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Luks AM, Grissom CK. Evaluation and Management of the Individual with Recurrent HAPE. High Alt Med Biol. 25:238–246, 2024. Individuals with a history of acute altitude illness often seek recommendations from medical providers on how to prevent such problems on future ascents to high elevation. Although many of these cases can be managed with pharmacologic prophylaxis and counseling about the appropriate rate of ascent alone, there are some situations in which further diagnostic evaluation may also be warranted. One such situation is the individual with recurrent episodes of high altitude pulmonary edema (HAPE), as one of several predisposing factors may be present that warrants additional interventions beyond pharmacologic prophylaxis and slow ascent and may even preclude future travel to high altitude. This review considers this situation in greater detail. Structured around the case of an otherwise healthy 27-year-old individual with recurrent episodes of HAPE who would like to climb Denali (6,190 m), the review examines the known risk factors for disease and then provides guidance regarding when and how to evaluate such individuals and appropriate steps to prevent HAPE on further ascents to high elevation. Except in rare circumstances, a history of recurrent HAPE does not preclude further ascent to high elevation, as a multipronged approach including pharmacologic prophylaxis, careful planning about the rate of ascent, and the degree of physical effort and other strategies, such as preacclimatization, staged ascent, and use of hypoxic tents, can be employed to reduce the risk of recurrence with future travel. [ABSTRACT FROM AUTHOR]

With ascent to high altitude, barometric pressure declines, leading to a reduction in the partial pressure of oxygen at every point along the oxygen transport chain from the ambient air to tissue mitochondria. This leads, in turn, to a series of changes over varying time frames across multiple organ systems that serve to maintain tissue oxygen delivery at levels sufficient to prevent acute altitude illness and preserve cognitive and locomotor function. This review focuses primarily on the physiological adjustments and acclimatization processes that occur in the lungs of healthy individuals, including alterations in control of breathing, ventilation, gas exchange, lung mechanics and dynamics, and pulmonary vascular physiology. Because other organ systems, including the cardiovascular, hematologic and renal systems, contribute to acclimatization, the responses seen in these systems, as well as changes in common activities such as sleep and exercise, are also addressed. While the pattern of the responses highlighted in this review are similar across individuals, the magnitude of such responses often demonstrates significant interindividual variability which accounts for subsequent differences in tolerance of the low oxygen conditions in this environment. [ABSTRACT FROM AUTHOR]

The article discusses how reductions in barometric pressure and subsequent decreases in the ambient partial pressure of oxygen, known as hypobaric hypoxia, will affect the safety of a planned high-altitude excursion. Many physiological responses show a dose response relationship, with greater hypoxia provoking stronger responses. The physiological responses to hypoxia are generally protective, but in some cases maladaptive responses occur, leading to some form of acute altitude illness.

Luks, Andrew M. and Colin K. Grissom. Return to high altitude after recovery from coronavirus disease 2019. High Alt Med Biol. 22: 119–127, 2021.—With the increasing availability of coronavirus disease 2019 (COVID-19) vaccines and the eventual decline in the burden of the disease, it is anticipated that all forms of tourism, including travel to high altitude, will rebound in the near future. Given the physiologic challenges posed by hypobaric hypoxia at high altitude, it is useful to consider whether high-altitude travel will pose risks to those previously infected with severe acute respiratory syndrome coronavirus 2, particularly those with persistent symptoms after resolution of their infection. Although no studies have specifically examined this question as of yet, available data on the cardiopulmonary sequelae of COVID-19 provide some sense of the problems people may face at high altitude and who warrants evaluation before such endeavors. On average, most individuals who have recovered from COVID-19 have normal or near normal gas exchange, pulmonary function testing, cardiovascular function, and exercise capacity, although a subset of individuals have persistent functional deficits in some or all of these domains when examined up to 5 months after infection. Evaluation is warranted before planned high-altitude travel in individuals with persistent symptoms at least 2 weeks after a positive test or hospital discharge as well as in those who required care in an intensive care unit or suffered from myocarditis or arterial or venous thromboembolism. Depending on the results of this testing, planned high-altitude travel may need to be modified or even deferred pending resolution of the identified abnormalities. As more people travel to high altitude after the pandemic and further studies are conducted, additional data should become available to provide further guidance on these issues. [ABSTRACT FROM AUTHOR]

The article provides information on the creation of a digital interactive 45-minute session to build skills for completing death certificates. Topics discussed include finding of a study of 601 death certificates reviewed by experienced pathologists, assessment of the efficacy of the intervention, and lessons learned from the session.

