Bashir A. Chaudhary

Sleep disorders: a risk factor for normal-tension glaucoma?

PurposeTo determine the prevalence of sleep-related symptoms and sleep-related breathing disorders by polysomnography in patients with normal-tension glaucoma (NTG). Patients and MethodsThis comparative case series included 23 patients with NTG, 14 NTG suspects, and 30 comparison patients without NTG. A sleep history was obtained and determined to be positive or negative. Polysomnography was offered for patients with a positive sleep history. Prevalence of a positive sleep history and prevalence of sleep disorders were the main outcome measures. ResultsThe NTG, NTG suspect, and comparison groups did not differ with respect to age, body mass index, systemic disease, gender, or race. Thirteen (57%) of 23 patients with NTG, 6 (43%) of 14 NTG suspects, and 1 (3%) of 30 comparison patients had a positive sleep history (P = 0.001). Nine of 13 patients with NTG and four of six NTG suspects with a positive sleep history chose to undergo polysomnography. Seven (78%) of nine patients with NTG and all four NTG suspects undergoing polysomnography were diagnosed with a sleep disorder. Five patients with NTG had sleep apnea and two had sleep hypopnea. Two NTG suspects had sleep apnea; one had sleep hypopnea; and one had upper airway resistance syndrome. The one comparison patient with a positive sleep history had upper airway resistance syndrome by polysomnography. ConclusionsSleep-disturbed breathing may be a risk factor for NTG. Although we do not provide evidence for a cause-and-effect relationship, various physiologic factors produced by sleep-disturbed breathing may play a significant role in the pathogenesis of this optic neuropathy. We recommend obtaining a sleep history from patients with NTG and performing polysomnography in those patients with sleep disturbance symptoms.

Sleep disorders: A risk factor for pseudotumor cerebri?

Objective To determine whether sleep-related breathing disorders are common in patients with idiopathic intracranial hypertension. Materials and Methods Medical records of 53 patients with idiopathic intracranial hypertension from a tertiary center neuro-ophthalmology practice were reviewed. Thirty-seven patients were identified who had a history of snoring, difficulty sleeping, or daytime somnolence. The data from polysomnograms were tabulated to determine the frequency of apneas, hypopneas, and arousals. Results Fourteen of 37 patients with idiopathic intracranial hypertension and symptoms of sleep disturbance underwent polysomnography. There were two men and 12 women varying in age from 24 to 58 years (mean, 39.4 ± 11.9). These patients were obese with body mass indexes varying from 33.0 to 63.2 (mean, 46.0 ± 9.5). A diagnosis of sleep apnea was made in six and upper airway resistance syndrome in seven patients. Conclusions Sleep-related breathing problems were common in our patients with idiopathic intracranial hypertension. Obesity was common in these patients and may be playing a causative role in sleep apnea and idiopathic intracranial hypertension. It is suggested that idiopathic intracranial hypertension patients who have symptoms of sleep disturbance should be further evaluated for the presence of sleep-related breathing problems.

Nocturnal Urinary Protein Excretion Rates in Patients with Sleep Apnea

We observed nocturnal urinary protein excretion to be 16.2 +/- 5.5 micrograms/min (mean +/- SE) in 9 healthy control subjects (group I), 29.3 +/- 9.5 micrograms/min in 12 obese patients suspected to have obstructive sleep apnea syndrome (OSAS) but with negative polysomnographic studies (group II), and 94.0 +/- 31.8 micrograms/min in 14 patients with documented OSAS (group III) (II vs. I, NS; III vs. I, p less than 0.05; III vs. II, p less than 0.05). The frequency of abnormal proteinuria, defined as protein excretion greater than the highest rate observed in group I (46 micrograms/min), was 14% in group II and 64% in group III (p less than 0.05). There were no significant differences in age, body weight, body surface area, blood pressure, or indices of sleep apnea between OSAS patients with and without proteinuria. Although the mechanism is unclear, this study shows that nocturnal protein excretion rates are commonly elevated in patients with OSAS.

The Effect of Sleep on Intracranial Hemodynamics: A Transcranial Doppler Study

The effect of sleep on intracranial blood flow velocities has not been reported in children or adults, even though blood flow velocities are evaluated for clinical purposes during both sleep and wakefulness. We report the effect of sleep on intracranial blood flow velocities of 11 healthy individuals (five children and six adults) who were monitored by polysomnography and transcranial Doppler sonography (TCD). Thirty-three TCDs were obtained on middle cerebral arteries. Before sleep, during non-rapid-eye-movement sleep, and after sleep, measurements of systolic, end diastolic, and mean flow velocities were obtained by TCD. Pulse oximetry and end tidal carbon dioxide were monitored during each 8-hour polysomnogram. The before-sleep blood flow velocity values were compared to sleep and after-sleep values in children and adults separately using ANOVA. A significant decrease in the blood flow velocities was noted during sleep compared to before-sleep values in both children (P < .05) and adults (P < .01). The blood flow velocities after sleep were also decreased compared to before-sleep values. This study shows that sleep reduces blood flow velocities in both children and adults. A decrease in blood flow velocities during normal sleep should be taken into account when interpreting TCDs in patients. (J Child Neurol 1991;6:155-158).

