Pickwickian Legacy: Obesity Hypoventilation Syndrome (Past to Present)
In its pages, the rotund and perpetually sleepy character Joe the Fat Boy embodies what 20th-century clinicians first described as the “Pickwickian syndrome”: profound obesity, excessive daytime somnolence, and elevated CO2 (earlier known to be polycythemia).
“It is remarkable to what extent the body may be overweight without serious inconvenience—until it is otherwise diseased.”
—Sir William Osler, Principles and Practice of Medicine (1892)
The Dickensian Beginning
The name “Pickwickian” still clings, like Victorian coal dust, to what we now call obesity hypoventilation syndrome (OHS). Its eponym originates not from a textbook, but from Charles Dickens’ The Posthumous Papers of the Pickwick Club (1836). In its pages, the rotund and perpetually sleepy character Joe the Fat Boy embodies what 20th-century clinicians first described as the “Pickwickian syndrome”: profound obesity, excessive daytime somnolence, and elevated CO2 (earlier known to be polycythemia).
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In 1956, Charles Burwell wrote a book “Colleagues in Discovery: one hundred years of improving respiratory health” which cemented Pickwickian Syndrome into Western medical lexicon but understand that he was not first to use this term for OSA.. The term was used as early as 1889 to describe sleepy patients.
A Deeper Historical Arc
But the roots run deeper than Dickens:
- Hippocrates (5th c. BCE) observed that “sudden death is more common in those who are naturally fat than in the lean,” an early recognition of obesity’s cardiopulmonary dangers.
- In medieval Persia, Avicenna’s Canon of Medicine (1025) described corpulence as a cause of “faintness, lassitude, and disturbed sleep,” almost predicting sleep-disordered breathing.
- By the 19th century, European clinicians catalogued “asthma of fat people” and “sleep apoplexy” as mysterious and enigmatic syndromes.
Burwell’s 1956 case series simply gave modern form to millennia-old observations.
Pathophysiology: The Burden of Flesh on Breath
For the modern pulmonologist, obesity hypoventilation syndrome (OHS) is defined as BMI ≥30 kg/m², awake daytime hypercapnia (PaCO₂ ≥45 mmHg), in the absence of other causes of hypoventilation.
Pathophysiology is multifactorial:
- Load: The chest wall bears excess weight, increasing elastic load and reducing tidal volume.
- Drive: Blunted ventilatory response to hypercapnia/hypoxia.
- Sleep: Over 90% of OHS patients also harbor obstructive sleep apnea (OSA), compounding nocturnal hypoventilation.
- Neurohormonal: Leptin resistance attenuates respiratory drive.
- Cardiovascular: Pulmonary hypertension and right heart failure accelerate morbidity.
Treatment Strategies: Evidence-Based and Practical
1. Non-Invasive Ventilation (NIV)
- CPAP vs Bilevel: The Pickwick Trial (2015) randomized 215 stable ambulatory patients with OHS + severe OSA (AHI >= 30 events/hr) to either CPAP vs noninvasive ventilation. Study was comparing CPAP vs NIV. Both modes (CPAP annd NIV/bilevel) were shown to improve daytime PaCO₂ and sleepiness, with no significant difference in overall mortality, cardiovascular events, hospitalizations per yr in that group over 5 year followup.
- Clinical pearl: Start with CPAP if severe OSA predominates; escalate to Bilevel/NIV if hypercapnia persists.
2. Supplemental Oxygen
- Should not be used in isolation—risk of worsening hypercapnia. Oxygen may be added to PAP therapy if persistent hypoxemia exists.
3. Weight Loss
- Bariatric surgery is an highly effective intervention shown to reverse OHS in large series, improving gas exchange and survival【Priou P et al. Chest. 2010】.
- Pharmacotherapy (GLP-1 receptor agonists, tirzepatide) is reshaping obesity care, but OHS-specific RCTs remain scarce.
4. Hospital Management
- In acute-on-chronic hypercapnic respiratory failure, NIV is first-line. Avoid excessive O₂; titrate cautiously.
- Intubation is challenging—anticipate difficult airway.
5. Cardiovascular Care
- Screen for pulmonary hypertension, right heart strain, arrhythmias. Multimodal management is essential.
🥼Doctor’s Orders
- Screen early: Up to 20% of patients referred for sleep studies with OSA have unsuspected OHS.
- Be vigilant perioperatively: OHS patients face higher risk of postoperative respiratory failure. Pre-op optimization with PAP is life-saving.
- Use PFTs wisely: Expect reduced FVC, preserved FEV₁/FVC, and elevated PaCO₂—pattern mimicking restrictive physiology.
- Don’t forget thyroid: Hypothyroidism can mimic or exacerbate OHS.
- Tele-ICU tip: In community hospitals, early recognition and initiation of Bilevel averts transfers and intubations.
References
- Burwell CS, Robin ED, Whaley RD, Bickelmann AG. Extreme obesity associated with alveolar hypoventilation—a Pickwickian syndrome. Am J Med. 1956;21:811-818.
- Masa JF, Corral J, Romero A, et al. Effectiveness of CPAP vs noninvasive ventilation in obesity hypoventilation syndrome: the Pickwick randomized clinical trial. ARJCCM. 2015;314(20):2280-2290.
- Priou P, Hamel JF, Person C, et al. Long-term outcome of noninvasive positive pressure ventilation for obesity hypoventilation syndrome. Chest. 2010;138(1):84-90.
- American Academy of Sleep Medicine. Clinical practice guideline for the treatment of OHS. J Clin Sleep Med. 2019;15(3):335–343.
- Osler W. The Principles and Practice of Medicine. 1892.
- Dickens C. The Posthumous Papers of the Pickwick Club. 1836.
- Avicenna. Canon of Medicine. 1025.
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