EV71:TLLcho virus murine model of enterovirus A71 neurological disease does not exhibit neurogenic pulmonary oedema

Small animal models play an important role in investigating and revealing the molecular determinants and mechanisms underlying neuro-virulence of enterovirus A71 (EV-A71). In our previous study, we successfully developed two mouse cell-line replication competent EV-A71 strains (EV71:TLLm and EV71:TLLmv) which were capable of inducing neuro-invasion in BALB/c mice. The more virulent EV71:TLLmv exhibited ability to induce acute encephalomyelitis accompanied by neurogenic pulmonary oedema. EV71:TLLcho virus strain was generated from EV71:TLLm by a series of passages in CHO-K1 cells. EV71:TLLcho demonstrated a broader range of infectivity across various mammalian cell lines and exhibited complete cytopathic effects (CPE) within 48 hours post-inoculation in comparison to EV71:TLLm or EV71:TLLmv. EV71:TLLcho consistently yielded higher levels of viral replication at all time points examined. In comparison to EV71:TLLm, EV71:TLLcho consistently induced more severe disease and increased mortality in one-week old BALB/c mice. However, unlike mice challenged with EV71:TLLmv, none of the mice challenged with EV71:TLLcho progressed to severe acute encephalomyelitis and developed neurogenic pulmonary oedema.

[Epidemiologic and clinical profile, 90 days survival of incident end stage renal patient in haemodialysis during SARS-CoV2 pandemic: Experience of the General Hospital of Douala]

BACKGROUND

The effect of COVID-19 pandemic on end stage renal disease patient who should initiated dialysis are limited in Sub-Saharan Africa is unknown. We sought to describe the epidemiologic and clinical profile of newly admitted patient in chronic haemodialysis during the COVID-19 pandemic in Cameroon and evaluate their survival between 90days of dialysis initiation.

MATERIAL AND METHOD

We conducted a cohort study of 6months from April to October 2020. End stage renal disease patients newly admitted in the haemodialysis facility of the General Hospital of Douala were included. Patients with confirmed or suspected COVID-19 were identified. Socio-demographic, clinical and biological data at dialysis initiation as well as mortality between the 90days of dialysis initiation were registered.

RESULTS

A total of 57 incident patients were recorded from April to October 2020 with a monthly mean of 9.5 patients. The mean age was 46.95±13.12years. Twenty-four COVID-19 were identified with a frequency of 49% among emergency admission. Pulmonary œdema (79.2% vs. 42.4%; P=0.006) and uremic encephalopathy (83.4% vs. 53.6%; P=0.022) were more common in COVID-19. The overall survival at 90days was 48% with a tendency to poor survival among COVID-19 and patients with low socioeconomic level. In Cox regression, low socioeconomic level increase the risk of instant death by 3.08.

CONCLUSION

SARS-CoV2 seem to increase nephrology emergency and poor survival in haemodialysis at 90days.

Endothelial cells and SARS-CoV-2: An intimate relationship

Angiotensin-converting enzyme 2 (ACE2) is an important player of the renin-angiotensin-aldosterone system (RAAS) in regulating the conversion of angiotensin II into angiotensin (1-7). While expressed on the surface of human cells, such as lung, heart, kidney, neurons, and endothelial cells (EC), ACE2 is the entry receptor for SARS-CoV-2. Here, we would like to highlight that ACE2 is predominant on the EC membrane. Many of coronavirus disease 2019 (COVID-19) symptoms have been associated with the large recruitment of immune cells, directly affecting EC. Additionally, cytokines, hypoxia, and complement activation can trigger the activation of EC leading to the coagulation cascade. The EC dysfunction plus the inflammation due to SARS-CoV-2 infection may lead to abnormal coagulation, actively participating in thrombo-inflammatory processes resulting in vasculopathy and indicating poor prognosis in patients with COVID-19. Considering the intrinsic relationship between EC and the pathophysiology of SARS-CoV-2, EC-associated therapies such as anticoagulants, fibrinolytic drugs, immunomodulators, and molecular therapies have been proposed. In this review, we will discuss the role of EC in the lung inflammation and edema, in the disseminate coagulation process, ACE2 positive cancer patients, and current and future EC-associated therapies to treat COVID-19.

