What is the initial approach to treating a patient with neurogenic cough?

Initial Approach to Treating Neurogenic Cough

The initial approach to treating neurogenic cough should follow a stepwise multimodal approach, beginning with neuromodulators with or without cough suppression therapy, followed by superior laryngeal nerve (SLN) block, and finally laryngeal botulinum toxin injections if needed. 1

Diagnosis and Initial Evaluation

• Neurogenic cough is defined as a cough persisting longer than 8 weeks that is refractory to standard therapy and is a diagnosis of exclusion 1
• Before diagnosing neurogenic cough, common causes must be ruled out:
  • Asthma, GERD, and upper airway cough syndrome 2
  • Medication side effects (particularly ACE inhibitors) 2
  • Smoking-related causes 2
• A chest radiograph should be obtained to rule out significant pathology 2
• Spirometry should be performed in all patients with chronic cough 2

Treatment Algorithm for Neurogenic Cough

Step 1: Neuromodulators and Cough Suppression Therapy

• First-line treatment should be neuromodulating medications, which have shown a response rate of approximately 75% 1
• Options include:
  • Gabapentin - effective for treating neuropathic cough 3
  • Amitriptyline - shown efficacy in treating neuropathic cough conditions 3
  • Guanfacine - case reports show successful treatment of refractory neurogenic cough 4
• Cough suppression therapy may be used alone or in combination with neuromodulators 1

Step 2: Superior Laryngeal Nerve (SLN) Block

• For patients who fail to respond to neuromodulators, SLN block should be considered 1, 5
• The procedure involves injecting a mixture of long-acting corticosteroid and local anesthetic 6
• Response rates of approximately 70% have been reported 5
• Benefits can be seen after a single injection in most responders (84.2%) 5
• Patients who fail the first injection may still benefit from a second attempt (40% response rate in initial non-responders) 5

Step 3: Laryngeal Botulinum Toxin Injections

• For patients who fail both neuromodulators and SLN block, laryngeal botulinum toxin injections should be considered 1
• Response rate of approximately 66% has been reported in patients who failed previous therapies 1

Monitoring and Follow-up

• Patient-reported improvement in cough symptoms should be assessed using a standardized scale 1
• The Cough Severity Index (CSI) can be used to objectively measure response to treatment 6
• Expect varying degrees of improvement:
  • Complete resolution in approximately 10% of patients 1
  • Significant improvement in approximately 40% of patients 1
  • Moderate improvement in approximately 33% of patients 1
  • Mild improvement in approximately 17% of patients 1

Common Pitfalls to Avoid

• Failing to rule out common causes of chronic cough before diagnosing neurogenic cough 2
• Stopping at one treatment modality when a stepwise approach shows better outcomes 1
• Not considering repeat SLN blocks in patients who fail initial injection 5
• Overlooking the neuropathic basis of chronic cough, which explains why traditional cough treatments may fail 3

Special Considerations

• Neurogenic cough is thought to be related to sensory neuropathy in the hypopharynx and larynx 1
• It represents a form of cough hypersensitivity syndrome with neuropathic features 3
• Patients often describe sensory symptoms suggestive of upper airway and laryngeal neural dysfunction 3
• No specific clinical factors have been identified as predictors of response to SLN block, suggesting a broad range of patients may benefit from this intervention 5