A 62-year-old male presented with a 15-day history of dyspnea on exertion, associated with both lower extremity edema.
Before this admission, he also had suffered from abdominal bloating and tasteless for a year with noticeable body weight loss at the same time (up to 20 kg).
Over the past 6 months, he developed a multiple system disorder, which included painless paresthesias in the lower limbs, erectile dysfunction, and chronic diarrhea.
He had an average stool frequency of up to ten times per day, with no obvious blood or mucus and no abdominal pain or tenesmus.
Unfortunately, previous stomach and rectum biopsy did not examine for accumulations of amyloid fibril protein.
His family history was unremarkable.
On physical examination, his blood pressure was 82/56 mmHg and heart rate was 52 bpm.
Significant jugular venous distention, moderate hepatomegaly, and lower extremity edema were noted.
A neurological examination revealed weakness and muscular atrophy in the bilateral tibialis anterior and gastrocnemius.
Hyporeflexia was noted on both knees and ankles.
Sensory examination revealed diminished tactile and pain sensation in a stocking and glove pattern and vibratory sensation was distally reduced in the lower limbs.
The motor and sensory functions of upper extremities were relatively spared.
Initial laboratory data that included full blood count, transaminase, creatinine, electrolytes, cardiac troponin, and thyroid function were normal or negative.
N-terminal fragment of pro-brain natriuretic peptide (NT-proBNP) was 3,996 pg/mL.
Nerve conduction studies confirmed bilateral sensory-motor neuropathy (Table 1).
An electromyography study demonstrated active denervation and chronic reinnervation changes in the tibialis anterior and gastrocnemius.
Electrocardiogram (ECG) revealed sinus rhythm, low voltages in limb leads, QS waves in precordial and inferior leads, first-degree atrioventricular block, and prolonged QTc (Figure 1).
Two-dimensional echocardiography revealed marked concentrically thickened and speckled appearance of ventricular walls, biatrial dilatation, and left ventricular ejection fraction of 70% (Figure 2).
Doppler revealed a severe restrictive mitral filling pattern with E/A ratio 2.1.
Coronary angiography findings were normal.
The combined occurrence of low QRS voltage in the ECG, ventricular thickening, and signs of diastolic dysfunction is strongly suggestive of cardiac amyloidosis.
The following serum λ light-chain concentration was 1,763 (normal range: 598–1,329 mg/dL, and κ light-chain concentration was normal.
Rectum biopsy confirmed amyloid infiltrate (Figure 3).
So, the diagnosis of AL amyloidosis was established.
Despite chemotherapy administration of melphalan, dexamethasone, immunomodulator lenalidomide, and supportive therapy including montmorillonite to decrease diarrhea and low-dose furosemide to alleviate fluid retention, the patient continued to deteriorate and died at home after 3 months after the initial diagnosis.