Syndrome X & Syndrome Z

Syndrome X

Syndrome X is the other name of Metabolic Syndrome. Metabolic syndrome is also known as metabolic syndrome X, cardiometabolic syndrome, syndrome X, insulin resistance syndrome, Reaven's syndrome (named for Gerald Reaven), and CHAOS (in Australia).

Clustering of cardiovascular risk factors was recognized around 1920s and is currently thought to be related to the underlying pathophysiology of insulin resistance and hyperinsulinemia. Various agencies have defined different criteria for the diagnosis of Metabolic Syndrome. The criteria proposed by the Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III) are the most current and widely used. According to the ATP III criteria, the metabolic syndrome is identified by the presence of three or more of these components:[Q]

Central obesity as measured by waist circumference: In men greater than 40 inches and in women greater than 35 inches
Fasting blood triglycerides greater than or equal to 150 mg/dL
Blood HDL cholesterol: In men less than 40 mg/dL, and in women less than 50 mg/dL
Blood pressure greater than or equal to 130/85 mmHg
Fasting blood glucose greater than or equal to 110 mg/dL

Syndrome Z

Syndrome Z is the other name of Obstructive Sleep Apnoea (OSA). Obstructive sleep apnea (OSA) also referred to as obstructive sleep apnea-hypopnea—is a sleep disorder that involves cessation or significant decrease in airflow in the presence of breathing effort. It is the most common type of sleep-disordered breathing and is characterized by recurrent episodes of upper airway collapse during sleep. These episodes are associated with recurrent oxyhemoglobin desaturations and arousals from sleep.

Signs and symptoms
Nocturnal symptoms may include the following:

Snoring, usually loud and bothersome.
Witnessed apneas, which often interrupt the snoring and end with a snort
Gasping and choking sensations that arouse the patient from sleep.
Nocturia
Insomnia; restless sleep, with patients often experiencing frequent arousals and tossing or turning during the night

Daytime symptoms may include the following:

Non restorative sleep (ie, “waking up as tired as when they went to bed”)
Morning headache, dry or sore throat
Excessive daytime sleepiness that usually begins during quiet activities
Daytime fatigue/tiredness
Cognitive deficits; memory and intellectual impairment (short-term memory, concentration)
Decreased vigilance
Morning confusion
Personality and mood changes, including depression and anxiety
Sexual dysfunction, including impotence and decreased libido
Gastroesophageal reflux
Hypertension

Diagnosis

Examination findings may include the following:

Abnormal (increased) Mallampati score: Identifies risk for difficult tracheal intubation
Narrowing of the lateral airway walls: Independent predictor of the presence of obstructive sleep apnea in men but not women
Enlarged (ie, "kissing") tonsils (3+ to 4+)
Retrognathia or micrognathia
Large degree of overjet
High-arched hard palate
Systemic arterial hypertension: Present in about 50% of obstructive sleep apnea cases
Congestive heart failure
Pulmonary hypertension
Stroke
Metabolic syndrome
Type 2 diabetes mellitus

Why mention Syndrome X and Syndrome Z together here?

A growing body of evidence supports an association between obstructive sleep apnoea (OSA) [or Syndrome Z] and cardiovascular disease. Pathophysiologic mechanisms that are present in patients with OSA – including sympathetic activation, endothelial dysfunction, oxidative stress, systemic inflammation, hypercoagulability, hyperleptinemia, and insulin resistance – may influence the development and progression of cardiac and vascular pathology. OSA is widely prevalent in patients with obesity, diabetes, and hypertension [Combination seen in Syndrome X]

The clustering of cardiovascular disease mechanisms in the metabolic syndrome and OSA are remarkably similar. Patients with OSA have abnormalities in each of the “core” components of the metabolic syndrome – high blood pressure, high fasting glucose, increased waist circumference, low HDL cholesterol, and high triglycerides – as well as in many of its other features, including sympathetic activation, endothelial dysfunction, systemic inflammation, hypercoagulability, and insulin resistance.1 It has even been suggested that the metabolic syndrome (“Syndrome X`') should encompass OSA (“Syndrome Z”). However, there is little information about the extent to which the cardinal features of the metabolic syndrome are present simultaneously in patients with OSA.

Extra Edge Facts

Cardiac syndrome X is angina (chest pain) with signs associated with decreased blood flow to heart tissue but with normal coronary arteries. Some studies have found increased risk of other vasospastic disorders in cardiac syndrome X patients, such as migraine and Raynaud's phenomenon. It is treated with beta-blockers, such as metoprolol, and usually carries a favorable prognosis.

Cardiac syndrome X is sometimes referred to as microvascular angina when there are findings of microvascular dysfunction.

Z Syndrome is a post operative complication of IOL. Asymmetric folding at the haptic-optic junction of the Crystalens IOL has been reported in the literature as a rare complication, and has been dubbed “Z syndrome.” In general, during Z syndrome, the capsule contracts and causes long-axis compression resulting in the asymmetric folding.