New Findings What is the central question of this study? Do the pulmonary vascular responses to hypoxia change during progressive exposure to high altitude and can alterations in these responses be related to changes in concentrations of circulating biomarkers that affect the pulmonary circulation?, What is the main finding and its importance? In our field study with healthy volunteers, we demonstrate changes in pulmonary artery pressure suggestive of remodelling in the pulmonary circulation, but find no changes in the acute responsiveness of the pulmonary circulation to changes in oxygenation during 2 weeks of exposure to progressive hypoxia. Pulmonary artery pressure changes were associated with changes in erythropoietin, 8-isoprostane, nitrite and guanosine 3′,5′-cyclic monophosphate., We sought to determine whether changes in pulmonary artery pressure responses to hypoxia suggestive of vascular remodelling occur during progressive exposure to high altitude and whether such alterations are related to changes in concentrations of circulating biomarkers with known or suspected actions on the pulmonary vasculature during ascent. We measured tricuspid valve transvalvular pressure gradients (TVPG) in healthy volunteers breathing air at sea level (London, UK) and in hypoxic conditions simulating the inspired O2 partial pressures at two locations in Nepal, Namche Bazaar (NB, elevation 3500 m) and Everest Base Camp (EBC, elevation 5300 m). During a subsequent 13 day trek, TVPG was measured at NB and EBC while volunteers breathed air and hyperoxic or hypoxic mixtures simulating the inspired O2 partial pressures at the other locations. For each location, we determined the slope of the relationship between TVPG and arterial oxygen saturation ( [ABSTRACT FROM AUTHOR]

Luks, Andrew M., Colin Grissom, Luanne Freer, and Peter Hackett. Medication use among mount Everest climbers: practice and attitudes. High Alt Med Biol. 17:315-322, 2016.-The lay public, media, and medical experts have expressed concern about the ethics of climbers using medications to improve performance and increase the odds of summit success while climbing at high altitude, but the true incidence of this practice remains unclear. We conducted an anonymous survey of climbers who have attempted to climb Mt. Everest to gather information about medication use and attitudes toward medication and supplemental oxygen use while climbing the mountain. One hundred eighty-seven individuals completed the survey, providing information about medication and oxygen use for 262 expeditions to Mt. Everest between 1963 and 2015, the majority of which occurred after the year 2000. The majority of respondents were male (82%) and from English-speaking countries (75%). Medications were used on 43% of climbs, with acetazolamide being the most commonly used medication. Reported use of dexamethasone, nifedipine, sildenafil, or tadalafil was uncommon as was use of multiple medications at the same time. The majority of respondents indicated that it was acceptable for climbers to use medications and supplemental oxygen to prevent altitude illness while climbing Mt. Everest. Opinions were more mixed regarding whether summiting without the use of medications or oxygen carried the same value as reaching the summit using those interventions. Our data suggest that less than one-half of Mt. Everest climbers use medications during their expedition, with the primary medication used being acetazolamide, for prevention of altitude illness. Given the limitations of the study design and preliminary nature of these data, further research is warranted to further clarify these issues. [ABSTRACT FROM AUTHOR]

As they regain active lifestyles following successful organ transplantation, transplant recipients may travel to high altitude for a variety of activities, including skiing, climbing, and trekking. This review is intended to provide information for medical providers who may encounter transplant patients seeking advice before planned high altitude travel or care for medical issues that develop during the actual sojourn. There is currently limited information in the literature about outcomes during high-altitude travel following solid organ transplantation, but the available evidence suggests that the physiologic responses to hypobaric hypoxia are comparable to those seen in nontransplanted individuals and well-selected transplant recipients with no evidence of organ rejection can tolerate ascents as high as 6200m. All transplant recipients planning high-altitude travel should undergo pretravel assessment and counseling with an emphasis on the recognition, prevention, and treatment of altitude illness, as well as the importance of preventing infection and limiting sun exposure. Transplant recipients can use the standard medications for altitude illness prophylaxis and treatment, but the choice and dose of medication should take into account the patient's preexisting medication regimen and current renal function. With careful attention to these and other details, the healthy transplant recipient can safely experience the rewards of traveling in the mountains. [ABSTRACT FROM AUTHOR]

