Ryland P. Byrd

The Association Between Obstructive Sleep Apnea Syndrome and Microvascular Complications in Well-Controlled Diabetic Patients

BACKGROUND Obstructive sleep apnea syndrome (OSAS) may promote hyperglycemia and insulin resistance. OBJECTIVE We studied the link between sleep apnea and microvascular diabetic complications in veterans with type 2 diabetes mellitus (DM-2). DESIGN A retrospective electronic chart of all veterans referred for sleep studies over a 1-year period was reviewed. Ninety-eight patients with a glycosylated hemoglobin < 6.5% were included in the study. The degree of glycemia (HbA1c) and presence of macro- and microvascular complications were compared with OSAS variables. METHOD Statistical analysis examined bivariate associations between OSAS variables and metabolic syndrome parameters. RESULTS The apnea hypopnea index was significantly related to diabetic microvascular complications, particularly retinopathy. Oxygen desaturation was significantly and inversely related to microalbuminuria, microvascular complications, retinopathy, and HbA1c. CONCLUSIONS Sleep apnea is associated with microvascular complications even in well-controlled DM-2 veterans. CLINICAL IMPLICATIONS Screening for OSAS should be considered in patients with DM-2.

Calciphylaxis: a rare association with alcoholic cirrhosis. Are deficiencies in protein C and S the cause?

Calciphylaxis is a rare condition of induced systemic hypersensitivity in which tissues respond to appropriate challenging agents with a sudden local calcification. It is characterized by acute calcium deposition in the medial layer of small and intermediate dermal vasculature that can lead to epidermal ischemia, ulceration, and necrosis. Calciphylaxis typically occurs in patients with end-stage renal disease who are undergoing dialysis and who have secondary hyperparathyroidism. Even in this population the incidence is less than 1%. The cause of calciphylaxis is unknown. However, it has been suggested that deficiencies of protein C and protein S may play a role in the pathophysiology of this disorder. Our patient is the fourth with cirrhosis to be reported to have developed calciphylaxis and adds further evidence that low levels of these anticoagulant factors may be an important etiologic factor for development of calciphylaxis. This report should alert the clinician that calciphylaxis occurs in patients with cirrhosis and should stimulate further research concerning the possible role of protein C and protein S deficiency in calciphylaxis.

Atypical Pott's disease: localized infection of the thoracic spine due to Mycobacterium avium-intracellulare in a patient without human immunodeficiency virus infection.

Mycobacterium avium-intracellulare (MAI) rarely causes disease of the spine in healthy individuals. We describe an elderly woman who had isolated skeletal involvement with MAI, mimicking Potts disease. She responded well to surgical excision of the inflamed tissue and antibiotic therapy. Osteomyelitis due to MAI must be differentiated from that due to Mycobacterium tuberculosis because the treatment regimens are different.

Amiodarone-induced alveolar hemorrhage.

Amiodarone is increasingly prescribed for patients with ventricular and supraventricular tachyarrhythmias. Many adverse effects have been reported due to this drug and include injury to the liver, thyroid, cornea, skin, and neuromuscular system. Pulmonary toxicity is one of the more serious side effects of this anti-arrhythmic drug and is potentially fatal. Since the first case of amiodarone-induced pneumonitis was described in the early 1980s, amiodarone pneumonitis has been recognized as a distinctive and not uncommon form of drug-induced lung injury. On the other hand, amiodarone-induced pulmonary toxicity resulting in alveolar hemorrhage is rare. The authors report a patient with amiodarone-induced alveolar hemorrhage and review the literature.

Desquamative interstitial pneumonia and hepatitis C virus infection: a rare association.

Extrahepatic manifestations of hepatitis C virus (HCV) infection are common. The authors report the unusual occurrence of desquamative interstitial pneumonia (DIP) in a patient with HCV. An immunologic response to HCV infection may have a role in the pathogenesis of DIP in patients with chronic HCV. Since DIP is treatable, HCV patients with pulmonary infiltrates should be thoroughly investigated for this disorder. In our experience, the use of steroids in HCV-associated DIP improved the patients respiratory status without increasing the viral load.

Peritoneal tuberculosis: modern peril for an ancient disease.

