Diaphragm Disorders Clinical Presentation

Background information is of prime importance when considering dysfunction of the diaphragm. An adequate history is essential to help identify potential causes. Even so, an etiology for diaphragmatic dysfunction is not ascertained in 50-60% of patients. Note the following:

• Congenital hernias: Respiratory distress and/or cyanosis may occur within the first 24 hours of life. If the defect is small enough, patients often remain asymptomatic for years or even decades.
• Traumatic rupture: The acute phase manifests with abdominal pain, concurrent intra-abdominal and intrathoracic injuries, respiratory distress, and cardiac dysfunction. Latent-phase symptoms include gastrointestinal complaints, pain in the left-upper quadrant or chest, pain in the left shoulder, dyspnea, and orthopnea. The gastrointestinal obstructive phase manifests with nausea and vomiting with unrelenting abdominal pain, prostration, and respiratory distress.
• Neurologic causes: Most patients with unilateral paralysis are asymptomatic. Manifestations include mild exertional dyspnea, generalized muscle fatigue, chest wall pain, and resting dyspnea while lying with the paralyzed side down. Symptoms are generally more severe in patients with concomitant lung disease. Bilateral paralysis manifests with shortness of breath, severe exertional dyspnea, and marked orthopnea.^[9] The orthopnea of bilateral diaphragmatic paralysis is dramatic and occurs within minutes after assuming the recumbent position. Orthopnea is associated with tachypnea and rapid, shallow breathing. Patients have a poor quality of sleep, which may cause fatigue. Significant orthopnea sometimes triggers a cardiac workup.

Physical findings upon examination vary depending on the etiology.

Congenital hernia findings are as follows:

• Right-sided heart
• Decreased breath sounds on affected side
• Scaphoid abdomen
• Auscultation of bowel sounds in the thorax

Traumatic rupture findings are as follows:

• Marked respiratory distress
• Decreased breath sounds on affected side
• Palpation of abdominal contents in the chest when inserting a chest tube
• Auscultation of bowel sounds in the chest
• Paradoxical movement of abdomen with breathing

Neurologic causes are as follows:

• Decreased breath sounds
• Generalized or focal neurologic deficits
• Dullness on lower chest upon percussion on the involved side
• Excursion of involved hemithorax decreased compared with healthy side
• Paralysis
• Paradoxical abdominal wall retraction during inspiration (best appreciated on supine position)
• Hypoxemia, secondary to atelectasis-induced ventilation-perfusion mismatch, exacerbated in supine position
• Signs of cor pulmonale are occasionally present

The etiology of diaphragmatic dysfunction is most easily separated into anatomic or neurologic causes.

Anatomic defects are as follows:

• Congenital defects - Bochdalek hernia, Morgagni hernia, eventration of the diaphragm, and diaphragmatic agenesis
• Acquired defects - Traumatic rupture, penetrating injuries, idiopathic etiologies, and iatrogenic responses to surgery or other invasive procedures

Innervation defects are as follows:

• Brain stem stroke
• Spinal cord disorders - Trauma to the cervical spinal cord, syringomyelia, poliomyelitis, anterior horn cell disease, amyotrophic lateral sclerosis, and motor neuron disease
• Phrenic nerve neuropathy^[10] - Trauma to the phrenic nerve from surgery,^[11] radiation,^[12] or tumor; Guillain-Barré syndrome; diabetic, nutritional, and alcoholic neuropathy; vasculitic neuropathy; lead and poison neuropathy; and infection-related nerve injury (eg, diphtheria, tetanus, typhoid, measles, botulism)
• Myasthenia gravis
• Muscular disorders - Myotonic dystrophies, Duchenne muscular dystrophy, and metabolic myopathies
• Idiopathic etiologies
• Postpolio syndrome presenting as isolated diaphragmatic paralysis
• Phrenic nerve injury due to cold cardioplegia during cardiac surgery^[11]
• Thyroid disorders
• Postviral neuropathy
• Connective-tissue disease (eg, systemic lupus erythematosus, rheumatoid arthritis)
• Acid maltase deficiency
• Malnutrition^[13]

Neurologic causes of diaphragmatic paralysis are as follows:

• Spinal cord transaction^[14]
• Multiple sclerosis
• Amyotrophic lateral sclerosis
• Cervical spondylosis
• Poliomyelitis
• Guillain-Barré syndrome
• Phrenic nerve dysfunction
• Compression by tumor
• Cardiac surgery cold injury^[11]
• Blunt trauma^{[15, 16]}
• Idiopathic phrenic neuropathy
• Postviral phrenic neuropathy
• Radiation therapy^[12]
• Cervical chiropractic manipulation^[17]

Myopathic causes of diaphragmatic paralysis are as follows:

• Limb-girdle dystrophy
• Hyperthyroidism or hypothyroidism
• Malnutrition
• Acid maltase deficiency
• Connective-tissue diseases
• Systemic lupus erythematosus
• Dermatomyositis
• Mixed connective-tissue disease
• Amyloidosis
• Infection
• Herpes zoster
• Idiopathic myopathy