Calcific Tendonitis and Parsonage-Turner Syndrome

There are a few uncommon shoulder conditions that might mimic more typical orthopedic conditions and could trip you up on the exam. Even though you may not see very many of these patients in the clinic, we would expect them to show up on the OCS. Today we cover calcific tendonitis and Parsonage-Turner Syndrome and how to distinguish them from more common conditions and from each other.

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Transcript

Hello and welcome back. This week, we’re continuing our shoulder series, and I want to start with a practice question.

A 44-year-old male presents to an outpatient clinic with a referral for treatment of R shoulder pain from his primary care physician. He reports that 3 weeks ago he woke up in the night with severe burning pain in the top and back of his R shoulder and into his R upper arm. Since then, the pain has slowly decreased, but he is now having trouble using his R arm for his work as a carpenter—especially reaching overhead. He denies any history of shoulder pain or any specific mechanism of injury, but he figures he must have "slept on it wrong." He reports that he had been in bed a lot the week prior as he had the flu. He now reports 3/10 pain localized to his right superior and posterior shoulder that he reports is constant but worse at night. On visual observation of the shoulder, you note decreased muscle mass in the supraspinous fossa and infraspinous fossa as well as right scapular winging. His right shoulder elevation AROM is limited to 80 degrees and is characterized by excessive scapular elevation and decreased upward rotation. He has normal cervical and elbow AROM. Manual muscle testing reveals weakness in shoulder external rotation, flexion, and abduction with a positive external rotation lag sign and drop arm test. Further examination reveals slight decreased sensation over the lateral upper arm, but normal upper limb tension testing. What is the most likely diagnosis for this patient?

A. rotator cuff tear 
 B. thoracic outlet syndrome
 C. Parsonage-Turner syndrome
 D. cervical radiculopathy

If this case has you scratching your head, that’s totally reasonable: there are different portions of this case that fit any of the available answers. That’s because the correct answer can masquerade as several other conditions. The answer is C, Parsonage-Turner syndrome, and by the end of the episode, you’ll clearly understand why.

The goal today is to cover two pretty rare conditions. The OCS *loves* rare and uncommon conditions. If there’s an obscure orthopedic condition with a confusing name that mimics a more common orthopedic condition, you can bet it will show up on the exam. 

So today we’re talking about calcific tendonitis and Parsonage-Turner syndrome. Both of these present with severe shoulder pain that can be insidious in nature, and both can mimic other common conditions.

First, let’s talk about calcific tendonitis. The etiology of calcific tendonitis is not well understood. However, we know that in this condition, tenocytes in the rotator cuff tendon transform into chondrocytes and start laying down calcium deposits in the tendon. After a while, the chondrocytes stop their activity, phagocytes infiltrate the area, and angiogenesis and remodeling occurs that restores the tendon to its normal state. I should mention that, because this process has more to do with chondrocytes than inflammation, you may see this condition called calcific tendinopathy. I think that’s a reasonable change, but for now, I’m sticking with calcific tendinitis because it is more common, and because it is less of a mouthful.

The condition typically affects individuals between 40 and 60, and women seem to be more affected than men. It seems to have no connection to any upper extremity activity like overhead throwing. Instead, it’s been suggested that it may be connected to metabolic conditions or genetic predisposition. The condition can affect any rotator cuff tendon or multiple tendons at once, but the most commonly affected tendon is the supraspinatus.

Patients who have calcific tendonitis will present with severe, spontaneous shoulder pain of insidious onset that tends to be worse in the morning. The pain is often in the anterior shoulder near the bicipital groove or in the posterior shoulder inferior to the spine of the scapula. Patients may experience a loss of active and passive range of motion that can trick you into a misdiagnosis of adhesive capsulitis. They may also present with rotator cuff weakness.

There are two signs that should help you distinguish calcific tendonitis from adhesive capsulitis. First, calcific tendonitis is typically worse in the morning; adhesive capsulitis is typically worse at night. Second, adhesive capsulitis tends to follow a capsular pattern of restriction, specifically with increased loss of external rotation at greater degrees of shoulder abduction.

To confirm that you’re dealing with calcific tendonitis and not adhesive capsulitis, imaging can help. The calcific deposits can be seen with ultrasound, radiographs, and MRI—with radiograph being the most commonly recommended.

If the location of the pain is anterior, near the bicipital groove, you might be mildly thrown off in suspecting biceps tendinopathy. But remember: biceps tendinopathy should not present with range of motion impairments.

Because calcific tendonitis spontaneously resolves, conservative treatment is going to be focused either on symptom modulation, functional improvement, or speeding up the resorptive process. Extracorporeal shockwave therapy has been shown to be effective in several studies. Additionally, steroid injections and percutaneous needling—where lidocaine is injected and the calcific material is aspirated—have both been helpful in some studies. Notably, iontophoresis with acetic acid was no more effective than placebo in one study, so right now, evidence does *not* favor iontophoresis.

