RESPIRATORY PATHOLOGY

Disease Assessment and Review

Michael Haines, MPH, RRT-NPS, AE-C

Respiratory Pathology Table of Contents

Topic / Page number
Introduction / 4-6
Symptoms and Diagnosis of Lung Disorders / 7-9
Diagnostic Tests / 9-14
Medical Terminology / 15-17
Common Respiratory Therapy Terms and Laboratory data / 17-21
Types of Hypoxemia / 21-22
Asthma / 22-26
ARDS / 27-29
ALS / 29-30
Alpha 1 Antitripsyin Disorder / 30-31
Anemia / 31-32
Aspiration Pneumonia / 32-33
Aspergillus / 33-34
Atelectasis / 34
Asbestosis / 35
AIDS / 35-36
Abruptio Placenta / 37-38
Bronchiectasis / 38-40
Bronchopulmonary Dysplasia / 41-42
Bronchitis / 42-44
Bronchiolitis / 45-46
Cystic Fibrosis / 46-50
Croup / 50-52
Cerebral Vascular Accident (CVA) / 52-54
Congestive Heart Failure (CHF) / 54-56
Coronary Artery Disease (CAD) / 56-57
Cor Pulmonale / 57-58
Congenital Diaphragmatic Hernia / 58-60
Cardiac Tamponade / 60-61
Central Sleep Apnea / 61-62
Choanal Atresia / 62
Coarctation of the Aorta / 62-63
Carbon Monoxide Posioning / 64-65
Diabetes/ Diabetic Keto acidosis / 65-66
Eclampsia / 66
Emphyema / 67
End Stage Renal Disease (ESRD) / 67-68
Epiglottitis / 68-70
Emphysema / 70-71
Endocarditis / 71-72
Flail Chest / 72
Foreign Body Airway Obstruction (FBAO) / 73
Gullian Barre Syndrome / 73-75
Gastroschisis / 75
Gastrointestinal Bleed (GIB) / 75-76
Good Pastures Syndrome / 76-77
Hepatic Encephalopathy / 77-78
HELLP Syndrome / 78
Hemothorax / 78-79
Infant Respiratory Distress Syndrome (RDS) / 79-80
Idiopathic Pulmonary Fibrosis / 80-84
Kyphoscoliosis / 84-85
Legionnaires Disease / 85
Lung Cancer / 85-87
Meconium Aspiration / 87-88
Muscular Dystrophy / 88-89
Myasthnia Gravis / 89-91
MRSA / 91-92
Mounier-Kuhn’s Syndrome / 92-93
Myocardial Infarction / 93-94
Obstructive Sleep Apnea (OSA) / 94-97
Pleurisy, Pleural effusion, Pneumothorax / 97-101
Pneumonitis / 101-103
Pulmonary Edema / 103-107
Pulmonary Emboli / 107-109
Pneumococcal Pneumonia/other pneumonia / 110-116
Pulmonary Hypertension/PPHN / 117-122
Pierre Robin Syndrome / 122-123
Paroxysmal Supraventricular Tachycardia / 123-124
Patent Ductus Arteriosus (PDA) / 124-125
Pectus Carinatum / 125-126
Poliomyelitis / 126-127
RSV / 127-128
ROP / 128-129
Sarcoidosis / 129-132
Sepsis / 132-133
Silicosis / 133
Subcutaneous Emphysema / 133
Systemic Lupus Erthematosus / 133-135
Tetanus / 135
Tetralogy of Fallot / 135-136
Tracheamalcia / 137
Transient Tachypnea of the Newborn / 137-138
Tuberculosis / 138-140
Ventricular Fibrillation / 140-141
Ventricular Septal Defect / 141-142
Ventricular Tachycardia / 142-143

Introduction

Being able to properly assess, treat and identify a patient with respiratory compromise is vital and the key to a successful and meaningful career in respiratory therapy. In order to do this, one must first have a thorough understanding of pulmonary physiology and anatomy. After this is mastered, you must then understand basic etiologies of the major pulmonary pathologies. Once this is accomplished one must then be able to identify and indirectly diagnose pulmonary pathology as it relates to specific symptoms and diagnostic tests.

Diseases and syndromes affecting the lung may occur either in the lung itself (such as in pneumonia, lung cancer, pulmonary fibrosis, asthma and COPD); in the interstial space (pulmonary emboli, widened AC membrane and pulmonary hypertension); in the pleural space (pleural effusion, pleurisy, pneumothorax, or empyema); neurological (brain death, spinal cord injury or anoxia); in muscle strength (myasthenia gravis, guillian baire, muscle dystrophy, or ALS); anatomical (kyphoscoliosis, pigeon chest, flail chest or malformation of lung); or as a secondary illness (ARDS, Sepsis, heart failure or renal failure). There are literally thousands of ailments leading to respiratory compromise. You must master the common ones and be able to treat and sustain ventilation for most.

