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P. Vaishnava and M. Miller
Pulmonary
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Approach to the Patient with Dyspnea
Eric Barna*
Key Pearls
• In the majority of patients with dyspnea, the root pathophysiology is
usually cardiac or pulmonary in nature.
• Dyspnea requires a thorough history and physical examination to
guide the diagnostic approach and intervention.
• A chest X-ray should be routinely performed. The use of advanced
diagnostic testing should be directed towards specific system
involvement.
• The differential diagnosis for dyspnea is broad, but can be divided
into more common systemic categories of disease processes.
• The hospitalist’s initial approach to the severely dyspneic patient
should involve recognition of the need for advanced airway manage-
ment, potential triage to higher level of monitoring, and early goal-
directed therapy for life-threatening etiologies.
DEFINITION: Dyspnea is multifactorial and complex, and can be
defined as “a subjective experience of breathing discomfort that comprises qualitatively distinct sensations that vary in intensity.”
1
The spectrum of disease that can be embedded into the clinical
presentation of dyspnea is extensive. These disease processes include
287
*Mount Sinai School of Medicine, New York, NY, USA.
26
Chapter
asthma, COPD, interstitial-lung disease and cardiac dysfunction, as well
as conditions beyond the cardiopulmonary system, and represent a large
percentage of patients being admitted to medical services across the
United States.
Pathophysiology
The mechanics of dyspnea rely on a complex set of interactions between
the cerebral cortex and brain stem respiratory center and chemoreceptors.
In order to better understand the physiologic mechanism as it relates to the
clinical perception, it helps to view the respiratory system in three major
functional roles
2–6
:
1) Efferent signaling: Signals that transmit to the muscles of
respiration. This will determine the rate and depth of each breath.
These efferent signals maintain sensitivity to any trigger that stim-
ulates the respiratory centers, e.g. diabetic ketoacidocis, aspirin
toxicity.
2) Ventilatory pump: These are the core anatomic components that
allow for movement of pulmonary gasses; included herein are the
muscles, bones, and luminal components of the airway. Pump failure
may be a result of any disease process, external trigger or environ-
mental factors that disrupt pump function. Examples include
neuromuscular disorders such as Guillain-Barre syndrome, and
myasthenia gravis.
3) Gas exchanger: Created by the anatomic surfaces that allow for
exchange of oxygen and carbon dioxide, namely, pulmonary capillar-
ies, and alveoli. It is at this level where localized impairment of gas
exchanges through surface destruction, inflammation, or barrier for-
mation lead to a sensation classically termed air gulping or air hunger.
Examples include emphysema, pulmonary fibrosis, and congestive
heart failure.
288
E. Barna
Diagnosis
Clinical History
The historical data gathered during the evaluation for dyspnea serves a key
role in allowing the hospitalist to distinguish between pulmonary, cardiac,
neuromuscular, or other root causes. The evaluation of the qualitative
descriptors of dyspnea will aid in identifying plausible pathophysiologic
etiologies (Table 1). The general history should be further tailored for the
dyspneic patient to further elucidate the cause. Table 2 describes the key
features of the medical history that should be emphasized for the dyspneic
patient.
Physical Examination
The physical examination contains many features that can aid the diagnosis as well as assess the severity of dyspnea. Key features include the
following:
289
Approach to the Patient with Dyspnea
Table 1. The Qualitative Descriptor, and Associated Pathophysiologic Mechanism
Descriptor Pathophysiology Disease Process
Chest tightness, or Broncho constriction, Asthma, myocardial
constriction interstitial edema ischemia
Increased work or effort of Obstructive airway disease, COPD, moderate to severe
breathing neuromuscular disease, asthma, myopathy,
reduced chest wall or pulmonary fibrosis
pulmonary compliance
Air hunger, need to breathe, Increased respiratory Heart failure, pulmonary
urge to breathe drive. embolism, moderate to
severe asthma, COPD
Rapid shallow breathing Decreased chest wall or Interstitial fibrosis
pulmonary compliance
Suffocating, smothering Alveolar edema Pulmonary edema
General Appearance
:
• Ability to communicate in full sentences
• Anxious
• Use of accessory muscles
• Cyanotic appearance
Vital Signs
:
• Hypotension
• Tachycardia
• Tachypnea
• Oxygen saturation
Chest
:
• Air entry
• Paradoxical motion of chest wall
290
E. Barna
Table 2. General History for the Dyspneic Patient
Components of General
History Targeting the Dyspneic Patient
General questions Medication compliance, common triggers
of comorbid conditions.
