Dyspnoea

Original Editor - Safiya Naz Memon

Top Contributors - Safiya Naz, Kim Jackson and Lucinda hampton

Introduction

Dyspnoea/ dyspnea also known as shortness of breath or breathlessness, is a subjective awareness of the sensation of uncomfortable breathing.
.it is a sensation of running out of the air and of not being able to breathe fast enough or deeply enough Dyspnoea is a subjective sensation which probably develops as a result of integration of signals from the central nervous system and some peripheral receptors. Known dyspnoegenic stimuli include the sensation of an increased effort of the respiratory muscles, information from chemoreceptors on the inadequacy of ventilation, from pulmonary receptors on the compression of the airways and disharmony between information on the tension of the respiratory muscles and the corresponding shortening of the muscle.Dyspnea represents one of the most frequent cardinal symptoms in general practice and interdisciplinary emergency care across all sectors

Mechanism

There is no universal theory that explains the mechanism of dyspnea in all clinical situationsIn the 1960s Campbell and Howell first introduced the theory of "length-tension appropriateness" to explain the sensation of dyspnea originating from the inappropriate response of the respiratory system to the outgoing motor command More recently this theory has been redefined and a mechanism based on a neuro-ventilatory dissociation has been proposed.The sensation of dyspnea seems to originate with the activation of sensory systems involved in respiration. Sensory information is, in turn, relayed to higher brain centers where central processing of respiratory-related signals and contextual, cognitive and behavioral influences shape the ultimate expression of the evoked sensation. The homeostatic systems involved in the regulation of respiration provide a framework for understanding the mechanisms of dyspneaAwareness of respiratory sensation can occur in normal situations. Dyspnea is a heightened level of awareness of respiratory sensation and has a strong emotional component. The neural basis of dyspnea is therefore likely to involve activation of both the cortex and the limbic system Healthy subjects can experience dyspnea in different situations, e.g. at high altitude, after breath-holding, during stressful situations that cause anxiety or panic, and more commonly during strenous exercise.Many factors play an important role in the mechanisms of dyspnea: functional status or respiratory muscles, mechanical and chemical afferents, central motor output.

Types

Orthopnea

is the sensation of breathlessness in the recumbent position, relieved by sitting or standing.

Paroxysmal nocturnal dyspnea (PND)

is a sensation of shortness of breath that awakens the patient, often after 1 or 2 hours of sleep, and is usually relieved in the upright position.

Trepopnea

is dyspnea that occurs in one lateral decubitus position as opposed to the other.

Platypnea

refers to breathlessness that occurs in the upright position and is relieved with recumbency.

Clinical Presentation

Some characteristics of breathlessness with different disorders; these are guidelines only, and patients vary Disorder..

COPD Asthma Interstitial lung disease Pneumonia Pneumothorax Hyperventilation Pulmonary oedema Neuromuscular Deconditioning Obesity/pregnancy

Slow onset Episodic, on exhalation Progressive, exertional Exertional Moderate/severe Air hunger, not relieved by rest Positional, on inhalation Exertional, on inhalation Heavy Exertional

Diagnostic Procedures

History Examination

A patient with dyspnea may say: "I feel short of breath," "I"m having difficulty breathing," "I can"t catch my breath," "I feel like I"m suffocating." Because it is a subjective phenomenon, the perception of dyspnea and its interpretation vary from patient to patient. Begin with a nonleading question: Do you have any difficulty breathing? If the response is affirmative and dyspnea is established as a problem, it should be characterized in detail. When did it begin? Has the onset been sudden or insidious? Inquire about the frequency and duration of attacks. The conditions in which dyspnea occurs should be ascertained. Response to activity, emotional state, and change of body position should be noted. Ask about associated symptoms: chest pain, palpitations, wheezing, or coughing. Sometimes a nonproductive cough may be present as a "dyspnea equivalent." What other significant medical problems does the patient have, and what medications has he been taking? How much has he smoked?

Additional questions should be aimed at ascertaining whether the patient has orthopnea or paroxysmal nocturnal dyspnea. Inquire about the number of pillows he uses under his head at night and whether he has ever had to sleep sitting up. Does he develop coughing or wheezing in the recumbent position? Did he ever wake up at night with shortness of breath? How long after lying down did the episode occur, and what did he do to relieve his distress? Characteristically, the patient with left ventricular failure sits up at bedside, dangles his feet, and refrains from ambulation or other activity that is likely to worsen his symptoms

