Salicylate-induced pulmonary edema. Clinical features and prognosis

Acute salicylate poisoning: risk factors for severe outcome

CONTEXT

Salicylate poisoning remains a significant public health threat with more than 20,000 exposures reported annually in the United States.

OBJECTIVE

We aimed to establish early predictors of severe in-hospital outcomes in Emergency Department patients presenting with acute salicylate poisoning.

METHODS

This was a secondary data analysis of adult salicylate overdoses from a prospective cohort study of acute drug overdoses at two urban university teaching hospitals from 2009 to 2013. Patients were included based on confirmed salicylate ingestion and enrolled consecutively. Demographics, clinical parameters, treatment and disposition were collected from the medical record. Severe outcome was defined as a composite occurrence of acidemia (pH <7.3 or bicarbonate <16 mEq/L), hemodialysis, and/or death.

RESULTS

Out of 1997 overdoses screened, 48 patients met inclusion/exclusion criteria. Patient characteristics were 43.8% male, median age 32 (range 18-87), mean initial salicylate concentration 28.1 mg/dL (SD 26.6), and 20.8% classified as severe outcome. Univariate analysis indicated that age, respiratory rate, lactate, coma, and the presence of co-ingestions were significantly associated with severe outcome, while initial salicylate concentration alone had no association. However, when adjusted for salicylate concentration, only age (OR 1.13; 95% CI 1.02-1.26) and respiratory rate (OR 1.29; 95% CI 1.02-1.63) were independent predictors. Additionally, lactate showed excellent test characteristics to predict severe outcome, with an optimal cutpoint of 2.25 mmol/L (78% sensitivity, 67% specificity).

CONCLUSIONS

In adult Emergency Department patients with acute salicylate poisoning, independent predictors of severe outcome were older age and increased respiratory rate, as well as initial serum lactate, while initial salicylate concentration alone was not predictive.

Drug-Induced Lung Toxicity

The number of blood-borne chemotherapeutic agents implicated in drug-induced lung toxicity continues to increase, although problems in detection remain. The initiation of drug-induced lung injury can have an immunologic or nonimmunologic basis. If endothelial cells are injured, interstitial pulmonary edema may result. Regardless of the source of injury, the progression of drug-induced lung toxicity is often quite similar, involving (1) parenchymal damage, (2) recruitment of inflammatory cells, and (3) progression of the inflammatory process. If the inflammatory reponse is sufficiently severe and disperse, increased collagen can be deposited in interstitial and intra-alveolar areas. The resulting attenuation of gas exchange can induce dyspnea and possibly death. Recent research suggests mediation of the fibrogenic process via cytokines such as transforming growth factor-β and tumor necrosis factor. Preliminary results demonstrating amelioration of cytokine mediated lung-induced fibrosis in animal models with appropriate antibodies suggest a possible future modality of therapy. Certain amphiphilic drugs are capable of eliciting a more specific form of lung toxicity. This class of drugs can interfere with phospholipid metabolism in pulmonary macrophages. In these cases, phospholipidosis results from phospholipid accumulation. The physiologic sequelae in human phospholipidosis is still uncertain.

Noncardiac Pulmonary Edema induced by Sitagliptin Treatment

A 74-year-old male patient with type 2 diabetes mellitus admitted to the emergency department with the complaints of progressive breathlessness, dry cough, and swollen lower extremities. Our patient had type 2 diabetes mellitus and hypertension for 3 years. His HbA1c was not within the target range so sitagliptin was added to on-going therapy. After 1 week of starting sitagliptin therapy, even though the patient had not heart failure he applied to the emergency department with a complaint of dyspnea. The cardiovascular safety and efficacy of many anti-hyperglycemic agents such as sitagliptin, saxagliptin are unclear. Our case has shown that dipeptidyl peptidase 4 inhibitors may cause pulmonary edema. Hence, it should be used with cautious, especially in patients with heart failure.