Past medical history Cardiopulmonary comorbid conditions,
prior intubation.
Time course Sudden, gradual
Chest pain Exertional or at rest, substernal or other
location.
Cough and sputum production Purulent, frothy, bloody, non productive
vs. productive.
Medications Medication changes, dosing adjustments,
recent antibiotics.
Social history Tobacco products may point towards a more
chronic process. A clear drug history is also
critical to evaluate for pulmonary effects of
specific inhaled agents.
• Audible wheeze
• Stridor
• Crackles
Cardiac Exam
:
• Jugular venous distention
• Audible murmur
• Audible S3
• Gallop
• Precordial impulse
Extremities
:
• Peripheral edema
• Cyanosis
• Cool and clammy
• Clubbing
Neurologic
:
• Altered mental status
• Focal neurologic deficit
Basic Diagnostic Testing
• Chest X-ray
• Electrocardiogram
• Cardiac enzymes (primary cardiac etiology is suspected)
• Brain natriuretic peptide (primary low cardiac output state suspected)
• Arterial blood gas (not routinely required), but useful when assessing
need for intubation and mechanical ventilation, evaluating complex
metabolic disturbances.
291
Approach to the Patient with Dyspnea
Advanced Diagnostic Testing
• Chest CT with IV contrast: If clinical suspicion of underlying pul-
monary embolism is high and there is no existing contraindication to
IV contrast exposure with respect to renal function, and or allergy.
• High resolution CT scan: For further evaluation of suspected underlying chronic interstitial lung disease.
• Ventilation perfusion scan: To be considered for evaluation of underlying pulmonary embolism, when patient cannot tolerate IV contrast.
• Pulmonary function testing: To better elucidate underlying restrictive
vs. obstructive pulmonary disease.
• 2 Dimensional echocardiography: For further evaluation of suspected
heart failure as root etiology of dyspnea.
• Cardiac catheterization: Left-sided for evaluation of underlying
ischemic disease should primary root pathophysiology point to heart
failure. Right-sided cardiac catheterization for further evaluation if
suspicion of pulmonary hypertension exists.
Differential Diagnosis
The differential diagnosis for the patient presenting with dyspnea is broad.
There are a few core diagnostic groupings that should serve as an initial
template for the approach to the dyspneic patient (Table 3).
Early Management of the Acutely Dyspneic Patient
The cornerstone of initial management of the severely dyspneic patient
relies on identifying and correcting the underlying disease process.
The role of the hospitalist in evaluating the dyspneic patient especially
in the acute setting is to improve the patients overall oxygenation, recognize the need for further advanced management of the airway, and initiate
the appropriate treatment course early on. It is also essential to recognize
the imminent and life-threatening etiologies of dyspnea and address these
concerns rapidly.
292
E. Barna
293
Approach to the Patient with Dyspnea
Table 3. Differential Diagnosis of Dyspnea
Cardiac
• Ischemic heart disease (acute coronary syndrome)
• Congestive heart failure
• Decompensated heart failure with pulmonary edema
• Valvular disease
• Intracardiac shunting
• Arrhythmias
• Cardiac tamponade
Pulmonary
• Asthma (acute exacerbation)
• COPD
• Pulmonary embolism
• Interstitial lung disease
• Pulmonary hypertension
• Pulmonary infection
• Pulmonary hemorrhage
• ARDS
• Pulmonary oncologic process
• Pleural effusion
• Pneumothorax
Neuro/Psychiatric
• Neuromuscular disorders
• Stroke
• Anxiety with or without panic
• Hyperventilation
• Renal tubular acidosis
Key Management Strategies
• Initiate oxygen supplementation.
• Continue to monitor oxygenation closely.
• Recognize the need for advanced airway management, and possible
need for Intensive Care Unit level of care.
• Patients with high clinical suspicion for pulmonary embolism and
without contraindication to systemic anticoagulation should be started
on heparin, while further imaging modalities are secured.