Extrapulmonary manifestations of Mycobacterium tuberculosis (MTB) in general, and tuberculous peritonitis (TBP) in particular, have posed complex diagnostic challenges for centuries. Peritoneal tuberculosis is a very rare manifestation of MTB with subtle clinical findings that may result in a significant diagnostic delay, often of more than four months. As the incidence of tuberculosis is declining in developed nations, clinicians may overlook the need to establish an early diagnosis and prompt therapy for this disorder. We present a case of peritoneal tuberculosis and a review of the literature.

Mycobacterium xenopi Pneumonia in the Southeastern United States

Mycobacterium xenopi (M. xenopi) is a slow-growing, nontuberculous mycobacterium (NTM). This organism is found in fresh water and has been isolated in water samples collected from water systems in homes and hospitals. Before the acquired immunodeficiency syndrome epidemic, M. xenopi infection was infrequent and occurred in clusters; however, M. xenopi is now a recognized cause of pulmonary infection in immunocompetent patients with preexisting lung disease. The classic chest x-ray appearance is cavitary apical pulmonary disease, which mimics tuberculosis. M. xenopi is currently one of the most common NTM pathogens in parts of England and Canada and has been reported in parts of the northeastern United States. Whether the isolation of M. xenopi from our patient in Tennessee represents a new geographic distribution of this organism or technologic advancements that now allow for reliable identification is debatable. This case serves as a reminder to clinicians that the incidence of NTM infection is rising in the United States and that unusual NTM are capable of causing disease even in patients who are not immunocompromised.

Difficult-to-manage asthma. How to pinpoint the exacerbating factors.

PREVIEW Asthma can be difficult to manage in some patients, and the reason may not be readily apparent to either physician or patient. When even aggressive treatment fails to control asthma symptoms, where do you begin to look for the possible cause or causes? This article provides a brief overview of the pathogenesis of asthma and a discussion of exacerbating factors to consider in evaluation of difficult-to-manage cases. A handy algorithm showing a stepwise approach to evaluation is included.

Reduction of amiodarone pulmonary toxicity in patients treated with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers

Background: Amiodarone (AM) is a widely used anti-arrhythmic medication. Its utility is, however, limited by adverse side effects. The mechanism of amiodarone-induced toxicity (APT) in the lungs is attributed primarily to stimulation of the angiotensin enzyme system leading to lung cell apoptosis and cell death. This mechanism has been demonstrated by in vitro and in vivo experimental animal studies. To date, however, no in vivo human studies have confirmed this mechanism for APT. Purpose: This study was undertaken to determine whether angiotensin converting enzyme inhibitors (ACE-I) or angiotensin receptor blockers (ARB) offer a protective effect against APT in humans. Demonstration of a protective effect of an ACE-I or ARB would suggest that stimulation of the angiotensin enzyme system may be a key process in APT. Design: An 8-year retrospective analysis of all patients on AM therapy at the James H. Quillen Veterans Affairs Medical Center was undertaken. Results: A total of 1000 patients on AM were identified. One-hundred-and-seventeen were excluded from the study. Five-hundred-and-twenty-four patients were simultaneously on an ACE-I or ARB. The remaining 359 patients were not. Pulmonary toxicity attributed to AM was identified in five and 14 patients with and without concomitant ACE-I or ARB therapy, respectively. The APT rate for the entire patient sample was 2.2%. APT occurred in 1% of patients on an ACE-I or ARB and in 3.9% of patients not taking an ACE-I or ARB. This observed difference in percentage of APT was statistically significant. Conclusion: The concomitant use of ACE-I or ARB in patients taking AM appears to offer a protective effect against APT. This observation suggests that the stimulation of the angiotensin enzyme system may play an important role in APT in humans.

All-trans retinoic acid syndrome : Another cause of drug-induced respiratory failure

It is now possible to achieve complete remission in the majority of patients with acute promyelocytic leukemia (APL) if all-trans retinoic acid (ATRA) is administered as a single agent or in combination with cytotoxic chemotherapy. Despite its positive influence on recovery, ATRA is not without the potential for toxicity. It is important for clinicians participating in the care of patients undergoing treatment with this drug to be aware of ATRA syndrome and institute the appropriate therapy to reduce the likelihood of an adverse outcome.