Noncardiac Pulmonary Edema induced by Sitagliptin Treatment

A 74-year-old male patient with type 2 diabetes mellitus admitted to the emergency department with the complaints of progressive breathlessness, dry cough, and swollen lower extremities. Our patient had type 2 diabetes mellitus and hypertension for 3 years. His HbA1c was not within the target range so sitagliptin was added to on-going therapy. After 1 week of starting sitagliptin therapy, even though the patient had not heart failure he applied to the emergency department with a complaint of dyspnea. The cardiovascular safety and efficacy of many anti-hyperglycemic agents such as sitagliptin, saxagliptin are unclear. Our case has shown that dipeptidyl peptidase 4 inhibitors may cause pulmonary edema. Hence, it should be used with cautious, especially in patients with heart failure.

Cigarette smoke causes lung vascular barrier dysfunction via oxidative stress-mediated inhibition of RhoA and focal adhesion kinase

Cigarette smoke (CS) is a major cause of chronic lung and cardiovascular diseases. Recent studies indicate that tobacco use is also a risk factor for acute lung injury (ALI) associated with blunt trauma. Increased endothelial cell (EC) permeability is a hallmark of ALI. CS increases EC permeability in vitro and in vivo; however, the underlying mechanism is not well understood. In this study, we found that only 6 h of exposure to CS impaired endothelial barrier function in vivo, an effect associated with increased oxidative stress in the lungs and attenuated by the antioxidant N-acetylcysteine (NAC). CS also exacerbated lipopolysaccharide (LPS)-induced increase in vascular permeability in vivo. Similar additive effects were also seen in cultured lung EC exposed to cigarette smoke extract (CSE) and LPS. We further demonstrated that CSE caused disruption of focal adhesion complexes (FAC), F-actin fibers, and adherens junctions (AJ) and decreased activities of RhoA and focal adhesion kinase (FAK) in cultured lung EC. CSE-induced inhibition of RhoA and FAK, endothelial barrier dysfunction, and disassembly of FAC, F-actin, and AJ were prevented by NAC. In addition, the deleterious effects of CSE on FAC, F-actin fibers, and AJ were blunted by overexpression of constitutively active RhoA and of FAK. Our data indicate that CS causes endothelial barrier dysfunction via oxidative stress-mediated inhibition of RhoA and FAK.

Rheumatoid arthritis-associated interstitial lung disease: diagnostic dilemma

Interstitial lung disease (ILD) is an increasingly recognized complication of rheumatoid arthritis (RA) contributing to significantly increased morbidity and mortality. Diagnosis can be challenging since patients are unlikely to report dyspnea due to an overall decrease in physical activity with advanced arthritic symptoms. Additionally, infections, drug toxicity, and environmental toxins can mimic ILD, creating significant diagnostic dilemmas for the clinician. In this paper we will explore an effective clinical algorithm for the diagnosis of RA-ILD. We will also discuss features of drug-related toxicities, infections, and environmental toxins that comprise the main entities in the differential diagnosis of RA-ILD. Finally, we will explore the known and experimental treatment options that may have some benefit in the treatment of RA-ILD.

Current management of salicylate-induced pulmonary edema

Salicylate-induced pulmonary edema (SIPE) can occur in both acute and chronic users of aspirin or salicylate products. The medical history, especially when it reveals the use of salicylates, is critical when considering this diagnosis. Unfortunately, the neurologic and systemic effects of salicylate toxicity may hinder the ability to obtain a reliable medical history. SIPE should be considered in patients who present with pulmonary edema and neurological changes, anion-gap metabolic acidosis, or possible sepsis. Some patients may be treated for "pseudosepsis" or other conditions, thereby delaying the diagnosis of salicylate intoxication. Misdiagnosis and possibly delayed diagnosis of SIPE can lead to a significant increase in morbidity and mortality. Serum and urine alkalinization by administration of intravenous sodium bicarbonate are commonly utilized therapeutic strategies. Finally, hemodialysis is a therapy which should be considered early in the course of treatment. The objective of this review was to emphasize the importance of rapid diagnosis and appropriate treatment in patients with SIPE, and summarize the current literature as it relates to the adult population.

