ROHHAD

Rapid-onset obesity with hypothalamic dysregulation, hypoventilation, and autonomic dysregulation (ROHHAD) is a rare condition whose etiology is currently unknown. ROHHAD mainly affects the endocrine system and autonomic nervous system, but patients can exhibit a variety of symptoms. Patients present with both alveolar hypoventilation along with hypothalamic dysfunction, which distinguishes ROHHAD from congenital central hypoventilation syndrome (CCHS). ROHHAD is a rare disease, with only 100 reported cases worldwide thus far. Rapid-onset obesity with hypothalamic dysregulation, hypoventilation, and autonomic dysregulation (ROHHAD) is a rare condition whose etiology is currently unknown. ROHHAD mainly affects the endocrine system and autonomic nervous system, but patients can exhibit a variety of symptoms. Patients present with both alveolar hypoventilation along with hypothalamic dysfunction, which distinguishes ROHHAD from congenital central hypoventilation syndrome (CCHS). ROHHAD is a rare disease, with only 100 reported cases worldwide thus far. The first sign of ROHHAD is a rapid weight gain between 1.5 and 11 years of age. Typically, hypoventilation, or abnormally slow breathing, presents after the rapid onset obesity. Symptoms of hypothalamic dysfunction and autonomic dysfunction present in a variety of ways, but in order for a diagnosis of ROHHAD they must be present in some form. Approximately 40% of patients will develop neuroendocrine tumors. There is also a possibility of behavioral disorders, but some children with ROHHAD have normal cognitive development and intelligence. Treatment plans for ROHHAD vary depending on each patient's symptoms. There is no cure, so treatment is geared toward managing the symptoms that each patient manifests. ROHHAD is fatal in 50-60% of cases when undiagnosed and untreated, due to cardiopulmonary arrest secondary to untreated hypoventilation. The earlier the disease is diagnosed and treatment starts, the better a child's prognosis is. The rapid onset obesity aspect of ROHHAD is usually the first diagnostic indicator of the disease. Patients often present with hyperphagia and rapid weight gain. This rapid weight gain is defined as 20-30 pounds over a 6-12 month period, and typically occurs between the ages of 1.5 and 11. Hypothalamic dysfunction refers to the hypothalamus, which is a structure within the brain which participates in regulating the pituitary gland, autonomic nervous system, and endocrine system. Symptoms related to hypothalamic dysfunction may include abnormal sodium balance (hyponatremia or hypernatremia), high progestin levels, low cortisol levels, delayed or early-onset puberty, and low thyroid hormone. Patients will also often experience a decelerated growth rate throughout childhood. Sodium imbalance within the body can have severe symptoms and be potentially life-threatening if not controlled. Hyponatremia, or low sodium levels, can cause symptoms such as nausea, headache, seizures, or even cause patients to become comatose. Hypernatremia, or high sodium levels in the blood, can cause nausea, muscle weakness, altered mental status, or coma. Irregular temperature regulation and diabetes insipidus are also possible symptoms of hypothalamic dysfunction. ROHHAD patients develop these symptoms at varying ages and in varying numbers, but all patients will develop some symptoms of hypothalamic dysfunction. Symptoms of hypoventilation and breathing malfunctions typically present after the rapid weight gain. Some patients may initially develop obstructive sleep apnea, which is common in obese children. Obstructive sleep apena is the most common form of sleep apnea, and causes breathing to abruptly stop and begin again during sleep. This is caused by throat muscles relaxing during sleep and blocking the airway, and is typically noticed as patients will snore loudly throughout the night. Every patient diagnosed with ROHHAD develops alveolar hypoventilation, regardless of whether they presented with sleep apnea. Alveolar hypoventilation is a condition in which patients have very low blood oxygen levels and shallow breathing. In healthy patients, when blood oxygen levels are low, the brain sends a signal to breathe and bring more oxygen to the blood. In ROHHAD patients, this reaction does not occur. This condition is usually only present during sleep, however in more severely affected patients shallow breathing may continue throughout the day. Hypoventilation can go unnoticed until cardiopulmonary arrest, which is why ROHHAD has the potential to be a fatal disease. Ventilatory support is required for patients during sleep, however it is only needed during waking hours for those most severely affected (about 50% of patients). Autonomic dysfunction refers to the autonomic nervous system, which is responsible for regulating internal processes without conscious intervention. This may involve abnormalities in cardiac rhythm, temperature regulation, digestion, and eye movements. Not all ROHHAD patients will experience all of these symptoms, however they will have at least some of these issues. Examples of autonomic dysfunction include hyperthermia, hypothermia, pupillary dysfunction, strabismus, chronic constipation, and chronic diarrhea.