Association between airway bacterial load and markers of airway inflammation in patients with stable chronic bronchitis

PURPOSE

Viable bacteria are often isolated from airway secretions in clinically stable patients with chronic bronchitis. We hypothesized that the number of organisms and bacterial species might be important modulators of airway inflammation.

SUBJECTS AND METHODS

We performed quantitative sputum cultures in 160 stable patients [55 with chronic obstructive pulmonary disease (COPD) and normal serum alpha(1)-antitrypsin levels, 62 with COPD and severe alpha(1)-antitrypsin deficiency (PiZ), and 43 with idiopathic bronchiectasis]. The results were related to several indicators of the mechanisms and severity of airway inflammation.

RESULTS

Airway bacterial load correlated with sputum myeloperoxidase level, an indirect measure of neutrophil activation and number (r = 0.50, P<0. 001); sputum neutrophil chemoattractants [interleukin-8 level (r = 0. 68, P<0.001) and leukotriene B4 level (r = 0.53, P<0.001)]; sputum leukocyte elastase activity (r = 0.55, P<0.001); and albumin leakage from serum to sputum (r = 0.26, P<0.01). Markers of inflammation increased at bacterial loads of 10(6) to 10(7) colony-forming units per milliliter, and increased progressively with increasing bacterial load. For example, the median (interquartile range) sputum myeloperoxidase level was 0.3 U/mL (0.1 to 0.5 U/mL) for patients who were not colonized or who had mixed normal oropharyngeal flora alone; 0.5 U/mL (0.2 to 0.7 U/mL) for patients with 10(5) to 10(6) colony-forming units per milliliter (P = 0.07); 0.5 U/mL (0.3 to 1.2 U/mL) for patients with 10(6) to 10(7) colony-forming units per milliliter (P<0.01); 0.7 U/mL (0.3 to 1.2 U/mL) for patients with 10(7) to 10(8) colony-forming units per milliliter (P <0.005); and 2.4 U/mL (0.7 to 4.8 U/mL) for patients with 10(8) or greater colony-forming units per milliliter (P<0.0001). The bacterial species influenced airway inflammation; for example, sputum myeloperoxidase activity was greater (P<0.005) in patients colonized with Pseudomonas aeruginosa [median 32 U/mL (interquartile range, 20 to 65 U/mL)] than those colonized with nontypeable Hemophilus influenzae [4 U/mL (2 to 31 U/mL)], which in turn was greater (P = 0.01) than among those colonized with Moraxella catarrhalis [1.1 U/mL (0.6 to 1.8 U/mL)]. We did not find a relation between bacterial load and lung function.

CONCLUSIONS

The bacterial load and species contribute to airway inflammation in patients with stable chronic bronchitis. Further studies are required to determine the consequences of bacterial colonization on patient morbidity and decline in lung function.

Physiological and radiological characterisation of patients diagnosed with chronic obstructive pulmonary disease in primary care

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is common although often poorly characterised, particularly in primary care. However, application of guidelines to the management of such patients needs a clear understanding of the phenotype. In particular, the British guidelines for the management of COPD recommend that the diagnosis is based on appropriate symptoms and evidence of airflow obstruction as determined by a forced expiratory volume in one second (FEV(1)) of <80% of the predicted value and an FEV(1)/VC ratio of <70%.

METHODS

A study was undertaken of 110 patients aged 40-80 years who had presented to their general practitioner with an acute exacerbation of COPD. The episode was treated at home and, when patients had recovered to the stable state (two months later), they were characterised by full lung function tests and a high resolution computed tomographic (HRCT) scan of the chest.

