Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ KEY FEATURES +++ ESSENTIALS OF DIAGNOSIS ++ Neurologic symptoms usually precede cardiac symptoms Gait ataxia and dysarthria Echocardiography shows concentric left ventricular hypertrophy ECG may show left or right ventricular hypertrophy and nonspecific ST-T changes +++ GENERAL CONSIDERATIONS ++ An autosomal recessive disorder, characterized by ataxia, areflexia, and extremity muscle weakness due to degeneration of the spinocerebellar tracts Found in 1:40,000 population and caused by trinucleotide expansion in the gene encoding frataxin (FXN) Cardiac hypertrophy is the most common heart manifestation and may lead to sudden death Cardiac manifestations appear with or up to 20 years after neurologic symptoms +++ CLINICAL PRESENTATION +++ SYMPTOMS AND SIGNS ++ Ataxia and dysarthria Dyspnea Palpitation +++ PHYSICAL EXAM FINDINGS ++ Absent tendon reflexes, diminished sensation, scoliosis Left ventricular lift S4 or S3 if heart failure Harsh systolic outflow tract murmur +++ DIFFERENTIAL DIAGNOSIS ++ Hypertrophic cardiomyopathy (asymmetric septal hypertrophy may occur, but myocardial fiber disarray as described in genetic hypertrophic cardiomyopathy is rare) Other causes of dilated cardiomyopathy in the later stages +++ DIAGNOSTIC EVALUATION +++ ELECTROCARDIOGRAPHY ++ Almost all patients have ECG abnormalities; the most common in order of prevalence are: – Nonspecific ST-T–wave changes – Right-axis deviation and other signs of right ventricular hypertrophy – Left ventricular hypertrophy – Supraventricular tachyarrhythmias – Inferolateral Q waves – Ventricular tachyarrhythmias are uncommon +++ IMAGING STUDIES ++ Echocardiogram may show: – Concentric left ventricular hypertrophy – Asymmetric septal hypertrophy – Global hypokinesis – Diastolic dysfunction – Dilated cardiomyopathy with systolic dysfunction +++ TREATMENT +++ CARDIOLOGY REFERRAL ++ Suspected cardiac disease +++ HOSPITALIZATION CRITERIA ++ Heart failure Syncope Tachyarrhythmias +++ MEDICATIONS ++ Symptomatic management of arrhythmias Pharmacologic management of heart failure No specific therapy exists +++ THERAPEUTIC PROCEDURES ++ Automatic implanted cardioverter-defibrillator in selected patients Heart transplantation is usually not indicated because the neuromuscular disease is progressive +++ MONITORING ++ ECG monitoring in hospital patients as appropriate +++ DIET AND ACTIVITY ++ Low-sodium diet if heart failure is present Restricted activity as appropriate for cardiac disease +++ ONGOING MANAGEMENT +++ HOSPITAL DISCHARGE CRITERIA ++ Resolution of heart failure Successful device placement +++ FOLLOW-UP ++ As appropriate for cardiac condition +++ COMPLICATIONS ++ Heart failure Syncope Progressive neuromuscular debilitation Sudden cardiac death +++ PROGNOSIS ++ Because the neuromuscular disease cannot be ... Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.