The respiratory system is a complex and vital part of the human body. The respiratory system must be fully operational (either naturally or artificially) to sustain life. To be considered functional, the respiratory system must possess six basic required functions. The first required function includes the location of the gaseous exchange, as it must occur deep within the lungs so that the air has had a chance to be warmed, moistened, and cleansed on its journey to be exchanged for waste gases. Air born particles must be removed during the oxygen’s journey deep into the lungs.


Secondly, the membrane lining of the lungs (mucosa) must be moist, as carbon dioxide and oxygen can undergo the process of gaseous exchange only in water soluble material. This process is called diffusion and can not happen in a dry lung. The respiratory system must have an extensive network of capillaries to allow the exchange of oxygen within the body’s tissues. An incompetent network of capillaries will result in some of the body’s tissue being denied life sustaining oxygen (as with diseases in the interstial space outside the lung parenchyma).
The respiratory system relies on a competent and efficient ventilation mechanism in order for there to be ample replenishment of the necessary oxygen. Ventilation is usually autonomic controlled by the medulla oblongata and PONS respiratory center. Chemoreceptor organs in the aortic, brain and carotid arteries may increase or decrease minute volume depending on high or low levels of paCo2 or paO2. The body’s tissue can not survive off of a minimal amount of oxygenation (minimum being 18-21%).
The respiratory system must be able to function automatically and not require constant conscious monitoring. Monitoring and feedback must all happen automatically throughout the body in order for the respiratory system to respond appropriately. The system also requires a conscious over ride in order to intentionally create a variance in airflow if desired or needed (when panicked or excited for example, an individual may increase ventilation to meet demand without help from chemorecptors).
By meeting these basic necessities, the respiratory system is designed with very intricate but purposeful properties, which allow it to take on a variety of responsibilities. The metabolic process and the sustaining of life rely entirely on the functions of these basic principles.
The respiratory system is responsible for providing the blood stream with life sustaining oxygen while removing toxic waste gases, enables the production of sound by passing over the vocal cords which in turn cause vibration, and is partially responsible for the compression of the abdominal muscles which assist in urination, defecation, and child birth as well as assists in laughter and other basic bodily functions surrounding the abdomen. The abdominal muscles rely on the respiratory system for functions which require significant exertion, as these muscles become more effective with a rush of extra oxygen, hence the natural desire to take a deep breath when pushing the abdominal muscles or even lifting a heavy object. In numerous ways, the back muscles benefit similarly from a rush of fresh oxygen.
Without the respiratory functions as they are designed, protective reflexes that require a lapse in breath such as coughing, sneezing, or hiccupping could not effectively occur. These reflexes enable the body to reject foreign substances and keep them from entering the body via the respiratory system. When these functions are inhibited as in neuromuscular or neurological compromise, individuals are more prone to infections.
The structure, design, and passages involving the respiratory system are quite extensive and include the nasal cavity, the larynx, the trachea, the pharynx, the bronchi, the bronchioles, and the pulmonary alveoli within the lungs. The upper respiratory system is segregated by the nasal passages, the pharynx, and the associated and necessary related structures while the lower respiratory system is segregated by the larynx, the trachea, the bronchiole system, the pulmonary alveoli, and the lungs. To keep the segregation and division of the respiratory system simple, it is typically divided by the generalization of conduction and respiration. A percentage of the respiratory system is divided up by its ability to relate to breathing in while the other half is associated with the body’s need for transportation of elements. These divisions are known as the respiratory division and the conduction division, respectively. The conduction division is created by any and all relative structures or cavities that “conduct” the gases in either form to and from the pulmonary alveoli while the respiratory division is defined by the pulmonary alveoli as well as any and all cavities or relative structures that assist with the exchange of gases in either form between the air and the blood.
The respiratory system, as complex and intricate as it is, is also quite viable and strong. The system is designed to compliment and function cooperatively with other systems to create and sustain life, energy, and endurance in nearly any reasonable situation.

Many ailments and diseases may directly or indirectly affect the lung itself, pleural space, neurological control of ventilation or diaphragm. Since the muscles surrounding the lung contain no skeletal muscle, they do not contract and therefore rely on either neurological stimulation (phrenic nerve) or assistance from abdominal, intercostals or neck muscles to contract. Conditions affecting muscle control or neurological control will impede normal ventilation even though it does not directly occur in the lung. Some muscular diseases include Myasthenia Gravis, Guilian Barre Syndrome, Muscle Dystrophy and ALS. Neurological conditions would include brain anoxia, spinal cord injuries or severed phrenic nerve. Without proper neurological stimulation, ventilation is erratic and ineffective, cough and gag reflex is absent or dulled requiring the aid of mechanical ventilation and bronchial hygiene techniques for proper gas exchange at a constant rate.