Luks, Andrew M., and Erik R. Swenson. Clinician's Corner: Evaluating the risks of high altitude travel in chronic liver disease patients. High Alt Med Biol 16:80-88, 2015.-With improvements in the quality of health care, people with chronic medical conditions are experiencing better quality of life and increasingly participating in a wider array of activities, including travel to high altitude. Whenever people with chronic diseases travel to this environment, it is important to consider whether the physiologic responses to hypobaric hypoxia will interact with the underlying medical condition such that the risk of acute altitude illness is increased or the medical condition itself may worsen. This review considers these questions as they pertain to patients with chronic liver disease. While the limited available evidence suggests there is no evidence of liver injury or dysfunction in normal individuals traveling as high as 5000 m, there is reason to suspect that two groups of cirrhosis patients are at increased risk for problems, hepatopulmonary syndrome patients, who are at risk for severe hypoxemia following ascent, and portopulmonary hypertension patients who may be at risk for high altitude pulmonary edema and acute right ventricular dysfunction. While liver transplant patients may tolerate high altitude exposure without difficulty, no information is available regarding the risks of long-term residence at altitude with chronic liver disease. All travelers with cirrhosis require careful pre-travel evaluation to identify conditions that might predispose to problems at altitude and develop risk mitigation strategies for these issues. Patients also require detailed counseling about recognition, prevention, and treatment of acute altitude illness and may require different medication regimens to prevent or treat altitude illness than used in healthy individuals. [ABSTRACT FROM AUTHOR]

While antiviral therapy is an important component of care in patients with the acute respiratory distress syndrome ( ARDS) following influenza infection, it is not sufficient to ensure good outcomes, and additional measures are usually necessary. Patients usually receive high levels of supplemental oxygen to counteract the hypoxemia resulting from severe gas exchange abnormalities. Many patients also receive invasive mechanical ventilation for support for oxygenation, while in resource-poor settings, supplemental oxygen via face mask may be the only available intervention. Patients with ARDS receiving mechanical ventilation should receive lung-protective ventilation, whereby tidal volume is decreased to 6 ml/kg of their predicted weight and distending pressures are maintained ≤30 cm H2O, as well as increased inspired oxygen concentrations and positive end-expiratory pressure ( PEEP) to prevent atelectasis and support oxygenation. While these measures are sufficient in most patients, a minority develop refractory hypoxemia and may receive additional therapies, including prone positioning, inhaled vasodilators, extracorporeal membrane oxygenation, recruitment maneuvers followed by high PEEP, and neuromuscular blockade, although recent data suggest that this last option may be warranted earlier in the clinical course before development of refractory hypoxemia. Application of these 'rescue strategies' is complicated by the lack of guidance in the literature regarding implementation. While much attention is devoted to these strategies, clinicians must not lose sight of simple interventions that affect patient outcomes including head of bed elevation, prophylaxis against venous thromboembolism and gastrointestinal bleeding, judicious use of fluids in the post-resuscitative phase, and a protocol-based approach to sedation and spontaneous breathing trials. [ABSTRACT FROM AUTHOR]

Abstract: Background: Pneumocephalus is a rare cause of altered mental status in patients presenting to the Emergency Department. Occurring as a result of traumatic or iatrogenic violation of the dura, it can cause significant morbidity and mortality if tension physiology develops whereby air continues to accumulate with no mechanism for escape. Objective: This case report will review the underlying pathophysiology, clinical presentation, diagnosis, and management of tension pneumocephalus. Case Report: We present the case of an 89-year-old man who presented to the Emergency Department with declining mental status 9h after endoscopic sinus surgery. He was subsequently found to have tension pneumocephalus and underwent emergent burr hole evacuation. Despite resolution of the pneumocephalus, the patient had persistent neurologic deficits related to ischemic infarcts that occurred as a result of the tension physiology and subsequently expired in the hospital. Conclusion: This case illustrates the importance of considering tension pneumocephalus on the differential diagnosis for any patient presenting with altered mental status after surgical or diagnostic procedures with potential to violate the dural space. [Copyright &y& Elsevier]