RESULTS

There was a wide range of impairment of FEV(1) which was in the normal range (>/=80%) in 30%, mildly impaired (60-79%) in 18%, moderately impaired (40-59%) in 33%, and severely impaired (<40%) in 19% of patients. A reduced FEV(1)/VC ratio was present in all patients with an FEV(1) of <80% predicted but also in 41% of those with an FEV(1) of >/=80% predicted. Only 5% of patients had a substantial bronchodilator response suggesting a diagnosis of asthma. Emphysema was present in 51% of patients and confined to the upper lobes in most (73% of these patients). HRCT evidence of bronchiectasis was noted in 29% of patients and was predominantly tubular; most (81%) were current or ex-smokers. A solitary pulmonary nodule was seen on 9% of scans and unsuspected lung malignancy was diagnosed in two patients.

CONCLUSIONS

This study confirms that COPD in primary care is a heterogeneous condition. Some patients do not fulfil the proposed diagnostic criteria with FEV(1) of >/=80% predicted but they may nevertheless have airflow obstruction. Bronchiectasis is common in this group of patients, as is unsuspected malignancy. These findings should be considered when developing recommendations for the investigation and management of COPD in the community.

A case of Haemophilus parainfluenzae pneumonia

A 41 year old woman presented with community acquired pneumonia (CAP) which failed to resolve following treatment with amoxycillin and cefaclor prior to referral. Quantitative culture of sputum revealed a pure growth of Haemophilus parainfluenzae and, following antibiotic susceptibility testing of the isolate, ciprofloxacin was prescribed resulting in resolution of the infection. Immunological investigations showed that the patient had a high titre of H parainfluenzae specific IgM. The combination of a pure growth of H parainfluenzae, a response to appropriate antimicrobial therapy, and the presence of a specific antibody response indicated that this organism had a pathogenic role in the patient's pneumonia and should be considered in the differential diagnosis of CAP.

Severe carotid arterial disease: a diagnostic enigma

The development of the duplex scanner has made the diagnosis of carotid arterial disease easy to those trained in its interpretation. The difficulty lies in the ability to define the patient population most likely to benefit from early diagnosis and treatment. All patients referred to the vascular laboratories at two major hospitals for evaluation of neurologic symptoms were entered into the study. The indications for the study, comorbid conditions, and medications were tabulated and compared with the results of the carotid duplex scan. The purpose was to see whether there was a relationship between the severity of carotid arterial disease and symptoms. A total of 5,807 carotid duplex scans were performed on 5,001 patients. There were 525 patients (11%) with an internal carotid artery stenosis of >70 per cent and 252 patients (5%) with an occlusion of the internal carotid artery. In addition, there were a group of 139 patients with severe bilateral carotid disease. Bruit and a history of known carotid disease were the only indications that were statistically related to severe carotid arterial disease. Smoking, diabetes, peripheral vascular disease, cardiac conditions, and hyperlipidemia were also statistically related to patients with significant carotid disease. This study indicates that the classic indications for carotid duplex scans such as transient ischemic attack, amaurosis fugax, and dizziness have no correlation with the severity of the disease.

Characterization of murine autoimmune myocarditis induced by self and foreign cardiac myosin

Previously we showed that autoimmune myocarditis could be induced in mice by immunization with purified murine cardiac myosin (MCM). In this study, we found that identical disease could also be induced in genetically susceptible mice by immunization with porcine cardiac myosin (PCM). The cardiac lesions induced by both antigens were characterized by extensive infiltration of the myocardium accompanied by myocyte necrosis. A novel finding was the presence of multinucleated giant cells and eosinophils in the cardiac infiltrates, in addition to a mixture of mononuclear cells and polymorphonuclear cells described previously. Immunohistochemical staining demonstrated that the mononuclear cells consisted predominantly of macrophages, CD4+ T cells and, to a lesser extent, CD8+ T cells and B cells. In addition, increased cardiac expression of adhesion molecules E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and intercellular cell adhesion molecule-1 (ICAM-1) were demonstrated in mice that developed myocarditis as compared with those that did not develop disease upon immunization with either PCM or MCM. The levels of TNFalpha detected in spleen cell culture supernatant were found to be higher in mice that developed myocarditis than in those that did not develop the disease. Mice immunized with PCM generated T cells and B cells reactive not only with PCM but also with MCM, and vice versa. In addition, the serum levels of IgG1 anti-MCM antibodies produced in mice immunized with PCM as well as MCM were found to correlate positively with the development of myocarditis. Such a detailed characterization of the murine model of autoimmune myocarditis induced by PCM or MCM allowed us to compare the disease process induced by homologous self and foreign antigens.