Respiratory involvement in inflammatory bowel diseases

Inflammatory bowel diseases (IBD) include ulcerative colitis (UC) and Crohn's disease (CD) and are due to a dysregulation of the antimicrobial defense normally provided by the intestinal mucosa. This inflammatory process may extend outside the bowel to many organs and also to the respiratory tract. The respiratory involvement in IBD may be completely asymptomatic and detected only at lung function assessment, or it may present as bronchial disease or lung parenchymal alterations. Corticosteroids, both systemic and aerosolized, are the mainstay of the therapeutical approach, while antibiotics must be also administered in the case of infectious and suppurative processes, whose sequels sometimes require surgical intervention. The relatively high incidence of bronchopulmonary complications in IBD suggests the need for a careful investigation of these patients in order to detect a possible respiratory involvement, even when they are asymptomatic.

Drug-induced pulmonary edema and acute respiratory distress syndrome

Noncardiogenic pulmonary edema, and, to a lesser extent, acute respiratory distress syndrome (ARDS), are common clinical manifestations of drug-induced lung diseases. Clinical features and radiographic appearances are generally indistinguishable from other causes of pulmonary edema and ARDS. Typical manifestations include dyspnea, chest discomfort, tachypnea, and hypoxemia. Chest radiographs commonly reveal interstitial and alveolar filling infiltrates. Unlike pulmonary edema that is due to congestive heart failure, cardiomegaly and pulmonary vascular redistribution are generally absent in cases that are drug-related. Rare cases of drug-induced myocarditis with heart failure and pulmonary edema have been described. Results from laboratory evaluation and respiratory function tests are nonspecific.

Toxicology in the critically ill patient

Intoxications present in many forms including: known drug overdose or toxic exposure, illicit drug use, suicide attempt, accidental exposure, and chemical or biological terrorism. A high index of suspicion and familiarity with toxidromes can lead to early diagnosis and intervention in critically ill, poisoned patients. Despite a paucity of evidence-based information on the management of intoxicated patients, a rational and systematic approach can be life saving.

Diffuse alveolar damage and recurrent respiratory failure: report of 6 cases

We report 6 patients in whom diffuse alveolar damage (DAD) was found on 1 or more lung biopsy specimens and who experienced recurrent episodes of acute respiratory failure. The patients ranged in age from 43 to 55 years. Two to five episodes of respiratory failure occurred in each over a period of 4 months to 2 years. One patient developed evidence of chronic lung disease; while the others remained well between episodes. Lung biopsies showed the acute stage of DAD in 3, overlapping acute and organizing stages in 3, and the organizing stage in 2. A definite cause was not identifiable in any. However, 4 had been treated with narcotics for chronic pain before the first episode, and 1 received this treatment before the recurrent episode. Three also were receiving psychotropic drugs for anxiety and depression. Five patients had evidence of gastroesophageal reflux disease (GERD) and/or hiatal hernia, 2 of whom underwent Nissen fundoplication in hopes of preventing future recurrences. Although a definite cause of the recurrent DAD was not identified, the findings suggest the possibility of a reaction to narcotics and/or psychotropic drugs in some patients, with a possible additional effect of GERD. A drug history should be carefully elicited in patients with recurrent DAD, and all potentially toxic drugs should be stopped.

NSAIDs and the kidney revisited: are selective cyclooxygenase-2 inhibitors safe?

Selective cyclooxygenase-2 (COX-2) inhibitors have provided relief for patients suffering from chronic pain and other inflammatory conditions and have reduced adverse gastrointestinal effects. The documented reduction in gastric erosions, ulcerations, and perforations during the use of COX-2-selective inhibitors raises the question: would the kidney be similarly spared? Our understanding of these enzyme isoforms in the kidney is incomplete. However, kidney tissue seems to possess "constitutive" or homeostatic COX-2 enzyme, suggesting a role for prostaglandins produced by this isoform. In addition, studies evaluating the renal effects of the selective nonsteroidal anti-inflammatory drugs (NSAIDs) are inconclusive, and available data on the renal effects of COX-2-selective inhibitors are conflicting. Inadequate numbers, varied baseline patient characteristics, and different doses and lengths of drug treatment hampers comparison of the small number of clinical investigations available for review. Therefore, this article reviews the role of cyclooxygenase enzyme activity and associated prostaglandins in the kidney and the adverse renal effects of nonselective NSAIDs. We also touch on the COX-1/COX-2 selectivity of NSAIDs, the localization of COX enzymes in kidneys, and clinical studies examining the renal effects of selective COX-2 inhibitors.

