ROHHAD Syndrome - Causes, Signs, Symptoms, Diagnosis, and Treatment

Introduction:

ROHHAD syndrome denotes a group of conditions first described by Fishman et al. It was renamed ROHHAD by Ize-Ludlow et al. in the year 2007. The clinical features of the syndrome resemble those of congenital central hypoventilation syndrome (CCHS) and late-onset central hypoventilation syndrome (LO-CHS). The syndrome is rare and needs to be diagnosed and treated earlier to avoid cardiopulmonary complications.

What Is ROHHAD Syndrome?

ROHHAD is the abbreviation of rapid-onset obesity (RO) with hypoventilation (H), hypothalamic dysregulation (H), and autonomic dysregulation (AD). It is a rare genetic disorder, which is life-threatening and carries high chances of mortality. It affects the part of the nervous system that controls involuntary functions like heart beating, digestion, eye reflexes, and breathing. It leads to rapid weight gain over a short time of six to twelve months during the first ten years of life. It is followed by disturbances in the functioning of the hypothalamus (part of the brain producing hormones that control body temperature, heart rate, hunger, etc.), endocrine system, and autonomic nervous system, along with alveolar hypoventilation. This syndrome makes an individual more prone to tumors originating from neural crest cells.

What Are the Causes of ROHHAD Syndrome?

The cause of ROHHAD syndrome is unknown. But there are three theories for its pathogenesis which are believed to be the cause of this syndrome.

• Genetic: After detailed studies and research, no genetic correlation was found between the genes like PHOX2B, which cause CCHS.

• Epigenetic: There is some evidence of changes in the epigenomes of monozygotic identical twins, indicating a possibility of being the cause of ROHHAD syndrome.

• Immunologic: There was the presence of antibodies against the hypothalamus and pituitary gland in the cerebrospinal fluid of affected patients, and the patients showed improvement with immunosuppressant drugs. It shows the possible role of the immune system in the pathogenesis of the disease.

What Is the Pathophysiology of ROHHAD Syndrome?

The syndrome affects the endocrine and autonomic nervous systems of the body. The disease begins when a child is two to four years old. But the symptoms can start anytime during the first ten years of life. The disease affects males and females equally. There are two types of systems that control hormone secretion from the hypothalamus: magnocellular and parvocellular. The magnocellular system controls the production of antidiuretic hormone and oxytocin, and the parvocellular system of hypophysiotropic hormone. The clinical features of ROHHAD syndrome are similar to the condition of deficiency of magno and parvocellular systems. The effect on breathing is due to disturbance in the respiratory center in the brainstem. The endocrine system is regulated by the hypothalamus and the hormones it produces. The body’s growth, fertility, sexual health, fluid balance, and stress response are controlled by the endocrine system. So, the impairment of the hypothalamic, endocrine, and autonomic nervous systems leads to a variety of symptoms in ROHHAD syndrome.

What Are the Signs and Symptoms of ROHHAD Syndrome?

Children manifest the symptoms around the age of three on average. Before this, they are normal and healthy.

1. Hypothalamic Endocrine Dysfunction Causes:

• Rapid weight gain of 10 kilograms (in 6 to 12 months time).

• Hyperphagia (increased hunger).

• Difficulty in maintaining water balance (either low or high sodium levels).

• Diabetes insipidus.

• Feeling extremely thirsty or diminished feeling of thirst.

• Polyuria (excess urine production).

• Increased prolactin levels.

• Hypothyroidism.

• Deficiency of growth hormone.

• Delayed or early puberty.

• Hypoventilation (shallow breathing).

• Obstructive sleep apnea with snoring and bruxism (teeth grinding while asleep).

• Disrupted breathing pattern.

• Cardiopulmonary arrest.

• Episodes of cyanosis (bluish discoloration of the skin and mucous membranes).

2. Autonomic Dysfunction Causes:

• Sweating.

• Uncoordinated body movements.

• Bradycardia (decreased heart rate) or tachycardia (increased heart rate).

• Diarrhea or constipation.

• Hypothermia (decreased body temperature) or hyperthermia (increased body temperature).

• Dysautonomia.

• Strabismus (a condition where eyes do not see in the same direction at the same time).

• Astigmatism (blurred vision at near and distant).

• Behavioral issues like hyperactivity.

• Anxiety and depression.

• Hallucinations.

• Psychosis.

• Some develop tumors in neural crest cells, namely ganglioblastoneuromas, and ganglioneuroma.

How Is ROHHAD Syndrome Diagnosed?

• Patient Evaluation and History: A history of weight gain, snoring with breathing difficulties, changes in behavior, and increased hunger and thirst will suggest ROHHAD syndrome.

• Blood Tests: Blood tests will show high prolactin, low thyroid stimulating hormone, abnormal vasopressin, very low growth hormone, and low or high sodium levels.

• Polysomnography: It is a sleep study that detects obstructive sleep apnea and hypoventilation.

• X-Ray: Chest X-ray will detect lung anomalies.

• Magnetic Resonance Imaging (MRI): Tumors in neural crest cells and brain abnormalities can be identified.

• Echocardiogram: To assess cardiac function.

• Genetic Study: To confirm the absence of mutation in the PHOX2B gene.

• Endocrine Function Assessment: To identify abnormalities in pituitary gland function and fluid balance regulation.

• Electroencephalogram (EEG): This test examines the electrical activity in the brain.

How Is ROHHAD Syndrome Treated?

The ROHHAD syndrome lacks specific treatment. Treatment consists of a multi-professional team that treats the symptoms of their respective specialties. So, the treatment varies according to a child’s complaints and manifestations.

• Weight Management: Regular physical activities like low intense exercises should be done. High-intense exercise should be avoided to prevent breathing issues. A healthy and balanced diet and adequate nutrition should be provided.

• Management of Hypothalamic Function: Hormonal replacement therapy to treat diabetes insipidus, growth hormone supplementation, and drinking plenty of water.

• Behavioral Management: Behavioral therapy and counseling sessions can help a child with negative behavior.

• Eye Health: Glasses and eye muscle exercises will improve vision.

• Medications: Anti-epileptic drugs like Phenytoin treat seizures, and laxatives for digestive issues are used.

• Immunosuppressive Drugs: Cyclophosphamide in high doses improves ROHHAD symptoms.

• Cardiac Pacemaker: It is a device implanted in the heart to regulate heart rate.

• Ventilation: Artificial ventilation through a respirator or ventilator supports breathing. A tracheostomy is done if needed.

• Surgery: To remove the neural crest cell tumors, surgery is done.

Conclusion

The prognosis of ROHHAD syndrome depends on how early the syndrome is diagnosed. An interdisciplinary approach is required for timely diagnosis and effective treatment planning. When diagnosed earlier and managed well, the child leads a healthy life. However, due to delayed diagnosis and treatment, fifty to sixty percent of affected patients die from cardiorespiratory failure or arrest. It is advisable to get a medical consult as early as possible for enhanced treatment outcomes.