Pearl of the Month

Is carpal tunnel syndrome the tip of the iceberg?


 

A 69-year-old man presents with increasing dyspnea on exertion. He has had recent orthopnea and paroxysmal nocturnal dyspnoea. He has a history of well controlled hypertension and hyperlipidemia. He takes the following medications: felodipine and atorvastatin. On exam, his blood pressure is 110/60 mm Hg, and his pulse is 90 beats per minute.

Dr. Douglas S. Paauw, University of Washington, Seattle

Dr. Douglas S. Paauw

A cardiac examination found normal heart sounds with no murmurs.

A chest examination found dullness to percussion at both bases and rales.

A chest x-ray showed bilateral effusions and mild pulmonary edema.

The brain natriuretic peptide test found a level of 1,300 picograms/mL.

An ECG found increased ventricular wall thickness, an ejection fraction of 32%, and normal aortic and mitral valves.

What history would be the most helpful in making a diagnosis?

A. History of prostate cancer

B. History of carpal tunnel syndrome

C. History of playing professional football

D. History of hyperlipidemia

E. History of ulcerative colitis

The correct answer here would be B. history of carpal tunnel syndrome (CTS). This patient has clinical heart failure, without a history of clinical ischemic disease. The differential diagnosis for causes of heart failure is long, with the most common causes being chronic hypertension and ischemic heart disease. Other common causes include chronic untreated sleep apnea and valvular heart disease.

This patient really does not have clear reasons for having clinical heart failure. His cardiovascular risk factors have been well controlled, and no valvular disease was found on ECG.

Several recent reports have raised the importance of a history of CTS significantly increasing the likelihood of amyloidosis being the cause of underlying heart failure.

CTS is such a common clinical entity that it is easy to not appreciate its presence as a clue to possible amyloid cardiomyopathy. Fosbøl et al. reported that a diagnosis of CTS was associated with a higher incidence of heart failure (hazard ratio, 1.54; CI, 1.45-1.64).1 They found a highly increased risk of amyloid (HR, 12.2) in patients who had surgery for CTS.

Sperry et al. found that over 10% of patients who underwent carpal tunnel release stained for amyloid on biopsy specimens, and that concomitant cardiac evaluation identified patients with cardiac involvement.2

Pinney et al. found that 48% of patients with transthyretin amyloidosis had a history of CTS.3

In a retrospective study of patients with wild-type transthyretin amyloid (253), patients with hereditary transthyretin amyloid (136), and asymptomatic gene carriers (77), participants were screened for a history of spinal stenosis and CTS.4 Almost 60% of the patients with amyloid had a history of CTS, and 11% had a history of spinal stenosis. Patients with CTS and hereditary amyloid had thicker interventricular septums, higher left ventricular mass, and lower Karnovsky index than those without CTS.

The diagnosis of CTS, especially in those who need surgery for treatment or have bilateral disease, should make us consider the possibility of underlying amyloidosis.

Pearl: In patients who have heart failure and a history of CTS, amyloidosis should be considered as a cause.

Dr. Paauw is professor of medicine in the division of general internal medicine at the University of Washington, Seattle, and serves as third-year medical student clerkship director at that university. Contact Dr. Paauw at [email protected].

References

1. Fosbøl EL et al. J Am Coll Cardiol. 2019;74:15-23.

2. Sperry BW et al. J Am Coll Cardiol. 2018 Oct 23;72(17):2040-50.

3. Pinney JH et al. J Am Heart Assoc. 2013 Apr 22;2(2):e000098.

4. Aus dem Siepen F et al. Clin Res Cardiol. 2019 Apr 5. doi: 10.1007/s00392-019-01467-1.

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