Ref: Harrison's Principles of Internal Medicine. 18th edition, Page 2188Explanation:OSAHS is defined as the coexistence of unexplained excessive daytime sleepiness with at least five obstructed breathing events (apnea or hypopnea) per hour of sleep.EPWORTH SLEEPINESS SCOREHow often are you likely to doze off or fail asleep in the following situations, in contrast to feeling just tired'* This refers to your usual way of life in recent times.Even if you have not done some of these things recently, fry to work out how they would have affected you.Use the following scale to choose the most appropriate number for each situation:= would never doze.= slight chance of dozing.= moderate chance of dozing.= high chance of dozing.* Sitting and reading--* Watching TV--* Sitting, inactive in a public place (e.g., a theater or a meeting)--* As a passenger in a car for an hour without a break--* Lying down to rest in the afternoon when circumstances permit--* Sitting and talking to someone--* Sitting quietly after lunch without alcohol--* In a car, while stopped for a few minutes in traffic--TOTAL--DiagnosisSleep history from the patient and partner, with both completing.Sleep questionnaires.Epworth Sleepiness Score.Assessment of:o Obesity.o Jaw structureo Upper airwayo Blood pressureo Hypothyroidismo Acromegaly.Polysomnography.The apnea-hypopnea index or apnoea-hypopnoea index (AHI)It is an index of sleep apnea severity that combines apneas and hvpopneas.The apneas (pauses in breathing) must last for at least 10 seconds and are associated with a decrease in blood oxygenation.Combining these gives an overall sleep apnea severity score that evaluates both number sleep disruptions and degree of oxygen desaturation (low blood level).The AHI is calculated by dividing the number of events by the number of hours of sleep.AHI values are typically categorized as:o Mild = 5-15/hro Moderate = 15-30/hro Severe = > 30/hTREATMENT: OBSTRUCTIVE SLEEP APNEAWhom to Treat-Indications for TreatmentGroup IPatients who have an:o Epworth Score >1Lo Troublesome sleepiness while driving or working.o >15 apneas + hypopneas per hour of sleep.Treatment is definitely indicated in this group- Maximum benefit.Treatment improves:o Symptomso Sleepinesso Drivingo Cognitiono Moodo Quality of lifeo Blood pressure.Group 2Patient who have:o Similar degrees of sleepiness as Group Io 5-15 events per hour of sleep.Treatment is indicated-But benefit is less than Group 1.Treatment improves:o Symptomso Subjective sleepiness.No significant improvement in cognition and quality of life.No improvements in Blood pressure.Group 3Patients who are/have:o Nonsleepy subjects.o Less than 5 events per hour of sleep.Treatment is not indicated.No benefit with treatment.Life style modifications advised.MANAGEMENT OPTIONSLifestyle ModificationsWeight loss.Alcohol Reduction-Alcohol acutely decreases URT dilating muscle tone.CONTINUOUS POSITIVE AIRWAY PRESSURE (CPAP)Blowing the airway open during sleep, usually with pressures of 5-20 mmllg.CPAP improves the following in patients with OSAHS:o Breathing during sleepo Sleep qualityo Sleepinesso Blood pressureo Vigilanceo Cognitiono Driving abilityo Moodo Quality of life.The main side effect of CPAP is airway drying (decreased by using heated humidifier).CPAP is effective for both Moderate and Severe disease.Most common treatment modality used in OS A.MANDIBULAR REPOSITIONING SPLINT (MRS)Also called oral devices.Holds lower jaw and tongue forward causing widening the pharyngeal airway.MRSs improve the follow ing in OSAHS patients:o Breathing during sleep.o Daytime somnolenceo Blood pressure.There are many devices with differing designs with unknown relative efficacy.Self-reports of the use of devices long-term suggest high dropout rates.SurgeryBariatric surgery can be curative in the morbidly obese.Tonsillectomy can be highly effective in children but rarely in adults.Tracheostomy is curative but rarely used because of the associated morbidity rate but should nor be overlooked in severe cases.Jaw advancement surgery--particularly maxillomandibular osteotomy--is effective in young and thin patients with retrognathia (posterior displacement of the mandible).There is no clear evidence that pharyngeal surgery , including uvulopalatopharyngoplasty (whether by scalpel, laser, or thermal techniques) helps OSAHS patients.DrugsNo drugs are clinically useful in the prevention or reduction of apneas and hypopneas.In CPAP refractory patients. Modafinil can be tried with limited success.Choice of TreatmentCPAP and MRS are the two most widely used and best evidence-based therapies.CPAP is the current treatment of choice.MRSs are evidence-based second-line therapy in those who fail CPAP.In younger. thinner patients, maxillomandibular advancement should be considered.Note:In the given case, patient has 5 events/hour of sleep. He is also obese, diabetic, smoker and hypertensive. So the next step in management is to advocate life style modifications to treat obesity advise smoking cessation and follow-up.