Chronic salicylism resulting in noncardiogenic pulmonary edema requiring hemodialysis

Salicylate intoxication is frequently overlooked as a cause of noncardiogenic pulmonary edema and altered mental status in adult patients. We describe a 42-year-old woman who presented with two episodes of recurrent noncardiogenic pulmonary edema requiring intubation. The first admission to hospital triggered an extensive initial workup that did not indicate a cause for the pulmonary edema. At the second presentation, recognition of the clinical syndrome in the emergency department led to the correct diagnosis of salicylate intoxication. The patient was successfully treated with hemodialysis and urinary alkalinization, leading to rapid resolution of pulmonary edema and extubation. Several aspects of the clinical presentation suggest that the patient suffers from chronic salicylism, probably complicated by episodic superimposed acute intoxication, a condition often misdiagnosed or diagnosed late in the course of disease, contributing to substantial morbidity and mortality in these patients. Maintenance of a high index of suspicion and rapid institution of appropriate therapy including hemodialysis once the diagnosis is established is an important determinant of outcome in this serious but underdiagnosed disorder.

Pulmonary manifestations of rheumatoid arthritis

Rheumatoid arthritis (RA) is the most common of the classic connective tissue diseases. Its manifestations in the chest are varied as the pleura, lung parenchyma, airways, and pulmonary vasculature can all be involved. The approach to a patient with RA and respiratory complaints, radiographic findings, or physiologic abnormalities requires a broad understanding of these manifestations. Moreover, the potential for therapy-related toxicity adds further complexity to the pulmonary evaluation of these patients.

Pulmonary toxicity of drugs used to treat systemic autoimmune diseases

A number of drugs used to treat systemic autoimmune diseases can cause respiratory complications. These include bronchospasm, noncardiac pulmonary edema, interstitial pneumonitis and fibrosis, hypersensitivity, and numerous other disorders. Additionally, some of these drugs increase the risk of infections, particularly with opportunistic organisms. This article reviews the clinical presentation and mechanism of toxicity of drug related pulmonary complications.

Salicylate Intoxication

Aspirin (acetylsalicylic acid) is one of the most widely used over-the-counter medications. Because of its availability and widespread use, aspirin has a long history of human toxicity from accidental or intentional overdosing. According to the American Association of Poison Control Centers aspirin was implicated in 19083 exposures in 1995, with 11800 cases treated in a health care facility, and 52 associated deaths. Aspirin toxicity may be a life-threatening condition that produces multiple system organ failure requiring treatment in an intensive care unit. Managing a patient with salicylism will challenge the skills of the critical care team, especially in the areas of life support, fluid and electrolyte balance, and acid-base management. This article reviews the physiology, pathophysiology, acute and chronic salicylism in children and adults, and management of salicylate intoxication.

Pulmonary edema in a woman following fetal surgery

Most cases of acute lung injury in pregnancy are attributed to hydrostatic pulmonary edema. In this report, however, we describe a 20-year-old pregnant woman who developed a unique case of increased permeability pulmonary edema following surgery for the repair of a fetal congenital diaphragmatic hernia. Two days after surgery, the patient developed acute respiratory failure and diffuse alveolar edema, requiring intubation and positive pressure ventilation for 5 days. The diagnosis of increased permeability pulmonary edema was confirmed by the ratio of pulmonary edema fluid to plasma protein (ratio=0.99). The patient received IV nitroglycerine for tocolysis. As a nitric oxide donor, the nitroglycerine may have combined with exogenous oxygen to form peroxynitrite, a known impediment to alveolar epithelial cell function. Many cases of pulmonary edema in pregnancy are diagnosed as hydrostatic based on clinical parameters, such as positive maternal fluid balance. In this case, these parameters would have been misleading. Measurement of the protein concentration in the pulmonary edema fluid allowed us to accurately determine that the patient had increased permeability pulmonary edema as the cause of her acute respiratory failure. Sampling of pulmonary fluid can differentiate the type of edema formation and in some cases help to identify mechanisms of acute lung injury.