Staphylococcus aureus Alpha-Toxin Disrupts Endothelial-Cell Tight Junctions via Acid Sphingomyelinase and Ceramide

Staphylococcus aureus (S. aureus) infections are among the most common and severe infections, garnering notoriety in an era of increasing resistance to antibiotics. It is therefore important to define molecular mechanisms by which this pathogen attacks host cells. Here, we demonstrate that alpha-toxin, one of the major toxins of S. aureus, induces activation of acid sphingomyelinase and concomitant release of ceramide in endothelial cells treated with the toxin. Activation of acid sphingomyelinase by alpha-toxin is mediated via ADAM10. Infection experiments employing alpha-toxin-deficient S. aureus and the corresponding wild-type strain reveal that activation of acid sphingomyelinase in endothelial cells requires alpha-toxin expression by the pathogen. Activation of acid sphingomyelinase is linked to degradation of tight junctions in endothelial cells in vitro, which is blocked by pharmacological inhibition of acid sphingomyelinase. Most importantly, alpha-toxin induces severe degradation of tight junctions in the lung and causes lung edema in vivo, which is prevented by genetic deficiency of acid sphingomyelinase. These data indicate a novel and important role of the acid sphingomyelinase/ceramide system for the endothelial response to toxins and provide a molecular link between alpha-toxin and the degradation of tight junctions. The data also suggest that inhibition of acid sphingomyelinase may provide a novel treatment option to prevent lung edema caused by S. aureus alpha-toxin.

Mahuang-Xixin-Fuzi decoction reduces the infection of influenza A virus in Kidney-Yang deficiency syndrome mice

ETHNOPHARMACOLOGICAL RELEVANCE

Mahuang-Xixin-Fuzi Decoction (MXF) as a famous formula for the treatment of colds, fever, nasal congestion and headache with elder people, has always been widely used in traditional Chinese medicine. The present study is aimed at investigating the treatment effect of MXF on Kidney-Yang deficiency syndrome in mice simultaneously infected with H1N1 virus.

MATERIALS AND METHODS

We employed the Kidney-Yang deficiency mouse model to investigate the effect of MXF against influenza A virus (A/FM/1/47, H1N1). Mice were infected with the virus after fifteen days Kidney-Yang deficiency syndrome was established (intraperitoneal injection of estradiol benzoate), while MXF was orally administrated with 1.2-4.7g/kg/d for 6 consecutive days after inoculation. Body weight, rectal temperature, morbidity, and mortality were recorded daily. Histopathologic changes, antioxidant activity of SOD and MDA were detected. Moreover, levels of inflammatory cytokines including IL-6, IL-10, MCP-1, TNF-α were measured in the sera of mice.

RESULTS

We found that the extract of MXF at dosages of 2.3-4.7g/kg could effectively diminish mortality rate, ameliorate lung edema and inflammation. Administration of MXF decoction significantly depressed the expression of IL-6, MCP-1 and TNF-α, and markedly increased expression of IL-10 in serum. Simultaneously, the extract was also found to reduce MDA and increase SOD in the lung tissue of mice.

CONCLUSION

These data support the notion that the extract of MXF could treat Kidney-Yang deficiency syndrome in mice simultaneously infected with influenza A virus by reducing inflammation and increasing antioxidant activities.

RISK FACTORS FOR SEVERE HAND, FOOT AND MOUTH DISEASE

We studied risk factors associated with severe hand, foot and mouth disease (HFMD) caused by enteroviruses among patients aged less than 15 years admitted to King Narai Hospital, Lopburi, Thailand during 2011-2013. Cases were divided into either mild or severe. Severe cases were those with encephalitis, meningitis, myocarditis, pneumonia, pulmonary edema or respiratory failure. Risk factors for severe infection were evaluated using univariate and multivariate logistic regression analysis. One hundred eighteen patients met the case definition of HFMD. Of these, 95 (80.5%) were classified as mild cases, and 23 (19.5%) as severe cases; there were 5 deaths (4.2%). Of the 23 severe cases, 9 were infected with coxsackievirus A16 (CA16), 8 with enterovirus 71 (EV71) and 4 with both EV71 and CA16. The most common presentations among the severe caseswere: seizures (74%), pneumonia (39%), encephalitis (39%), and meningitis (13%). The clinical manifestations significantly related to severe HFMD on univariate analysis were highest body temperature 39.00C, duration of fever 23 days, absence of skin lesions, diarrhea, dyspnea, seizures and hyperglycemia. The clinical manifestations significantly related to severe HFMD on both univariate and multivariate analyses were age less than 1 year, absence of oral lesions and drowsiness/lethargy. Clinicians should be aware of these factors. Early recognition of severe cases is important to increase the rates of successful outcomes and reduce mortality.