Relationship of sputum color to nature and outpatient management of acute exacerbations of COPD

STUDY OBJECTIVES

To stratify COPD patients presenting with an acute exacerbation on the basis of sputum color and to relate this to the isolation and viable numbers of bacteria recovered on culture.

DESIGN

Open, longitudinal study of sputum characteristics and acute-phase proteins.

SETTING

Patients presenting to primary-care physicians in the United Kingdom. Patients were followed up as outpatients in specialist clinic.

PATIENTS

One hundred twenty-one patients with acute exacerbations of COPD were assessed together with a single sputum sample on the day of presentation (89 of whom produced a satisfactory sputum sample for analysis). One hundred nine patients were assessed 2 months later when they had returned to their stable clinical state.

INTERVENTIONS

The expectoration of green, purulent sputum was taken as the primary indication for antibiotic therapy, whereas white or clear sputum was not considered representative of a bacterial episode and the need for antibiotic therapy.

RESULTS

A positive bacterial culture was obtained from 84% of patients sputum if it was purulent on presentation compared with only 38% if it was mucoid (p < 0.0001). When restudied in the stable clinical state, the incidence of a positive bacterial culture was similar for both groups (38% and 41%, respectively). C-reactive protein concentrations were significantly raised (p < 0.0001) if the sputum was purulent (median, 4.5 mg/L; interquartile range [IQR], 6. 2 to 35.8). In the stable clinical state, sputum color improved significantly in the group who presented with purulent sputum from a median color number of 4.0 (IQR, 4.0 to 5.0) to 3.0 (IQR, 2.0 to 4. 0; p < 0.0001), and this was associated with a fall in median C-reactive protein level to 2.7 mg/L (IQR, 1.0 to 6.6; p < 0.0001).

CONCLUSIONS

The presence of green (purulent) sputum was 94.4% sensitive and 77.0% specific for the yield of a high bacterial load and indicates a clear subset of patient episodes identified at presentation that is likely to benefit most from antibiotic therapy. All patients who produced white (mucoid) sputum during the acute exacerbation improved without antibiotic therapy, and sputum characteristics remained the same even when the patients had returned to their stable clinical state.

MEKC of desmosine and isodesmosine in urine of chronic destructive lung disease patients

Degradation of extracellular matrix components is central to many pathological features of chronic destructive lung disorders. Desmosine and isodesmosine are elastin-derived cross-linked amino acids whose urine levels are considered representative of elastin breakdown. The aim of this study was to apply a novel methodology, based on high-performance capillary electrophoresis, to the quantification of desmosine and isodesmosine in 11 patients with stable chronic obstructive pulmonary disease (COPD), 10 with an exacerbation of COPD, nine with alpha1-antitrypsin deficiency, 13 with bronchiectasis, and 11 adults with cystic fibrosis, in comparison to 24 controls. It was found that, in patients with stable COPD, urinary desmosine levels were higher than in controls (p=0.03), but lower than in COPD subjects with an exacerbation (p< or =0.05). The highest desmosine levels were found in subjects with alpha1-antitrypsin deficiency, bronchiectasis and cystic fibrosis (p<0.001 versus stable COPD). In a short-term longitudinal study, five stable COPD patients showed a constant rate of desmosine excretion (mean coefficient of variation <8% over three consecutive days). In conclusion, the present method is simple and suitable for the determination of elastin-derived cross-linked amino acid excretion in urine, giving results similar to those obtained using other separation methods. In addition, evidence is presented that urinary desmosine excretion is increased in conditions characterized by airway inflammation, such as exacerbations of chronic obstructive pulmonary disease, bronchiectasis and cystic fibrosis. Results obtained in subjects with alphal-antitrypsin deficiency suggest that this method might be used to evaluate the putative efficacy of replacement therapy.

