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Cardiac Amyloidosis Doesn't Have to Be Intimidating: A Primer on Diagnosis
- By: admin
- On: 04/09/2019 16:24:37
- In: Guidelines & Quality
By Noel Dasgupta, MD
Many physicians learned a bit about amyloidosis in medical school but never expected to diagnose or treat it. Even today, as amyloidosis becomes more visible, it can be unsettling for us even to contemplate because there are multiple types and treatments vary.
That's why the key is to start with the basic structure for obtaining a history and making a diagnosis. Here's how I tackle it:Many physicians learned a bit about amyloidosis in medical school but never expected to diagnose or treat it. Even today, as amyloidosis becomes more visible, it can be unsettling for us even to contemplate because there are multiple types and treatments vary.
1. Take a history, and look for the involvement of multiple systems. Ask questions that probe past medical history and surgeries. Be on the lookout for past carpal tunnel surgery, spinal stenosis, low blood pressure, arrhythmias and passing out.
2. Take a detailed family history. In the United States, the Val122Ile mutation is the most common hereditary transthyretin mutation. It is found in 3 to 4 percent of African-Americans so be sure to ask about race/ethnicity.
3. Move on to the physical exam. Look for evidence of orthostatic hypotension, bruising, irregular heart rhythms, muscular weakness, and numbness and tingling in the lower extremities.
4. If after the history and physical exam you suspect amyloidosis, consider ordering basic lab work, an ECG and cardiac imaging. A standard lab workup for amyloidosis examines multiple body systems and screens for light-chain amyloidosis, which is one of the main causes of cardiac amyloidosis. The lab work generally should include a CBC, serum creatinine, BNP liver function tests, urinalysis to look for proteinuria, serum and urine free light chains to screen for light-chain amyloidosis, and a SPEP/UPEP with reflex immunofixation.
Cardiac imaging may include an echocardiogram or cardiac MRI to evaluate for a normal left ventricular cavity with thick walls. Amyloid does not conduct an electrical current so finding thick walls with low voltage on an ECG should raise your suspicion of amyloidosis. Left ventricular hypertrophy without a history of hypertension also should raise your index of suspicion.
5. Once you have a high index of suspicion for amyloidosis, you must order additional tests to confirm the diagnosis and determine the specific amyloidosis type. This additional work-up may include nuclear pyrophosphate scans, genetic testing and/or biopsies with special staining with Congo red and typing with mass spectroscopy
These five steps will take you a long way toward accurately and confidently diagnosing cardiac amyloidosis, but there's another resource you have at your fingertips because you're an ASNC member: If you get stuck or confused, reach out to another member. The support we have through our ASNC network is one of the best benefits of membership. Take advantage of it. In fact, I invite you to contact me anytime at ndasgupt@iu.edu.
Noel Dasgupta, MD, is an Assistant Professor of Clinical Medicine at the Krannert Institute of Cardiology, Indiana University, in Indiana.
To access education, guidelines, practice points and more about cardiac amyloidosis, visit ASNC's Cardiac Amyloidosis Resource Center
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