Brachial Neuritis (Parsonage-Turner Syndrome)

What happens in brachial neuritis

The brachial plexus is formed by nerve roots from the lower neck (C5 to T1). In brachial neuritis, the immune system inflames parts of this network or individual nerves branching from it. The cause is thought to be an autoimmune reaction, often triggered by a recent event, in someone with a susceptibility.

It is uncommon but likely underdiagnosed, and is often first mistaken for a rotator cuff problem, frozen shoulder or a pinched neck nerve.

Symptoms

Phase 1: pain

• sudden, severe, sharp or burning pain in the shoulder, upper arm, shoulder blade or neck
• often begins at night and wakes the person
• usually on one side, though both sides can be affected
• standard pain medicines help little
• lasts from days to a few weeks

Phase 2: weakness

As pain improves, weakness becomes apparent, usually within days to 2 weeks:

• difficulty lifting the arm, rotating the shoulder, or bending the elbow
• winging of the shoulder blade (the long thoracic nerve is commonly affected)
• muscle wasting around the shoulder
• patches of numbness or tingling in the arm or hand, usually mild compared with weakness
• in some people, weakness of the hand (anterior interosseous nerve), causing difficulty with a pinch grip

Breathlessness

The phrenic nerve, which controls the diaphragm, can be affected. This causes shortness of breath, especially when lying flat, bending forward or in water, and poor sleep. Anyone with brachial neuritis who becomes breathless should be assessed for diaphragm weakness.

Triggers and causes

In about half of cases, a trigger occurs in the days to weeks before:

• viral or bacterial infections
• vaccinations
• surgery, including operations unrelated to the arm
• pregnancy and childbirth
• unusually strenuous exercise
• trauma
• autoimmune conditions

Hereditary neuralgic amyotrophy is a rare inherited form, often linked to SEPT9 gene changes, which causes recurrent attacks, sometimes with distinctive facial features such as closely spaced eyes.

Brachial neuritis vs common look-alikes

Diagnosis

1. History and examination: the sequence of severe pain followed by patchy weakness in nerves of the brachial plexus is highly suggestive.
2. EMG and nerve conduction studies: best done 3 to 4 weeks after onset, they show which nerves are damaged and rule out other conditions.
3. MRI of the neck and brachial plexus: to exclude disc problems, tumors or other compressive causes. MRI may show swelling of the affected nerves or changes in muscles.
4. Breathing tests: chest X-ray, ultrasound of the diaphragm or lung function tests if the phrenic nerve may be affected.
5. Blood tests: to look for other causes such as diabetes, inflammation, or recent infection like hepatitis E.

Treatment

There is no proven cure, but treatment focuses on pain control and recovery of function:

• Pain relief: NSAIDs, nerve pain medicines (gabapentin, pregabalin, amitriptyline), and short-term stronger painkillers if needed.
• Corticosteroids: a short course of oral steroids in the first weeks may shorten pain and possibly speed recovery, based on limited evidence.
• Physical and occupational therapy: maintaining range of motion to prevent a frozen shoulder, then strengthening and retraining shoulder blade control as nerves recover. Overdoing exercise early can worsen symptoms.
• Braces for a winging shoulder blade in some cases.
• Surgery: nerve or tendon transfers for people who do not recover after a long period.
• Breathing support: for significant diaphragm weakness, including noninvasive ventilation at night in rare cases.

Outlook

Pain usually subsides within weeks. Nerves regrow slowly, about 1 mm a day, so strength returns gradually over months to 2 to 3 years. Many people recover most function, but a substantial minority have lasting weakness, reduced endurance or shoulder pain from altered mechanics. Recurrence is uncommon in the non-inherited form but frequent in the hereditary form.

Frequently asked questions

What are the symptoms of brachial neuritis?

It usually starts with sudden, severe pain in the shoulder and upper arm, often at night. Within days to weeks, the pain eases and weakness appears, with difficulty lifting the arm, winging of the shoulder blade, muscle wasting and sometimes numbness. Some people become breathless if the diaphragm nerve is involved.

Can brachial neuritis cause breathlessness?

Yes. If the phrenic nerve is affected, the diaphragm weakens, causing shortness of breath, especially when lying flat or bending. This can be missed, so mention any breathlessness to your doctor, who may arrange a chest X-ray, ultrasound or breathing tests.

How long does brachial neuritis take to recover?

Pain typically settles in a few weeks. Strength returns slowly as nerves regrow, often over 6 months to 3 years. Most people regain much of their function, but some have lasting weakness.

What causes Parsonage-Turner syndrome?

It is thought to be an immune attack on the brachial plexus nerves, often triggered by infection, vaccination, surgery, childbirth or strenuous exercise. A rare inherited form causes repeated attacks.

Is brachial neuritis the same as a pinched nerve?

No. A pinched nerve in the neck is caused by compression, usually from a disc or arthritis, and is typically worse with neck movement. Brachial neuritis is inflammation of the nerves in the shoulder region without compression, and it causes more prominent weakness and wasting.