Airways inflammation in chronic bronchitis: the effects of smoking and alpha1-antitrypsin deficiency

Airways inflammation in chronic bronchitis is thought predominantly to be a direct consequence of neutrophil recruitment and release of elastase in response to factors such as cigarette smoke. The aims of this study were to assess the role of smoking and determine whether the serum elastase inhibitor alpha1-antitrypsin (alpha1AT) influenced the process. Airways inflammation was compared between patients with chronic obstructive bronchitis with (n=39) and without (n=42) severe alpha1AT deficiency. The authors assessed the sputum concentration of the neutrophil chemoattractants interleukin-8 (IL-8) and leukotriene (LT)B4, myeloperoxidase (MPO) as a marker of neutrophil influx, neutrophil elastase activity and its natural inhibitors, alpha1AT and secretory leukoprotease inhibitor (SLPI). Finally serum alpha1AT was measured to determine the degree of protein leakage (sputum sol serum alpha1AT ratio). Compared to current smokers, the exsmokers had a lower concentration of the chemoattractant IL-8 (p<0.05) and a lower MPO concentration, although this failed to reach conventional statistical significance (p=0.06). Patients with alpha1AT deficiency had greater inflammation in the larger airways with increased LTB4 (p<0.005), MPO (p<0.001), neutrophil elastase activity (p<0.01), protein leak (p<0.001), and were found to have a lower anti-proteinase screen with both reduced sputum alpha1AT (p<0.001) and SLPI concentrations (p<0.05). The reduction in sputum interleukin-8 levels in exsmokers may decrease neutrophil influx and thus explain the slower rate of neutrophil mediated progression of lung disease compared to subjects who continue to smoke. Patients with alpha1-antitrypsin deficiency had greater inflammation suggesting that alpha1-antitrypsin plays an important role in protecting the larger airways from the inflammatory effects of elastase activity and may explain their more rapid progression of disease.

Bronchial inflammation: its relationship to colonizing microbial load and alpha(1)-antitrypsin deficiency

Neutrophil elastase is capable of generating many of the features of chronic bronchial disease. In patients with COPD, airways inflammation with neutrophil recruitment and elastase release is positively correlated with colonizing bacterial load in the stable clinical state (p < 0.0005). In addition, alpha(1)-antitrypsin deficiency is associated with a greater neutrophil load, higher elastase activity, leukotriene-B(4) concentration, and serum protein leak than matched patients without deficiency (p < 0.005). These data confirm an effect of bronchial colonization on airways inflammation in COPD and indicate the role of alpha(1)-antitrypsin in its modulation.

Prevalence of enteric zoonotic organisms in cats

OBJECTIVE

To determine prevalence of enteric zoonotic organisms in cats in north-central Colorado.

DESIGN

Prospective study.

SAMPLE POPULATION

Serum and fecal samples from 87 cats with diarrhea, 106 cats without diarrhea, and 12 cats for which fecal consistency was unknown.

PROCEDURES

Samples were obtained from client-owned cats and cats at a humane society shelter. Serum was assayed for feline leukemia virus antigen and antibodies against feline immunodeficiency virus, IgM antibodies against Toxoplasma gondii, and IgG antibodies against T gondii and Cryptosporidium parvum. Microscopic examination of unstained feces was performed after centrifugation in a zinc sulfate solution, thin fecal smears were stained with acid fast stain and examined for C parvum, and bacteriologic culture of feces was used to detect aerobic and anaerobic bacteria.

RESULTS

Enteric zoonotic organisms were detected in feces from 27 of 206 (13.1%) cats and included C parvum (5.4%), Giardia spp (2.4%). Toxocara cati (3.9%), Salmonella enterica serotype Typhimurium (1.0%), and Campylobacter jejuni (1.0%); each organism was detected in samples from cats with and without diarrhea. Although differences between groups were not significant, a higher proportion of shelter cats (18.2%) had enteric zoonotic organisms than client-owned cats (10.1%).