The effect of TIP on pneumovirus-induced pulmonary edema in mice

Background

Pulmonary edema plays a pivotal role in the pathophysiology of respiratory syncytial virus (RSV)-induced respiratory failure. In this study we determined whether treatment with TIP (AP301), a synthetic cyclic peptide that mimics the lectin-like domain of human TNF, decreases pulmonary edema in a mouse model of severe human RSV infection. TIP is currently undergoing clinical trials as a therapy for pulmonary permeability edema and has been shown to decrease pulmonary edema in different lung injury models.

Methods

C57BL/6 mice were infected with pneumonia virus of mice (PVM) and received TIP or saline (control group) by intratracheal instillation on day five (early administration) or day seven (late administration) after infection. In a separate set of experiments the effect of multiple dose administration of TIP versus saline was tested. Pulmonary edema was determined by the lung wet-to-dry (W/D) weight ratio and was assessed at different time-points after the administration of TIP. Secondary outcomes included clinical scores and lung cellular response.

Results

TIP did not have an effect on pulmonary edema in different dose regimens at different time points during PVM infection. In addition, TIP administration did not affect clinical severity scores or lung cellular response.

Conclusion

In this murine model of severe RSV infection TIP did not affect pulmonary edema nor course of disease.

[The exploration of the role of angiopoietin-2 in pulmonary edema induced by EV71 infection]

OBJECTIVE

To observe the clinic character of pulmonary edema (PE) induced by enterovirus 71 (EV71) and the change in angiopoietin-2 (Ang-2), and to explore the correlation between Ang-2 and PE.

METHODS

Twenty consecutive infants with PE induced by EV71 admitted to intensive care unit (ICU) of Binzhou Medical College Affiliated Hospital from May 2011 to September 2013 were prospectively enrolled in PE group; 20 infants with similar age infected by EV71 without PE and hospitalized in ICU were enrolled as non-PR group; and 20 similar age infants suffering from selective inguinal hernia operation were served as control group. Data of infants with or without PE were collected including vital signs, complete blood count, blood biochemistry tests, chest X-ray and cerebrospinal fluid at ICU admission. Pulmonary edema liquid and serum were collected from infants suffered from severe PE by tracheal intubation. Total protein, albumin and Ang-2 [enzyme linked immunosorbent assay (ELISA)] were determined and those of pulmonary edema liquid/serum (P/S) ratio were calculated.

RESULTS

Nine infants with PE died, and all of infants without PE survived. Body temperature, heart rate, blood pressure, white blood cell count (WBC), blood sugar and MD isoenzyme of creatine kinase (CK-MD) in EV71 infection infants were higher than those in controls, and albumin and oxygenation index (PaO(2)/FiO(2)) were lowered. Heart rate, blood sugar and WBC of infants with PE were significantly higher than those of infants without PE [heart rate (bmp): 181 ± 31 vs. 146 ± 19, t=3.397, P=0.003; blood sugar (mmol/L: 14.9 ± 9.8 vs. 6.3 ± 1.5, t=2.793, P=0.012; WBC (x10(9)/L): 22.1 ± 9.8 vs. 10.2+3.6, t=3.579, P=0.002], and serum albumin and PaO(2)/FiO(2) of infants with PE were significantly lower [albumin (g/L): 33.6+5.9 vs. 42.7 ± 2.9, t=3.258, P=0.004; Pa(2)/FiO(2) (mmHg, 1mmHg=0.133 kPa): 142 ± 76 vs. 396 ± 39, t=3.927, P=0.000]. Cerebrospinal fluid pressure was significantly elevated in both non-PE and PE groups, the number of nucleated cells were normal or mildly to moderately elevated, most were mononuclear cells, and protein content were normal. Ang-2 levels of infants with PE [236.17 (167.63, 366.65) ng/L] was higher than that of control infants [19.67 (8.72, 33.68) ng/L] and infants without PE [23.46 (13.28, 46.77) ng/L, both T=210, both P=0.000]. Pulmonary edema liquid was collected from 8 infants with severe PE. Total protein, albumin, lactate dehydrogenase (LDH) and Ang-2 in severe PE infants were elevated. Total protein of P/S ratio was 0.67, 1.33, 1.12, 0.72, 0.84, 0.73, 1.09, 1.24, albumin of P/S ratio was 0.72, 1.64, 0.84, 0.87, 1.06, 0.92, 1.12, 1.48, LDH of P/S 0.92, 1.03, 1.17, respectively.

