Case 70 - postherpatic neuralgia

Question 1

What is postherpatic neuralgia (PHN)?

Answer 1

• chronic pain syndrome
• develops after acute outbreak of varicella-zoster virus - shingles
• reactivation of dorant virus in DRG –> pain and characteristic rask in one or more dermatome distribution

Question 2

What are the clinical manifestations of PHN?

Answer 2

• sharp or burning pain over distribution of thoracic, cervical, or trigeminal nerve –> in area of resolved rash
• may experience allodyina –> pain to nonnoxius stimuli

Question 3

How can you prevent PHN?

Answer 3

• vaccination –> most effective preventive measure
• antiviral agents
• TCA
• gabapentin
• paravertebral block
• stellate ganglion block

Question 4

Patient develops rash followd by PHN? Prevention is unsuccessful, and now he is miserable and experiecing severe pain. How will you treat this?

Answer 4

first line therapy

• TCA, gabapentin, topical lidocaine 5% patches

Second line

• Opioids, topical capsaicin