Aspirin, salicylate, sulfite and tartrazine induced bronchoconstriction. Safe doses and case definition in epidemiological studies

Allergic-like reactions to chemical components of foods and medicines may be common. The prevalence of idiosyncratic reactions to aspirin, salicylate, metabisulfite and tartrazine is not known. We used a tertiary referral clinic population to estimate safe exposure doses for epidemiological studies. A 15% decrease in the amount of air expired in one second was defined a positive response. The median effective molar doses of the agents were remarkably similar: metabisulfite 0.19 mM, 34.4 mg [95% confidence interval (CI) 0.14, 0.27 mM]; tartrazine 0.10 M, 55.0 mg (95% CI 0.05, 0.21 mM); aspirin 0.09 mM, 16.5 mg (95% CI 0.04, 0.19 mM); and salicylate 0.11 mM, 15.3 mg (95% CI 0.05, 0.27 mM). Doses to which the most sensitive (5%) and practically all (95%) susceptible persons might respectively respond are: metabisulfite 4.6 mg, 255.8 mg; tartrazine 3.4 mg, 885.6 mg; aspirin 0.8 mg, 332.3 mg; and salicylate 2.6 mg, 89.9 mg. Doses within these ranges can be used in epidemiological studies.

Transient myocardial dysfunction in a child with salicylate toxicity

Aspirin overdose may result in acid-base disturbances, electrolyte abnormalities, pulmonary edema, chemical hepatitis, seizures, and mental status alteration, but myocardial depression has not been reported following aspirin overdose in children. In addition to these more typical features, the 13-month-old boy reported here developed clinical, radiographic, and echocardiographic evidence of myocardial impairment with pulmonary edema and moderately severe global left ventricular dysfunction (estimated shortening fraction of 23%). Complete resolution of the myocardial dysfunction was demonstrated on follow-up echocardiography as the child recovered from the aspirin intoxication. This case suggests that myocardial dysfunction can occur as a result of toxic aspirin ingestion, and that it may contribute to salicylate-induced pulmonary edema.

Drug-induced pulmonary disease

Drug-induced disease of any system or organ can be associated with high morbidity and mortality, and it is tremendously costly to the health care of our country. More than 100 medications are known to affect the lungs adversely, including the airways in the form of cough and asthma, the interstitium with interstitial pneumonitis and noncardiac pulmonary edema, and the pleura with pleural effusions. Patients commonly do not even know what medications they are taking, do not bring them to the physician's office for identification, and usually do not relate over-the-counter medications with any problems they have. They assume that all nonprescription drugs are safe. Patients also believe that if they are taking prescription medications at their discretion, meaning on an as-needed basis, then these medications are also not important. This situation stresses just how imperative it is for the physician to take an accurate drug history in all patients seen with unexplained medical situations. Cardiovascular drugs that most commonly produce a pulmonary abnormality are amiodarone, the angiotensin-converting enzyme inhibitors, and beta-blockers. Pulmonary complications will develop in 6% of patients taking amiodarone and 15% taking angiotensin-converting enzyme inhibitors, with the former associated with interstitial pneumonitis that can be fatal and the latter associated with an irritating cough that is not associated with any pathologic or physiologic sequelae of consequence. The beta-blockers can aggravate obstructive lung disease in any patient taking them. Of the antiinflammatory agents, acetylsalicyclic acid can produce several different airway and parenchymal complications, including aggrevation of asthma in up to 5% of patients with asthma, a noncardiac pulmonary edema when levels exceed 40 mg/dl, and a pseudosepsis syndrome. More than 200 products contain aspirin. Low-dose methotrexate is proving to be a problem because granulomatous interstitial pneumonitis develops in 5% of those patients receiving it. This condition occurs most often in patients receiving the drug for rheumatoid arthritis, but it has been reported in a few patients receiving it for refractory asthma. Chemotherapeutic drug-induced lung disease is almost always associated with fever, thus mimicking opportunistic infection, which is the most common cause of pulmonary complications in the immunocompromised host. However, in 10% to 15% of patients, the pulmonary infiltrate is due to an adverse effect from a chemotherapeutic agent. This complication is frequently fatal even when recognized early.(ABSTRACT TRUNCATED AT 400 WORDS)

Antirheumatic drug reactions in the lung

Drug-induced lung disease during treatment with antirheumatic drugs should be considered in all patients receiving these agents who develop new pulmonary symptoms. When a potential drug-related reaction is identified, the possible offending agents should be discontinued, appropriate respiratory support initiated, and a thorough investigation for other causes of respiratory disease launched to exclude infection or other pulmonary processes. Lung biopsy may be needed to define the disorder completely. In patients with acute pneumonitis, the use of corticosteroids should be considered. Although significant morbidity and even mortality may occur with drug-induced pulmonary events, proper and prompt evaluation and treatment of these disorders can often result in complete resolution of the pulmonary disease.