CONCLUSIONS

Pulmonary edema liquid of infants with PE induced by EV71 infection os rich of protein, and Ang-2 level rises in serum and pulmonary edema liquid. Ang-2 may involve in pulmonary vascular leak and developments of PE.

[Identification of an enterovirus 71 receptor; SCARB2]

Enterovirus 71 (EV71) and coxsackievirus A16 (CVA16), belonging to family Picornaviridae, genus Enterovirus, species A, are causative agents of hand-foot-mouth disease (HFMD). Infections involving EV71, but not CVA16, can progress to severe neurological disease, including aseptic meningitis, encephalitis, acute flaccid paralysis and neurogenic pulmonary edema. EV71 is thus considered to be a neuropathogenic virus and EV71 outbreak has become a major public health concern. Human RD cells are highly susceptible to EV71, while mouse L929 cell are not. We established mouse cell lines that acquired EV71-susceptibility by transfecting human genomic DNA. We succeeded in identifying a human gene, scavenger receptor B2 (SCARB2), integrated in one of the transformant cells by microarray analysis and showed that SCARB2 can serve as a EV71 receptor. I will summarize this result, background and the methodology of the study.

S-nitroso-human-albumin: a new therapeutic approach in endotoxic shock

INTRODUCTION

Endotoxemia leads to induction of inducible nitric oxide synthase (iNOS) and increased expression of numerous inflammatory mediators, contributing to endotoxin-induced acute lung injury.

OBJECTIVES

We examined the hypothesis that supplementation of nitric oxide (NO) with the novel NO donor, S-nitroso-human-serum-albumin (S-NO-HSA), may reduce iNOS expression, lung inflammation and acute lung injury in a rat model of septic shock.

MATERIAL AND METHODS

Rats were divided into 4 groups: sham-operated (no treatment), LPS (lipopolysaccharide), LPS + HSA, and LPS + S-NO-HSA. Endotoxin-induced (20 mg kg-1, iv) lung injury was characterized by measurement of wet/dry weight ratio (pulmonary edema), myeloperoxidase activity (pulmonary neutrophil infiltration), expression of intercellular adhesion molecule-1, iNOS, and cyclooxygenase-2.

RESULTS

LPS-induced acute lung injury involved pulmonary edema, neutrophil infiltration and a strong inflammatory response, resulting in high mortality within 6 h. S-NO-HSA prolonged survival of endotoxemic rats, reduced hypotensive response to LPS, and minimized LPS-induced lung edema by modulation of systemic inflammatory response.

CONCLUSIONS

NO supplementation with S-NO-HSA after LPS administration prevents induction of iNOS, protects against endotoxin-induced acute lung injury, and reduces early mortality in endotoxic rats. The results of the study support a therapeutic role of S-NO-HSA in the treatment of endotoxemia.

[Three cases of enterovirus 71 infection with pulmonary edema or pulmonary hemorrhage as the early clinical manifestation]

OBJECTIVE

To recognize the clinical features of the enterovirus 71 (EV71) infection with pulmonary edema or pulmonary hemorrhage as a fulminant and often fatal illness.

METHODS

We retrospectively reviewed the medical records of the three cases with EV71 infection for clinical manifestation, laboratory data, medications, outcome etc.

RESULTS

All the cases were infants and they all died. These infants had no skin or mucosal lesions, however, they had sudden onset of cyanosis and tachypnea 1 to 2 days after the onset of the febrile disease with vomiting. All these 3 cases were misdiagnosed and were treated for shock on admission. Pulmonary hemorrhage was not considered in any of the cases on admission. All the cases received tracheal intubation when foamy secretions were discharged from mouth and nose of the patients and notable cyanosis was noted. After intubation, all had pink foamy fluid flew out from the endotracheal tube. The patients had hyperglycemia and limb weakness, two had tachycardia, and hypertension was found in one case. Chest X-ray showed bilateral or unilateral widespread air space opacity, but the cardiac size and shape were normal. All the patients had leucocytosis. EV71 infection was confirmed by detection of specific sequences of the virus in throat swab and tracheal secretions samples and in one case in cerebrospinal fluid sample.

