‘The Pickwick Papers’ is the first novel of Charles Dickens. The novel's main character, Samuel Pickwick, is a kind and wealthy old obese gentleman. Obesity Hypoventilation Syndrome (OHS), a condition related to sleep apnoea, was first called Pickwickian Syndrome. It’s named after Dickens’s ‘The Pickwick Papers’ because the novel features a character who has all the classic symptoms of the condition including snoring, obesity, sleepiness and dropsy.
Mrs. X, 50 years pleasant lady with a BMI 43, diabetic, hypertensive admitted in Square hospital on 26th November in ICU with severe shortness of breath and deteriorating conscious level. On admission, her ABG revealed pH 7.08, PCO2 106 mmHg, PO2 54 mmHg with 7 lt/min O2 and HCO3 34 mEq/l. She was managed in CPAP with FiO2 50%. Later she shifted to HDU. Most of the time in HDU, she was treated by BiPAP (IPAP 14 cm H20 & EPAP 6 cm H2O). Gradually her demand of O2 was reduced but required at least 2 lt /min to maintain SpO2 at least 90%. PFT was performed and revealed severe obstructive airway with FEV1- 46%. Her serum total IgE was 933 UI/ml. Colour Doppler Echocardiography detected severe pulmonary hypertension (PASP- 60 mm of Hg) with moderate tricuspid regurgitation. Split night Polysomnography was performed which revealed 65% sleep efficiency with 0% REM sleep and 79.9% stage II, NREM sleep, moderate obstructive sleep apnoea (RDI- 23) with severe nocturnal hypoxemia (lowest SpO2- 64 %), highest Capnograph reading revealed PCO2- 66.7 mmHg, moderate periodic leg movement (PLM index 36.3) which was completely corrected by BiPAP (IPAPP- 15 & EPAP 11 cm H2O) with oxygen 2 lt/min. 25.4% REM sleep was achieved. Finally she was diagnosed as a case of Obesity Hypoventilation Syndrome with severe pulmonary hypertension with chronic persistent Bronchial Asthma (Alternative Overlap Syndrome) and Diabetes Mellitus, Hypertension and subclinical hypothyroidism. She was discharged with BiPAP (S/T) and oxygen concentrator. Other medical management was appropriately prescribed.
OHS is the combination of Obesity (BMI ≥27.5 kg/m2), Hypercapnia (PaCO2 ≥ 45 mmHg) and Sleep-disordered breathing. Patients are usually middle-aged with male predominance. It’s prevalence among OSA is 10 to 20%. Common symptoms of OHS includes snoring, witnessed apnoea, frequent nocturnal awakenings, waking up choking or gasping for air, unrefreshed sleep, restless sleep, nocturia, dry mouth, decreased libido, early morning headache, fatigue, daytime sleepiness, poor memory, unproductive at work, falling asleep during driving and depression. OHS may cause neurocognitive deficit, automobile accidents, low health related quality of life, hypertension, stroke, coronary artery disease, congestive heart failure, arrythmia ( bradyarrythmia, ventricular ectopic), pulmonary hypertension and diabetes mellitus. Polysomnography is the gold standard tool to diagnose OHS and positive airway pressure (PAP) therapy is the main stay of treatment of OHS. Patients with untreated OHS have a significant risk of death.
A retrospective study reported that 46% patients with OHS who refused long-term noninvasive positive airway pressure (PAP) therapy died during an average 50-month follow-up period.
References:
Mokhlesi, B., Tulaimat, A. (2007), “Recent Advances in Obesity Hypoventilation Syndrome”, Chest 132 (4),1322-1332.
Weinberger, S.E., Drazen, J.M., “Disturbances in Respiratory Function”, in Kasper et al (eds), Harrison’s Principles of Internal Medicine (16th Edition), New York: McGraw-Hill, pp. 1498-1505.
Guyton, A.C., Hall, J.E. (2000), Textbook of Medical Physiology (10th edition), Philadelphia: W.B. Saunders.