The diaphragm, located below the lungs, is the major muscle of respiration. It is a large, dome-shaped muscle that contracts rhythmically and continually, and most of the time, involuntarily. Upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarges. This contraction creates a vacuum, which pulls air into the lungs. Upon exhalation, the diaphragm relaxes and returns to its domelike shape, and air is forced out of the lungs. With diseases affecting the pleural space (which is normally negative) the normal vacuum affect is hindered and tidal volume is reduced; impairing gas exchange.

Symptoms and Diagnosis of Lung Disorders

Being able to first recognize respiratory symptoms as an acute or chronic disease or condition is vital for haste treatment. Some conditions such as COPD have chronic symptoms which become tolerable to patients and may require little intervention while other conditions such as CHF result in acute pulmonary edema requiring immediate attention. In order to classify acute from chronic one must look at the overall picture. Vital signs for example with an acute patient will reflect a panicked metabolic state (uncompensated mechanisms). Chronic on the other hand will reflect a compensated system (enlarged heart, balanced pH, enlarged respiratory muscles and so forth). I

Most lung disorders first present themselves with a subjective feeling of shortness of breath. This is later assessed objectively as being dyspnea secondary to an increased work of breathing due to a defined underlying cause. Secondly auscultation of the lungs reveals adventitious sounds indicating either reduced airflow (decreased or diminished breath sounds), fluid in the alveoli (crackles), secretions in the bronchi (rhonci), rubbing of pleural space (pleural friction rub) or narrowing of the air passages (wheezing or stridor). Thirdly cough is produced as a result of compromised airflow with or without accumulation of secretions. Sputum of varying colors may be produced (darker pigments reveal infection while lighter sputum reveals inflammatory cells), blood may also be produced. Increased cough may be a sign of a bacterial infection in the lining of the airway (acute bronchitis) or as a result of decreased or ineffective cilia (chronic bronchitis).

Other symptoms of respiratory disease include:

·  Tachypnea= respiratory rate greater than 20 but depends on age. Caused as a result of hypoxemia, pain from displaced pleural pressure, infiltrative processes in the lung, decreased FRC or compensating acidosis. Increased rates may also be caused by fever, being anxious, having pain, emotional distress, or exercise. You must decide if the tachypnea is from a pathological condition or less intrusive means.

·  Cyanosis = A bluish color of the skin and the mucous membranes due to insufficient oxygen in the blood. For example, the lips may show cyanosis. Cyanosis can be evident at birth, as in a "blue baby" who has a heart malformation that permits blood that is not fully oxygenated to enter the arterial circulation. Cyanosis can also appear at any time later in life. The blue discoloration of cyanosis is seen most readily in the beds of the fingernails and toenails, and on the lips and tongue. It often appears transiently as a result of slowed blood flow through the skin due to the cold. As such, it is not a serious symptom. However, in other cases cyanosis is a serious symptom of underlying disease or a chronic symptom as in COPD.

·  Cough = A normal reflex that clears the lung of debris or retained secretion. The character and frequency of the cough may indicate pathology. Asthma often presents with a cough due to inflammation and increased production from goblet cells. Other common conditions with cough include: TB (hemoptysis), bronchitis. Bronchiactasis, emphysema and lung cancer (hemopysis). The amount, color, and consistency of sputum produced from cough are important. For example: Yellow, Green and brownish indicate a bacterial infection whereas white/clear sticky (Mucoid) sputum represents inflammatory cells such as in Asthma.

·  Tachycardia = HR greater than 100 but depends on age. May result from benign origins such as exercise, excitement or agitation. It may be caused from cardiac disease such as artrial fibrillation/flutter, cardiac myopathy or supraventricular tachycardia. It may also present in the presence of hypoxia/hypoxemia from pulmonary or other disease.

·  Dyspnea= A breathlessness condition caused by numerous factors. Normal dyspnea may occur after exercise as oxygen demand increases; or at high altitudes with less barometric pressure or from anxiety. It may occur from anemia, kidney failure (kussmauls) obstructive or restrictive lung disease, cardiac disease or other pulmonary impairment. Types include orthopnea which occurs as fluid in or around the lung shifts as the person lays flat causing a short of breath feeling. Dyspnea with mild exercise may indicate pulmonary disease.

·  Chest Pain= May arise from the heart, indigestion, pleura or in the lung itself. For example: heart attack occurs as the myocardium is deprived of oxygen and nutrients causing a crushing sensation felt into the arms and neck. Chest pain on inspiration or cough may be caused by problems inside the lung such as with pneumonia or tumor or within the pleural space as in pleurisy or pleural effusion. Indigestion occurs in the epigastria area and should not be confused with myocardial pain.