CONCLUSION

Pulmonary edema or pulmonary hemorrhage occurred in the 3 cases with EV71-infected infants. The initial presentation was often nonspecific with fever and vomiting, and sudden appearances of cyanosis, tachypnea, tachycardia, hypertension or hypotension, limb weakness may suggest pulmonary edema or hemorrhage. Excessive fluid resuscitation may deteriorate the illness, on the contrary, fluid restriction and inotropic agents, and early intubation with positive pressure mechanical ventilation may be the proper treatment.

Diagnosis and treatment of new world hantavirus infections

PURPOSE OF REVIEW

The purpose of this review is to summarize the current knowledge regarding the diagnosis and treatment of indigenous new world hantavirus infections.

RECENT FINDINGS

Recent studies have defined the incubation period of new world hantavirus infections, provided additional evidence for person-to-person transmission of Andes virus, described a rapid method for the presumptive diagnosis of infection in the cardiopulmonary phase through a review of the peripheral smear, and suggested that intravenous ribavirin is probably not effective for the treatment of new world hantavirus infections when started in the cardiopulmonary phase.

SUMMARY

Presumptive diagnosis may be made by a review of the peripheral blood smear after the onset of the cardiopulmonary phase. Critical care management includes the avoidance of fluid overload, pressors to maintain cardiac output, and the use of extracorporeal membrane oxygenation in the most severe cases, but treatment with intravenous ribavirin is probably not effective.

Critical management in patients with severe enterovirus 71 infection

OBJECTIVE

The aim of this study was to analyze clinical details occurring in children with severe enterovirus 71 (EV71) infection and synthesize the critical care experience for patients with severe EV71 infection.

METHODS

A retrospective clinical, laboratory, and hemodynamic study was performed in a pediatric intensive care unit in a university hospital. From March 1998 to April 2000, seven consecutive pediatric patients with severe EV71 infection were retrospectively analyzed as the comparison group. From May 2000 to March 2003, eight consecutive patients with severe EV71 infection who had received the protocol therapy were enrolled as the study group. Detailed information about clinical treatment and pharmacological therapy was collected for comparison.

RESULTS

The clinical presentations and laboratory findings between the comparison and the study groups were not significantly different. The amount of intravenous fluid in the first 24 h was significantly higher in the comparison group (9.2+/-5.0 vs 4.9+/-1.3 mL/kg per h). More patients in the study group received low doses of dopamine infusion, patients in the comparison group received more epinephrine, and none of them received milrinone. The acute-stage and long-term survival rates were higher in the study group (100% vs 43%, 87% vs 29%).

CONCLUSION

Early cardiopulmonary support may prevent the vicious cycle of cardiopulmonary failure and improve the clinical outcome of severe EV71 infection. Milrinone may be the ideal inotropic agent for these patients. Echocardiography, a central line, and an arterial line could be an alternate method to replace direct intracardiac hemodynamic monitoring for guiding critical management.

Endothelin-mediated increases in lung VEGF content promote vascular leak in young rats exposed to viral infection and hypoxia

Viral respiratory infections increase the susceptibility of young animals to hypoxia-induced pulmonary edema formation. Previous work has shown that increased lung levels of endothelin (ET) contribute to this effect, though the mechanisms by which ET promotes vascular leak remain uncertain. Both in vitro and in vivo evidence suggests that ET can upregulate the production of VEGF, which is known to increase vascular permeability. We hypothesized that increases in lung ET promote increases in lung VEGF, which in turn increases vascular leak in the lung. Weanling rats were exposed to moderate hypoxia for 24 h while recovering from a mild viral respiratory infection, to hypoxia alone, or to viral infection alone. Lung VEGF mRNA and protein content were measured by RT-PCR and Western blotting, respectively. Animals exposed to hypoxia + virus demonstrated significant increases in lung VEGF mRNA and protein content. Immunohistochemical studies showed increased VEGF expression in alveolar septa and small pulmonary vessels in those animals. ET receptor blockade with bosentan prevented this increase in lung VEGF content, suggesting that ET promotes VEGF accumulation in the lung in this setting. Animals exposed to hypoxia + virus also demonstrated substantial increases in lung albumin extravasation, and those increases were blocked by both ET receptor blockade and VEGF antagonism. These findings suggest that ET-driven increases in lung VEGF content can contribute to the formation of pulmonary edema.

