What is Pickwickian syndrome, also known as Obesity Hypoventilation Syndrome (OHS)?

From the Guidelines

Pickwickian syndrome, also known as obesity hypoventilation syndrome (OHS), is a condition that requires prompt treatment with weight loss, positive airway pressure therapy, and management of underlying conditions to prevent serious complications including pulmonary hypertension, right heart failure, and increased mortality. The treatment typically involves starting with continuous positive airway pressure (CPAP) therapy at night, typically at pressures of 10-15 cmH2O, or bi-level positive airway pressure (BiPAP) if CPAP is insufficient, as suggested by the American Thoracic Society clinical practice guideline 1. Supplemental oxygen may be needed if hypoxemia persists. Weight loss is crucial, with a goal of reducing body weight by at least 10% initially through dietary changes and increased physical activity. Bariatric surgery may be considered for those with BMI >40 kg/m² or >35 kg/m² with comorbidities, as recommended by the guideline 1. Medications like acetazolamide (250mg twice daily) may help stimulate breathing in some cases.

Key Considerations

• The underlying mechanism of OHS involves a combination of mechanical restriction from excess weight on the chest and abdomen, along with abnormal respiratory drive regulation, creating a vicious cycle of hypoventilation, especially during sleep 1.
• The American Thoracic Society clinical practice guideline suggests that patients with OHS should be treated with PAP during sleep, and that CPAP therapy should be initiated first-line for patients with concomitant severe OSA 1.
• The guideline also recommends that weight-loss interventions should aim to produce sustained weight loss of 25-30% of actual body weight, which is most likely required to achieve resolution of hypoventilation 1.

Treatment Approach

• Start with CPAP therapy at night, typically at pressures of 10-15 cmH2O, or BiPAP if CPAP is insufficient.
• Supplemental oxygen may be needed if hypoxemia persists.
• Weight loss is crucial, with a goal of reducing body weight by at least 10% initially through dietary changes and increased physical activity.
• Bariatric surgery may be considered for those with BMI >40 kg/m² or >35 kg/m² with comorbidities.
• Medications like acetazolamide (250mg twice daily) may help stimulate breathing in some cases.

Monitoring and Follow-up

• The long-term efficacy of prescribed PAP settings should be monitored, and adjustments made as needed.
• Patients should be followed up regularly to assess their response to treatment and to monitor for any complications.

From the Research

Definition and Characteristics of Pickwickian Syndrome

• Pickwickian syndrome, also known as obesity-hypoventilation syndrome (OHS), is a respiratory consequence of morbid obesity, characterized by sleep-disordered breathing, obesity, and daytime hypercapnia 2, 3.
• The syndrome is a diagnosis of exclusion after every other possible etiology is ruled out, and patients can present with an exacerbation of or a chronic state of progressive dyspnea 3.
• The characteristic signs of Pickwickian syndrome include a high degree of obesity, cardiovascular and respiratory insufficiency, somnolence, lassitude, enhanced appetite, cyanosis, and dyspnea with unrestful sleep 4.

Treatment and Management of Pickwickian Syndrome

• Treatment of Pickwickian syndrome typically involves non-invasive positive airway pressure (PAP) therapies, weight loss, and supportive management 2, 3.
• Reduction of body weight has been shown to improve functional respiratory parameters, ECG, and lipid, carbohydrate, and purine metabolism in patients with Pickwickian syndrome 4.
• Medroxyprogesterone acetate therapy has also been found to be useful in the management of Pickwickian syndrome, with improvements in arterial blood gas values and clinical state 5.
• Non-invasive ventilatory (NIV) support and overnight NIV have been used to manage patients with Pickwickian syndrome, with significant improvements in symptoms and quality of life 3.

Reversibility and Prognosis of Pickwickian Syndrome

• The manifestations of Pickwickian syndrome are completely reversible with weight loss, highlighting the importance of obesity management in the treatment of the syndrome 6.
• With appropriate treatment and management, patients with Pickwickian syndrome can experience significant improvements in symptoms, quality of life, and prognosis 2, 3, 4.
• However, weight loss alone may not improve hypoventilation and wean the patient from non-invasive positive-pressure ventilation (NPPV), and a comprehensive assessment of hypoventilation is essential to determine whether NPPV withdrawal is possible after body weight loss 2.