Disease Description (Causes and Symptoms)
- Definition summary: ROHHAD (Rapid-onset Obesity with Hypothalamic dysfunction, Hypoventilation and Autonomic Dysregulation) syndrome is a very rare disorder characterized by rapid weight gain in early childhood, hypothalamic dysfunction, sleep-related/apneic hypoventilation, and autonomic nervous system dysfunction (the number of reported patients is extremely small).
- Causes and pathophysiology: The cause is not clearly known, but dysfunction of the hypothalamus and related neural regulatory systems causes abnormalities in the regulation of satiety, body temperature, fluids, hormones, and breathing. Some patients may also have tumors of the peripheral nervous system, such as neuroblastoma.
- Main symptoms
- Rapid-onset obesity in previously healthy children around 1–9 years of age (sudden increase in appetite, overeating)
- Hypoventilation/sleep apnea during sleep (evaluated by polysomnography)
- Hypothalamic and endocrine abnormalities: abnormal temperature regulation (hyperthermia/hypothermia), electrolyte abnormalities (sodium imbalance), elevated prolactin, low cortisol, low thyroid hormone, etc.
- Autonomic dysfunction: bradycardia, abnormal sweating, constipation/diarrhea, strabismus, etc.
- Neurological symptoms: seizures, developmental and behavioral problems, delayed puberty
- Possibility of malignant neuroectodermal tumors
- Prognosis: As no established treatment is available and complications such as respiratory failure may occur, the prognosis may be poor (when respiratory failure occurs, the risk of death is very high because it can lead to cardiopulmonary arrest).
Treatment
- General principles: Because treatment of the underlying cause is often not possible, multidisciplinary symptom management (respiratory, endocrine, oncology, and cardiac/autonomic management) is essential.
- Respiratory management
- Noninvasive ventilation (CPAP/BiPAP) based on the results of polysomnography, or mechanical ventilation when necessary
- Oxygen therapy when oxygen saturation decreases; continuous monitoring and consideration of mechanical ventilation in cases of severe hypoventilation
- Caution is required when using anesthesia, sedatives, or analgesics because of the risk of worsening hypoventilation (prior consultation with the anesthesia team is necessary)
- Endocrine and metabolic management
- Endocrine evaluation (cortisol·ACTH, TSH·fT4, prolactin, sex hormones, etc.) followed by hormone replacement therapy when necessary (e.g., adrenal corticosteroid replacement, thyroid hormone, sex hormone supplementation, etc.)
- Weight management: nutritional management, regular exercise, and calorie control; screening and management of obesity-related complications (hyperlipidemia, diabetes, fatty liver)
- Tumor treatment
- If malignant tumors such as neurogenic tumors are detected, oncological treatment (surgery, chemotherapy, radiation therapy, etc.) is performed
- Cardiac and autonomic monitoring
- Holter monitoring, echocardiography, and other tests as needed to evaluate bradycardia and arrhythmias
- Rehabilitation and psychosocial support
- Psychological and educational interventions for developmental and behavioral problems
- Precautions and self-care
- Avoid or administer cautiously respiratory-depressant medications such as sedatives, opioids, and central nervous system depressants
- Seek medical care early because fever or infection may worsen respiratory depression
- Monitor oxygen saturation at home (when instructed) and establish an emergency response plan
- Regular endocrine, sleep, cardiac, and tumor follow-up is necessary
- Risk of complications: cardiopulmonary arrest, metabolic complications (diabetes, lipid abnormalities, fatty liver), permanent neurodevelopmental disabilities, etc.
Outpatient Visit Checklist (Items to Bring, Tests, and Records)
- Items to bring
- A list of currently used medications (including dosage and administration times)
- Copies of previous test results (blood tests, hormone tests, polysomnography, imaging studies, etc.)
- Weight and height records (clearly note when rapid weight gain and symptoms began) — growth chart
- Records of sleep- and breathing-related symptoms (snoring, observed pauses in breathing, daytime/nighttime sleepiness)
- Records of seizures, sweating, temperature abnormalities, and gastrointestinal symptoms (constipation/diarrhea)
- Tests that may be performed at the outpatient visit (advance preparation recommended)
- Blood tests: electrolytes (especially sodium), cortisol·ACTH, TSH·fT4, prolactin, glucose·lipids, etc.
- Polysomnography (referral if unavailable)
- Cardiac evaluation: ECG, Holter monitoring, echocardiography (if necessary)
- Brain and abdominal imaging (evaluation of the hypothalamus/pituitary gland and detection of neuroectodermal tumors): MRI/CT
- Respiratory function and oxygen saturation monitoring
Examples of General Questions to Ask the Doctor
- What does this diagnosis mean for us (the guardian/patient)? What is the expected course?
- Which tests do you recommend and why, and what can the tests determine?
- What are the specific treatment plan and goals for the current symptoms (breathing, endocrine function, weight, etc.)?
- What are the side effects and precautions for the prescribed medications?
- What actions should be taken immediately if an emergency occurs (worsening breathing, decreased consciousness, etc.)?
Examples of Disease-Specific Questions
- Based on the polysomnography results, what type of respiratory support do you recommend (e.g., CPAP vs BiPAP vs mechanical ventilation)? How will we receive education on home monitoring and equipment use?
- If an endocrine abnormality (e.g., low cortisol or low thyroid hormone) is confirmed, what hormone replacement therapy should be started, when, and how? At what intervals should long-term follow-up be performed?
(Note: Multidisciplinary care (pediatric endocrinology, pulmonology/sleep medicine, cardiology, oncology, genetics/neurology, etc.) is necessary, and special caution is required when using anesthesia or sedative medications.)