Background: Night float rotations are being increasingly used in the era of resident physician work-hour regulations, but their impact on resident education is not clear. Purpose: Our objective was to clarify resident perceptions of the educational aspects of night float rotations. Methods: An anonymous survey of internal medicine residents at a university-based residency program was completed. Results: Responses were received from 116 of 163 surveyed residents (71%). Residents attended less residents' report (0.10 ± .43 vs. 2.70 + 0.93 sessions/week, p< .001) and fewer grand rounds sessions (0.14 ± 0.25 vs. 0.43 ± 0.28 sessions/week, p< .001) and spent less time reading, (2.63 ± 2.0 vs. 3.33 ± 1.6 hr/week, p< .001) interacting with attending physicians (0.57 ± 1.1 vs. 2.97 ± 1.5 hr/week, p< .001) and sleeping at home (6.3 ± 1.2 vs. 7.10 ± 0.9 hr/day, p< .001) on night float rotations than on non-night float rotations. Residents had strongly negative opinions about the educational value of night float, sleep cycle adjustment issues, and impact on their personal lives, which correlated with resident evaluations from the regular program evaluation process. In free responses, residents commented that they liked the autonomy and opportunity to improve triage skills on these rotations and confirmed their negative opinions about the sleep-wake cycle and interference with personal lives. Conclusions: Internal medicine residents at a university-based program have negative opinions regarding the educational value of night float rotations. Further work is necessary to determine whether problems exist across programs and specialties. [ABSTRACT FROM AUTHOR]

The article examines how the dose and choice of drugs used to treat high altitude sickness are influenced by the patient's inherent medical situation. The recommended drugs and dosing regimens are discussed for healthy individuals. The possibility of serious drug interactions in patients with liver insufficiency, renal impairment and other significant medical conditions is discussed.

The article presents sports medicine research that describes the clinical case of a male cyclist who developed pulmonary edema during the ultraendurance sport Bicycle Race Across America while cycling at an altitude of 2,380 meters. Post-race examination revealed no evidence of susceptibility to high-altitude pulmonary edema or an underlying cardiopulmonary disease. The edema is attributed to daily sodium intake of 23 to 25 grams, ambient hypoxia, reduced renal perfusion, increased hydrostatic pressure, and expanded extracellular volume.

Keywords: ARDS; high altitude pulmonary edema; hypoxemia; nifedipine EN ARDS high altitude pulmonary edema hypoxemia nifedipine 192 193 2 06/22/20 20200601 NES 200601 As medical providers around the world struggle to care for patients with acute respiratory failure secondary to corona virus disease 2019 (COVID-19), extensive efforts have been made to compare this entity to other forms of acute respiratory failure observed prior to the current pandemic. Among the variety of theories put forth, one argument that has been made and amplified via social media is that COVID-19 lung injury is not like typical acute respiratory distress syndrome (ARDS) and instead is similar to high altitude pulmonary edema (HAPE) (Solaimanzadeh, [1]). COVID-19 mediated lung injury has proven to be a heterogeneous disease in which patients present with varying degrees of hypoxemia, alterations in lung compliance and other physiologic derangements. [Extracted from the article]

The literature on diffuse alveolar hemorrhage heavily emphasizes the causal role of vasculitides. We present a patient with diffuse alveolar hemorrhage caused by leptospirosis. Although the pathology in leptospirosis occurs secondary to a vasculitic process, this disease is not listed as a cause of diffuse alveolar hemorrhage in the review literature. In the right clinical scenario, the disease should be considered in a patient presenting with diffuse alveolar hemorrhage. [ABSTRACT FROM AUTHOR]

The article presents the randomized controlled trial on ways to prevent hypoxemia in endotracheal intubation. The topics discussed include the comparison between positive-pressure ventilation using bag-mask device and no manual ventilation, measures used in detecting aspiration, and the safety of the bag-mask ventilation in rapid-sequence intubation.

The article deals with the case of a 65-year-old man with a history of cocaine abuse and heavy alcohol consumption. The patient was brought to an emergency department after he exhibited bizarre behavior and altered mental status. Medical examination of the patient revealed that he is critically ill and suffering from hyponatremia which can be treated by minimizing exogenous solutes in his fluids, medications and diet.

The article presents the authors' comments on a study conducted by physician Peter J. Fagenholz and his colleagues in which the comet-tail technique of chest ultrasonography was used to diagnose and monitor high-altitude pulmonary edema (HAPE). The authors mention that the technique used by Fagenholz and his colleagues may have limited clinical utility, but it holds great promise as a research tool for studying different aspects of HAPE.