Case Report: Sleep Apnea, Sleep Disorders, and Hypothyroidism

The symptoms of hypothyroidism are protean and include apathy, somnolence, lethargy, personality change, and intellectual deterioration. Many of these symptoms may be related to hypothyroid-induced sleep disorders. Hypothyroidism is associated with abnormal ventilatory drive, abnormal sleep architecture, and sleep apnea. Central, obstructive, and mixed patterns of sleep apnea are commonly observed in hypothyroidism. A case of severe sleep apnea in a grossly myxedematous patient who improved dramatically following thyroid replacement alone is presented. Myxedema is a reversible cause of sleep apnea, and thyroid function testing should be considered in its diagnostic work-up.

Studies of mediator involvement in cooling-induced alterations of guinea pig tracheal smooth muscle contractility.

Abstract Heat loss from airway smooth muscle is a potent stimulus which causes substantial, but poorly understood, alterations in muscle tension. This study considered the involvement of endogenous mediators in cooling-induced tension changes in incubated guinea pig trachea. Smooth muscle tension was monitored in tracheal cylinders which were carefully cooled from 37 to 30°C in the presence or absence of various inotropic mediators. In our study, cooling alone, at a rate of 1 °C/min, was associated with an average loss of smooth muscle tension of 88.2 mg. Cooling tracheal tissue that had been previously exposed to 3 × 10-6 M histamine, however, caused an additional increase in tracheal tension of 133 mg, over and above that caused by histamine alone. In the presence of 10-5 M prostaglandin F2α, or 10-5 M thromboxane B2, cooling was associated with respective losses of smooth muscle tension of 211.4 and 211.2 mg, as compared to the tension associated with these mediators when they were used alone under control conditions. When the speed of tracheal cooling was increased to 40°C/min, there was a slight increase in tension for 20 sec followed by a pronounced and sustained relaxation. The mechanisms involved in the response of airway smooth muscle to cooling are complex. The results of our study, however, suggest that mediators may play a role in the cooling-induced alterations of airway smooth muscle tension.

Case report: multiple negative polysomnograms in patients with obstructive sleep apnea.

A single overnight polysomnogram usually is adequate to exclude a diagnosis of obstructive sleep apnea. We report three patients who had multiple negative polysomnograms before a diagnosis of sleep apnea was made. Factors that may cause a false-negative polysomnogram include reduced total or rapid eye movement sleep time, sleeping in the lateral posture, manifestation of the disease predominantly by hypopneas, and recent medical therapy to treat sleep apneas. In patients with a strong clinical suspicion of sleep apnea and a negative polysomnogram, sleep and clinical parameters should be reevaluated and a repeat polysomnogram may be indicated.

Introduction to Polysomnography

A typical polysomnogram (Current Procedural Terminology code 95810) includes recording of an electroencephalography (EEG), an electro-oculogram (EOG), an electromyogram (EMG) of chin muscles, oronasal airflow, chest and abdominal movements, leg movements, snoring, and oximetry. Following is a discussion of some of the aspects of polysomnography.

Establishing the Etiologic Diagnosis of Pneumonia

DOI: http://dx.doi.org/10.5915/23-1-14324 Pneumonia is a serious entity with a mortality in the U.S. of from 6-24%. Many invasive and non-invasive procedures are used to establish an etiologic diagnosis. An acceptable sputum smear is characterized by a low number of epithelial cells, higher number of leukocytes, and the presence of alveolar macrophages. A gram-stain provides good clues about pneumococcal, Klebsiella, and mixed anaerobic infections. Common problems include interpretation of streptococci as S. pneumoniae and missing H. influenzae. A culture of sputum is frequently unreliable because of contamination by the upper airway bacteria. Transtracheal aspiration can minimize the upper airway contamination. Broncho-alveolar lavage is helpful in diagnosing pneumocystis infections in AIDS patients. Double lumen catheter systems can obtain secretions from the site of pneumonia without contamination. Transbronchial biopsy provides tissue specimens for stains and cultures. Transthoracic needle aspiration provides diagnostic yield of 56 to 82% of cases with a false negative rate of 22%. Open lung biopsy is usually done in very sick, immunocompromised patients if other diagnostic procedures have been unsuccessful. Presented at the IMA 22nd Annual Convention Orlando, Florida, July 1989. Part of Symposium: Update on the Diagnosis and Treatment of Respiratory Tract Infection.

SLEEP APNEA, PULMONARY HYPERTENSION AND NEPHROTIC SYNDROME *

DOI: http://dx.doi.org/10.5915/16-1-12440 Many cardiopulmonary abnormalities have been described in patients with sleep apnea syndrome. We are reporting a patient with severe obstructive sleep apnea who had severe episodic pulmonary hypertension, hypoxemia, and nephrotic syndrome. We are postulating that nephrotic syndrome was causally related to sleep apneas. Presented at the 16th Annual Meeting: of the Islamic Medical Association (September 1983), Oakbrook, Illinois, United States of America