CONCLUSIONS AND CLINICAL RELEVANCE

Enteric zoonotic organisms were detected in feces of 13.1% of cats, suggesting that cats, particularly those in homes of immunocompromised humans, should be evaluated for enteric zoonotic organisms.

Bronchial inflammation in acute bacterial exacerbations of chronic bronchitis: the role of leukotriene B4

Neutrophils recruited to the airways in chronic obstructive pulmonary disease (COPD) are thought to mediate tissue destruction. Neutrophil recruitment is increased during bacterial exacerbations. The inflammatory process was studied in patients with an acute exacerbation of COPD in order to ascertain the role of leukotriene B4 (LTB4). The sputum of eight subjects with a bacterial exacerbation of COPD was analysed for neutrophil products (myeloperoxidase, elastase) and chemoattractants (interleukin-8 (IL-8) and LTB4). The contribution of LTB4 to the chemotactic activity of the sputum sol phase was determined using the LTB4 receptor antagonist LY293111. The concentrations of the serum acute phase proteins alpha1-proteinase inhibitor, alpha1-antichymotrypsin and C-reactive protein were measured. All patients received appropriate broad-spectrum antibiotic treatment for 7-14 days. Initially, the sputum myeloperoxidase activity was high, indicating neutrophil influx; this was associated with high levels of IL-8 and LTB4. All these concentrations fell with treatment (p<0.01). The chemotactic activity of the sputum was raised on presentation and fell with treatment (p<0.01). LTB4 contributed approximately 30% of the total chemotactic activity on presentation; this diminished with therapy. All acute phase proteins were raised on presentation and fell with therapy (p<0.01). These findings suggest that leukotriene B4 contributes to neutrophil influx into the airway in chronic obstructive pulmonary disease and may influence disease progression.

Immune response to Haemophilus parainfluenzae in patients with chronic obstructive lung disease

Haemophilus parainfluenzae is often isolated from the sputa of patients with chronic obstructive lung disease. We have investigated the immune response to this organism in patients with chronic bronchitis (n = 3) and bronchiectasis (n = 10) and in healthy controls (n = 9). Outer membrane proteins (OMPs) of H. parainfluenzae were purified for use in enzyme-linked immunosorbent and immunoblot assays. Whole-cell H. parainfluenzae preparations were used to adsorb antibodies from serum samples, which were subsequently immunoblot assayed to investigate the antibody response to surface-exposed epitopes. Levels of H. parainfluenzae-specific immunoglobulin G (IgG), but not IgA or IgM, were increased in the sera of patients with chronic obstructive lung disease compared to levels in control subjects. The species specificity of the antibody response was confirmed, although a degree of cross-reactivity with H. influenzae antigens was observed. IgA and IgG specific for OMPs of H. parainfluenzae were demonstrated to be present in the sputa and sera of five patients with chronic obstructive lung disease. Variation in the pattern and intensity of antigen recognition was observed among patients and among immunoglobulin classes. OMPs of approximately 36, 22, and 15 kDa were confirmed to possess epitopes exposed on the surface of intact H. parainfluenzae. We have demonstrated the presence of a species-specific systemic immune response to H. parainfluenzae in colonized patients. A specific antibody response was also observed in sputum, and the antigen specificity of these responses in patients with chronic obstructive lung disease was investigated for the first time. The presence of a specific immune response suggests that H. parainfluenzae may have a pathogenic role in patients with chronic obstructive lung disease.