Therapeutic efficacy of milrinone in the management of enterovirus 71-induced pulmonary edema

Hand, foot, and mouth disease and herpangina are the major clinical manifestations of enterovirus 71 (EV71) infections. Brain-stem encephalitis and pulmonary edema are severe complications that can lead to death. This study was designed to evaluate the potential therapeutic effect of milrinone, a phosphodiesterase (PDE) inhibitor, in the treatment of patients with EV71-induced pulmonary edema. We conducted a historically controlled trial of 24 children with severe EV71-induced pulmonary edema from April 1998-June 2003 in southern Taiwan. Patients were divided into groups treated before and after the introduction of milrinone therapy. Etiological diagnosis was established by viral cultures and confirmed by specific immunofluorescence and neutralization tests. All 24 patients were below 5 years of age. The mortality was lower in the milrinone-treated vs. nontreated group (36.4% vs. 92.3%, P=0.005). Sympathetic tachycardia was decreased in patients treated with milrinone compared to controls (144 +/- 17/min vs. 206 +/- 26/min, P=0.004). A marked decrease in IL-13 (77 +/- 9 pg/ml vs. 162 +/- 88 pg/ml, P=0.001) was observed in milrinone-treated patients compared to controls. There was a significant reduction in white blood cell (10,838 +/- 4,537/mm3 vs. 19,475 +/- 7,798/mm3, P=0.009) and platelet (257 +/- 45 x 10(3)/mm3 vs. 400 +/- 87 x 10(3)/mm3, P=0.001) counts in milrinone-treated patients compared to controls. These results were associated with improvement in sympathetic regulation and decrease in IL-13 production. Milrinone therapy may provide a useful therapeutic approach for this highly lethal disorder.

Mechanism of fulminant pulmonary edema caused by enterovirus 71

Pulmonary edema (PE) may occur with enterovirus 71 (EV71) infection. We monitored arterial pressure (AP) and heart rate (HR) in patients with EV71 infection and analyzed the variability of AP and HR. Sympathetic activity, AP, and HR increased with respiratory stress. Thereafter, parasympathetic activity increased with decreases in AP and HR. The lungs showed edema with inducible nitric oxide synthase (iNOS) expression. Destruction of the medial, ventral, and caudal medulla may lead to sympathetic overactivation, causing blood to shift to the lungs. The pathogenesis of PE may also involve iNOS and nitric oxide.

Survival after pulmonary edema due to enterovirus 71 encephalitis

BACKGROUND

A distinctive pattern of enterovirus 71 (EV71) infection, characterized by fever, exanthem, acute pulmonary edema (PE), brainstem encephalitis, and flaccid paresis, affects infants and young children. Most die rapidly owing to respiratory failure and fulminant PE.

METHOD

The authors report short- and long-term outcome of six survivors of the acute illness.

RESULTS

In the context of acute PE and widespread weakness, recognition of the underlying neurologic disorder was facilitated by the distinctive pattern of MRI signal abnormalities in posterior pons and medulla. EV71-specific PCR of clinical samples helped confirm the diagnosis. Acute PE was managed with mechanical ventilation, afterload reduction, and inotrope support, and resolved completely over days. One patient with minimal neurologic recovery died 9 weeks after disease onset. The other patients have residual neurologic dysfunction, varying from subtle monoparesis to severe bulbar dysfunction, central and peripheral respiratory failure, and flaccid quadriparesis. Faster neurologic recovery was associated with less long-term deficit. Long-term outcome was similar in patients treated with and without pleconaril or IV immunoglobulin. Three long-term survivors treated with IV corticosteroids had less severe long-term neurologic disability than two not treated with steroids.

CONCLUSION

Acute pulmonary edema and encephalomyelitis occurs with EV71 infection in infants. Long-term neurologic outcome varied from minor, focal weakness to profound, global motor dysfunction with respiratory failure.

