light - chain ( al ) amyloidosis is a disorder characterized by deposition of insoluble , monoclonal immunoglobulin light - chain fragments in various tissues . clinical features depend on organs involved but can include restrictive cardiomyopathy , nephrotic syndrome , hepatic failure , and peripheral / autonomic neuropathy . the patients often have a long period of a certain organ involved before systemic multiorgan involvement or heart failure has already developed . cardiac involvement is a leading cause of morbidity and mortality , especially in al amyloidosis.1 once congestive heart failure occurs in al amyloidosis , median survival is less than 6 months if left untreated . thus , an early and accurate diagnosis with an earlier start or more intensive treatment may have resulted in a better outcome . 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 . sensory examination revealed diminished tactile and pain sensation in a stocking and glove pattern and vibratory sensation was distally reduced in the lower limbs . 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 . 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 ) . 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  light - chain concentration was 1,763 ( normal range : 5981,329 mg / dl , and  light - chain concentration was normal . 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 . amyloidosis refers to a collection of conditions in which abnormal protein folding results in insoluble fibril deposition in tissues . the major types of amyloidosis , classified on the basis of their precursor protein , include light - chain , senile systemic ( wild - type transthyretin ) , hereditary ( mutant transthyretin ) , and secondary ( aa ) diseases . the frequency of cardiac involvement varies among the types of amyloidosis and is common with al disease.2 myocardial amyloid involvement leads to a restrictive cardiac physiology with possible concomitant conduction system disease , and the patients may present with nonspecific dyspnea , lower extremity edema , and syncope . death in more than half of the patients with cardiac amyloidosis is due to heart failure or refractory arrhythmia . these findings are also prevalent in other cardiac conditions such as hypertrophic nonobstructive cardiomyopathy . however , ecg of our patient revealed low voltages , which was not typical for hypertrophic cardiomyopathy . increased myocardial echogenicity with a granular or sparkling appearance is the most characteristic feature , as seen in the case . but this feature has limited sensitivity in cardiac amyloidosis and may be more indicative of late - stage disease . advanced echocardiographic techniques are beginning to reveal more about the underlying pathology and functional abnormalities . with the tissue doppler imaging technique , measurement of myocardial tissue velocity however , a limitation of tissue doppler imaging lies in its inability to distinguish between actively contracting myocardium and adjacent tethered akinetic myocardial segments . this limitation can be overcome by strain and strain rate imaging , which derives from speckle tracking imaging and is better able to distinguish among segmental wall motion differences.3 it is particularly helpful and demonstrates a very typical pattern in cardiac amyloidosis , characterized by relative sparing of apical longitudinal contraction compared to basal contraction . this appearance is not typically seen in other cardiomyopathies such as hypertrophic cardiomyopathy and aortic stenosis . the use of a combination of echocardiographic and electrocardiographic features increases specificity . a low voltage on the ecg and increased septal and posterior left ventricle wall thickness on the echocardiogram are highly specific for cardiac amyloidosis in the setting of biopsy - proven systemic amyloidosis . low qrs voltages ( all limb leads < 5 mm in height ) with poor r - wave progression in the chest leads ( pseudoinfarction pattern ) occur in up to 50% of patients with cardiac al amyloidosis , and this is the most common finding in affected individuals . ischemic cardiomyopathy may also result in decreased voltages and infarction pattern on ecg but leads to dilated , eccentric ventricular hypertrophy with reduced ejection fraction . other findings include first - degree atrioventricular block ( 21% ) , nonspecific intraventricular conduction delay ( 16% ) , second- or third - degree atrioventricular block ( 3% ) , atrial fibrillation / flutter ( 20% ) , and ventricular tachycardia ( 5% ) . amyloid deposits produce characteristic apple - green birefringence under polarized light when stained with congo red . the gold standard for diagnosis of cardiac amyloidosis is still myocardial biopsy , but it may be connected with severe complications ( ventricular free wall perforation up to 0.4% , arrhythmia 0.5%1.0% , and conduction disorders 0.2%0.4%).4 according to the american heart association / american college of cardiology guidelines , there is a class ii - a recommendation to perform endomyocardial biopsy in heart failure associated with unexplained restrictive cardiomyopathy . theoretically , typical echocardiographic appearances with a positive biopsy for amyloid , commonly from an extracardiac site ( such as rectum or abdominal fat ) , is sufficient to make a diagnosis of cardiac amyloidosis.5 our patient had gastrointestinal symptoms , and the autonomic neuropathy has been considered to explain the symptoms . biopsy from rectum confirmed amyloid infiltrate on congo red staining . the initial clinical presentation was dominated by chronic neuropathy and the diagnosis of al amyloidosis took 1 year after the first symptom . this delay is unfortunately common to al amyloid neuropathy , and the median duration of symptoms before diagnosis was 29 months . pathologically , amyloid neuropathy is characterized by the deposition of insoluble -fibrillar proteins in the epineurium , perineurium , endoneurium , perineuronal tissues , and neural vasculature . the first is familial amyloid polyneuropathy ( also known as hereditary amyloidosis).6 the second is al amyloidosis . peripheral neuropathy occurs in 17% of patients with al amyloidosis , making it the most common type of acquired amyloid polyneuropathy . sensory - motor axonal polyneuropathy and carpal tunnel syndrome are the most common types of neuropathy associated with al amyloidosis . symptoms typically begin with painful paresthesias in the feet signifying small fiber involvement . as the disease progresses , it can affect larger nerve fibers and patients may complain of numbness and motor weakness.7 up to 65% of patients with peripheral neuropathy also have autonomic nervous system involvement . the clinical manifestations of autonomic disorders are nonspecific and symptoms can include nausea , vomiting , early satiety , bloating , constipation , diarrhea , postural lightheadedness , and erectile dysfunction . due to varying clinical symptoms , however , it is important to recognize and distinguish neuropathy from diseases of the end organs themselves . diagnostic testing can include electromyography / nerve conduction studies , autonomic function tests.8 in this case , early diagnosis is particularly crucial so that patients might undergo the appropriate testing to find cardiac involvement in early stage often , the discovery of cardiac involvement is a sign of late - stage disease . increasing medical alertness of the natural history of al amyloidosis could reduce the time to achieve the diagnosis and therapeutic decisions , also improving the prognosis . it should be stressed that some symptoms , seemingly unrelated to each other , are actually early and specific red flags of the amyloid process .
light - chain amyloidosis is a relatively rare multisystem disorder . 
 the disease often is normally difficult to diagnose due to its broad range of characters without specific symptoms . a 62-year - old male patient presented with heart failure after experiencing a long period of unexplained and untreated gastrointestinal symptoms . 
 clinical examination and laboratory findings indicated a systemic process with cardiac involvement . 
 echocardiography revealed concentric left ventricular hypertrophy with enhanced echogenicity and preserved ejection fraction . 
 rectum biopsy confirmed amyloid deposition . 
 the side effect of delayed diagnosis on prognosis and the appropriate diagnostic strategy has been discussed .