So to summarize: calcific tendonitis starts and resolves spontaneously. It affects those in their 40s-60s and affects women somewhat more than men. Pain is insidious and severe, and it’s often worse in the morning. Patients may present with limited range of motion and rotator cuff weakness. Ultrasound, radiographs, and MRI are all good imaging options for ruling in calcific tendonitis. And effective treatments include extracorporeal shockwave therapy, steroid injections, and percutaneous needling—but not iontophoresis.

Okay, let’s talk about Parsonage-Turner Syndrome next. Parsonage-Turner syndrome is another condition with an unclear etiology. It’s also called idiopathic brachial plexopathy, brachial neuritis, or neuralgic amyotrophy—not to be confused with *hereditary* neuralgic amyotrophy, which is different. As you can tell from the alternative names, this condition has to do with nerve and brachial plexus-related pain.

Although the etiology is unclear, Parsonage-Turner syndrome seems to be an autoimmune response that occurs following infection, vaccination, or surgery. It’s more common in men than in women. The condition presents with constant, severe unilateral shoulder girdle pain that     usually worse at night and may disturb sleep. The pain can extend into the traps, shoulder, upper arm, lower arm, and/or the hand. There are no constitutional symptoms associated with the syndrome. The condition is self-limiting, and the pain usually resolves in 1-2 weeks. Although the severe pain is often the primary symptom, because this is a neural condition, patients will often have progressive weakness, reflex changes, and sometimes sensory changes as well. Depending on the extent of the nerve injury, these symptoms—particularly the weakness—can last beyond the initial 1-2 weeks of pain.

You can see how some of these symptoms might mimic some other conditions. The neuro signs should help you rule out any purely muscular, tendinous, or capsular pathology. Because Parsonage-Turner affects the brachial plexus, it can mimic cervical radiculopathy or neurogenic thoracic outlet syndrome. The disabling, constant pain and a negative cervical screen and radiculopathy cluster should help you rule out cervical radiculopathy. Similarly, constant pain and negative thoracic outlet syndrome tests should help rule thoracic outlet syndrome out, since neurogenic thoracic outlet syndrome is typically associated with postures, positions, or activities.

To confirm the diagnosis, imaging is not very helpful. However, electrodiagnostic EMG can help confirm Parsonage-Turner Syndrome.

As far as treatment is concerned, because the pain starts and resolves spontaneously—usually within days or just a couple weeks—rehab is mostly focused on restoring strength. The syndrome is thought to be an axonal condition, so it can cause some significant denervation of the affected muscles. Very detailed manual muscle testing is going to be important to recognize weakness and identify impairments.

In wrapping up, I want to go back and revisit hereditary neuralgic amyotrophy. I said that Parsonage Turner syndrome, which is just plain neuralgic amyotrophy, is different from the hereditary variety. The key, clearly, is that hereditary neuralgic amyotrophy is genetic. But it can also present a little differently. It similarly affects the brachial plexus with sudden, severe pain and muscle loss. However, the hereditary variety can present with repeated episodes of this process, it can be unilateral or bilateral, and the episodes can last from hours to weeks. So the symptoms are similar to Parsonage-Turner syndrome, but the etiology and episodic nature are different.

Now before we wrap up, I want to compare and contrast these two conditions to help you recognize them in the clinic and on the exam. Both can present as insidious, severe, and sometimes debilitating shoulder pain. However, Parsonage-Turner syndrome is usually connected to some kind of trauma, like infection, vaccination, or surgery. Calcific tendonitis pain tends to be worse in the morning. Parsonage-Turner pain tends to be constant and worse at night. Calcific tendonitis pain is usually located at the anterior or the posterior shoulder, but Parsonage-Turner syndrome can follow any brachial plexus distribution, including pain down the arm and even into the hand. Calcific tendonitis sometimes presents with loss of active and passive range of motion. Parsonage-Turner might present with loss of active range of motion due to muscle weakness, but passive range of motion will be unaffected. Calcific tendonitis should not have any associated neuro signed; Parsonage-Turner may have reflex and sensory changes, and eventually can present with muscle atrophy. So although these conditions are similar in their severity and insidious nature, the rest of their presentation and symptoms are quite different.

So think back to the case at the beginning of the episode. We have a case of insidious shoulder pain following a bout with the flu. The pain was constant and worse at night. After a couple weeks, the pain mostly resolved, but then he started noticing motor and sensory disturbances, and you have visual evidence of atrophy. All of this together should point you toward Parsonage-Turner syndrome.

We’re going to wrap up there. If you need a quick cheat sheet for recognizing these two diagnoses, we’ve got one on our Patreon. While these conditions can be tough to catch you’re not looking for them, you should now be able to recognize them on the exam. Thank you all for listening, and we’ll look forward to next time.