For often unclear reasons, the survival times of critically buried avalanche victims vary widely from minutes to hours. Individuals can survive and sustain organ function if they can breathe under the snow and maintain sufficient delivery of oxygen and efflux of carbon dioxide. We review the physiological responses of humans to critical avalanche burial, a model which shares similarities and differences with apnoea and accidental hypothermia. Within a few minutes of burial, an avalanche victim is exposed to hypoxaemia and hypercapnia, which have important effects on the respiratory and cardiovascular systems and pose a major threat to the central nervous system. As burial time increases, an avalanche victim also develops hypothermia. Despite progressively reduced metabolism, reduced oxygen and increased carbon dioxide tensions may exacerbate the pathophysiological consequences of hypothermia. Hypercapnia seems to be the main cause of cardiovascular instability, which, in turn, is the major reason for reduced cerebral oxygenation despite reductions in cerebral metabolic activity caused by hypothermia. ‘Triple H syndrome’ refers to the interaction of hypoxia, hypercapnia and hypothermia in a buried avalanche victim. Future studies should investigate how the respiratory gases entrapped in the porous snow structure influence the physiological responses of buried individuals and how haemoconcentration, blood viscosity and cell deformability affect blood flow and oxygen delivery. Attention should also be devoted to identifying strategies to prolong avalanche survival by either mitigating hypoxia and hypercapnia or reducing core temperature so that neuroprotection occurs before the onset of cerebral hypoxia. [ABSTRACT FROM AUTHOR]

The article focuses on the dissemination of portfolio practices to help clinician-educators in documenting the nature and quality of their work. It cites that clinician-educator pathway remains poorly defined at many institutions and departments lack criteria for promotion evaluations. It discusses the online survey of 294 clinician-educators and paper-based survey of 17 department chairs conducted to define current portfolio practices in an institution.

A description of the course on pulmonary physiology and pathophysiology being offered at the University of Washington in Seattle, Washington is provided.

Berendsen, Remco R., Peter Bärtsch, Buddha Basnyat, Marc Moritz Berger, Peter Hackett, Andrew M. Luks, Jean-Paul Richalet, Ken Zafren, Bengt Kayser, and the STAK Plenary Group. Strengthening altitude knowledge: a Delphi study to define minimum knowledge of altitude illness for laypersons traveling to high altitude. High Alt Med Biol. 23:330–337, 2022. Introduction: A lack of knowledge among laypersons about the hazards of high-altitude exposure contributes to morbidity and mortality from acute mountain sickness (AMS), high-altitude cerebral edema (HACE), and high-altitude pulmonary edema (HAPE) among high-altitude travelers. There are guidelines regarding the recognition, prevention, and treatment of acute-altitude illness for experts, but essential knowledge for laypersons traveling to high altitudes has not been defined. We sought expert consensus on the essential knowledge required for people planning to travel to high altitudes. Methods: The Delphi method was used. The panel consisted of two moderators, a core expert group and a plenary expert group. The moderators made a preliminary list of statements defining the desired minimum knowledge for laypersons traveling to high altitudes, based on the relevant literature. These preliminary statements were then reviewed, supplemented, and modified by a core expert group. A list of 33 statements was then presented to a plenary group of experts in successive rounds. Results: It took three rounds to reach a consensus. Of the 10 core experts invited, 7 completed all the rounds. Of the 76 plenary experts, 41 (54%) participated in Round 1, and of these 41 a total of 32 (78%) experts completed all three rounds. The final list contained 28 statements in 5 categories (altitude physiology, sleeping at altitude, AMS, HACE, and HAPE). This list represents an expert consensus on the desired minimum knowledge for laypersons planning high-altitude travel. Conclusion: Using the Delphi method, the STrengthening Altitude Knowledge initiative yielded a set of 28 statements representing essential learning objectives for laypersons who plan to travel to high altitudes. This list could be used to develop educational interventions. [ABSTRACT FROM AUTHOR]