Fever, hyperdynamic shock, and multiple-system organ failure. A pseudo-sepsis syndrome associated with chronic salicylate intoxication

OBJECTIVE

To describe a sepsis-like syndrome associated with chronic salicylate intoxication.

DESIGN

Retrospective clinical study.

SETTING

University-affiliated county hospital.

PATIENTS

Five patients who became accidentally intoxicated while ingesting salicylates on a long-term daily basis.

RESULTS OF DATA ANALYSIS

All five salicylate-intoxicated patients had clinical and laboratory features that were highly suggestive of sepsis, but no bacteriologic or pathologic evidence of infection could be documented. Features included fever, leukocytosis with increased band forms, hypotension with a reduced SVR and multiple system organ failure (ARDS, encephalopathy, renal failure, and DIC). A diagnosis of salicylate intoxication was made at the time of admission to the hospital in only one case. In the other four cases, the presumptive diagnosis was sepsis; a correct diagnosis of salicylate intoxication was not established until between 16 h and 10 days after admission in these four cases. Two patients died, one patient required permanent hemodialysis, and two patients recovered fully only after prolonged and complicated hospitalizations. The pathogenesis of this syndrome is uncertain. In two cases, serum levels of TNF-alpha, IL-1 beta and IL-6 were measured by ELISA. In both cases serum IL-6 was markedly increased, and in one case serum TNF-alpha was also elevated.

CONCLUSION

Occult salicylate intoxication should be considered when apparent sepsis syndrome occurs without a readily easily identifiable source of infection.

Pulmonary complications of antirheumatic drug therapy

Drug-induced pulmonary disease should be considered in all patients receiving these antirheumatic agents who develop new pulmonary symptoms. When a drug reaction is suspected, the possible offending agents should be discontinued, required respiratory support instituted, and infection or other pulmonary processes excluded. Pathological evaluation by lung biopsy may be needed to define the disorder and rule out infection. Treatment with corticosteroids should be considered in patients with acute pneumonitis. While significant morbidity and even death may occur with drug-induced pulmonary disease, prompt evaluation and treatment of these disorders often results in complete resolution of the process.

Chronic salicylate intoxication. A common cause of morbidity in the elderly

We reviewed the clinical profile of adults with chronic salicylate intoxication by evaluating the experience of our community teaching hospital between 1977 and 1987. Data on similar patients reported was obtained from an English-language literature search using MEDLINE (1966-88) and bibliographic reviews of textbooks and review articles. We also examined the impact of education and incentive on increasing the awareness and ability of physicians to diagnose the disorder. Chronic salicylate intoxication was defined by 1) a compatible clinical syndrome; 2) a serum level in the toxic range; and 3) improvement with withdrawal of the drug. Patients with chronic salicylism represent a cross-section of an elderly population. Our review suggests that diminished body mass, concurrent administration of drugs and conditions which exacerbate renal insufficiency may predispose to salicylate intoxication; however, few specific precipitants of chronic salicylism were recognized. Salicylate intoxication should be considered in all elderly patients with delirium and/or dementia.

Acute salicylate self-poisoning in 177 consecutive patients treated in ICU

The course of 177 consecutive patients with severe salicylate self-poisoning treated in an intensive care unit (ICU) during a period of 15 years is presented. On admission, cerebral depression was observed in 61% respiratory failure was present in 47%, acidosis in 36% and cardiovascular function was impaired in 14%. A mortality rate of 15% was observed, which was proportionally higher in patients more than 40 years old and in patients with delayed diagnosis. Twenty-seven patients died and an autopsy was performed on 26 patients. The main autopsy diagnosis was ulcers of the gastrointestinal tract in 46%, pulmonary oedema in 46%, cerebral oedema in 31% and cerebral haemorrhage in 23%.

