Further Outpatient Care
See the list below:
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Most of the cardiac care for patients with Danon disease can be provided in an outpatient setting.
This care should include routine echocardiography to monitor the progression of hypertrophy and to detect changes suggestive of decreased left ventricular function and evolution to dilated cardiomyopathy.
Holter monitoring should be followed up every 6-12 months depending on the patient's symptoms and degree of hypertrophy, as determined with echocardiography.
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Male patients with Danon disease may require physical therapy for range-of-motion exercises and should be seen as needed by a pediatric neurologist. No medications cure or ameliorate the neuromuscular symptoms of Danon disease.
Further Inpatient Care
See the list below:
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Inpatient care is needed for patients with Danon disease who present with life-threatening arrhythmias or clinically significant congestive heart failure (CHF).
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When the patient develops CHF due to the dilated form of the disease, inpatient medical care may be indicated to administer intravenous inotropic agents and diuretics.
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When arrhythmias are noted, inpatient telemetry is helpful. Implantation of an implantable cardioverter-defibrillator (ICD) or pacemaker often necessitates an overnight admission with telemetry.
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Inpatient care is usually not required to manage the neurologic symptoms of Danon disease.
Deterrence/Prevention
See the list below:
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Currently, no treatment prevents the onset of Danon disease. Early and repeated echocardiographic surveillance of young male relatives of anyone with Danon disease should be performed. Identification of a specific mutation in LAMP2 in a family may allow relatives to consider presymptomatic DNA testing after thorough genetic counseling.
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Holter monitoring should also be performed when Danon disease is diagnosed.
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An ICD should be implanted when clinically significant septal thickening of more than 30 mm is noted on echocardiography, when a poor increase in blood pressure is noted during exercise testing, when ventricular tachycardia is noted on Holter monitoring, or if the patient has a family history of sudden death, as is recommended for patients with hypertrophic cardiomyopathy (HCM). [43] The data are insufficient to make a specific recommendation about ICDs in patients with Danon disease alone.
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From a neurologic perspective, range-of-motion exercises help to prevent joint contractures as the skeletal muscles weaken.
Complications
See the list below:
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Potential complications for this disease include syncope or sudden death before placement of an ICD.
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As with other forms of dilated cardiomyopathy, low-flow states can pose a risk of intracardiac thrombus formation with the potential for stroke.
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The onset of CHF symptoms can be abrupt and should initiate a discussion about and workup for cardiac transplantation.
Prognosis
See the list below:
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Patients with Danon disease have a poor life expectancy.
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See Mortality/Morbidity.
Patient Education
See the list below:
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The Hypertrophic Cardiomyopathy Association may have materials that can help patients and families understand the cardiac aspect of this disease, although Danon disease is not specifically mentioned.
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The following Web sites may have information of interest regarding Danon syndrome:
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Echocardiogram of a patient with Danon disease and severe hypertrophy. The septum is between the arrows. Note the asymmetry between the septum and the posterior wall of the left ventricle. Also see Media files 2-3. Calibration markings are in centimeters. Ao = ascending aorta just above the aortic valve; LV = left ventricle; LVPW = left ventricular posterior wall.
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Echocardiogram, short-axis view in diastole, in the same patient as in Media files 1 and 3. Because of the degree of hypertrophy, the cavitary volume is smaller than normal. Calibration markings are in centimeters. Ao = ascending aorta just above the aortic valve; LV = left ventricle; LVPW = left ventricular posterior wall.
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Echocardiogram, short-axis view in systole, in the same patient as in Media files 1-2. Note the increased thickening of the septum. Calibration markings are in centimeters. Ao = ascending aorta just above the aortic valve; LV = left ventricle; LVPW = left ventricular posterior wall.
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Horizontal ventricular sections of the heart from 16-year-old male adolescent with Danon disease obtained after orthotopic cardiac transplantation. Massive hypertrophy is present (heart weight, 785 g), with diffuse severe fibrosis and marked ventricular dilatation.
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Myocyte hypertrophy and vacuolization with interstitial fibrosis in the myocardium of a heart removed during cardiac transplantation (periodic acid-Schiff [PAS] stain; original magnification, X400).
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Electron photomicrograph shows autophagic vacuoles with glycogen in a heart removed during cardiac transplantation (uranyl acetate and Reynolds lead citrate; original magnification X20,000).
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Electron photomicrograph shows increased amounts of intermyofibrillar glycogen in the myocardium (uranyl acetate and Reynolds lead citrate; original magnification, X13,000).
