What is the cause of paresthesia in a 36-year-old male with a history of IV drug use and recent discontinuation of amitriptyline (Elavil) due to adverse effects with Effexor (venlafaxine)?

From the Guidelines

The patient's symptoms suggest possible peripheral neuropathy or ulnar nerve entrapment, and I strongly recommend adding nerve conduction studies to evaluate for ulnar neuropathy or cervical radiculopathy, in addition to the already ordered laboratory tests, to determine the underlying cause of his symptoms. The tingling in the 4th and 5th fingers (ulnar nerve distribution), reduced grip strength, and pain radiating from the shoulders are concerning. Given his history of IV drug use, there are multiple potential causes including nerve compression, nutritional deficiencies, or infectious complications. The ordered laboratory tests (CBC, CMP, A1C, TSH, B12) are appropriate to evaluate for metabolic causes such as diabetes, thyroid dysfunction, and vitamin deficiencies. Discontinuing amitriptyline was reasonable due to potential drug interactions with Effexor, as cautioned against in the use of serotonergic drugs, especially when combining with other medications or substances that may increase the risk of serotonin syndrome, as noted in 1.

Physical examination should include assessment of muscle strength, deep tendon reflexes, and sensation in the affected limbs. Consider referral to neurology if symptoms persist after initial workup. Pain management could include acetaminophen or NSAIDs if not contraindicated. Patient education about proper sleeping position to avoid nerve compression and stretching exercises for the neck and shoulders may provide symptomatic relief while awaiting diagnostic results and follow-up in two weeks. It is essential to monitor the patient's symptoms and adjust the treatment plan accordingly, taking into account the potential for discontinuation syndrome when stopping or changing antidepressant medications, as discussed in 1.

Key considerations in the patient's management include:

• Monitoring for symptoms of serotonin syndrome, especially when combining serotonergic drugs
• Gradually increasing or decreasing doses of medications to minimize the risk of discontinuation syndrome
• Regular assessment of treatment response and adjustment of the medication regimen as needed
• Patient education on proper medication use, potential side effects, and the importance of follow-up appointments.

From the Research

Patient Symptoms and History

• The patient is a 36-year-old male with complaints of tingling in his left 4th and 5th fingers.
• He reports walking and jogging daily, with pain originating from the shoulders at night.
• The patient has limited grip strength, only using his 1st, 2nd, and 3rd fingers.
• He has a history of heavy IV drug use and was previously taking amitriptyline, which was discontinued due to adverse effects with Effexor.

Potential Causes and Treatments

• The patient's symptoms may be related to lumbar radiculopathy or subacromial impingement syndrome, as suggested by studies 2, 3, 4.
• Gabapentinoids, such as pregabalin and gabapentin, have been shown to be effective in reducing pain in patients with lumbar radiculopathy 2, 3, 5.
• However, the effectiveness of these medications may vary depending on the individual patient and the specific condition being treated 6.
• The patient's history of heavy IV drug use may also be a contributing factor to his symptoms, and further evaluation and treatment may be necessary to address this issue.

Diagnostic Tests and Follow-up

• The patient will undergo laboratory tests, including CBC, CHEM, CMP, A1C, TSH, and B12, to rule out any underlying conditions that may be contributing to his symptoms.
• Follow-up appointments will be scheduled to monitor the patient's progress and adjust treatment as necessary.
• Further studies, such as nerve conduction studies, may be necessary to determine the underlying cause of the patient's symptoms and to guide treatment 4.