Evidence for excessive bronchial inflammation during an acute exacerbation of chronic obstructive pulmonary disease in patients with alpha(1)-antitrypsin deficiency (PiZ)

Patients with homozygous (PiZ) alpha(1)-antitrypsin (AAT) deficiency have not only low baseline serum AAT levels (approximately 10 to 15% normal) but also an attenuated acute phase response. They are susceptible to the development of premature emphysema but may also be particularly susceptible to lung damage during bacterial exacerbations when there will be a significant neutrophil influx. The purposes of the present study were to assess the inflammatory nature of acute bacterial exacerbations of chronic obstructive pulmonary disease (COPD) in subjects with AAT deficiency, to compare this with COPD patients without deficiency, and to monitor the inflammatory process and its resolution following appropriate antibacterial therapy. At the start of the exacerbation, patients with AAT deficiency had lower sputum AAT (p < 0.001) and secretory leukoprotease inhibitor (SLPI; p = 0.02) with higher elastase activity (p = 0.02) compared with COPD patients without deficiency. Both groups had a comparable acute phase response as assessed by C-reactive protein (CRP) but the AAT-deficient patients had a minimal rise in serum AAT (to < 6 microM). After treatment with antibiotics, in patients with AAT deficiency, there were significant changes in many sputum proteins including a rise in SLPI levels, and a reduction in myeloperoxidase (MPO) and elastase activity (p < 0. 005 for all measures); the sputum chemoattractants interleukin-8 (IL-8) and leukotriene B(4) (LTB(4)) fell (p < 0.01), and protein leak (sputum/serum albumin ratio) became lower (p < 0.01). The changes were rapid and within 3 d of the commencement of antibiotic therapy the biochemical markers had decreased significantly, but took a variable time thereafter to return to baseline values. In conclusion, patients with AAT deficiency had evidence of increased elastase activity at the start of the exacerbation when compared with nondeficient COPD patients which probably reflects a deficient antiproteinase screen (lower sputum AAT and SLPI). The increased bronchial inflammation at presentation resolved rapidly with 14 d of antibiotic therapy.

The message from the World Asthma Meeting. The Working Groups of the World Asthma Meeting, held in Barcelona, Spain, December 9-13, 1998

The 1998 World Asthma Meeting (WAM) has been the first multidisciplinary event aimed to consider asthma as a global public health problem in children and adults. The purpose of the meeting was to present state-of-the-art scientific information and to make recommendations on the research agenda for the coming years. Five Working Groups of invited experts were appointed to pin-point the established knowledge and the important questions in the areas of epidemiology, prevention, pathogenesis, management, and education. Their reports were discussed during the final plenary session, and are forming the current proceedings of the meeting. The message of the World Asthma Meeting provides a research agenda supported by the major international bodies involved in this disease. An integrated approach is considered to be essential in order to improve the prevention and care of asthma in all countries of the world.

Effect of carbon dioxide on testing of susceptibilities of respiratory tract pathogens to macrolide and azalide antimicrobial agents

The in vitro activities of erythromycin, azithromycin, and clarithromycin against 178 clinical isolates from the lower respiratory tract of patients with chronic obstructive pulmonary disease were determined by an agar dilution method. The plates were incubated in air alone or in 5% carbon dioxide. The MICs measured in air alone were lower for most isolates than those measured in 5% carbon dioxide, illustrating the "pH effect" of incubation in carbon dioxide. Testing of isolates in 5% carbon dioxide on pH-adjusted medium (pH 8.4) resulted in MICs of one or two doubling dilutions lower than those obtained on agar with a neutral pH. A bioassay of the three agents incubated in air and in 5% carbon dioxide resulted in a significant loss of activity of all three agents in the carbon dioxide-enriched atmosphere. However, this loss-of-activity effect was significantly reduced when the bioassay medium was adjusted to pH 8.4 prior to incubation in 5% carbon dioxide.