A comparison of the effects of aspirin and histamine of fluid balance in the recruited lung

Salicylate administration has been reported to increase the flow of protein-rich lymph from the lungs of animals, however, the mechanism of this response is unclear. In the present study we measured pulmonary hemodynamics and lung fluid and protein flux in anesthetized sheep, surgically prepared for the collection of lung lymph, in order to examine the possible effect of aspirin (ASP) on lung vascular permeability. ASP was given during recruitment of pulmonary microvascular surface area induced by sustained elevation of left atrial pressure (Pla) (Group 1) or continuous infusion of adenosine triphosphate (ATP) (Group 2). We compared the results of ASP administration to those found in similarly prepared animals given histamine (H) during like periods of increased Pla (Group 3) or ATP infusion (Group 4). ASP administration resulted in increased lymphatic protein clearance (Cp) in both Groups 1 and 2. In Group 1, following the characteristic increase in lung lymph flow (Q1) and fall in the ratio of lung lymph to plasma protein concentration (L/P) produced by Pla elevation, ASP administration resulted in a further increase in Q1 and a significant increase in L/P. The results found in ASP animals are qualitatively similar to those observed in Groups 3 and 4 after H. While we cannot specifically rule out a hemodynamic effect of the drug, our results suggest the increased protein flux observed following ASP administration was mediated at least in part through an increase in lung microvascular permeability.

Drug-induced pulmonary disease

Administration of more than 40 separate pharmacologic agents has been associated with some form of pulmonary toxicity. This problem is becoming more significant every year. Occasionally, effective modes of therapy must be withdrawn because of undesirable pulmonary side effects, putting patients at risk for potentially lethal diseases. Pulmonary parenchymal damage due to drugs is an especially troublesome problem because irreversible pulmonary disease may occur. Mechanisms of pulmonary parenchymal tissue damage by drugs are unclear. It appears that some drugs induce direct tissue injury in addition to indirect tissue damage through amplification of pulmonary inflammation; other drugs cause pulmonary alterations solely through indirect mechanisms. Common clinical syndromes associated with drug-induced pulmonary parenchymal disease include pneumonitis/fibrosis, hypersensitivity lung disease, and noncardiogenic pulmonary edema. Less common patterns of pulmonary parenchymal injury by drugs include bronchiolitis obliterans and a pulmonary renal syndrome. Risk factors for pulmonary injury due to pharmacologic agents are partially defined but not entirely understood. To date, there are no adequate tests for early detection of pulmonary damage by drugs, although research into this area is active. This review discusses mechanisms and clinical features of drug-induced pulmonary parenchymal injury to aid the clinician in recognizing and understanding these syndromes.

Physical assessment and differential diagnosis of the poisoned patient

The rapid diagnosis and immediate intervention required in patients with serious drug overdose or poisoning makes toxicological screening of limited value to the emergency department physician. Instead, a careful clinical evaluation using the history, physical examination, and the more readily available laboratory tests may allow a tentative diagnosis and the initiation of life-saving treatment. Laboratory tests should include serum osmolality, electrolytes, glucose, BUN and an estimation of the anion and osmolar gaps. The ECG can also provide useful information. Clinical findings of important include altered blood pressure, pulse, respiration and body temperature, the presence of coma, agitation, delirium or psychosis, and muscular weakness. An ophthalmological examination is also of importance in the acutely poisoned patient. Oral burns or dysphagia may occur following ingestion of any strongly reactive substance, but the absence of oral burns does not preclude the possibility of oesophageal or stomach injury. Odours and skin colour may also contribute to the diagnosis. Comprehensive toxicology screening may not be immediately available, or may be inaccurate, thus adding little to the information obtained during the initial evaluation of the poisoned patient.

Bronchoalveolar lavage in recurrent aspirin-induced adult respiratory distress syndrome

Aspirin has been reported to induce the adult respiratory distress syndrome (ARDS) in humans. The mechanism of injury appears to be similar to other forms of experimentally induced high-permeability edema in which leukocytes play an important role. In a patient who suffered two episodes of aspirin-related ARDS, bronchoalveolar lavage showed a significant influx of leukocytes. This represents the first reported bronchoalveolar lavage in aspirin-related ARDS, as well as the first documentation of the nonhydrostatic nature of the edema in a patient with recurrence of this entity.