The nose of dogs and cats is largely filled with richly recognizable to the owner and the examiner when the vascularized conchae. A bullous extension of the ventral animal is at rest. In other cases the signs occur only concha (plica alaris), which proceeds craniolaterally into during exercise (dyspnea of exertion). In the latter case the nasal ala, divides the incoming air over the dorsal, one must be aware that owners do not always medial, and ventral nasal passages. Most of the air is recognize the difference between the rapid development turned ventromedially toward the largest passage, the of fatigue during exercise and the loss of interest in ventral nasal passage (ventral nasal meatus). It is only via exercise. The latter is an apathy, for which there need be this passage that a tube can be passed (hence also no cardiopulmonary problem. It is also possible that the ventromedially) into the esophagus for artificial feeding animal does not want to continue exercising because of (Fig.

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