Quality of life in elderly subjects with a diagnostic label of asthma from general practice registers

The aim of this study was to assess health-related quality of life (QoL) in elderly subjects with a diagnostic label of asthma from a general practice population, and to determine the main contributory factors. Sixty people aged > or =70 yrs with a primary care diagnostic label of asthma, and 43 control subjects were recruited. Assessment of bronchodilator response, and oral steroid trials were conducted where possible. The main outcome measures were QoL scores for the Short Form (SF)-36 and the St George's Respiratory Questionnaire (SGRQ). In the asthma group, 29 subjects demonstrated a significant airway response to bronchodilators or steroids. Mean SF-36 scores were significantly worse in the total asthma group for components of physical function, physical role limitation, and general health, although psychological scores were similar. QoL remained worse than controls in those subjects with a significant bronchodilator response. Dyspnoea and depression accounted for 61% of the variance in the SGRQ, but forced expiratory volume in one second was not an independent variable. Quality of life is impaired in elderly people with a diagnosis of asthma, including those with demonstrable airway variability. Many older subjects with asthma note a variety of symptoms, highlighting the need for further research into the adequacy and efficacy of their treatment.

The effects of peripheral vascular disease with osteomyelitis in the diabetic foot

BACKGROUND

Osteomyelitis in the diabetic foot is a difficult problem with multiple etiologies. The effects of peripheral vascular disease, neuropathy, and repetitive trauma all interact to produce complex lesions with exposed bone, surrounding cellulitis, and gangrenous changes.

METHODS

We performed a retrospective study over a 14-year period at a community hospital looking at osteomyelitis in the diabetic foot. We looked at the contributing factors, organisms involved, most common locations, physical findings, and surgical procedures necessary to treat this condition. The purpose of the study was to determine the incidence and effect of peripheral vascular disease in diabetic patients with foot ulcers.

RESULTS

There were a total of 150 patients requiring 278 hospitalizations over the 14-year period who represented 14% of all diabetic admissions. A total of 438 surgical procedures were necessary in these patients, with the most common being debridement (39%) and toe amputation (19%). There were 6 deaths (4%) in this series, and leg amputation was necessary in 21 patients (14%). A vascular bypass was necessary for healing and limb salvage in 36 patients (24%). Most of the bypasses (85%) were with autogenous tissue to the distal leg in order to limit the extent of amputation and to preserve a functional limb.

CONCLUSION

Ischemia is often a contributing factor in the diabetic foot ulcer that must be recognized and treated to avoid prolonged hospitalization, spreading infection, and unnecessary amputation.

The occult pneumothorax: an increasing diagnostic entity in trauma

The increasing use of CT for the evaluation of blunt abdominal trauma has diagnosed undetected pneumothoraces in many patients. We performed a retrospective study at a major trauma center to determine the incidence of occult pneumothorax in the trauma patient. All trauma patients (3121) admitted to a Level I trauma center over a 51-month period were reviewed to determine the incidence of pneumothorax and occult pneumothorax, the method of diagnosis, and treatment. All major trauma patients received a chest X-ray (CXR), whereas 842 patients (27%) underwent an abdominal CT scan. In the 172 patients diagnosed with pneumothorax, 157 abdominal CT scans were performed and 143 were positive for pneumothorax. CXR revealed 49 right-sided pneumothoraces and 58 left-sided pneumothoraces in 95 patients. Abdominal CT scans diagnosed 73 right pneumothoraces and 90 left pneumothoraces in 143 patients. There were 67 patients (71 thoraces) who were seen to have a pneumothorax on abdominal CT scan not seen on admission CXR. This represents 2.2 per cent of all trauma patients and 7.9 per cent of patients with abdominal CT scans. In looking at just trauma patients with pneumothorax, the CT scan was responsible for diagnosing 39 per cent of the patients with a pneumothorax. The occult pneumothorax is being diagnosed more frequently as methods of evaluating and diagnosing trauma patients become more sensitive.

Comparison of frequency of complications of implantable cardioverter-defibrillators in children versus adults

Compared with adults patients (n = 309) receiving implantable cardioverter-defibrillators at the same institution, pediatric patients (n = 11) exhibited a trend toward lower defibrillation thresholds. At follow-up of 29 +/- 17 months, the incidence of recurrent arrhythmias was similar, but lead revisions and device infections were more common in the pediatric patients.