• Obstructive airway diseases (↑ resistance to airflow):
  • Asthma
  • Chronic obstructive pulmonary disease (COPD)
  • Bronchitis
  • Bronchiectasis
  • Cystic fibrosis
  • Emphysema
  • Tumor
  • Foreign body
  • Vocal cord dysfunction,
  • Anaphylaxis
• Restrictive lung diseases:
  • Interstitial lung diseases (e.g., pulmonary fibrosis, sarcoidosis)
  • Obesity hypoventilation syndrome
  • Chest wall/diaphragm:s - ↑ resistance to expansion
• Infections:
  • Pneumonia
  • Tuberculosis
• Pulmonary vascular diseases:
  • Pulmonary embolism
  • Pulmonary hypertension
  • Tumor emboli
  • Pulmonary artery vasculitis
• Pleural diseases:
  • Pleural effusion
  • Pneumothorax
  • Pleural fibrosis
• Other:
  • Acute respiratory distress syndrome (ARDS)
  • Foreign body aspiration
  • Pulmonary edema: cardiogenic or noncardiogenic
  • Atelectasis

• Heart failure (left or right-sided)
• Acute coronary syndrome or myocardial infarction
• Valvular heart disease (e.g., aortic stenosis, mitral regurgitation)
• Pericardial diseases (e.g., pericarditis, cardiac tamponade)
• Arrhythmias (e.g., atrial fibrillation, tachycardia)

 

3.

• Anemia
• Carbon monoxide poisoning
• Methemoglobinemia

 

• Neuromuscular diseases (e.g., myasthenia gravis, Guillain-Barré syndrome)

• Neuromuscular disorders (ALS, GBS, MG)

  Chest wall (↑ resistance to expansion; weakness of respir. muscles)

• Diaphragmatic paralysis

 

• Kyphoscoliosis
• Abdominal Swelling

Diaphragmatic paralysis occurs when the diaphragm cannot contract normally because the phrenic nerve or its neuromuscular pathway is damaged. The diaphragm itself is usually normal — the problem is almost always nerve injury, compression, or neuromuscular disease.

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🫁 Core Causes of Diaphragmatic Paralysis

Below are the major categories, each beginning with a Guided Link so you can explore any cause further.

1. Phrenic nerve injury — the most common cause

Damage to the phrenic nerve (C3–C5) disrupts the diaphragm’s motor supply.
Common mechanisms include:

• Cardiothoracic surgery (up to 27% of cardiac procedures may injure the nerve) UpToDate
• Neck trauma — penetrating, blunt, or even severe stretch injuries (e.g., heavy lifting with neck strain) pmc.ncbi.nlm.nih.gov
• Surgical trauma during cervical or thoracic procedures cedars-sinai.org

2. Cervical spinal cord injury

High cervical injuries can interrupt phrenic nerve output.

• Up to 75% of cervical spinal cord injuries may lead to diaphragmatic paralysis. UpToDate

3. Compression of the phrenic nerve

Anything that presses on the nerve can impair function:

• Lung cancer or mediastinal tumors
• Enlarged lymph nodes
  These can physically compress the nerve. pennmedicine.org

4. Neuromuscular diseases

These weaken the nerve or muscle:

• ALS
• Multiple sclerosis
• Muscular dystrophy
  These conditions increase vulnerability to diaphragm paralysis. pennmedicine.org

5. Neuropathic illnesses

Systemic diseases that damage peripheral nerves:

• Thyroid disease
• Autoimmune disorders
• Guillain‑Barré syndrome
  These can impair phrenic nerve conduction. pennmedicine.org

6. Idiopathic causes

In 40–50% of cases, no clear cause is found.
Often suspected:

• Viral neuropathy
• Neuralgic amyotrophy (Parsonage‑Turner syndrome)
  columbiasurgery.org

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🧠 How These Causes Lead to Paralysis

Regardless of the underlying condition, the mechanism is similar:

1. Phrenic nerve fails to deliver motor signals
2. Diaphragm cannot contract → moves paradoxically or not at all
3. Lung expansion decreases → reduced ventilation and lung volumes

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🩺 Visual Overview

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🧩 Summary Table

Cause	Mechanism	Key Evidence
Phrenic nerve injury	Direct trauma or surgical damage	Cardiac surgery injury up to 27% UpToDate
Cervical spinal cord injury	Disruption of motor pathways	Up to 75% develop paralysis UpToDate
Compression by tumors	Mechanical pressure on nerve	Lung cancer/lymph nodes compress nerve pennmedicine.org
Neuromuscular disease	Weakness of nerve or muscle	ALS, MS, muscular dystrophy implicated pennmedicine.org
Neuropathic illness	Peripheral nerve dysfunction	Thyroid disease, autoimmune disease, GBS pennmedicine.org
Idiopathic	Unknown; often viral or neuralgic	40–50% idiopathic cases columbiasurgery.org

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🔍 Want to go deeper?

Would you like to explore:

• How diaphragmatic paralysis is diagnosed
• Unilateral vs bilateral paralysis differences
• How diaphragmatic paralysis affects anesthesia

 

• Anxiety or panic disorders
• Hyperventilation syndrome

 

6.

• Diabetic ketoacidosis
• Lactic acidosis
• Hypothyroidism or hyperthyroidism

 

 

• Obesity
• Deconditioning or physical inactivity
• Drug-induced (e.g., beta-blockers, chemotherapy agents)
• High altitude or hypoxia
• Toxic exposures (e.g., smoke inhalation, allergens)

 

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