High altitude (HA)-induced pulmonary hypertension may be due to a free radical-mediated reduction in pulmonary nitric oxide (NO) bioavailability. We hypothesised that the increase in pulmonary artery systolic pressure (PASP) at HA would be associated with a net transpulmonary output of free radicals and corresponding loss of bioactive NO metabolites. Twenty-six mountaineers provided central venous and radial arterial samples at low altitude (LA) and following active ascent to 4559 m (HA). PASP was determined by Doppler echocardiography, pulmonary blood flow by inert gas re-breathing, and vasoactive exchange via the Fick principle. Acute mountain sickness (AMS) and high-altitude pulmonary oedema (HAPE) were diagnosed using clinical questionnaires and chest radiography. Electron paramagnetic resonance spectroscopy, ozone-based chemiluminescence and ELISA were employed for plasma detection of the ascorbate free radical (A), NO metabolites and 3-nitrotyrosine (3-NT). Fourteen subjects were diagnosed with AMS and three of four HAPE-susceptible subjects developed HAPE. Ascent decreased the arterio-central venous concentration difference (a-cv) resulting in a net transpulmonary loss of ascorbate, α-tocopherol and bioactive NO metabolites ( P < 0.05 vs. LA). This was accompanied by an increased a-cv and net output of A and lipid hydroperoxides ( P < 0.05 vs. sea level, SL) that correlated against the rise in PASP ( r= 0.56-0.62, P < 0.05) and arterial 3-NT ( r= 0.48-0.63, P < 0.05) that was more pronounced in HAPE. These findings suggest that increased PASP and vascular resistance observed at HA are associated with a free radical-mediated reduction in pulmonary NO bioavailability. What causes pulmonary hypertension at high altitude remains unknown. By measuring the transpulmonary exchange kinetics of redox-reactive biomarkers, this study suggests that hypertension may be related to a free radical-mediated reduction in pulmonary vascular nitric oxide bioavailability due in part to inadequate antioxidant defence. These findings have broader implications for other clinical models of human disease characterised by global hypoxaemia and identify the hypoxic human lungs as a contributory source of oxidative-nitrosative-inflammatory stress. [ABSTRACT FROM AUTHOR]

Case Presentation: A 79-year-old man with medical history of atrial fibrillation and esophageal cancer status post trans-hiatal esophageal resection and chemotherapy presented with altered mental status after outpatient esophagogastroduodenoscopy (EGD). One month before presentation, the patient was seen at another hospital with severe anemia and melena requiring transfusion of multiple units of RBCs. No endoscopy was performed during that admission, but his anticoagulation was held. After follow-up with his oncologist, he was referred for outpatient endoscopy. His esophagogastroduodenoscopy demonstrated an intact esophagogastric anastomosis as well as two gastric ulcers with no stigmata of recent bleeding. The patient was discharged to home in good condition with normal mental status. Several hours later, he developed a deteriorating level of consciousness, prompting presentation to the hospital. [ABSTRACT FROM AUTHOR]

Roach, Robert C., Peter H. Hackett, Oswald Oelz, Peter Bärtsch, Andrew M. Luks, Martin J. MacInnis, J. Kenneth Baillie, and The Lake Louise AMS Score Consensus Committee. The 2018 Lake Louise Acute Mountain Sickness Score. High Alt Med Biol 19:1–4, 2018.— The Lake Louise Acute Mountain Sickness (AMS) scoring system has been a useful research tool since first published in 1991. Recent studies have shown that disturbed sleep at altitude, one of the five symptoms scored for AMS, is more likely due to altitude hypoxia per se, and is not closely related to AMS. To address this issue, and also to evaluate the Lake Louise AMS score in light of decades of experience, experts in high altitude research undertook to revise the score. We here present an international consensus statement resulting from online discussions and meetings at the International Society of Mountain Medicine World Congress in Bolzano, Italy, in May 2014 and at the International Hypoxia Symposium in Lake Louise, Canada, in February 2015. The consensus group has revised the score to eliminate disturbed sleep as a questionnaire item, and has updated instructions for use of the score. [ABSTRACT FROM AUTHOR]

The literature on diffuse alveolar hemorrhage heavily emphasizes the causal role of vasculitides. We present a patient with diffuse alveolar hemorrhage caused by leptospirosis. Although the pathology in leptospirosis occurs secondary to a vasculitic process, this disease is not listed as a cause of diffuse alveolar hemorrhage in the review literature. In the right clinical scenario, the disease should be considered in a patient presenting with diffuse alveolar hemorrhage. [ABSTRACT FROM AUTHOR]