Physical Examination

physical exam should begin with a rapid assessment of the ABCs (airway, breathing, and circulation). Once a patient is determined to be stable, a full physical exam can be done. To determine the severity of dyspnea, observe respiratory effort, use of accessory muscles, mental status, and speaking ability. Distention of the neck veins implies cor pulmonale caused by severe COPD, congestive heart failure, or cardiac tamponade. Thyromegaly may indicate hyperthyroidism or hypothyroidism. The tracheal deviation may indicate possible anatomic abnormality or pneumothorax. Auscultate for stridor in the upper airways indicates obstructed airway. Palpation of the chest can determine the presence of subcutaneous emphysema or crepitus. Percussion of the lung lobes for dullness can determine the presence or absence of consolidation and effusion. Hyperresonance on percussion is a worrisome finding that indicates possible pneumothorax or severe bullous emphysema. Lung auscultation may reveal absent breath sounds indicating the presence of pneumothorax or region occupying mass such as pleural effusion or malignancy. The presence of wheezing is highly consistent with the diagnosis of an obstructive lung disease such as asthma or COPD.  However, wheezing may be associated with pulmonary edema or pulmonary embolism. Pulmonary edema and pneumonia may present with rales on auscultation. Auscultation of the heart may reveal the presence of dysrhythmia, cardiac murmurs, or aberrant heart gallops. An S3 gallop indicates cardiac overfilling seen in left ventricular systolic dysfunction and congestive heart failure. An S4 gallop suggests left ventricular dysmotility and dysfunction. A loud P2 indicates possible pulmonary hypertension. Murmurs may indicate valvular dysfunction. Diminished heart sounds may indicate cardiac tamponade. Pericarditis may present with a rubbing cardiac sound on auscultation. On abdominal examination, hepatomegaly, ascites, positive hepatojugular reflux may indicate the diagnosis of congestive heart failure. Lower extremities edema is associated with congestive heart failure, and extreme swelling of the extremities suggest possible deep venous thrombosis that can lead to a pulmonary embolism. Digits clubbing is present in some forms of lung malignancy or severe chronic hypoxia. Cyanosis of the extremities indicates hypoxia.

Differential Diagnosis

Dyspnea is a symptom of the disease, rather than a disease itself. As such, its etiology can be designated as arising from four primary categories: respiratory, cardiac, neuromuscular, psychogenic, systemic illness, or a combination of these.

Respiratory causes may include asthma, acute exacerbation of or chronic congestive obstructive pulmonary disorder (COPD), pneumonia, pulmonary Embolism, lung malignancy, pneumothorax, or aspiration.

Cardiovascular causes may include congestive heart failure, pulmonary edema, acute coronary syndrome, pericardial tamponade, valvular heart defect, pulmonary hypertension, cardiac arrhythmia, or intracardiac shunting.

Neuromuscular causes may include chest trauma with fracture or flail chest, massive obesity, kyphoscoliosis, central nervous system (CNS) or spinal cord dysfunction, phrenic nerve paralysis, myopathy, and neuropathy.

Psychogenic causes may include hyperventilation syndrome, psychogenic dyspnea, vocal cord dysfunction syndrome, and foreign body aspiration.

Other systemic illnesses may include anemia, acute renal failure, metabolic acidosis, thyrotoxicosis, cirrhosis of the liver, anaphylaxis, sepsis, angioedema, and epiglottitis

Physiotherapy Management

Dyspnea can be either acute or chronic with acute occurring over hours to days and chronic occurring for more than 4 to 8 weeks.

Acute dyspnea typically is due to a more life-threatening process and requires rapid intervention. All patients should be placed on supplemental oxygen, pulse oximetry, and a cardiac monitor. Then the appropriate therapy should be initiated based on the suspected or diagnosed etiology. If respiratory failure is imminent, there should be a low threshold for intubating patients. Diagnostic workup should be performed only once appropriate, and the patient is stable.

In respiratory disease populations such as COPD, randomized trials have demonstrated that both aerobic (e.g., walking and cycling) and resistance exercise training cause significant reductions in dyspnea demonstrated that supervised exercise training with education and psychosocial support significantly reduced dyspnea and improved disease specific health-related QOL in 1218 patients with COPD. The mechanisms of exercise-induced improvement in dyspnea remain to be fully elucidated but adaptations to peripheral muscle function leading to enhanced extraction and utilization of O₂, which reduces metabolic acidosis and ventilatory demand and improves lung mechanics are likely responsible

Many breathless people automatically assume a posture that eases their breathing, but others need advice to find the position that best facilitates their inspiratory muscles. Patients with a flat diaphragm may benefit from positions that use pressure from the abdominal contents to dome the muscle and provide some stretch to its fibres so that it can work with greater efficiency. The arms are best supported, to optimize accessory muscle function, but without tension or active fixation. Positions to facilitate efficient breathing in breathless people include:

• high side-lying . • sitting upright in a chair with supported arms; for many patients, it is easier to breathe in this position than in bed. Some like to lean back for support, others prefer to lean slightly forward to put some stretch on the diaphragm • sitting leaning forward from the waist, arms resting on pillows on a table, feet on the floor • standing relaxed, leaning forwards with arms resting on a support such as a window sill. • standing relaxed, leaning back against a wall with legs slightly apart. • standing relaxed leaning sideways against a wall, arms in pockets if support is needed for the accessory muscles. • occasionally, lying flat is beneficial because of pressure from the abdominal contents against the diaphragm. A few patients even find a slight head-down tip helpful.

Outcome Measures

In itself, dyspnea is harmless. However, it is a symptom, not an illness.  Therefore, the outcomes is highly variable depending on the exact etiology and patient demographics.