Acute pulmonary oedema: rare causes and possible mechanisms

Acute pulmonary oedema usually has a fatal outcome. In this clinical report, we present rare cases of pulmonary oedema that were associated with Japanese B encephalitis, lymphangitis in breast carcinoma, fat embolism due to long-bone fracture, and the rupture of cerebral mycotic aneurysms. A total of 18 patients in the four disease categories were collected in two teaching hospitals in Taipei and Hualien. Upon admission, routine and specific examinations were taken and all patients showed clear lungs by chest X-ray; however, signs of acute pulmonary oedema occurred within 7 days. After resuscitation, all patients died of acute pulmonary oedema. In patients with fat embolism, the levels of non-esterified plasma fatty acids, cGMP, 5-hydroxytryptamine (serotonin) and nitrates/nitrites were increased during pulmonary oedema. Immunohistochemical staining revealed virus infection and neuronal death, predominantly in the medial, ventral and caudal medulla in cases of Japanese B encephalitis. The pulmonary oedema due to central sympathetic activation in Japanese B encephalitis may be related to destruction of depressor mechanisms in the medulla. The rupture of mycotic aneurysms is known to cause cerebral compression that results in acute pulmonary oedema. Blockade of lymphatics, capillaries and venules in breast carcinoma with lymphangitis causes the development of rapid lung oedema. The pathogenesis of pulmonary oedema is much more complicated in fat embolism. Mediators such as cGMP, 5-hydroxytryptamine, nitric oxide and presumably other chemical substances may also be involved.

Cardiopulmonary manifestations of fulminant enterovirus 71 infection

BACKGROUND

The pathogenesis of acute pulmonary edema and cardiac collapse after enterovirus 71 (EV71) infection are not completely understood.

OBJECTIVE

To determine the hemodynamic features and the mechanism of pulmonary edema (PE) after EV71 infection by direct intracardiac monitoring.

DESIGN

Prospective clinical and laboratory study at a tertiary medical center.

PARTICIPANTS

Five consecutive infants, ages 2 to 13 months, with EV71 infection-proved by viral isolation in 4 and antibody in 1-with PE were enrolled. The clinical characteristics were systemically assessed. Hemodynamic profiles were determined every 4 hours by simultaneously implanted pulmonary arterial and central venous catheters during the acute stage.

RESULTS

Magnetic resonance imaging revealed that all 5 infants had brainstem lesions. All patients had tachycardia and hyperthermia. Transient systolic hypertension was noted in 1 patient, and 1 presented with hypotension. Pulmonary artery pressure in all 5 infants was normal or mildly elevated (26-31 mm Hg), and central venous pressure ranged from 10 to 22 mm Hg. Pulmonary artery occlusion pressures were normal or slightly elevated (13-16 mm Hg). Systemic and pulmonary vascular resistances were transiently increased in only 1 patient. The stroke volume index decreased to 15.3 to 35.7 mL/M2 (normal: 30-60 mL/M2), but because of the elevated heart rate, the cardiac index did not decrease. All hemodynamics normalized within days.

CONCLUSION

Fulminant EV71 infection may lead to severe neurologic complications and acute PE. The acute PE and cardiopulmonary decompensation in EV71 infection are not directly caused by viral myocarditis. The mechanism of PE may be related to increased pulmonary vascular permeability caused by brainstem lesions and/or systemic inflammatory response instead of increased pulmonary capillary hydrostatic pressure.

Rapid presumptive diagnosis of hantavirus cardiopulmonary syndrome by peripheral blood smear review

Hantavirus cardiopulmonary syndrome (HCPS) is a rare but frequently lethal acute zoonotic viral infection in rural North America. The rapidity of progression from febrile prodrome to cardiogenic shock and noncardiogenic pulmonary edema requiring intensive care creates high diagnostic urgency and a need for a rapid screening tool. In this retrospective cohort study, 2 pathologists scored blinded peripheral blood smears from 52 patients with HCPS and 128 seronegative patients referred for diagnosis of suspected hantavirus infection. During the prodromal phase, thrombocytopenia was the only consistent abnormality and could be used to indicate hantavirus serologic testing. After the onset of pulmonary edema detected radiographically, the presence of 4 of 5 findings (thrombocytopenia, myelocytosis, hemoconcentration, lack of significant toxic granulation in neutrophils, and more than 10% of lymphocytes with immunoblastic morphologic features) has a sensitivity for HCPS of 96% and a specificity of 99% and missed no patients with HCPS who required intensive care. While each abnormality is commonly seen, the combination of at least 4 of these CBC count data and peripheral blood smear findings can guide early treatment and patient transport decisions until rapid, specific, serologic testing becomes widely available.

Acute pancreatitis in patients with hemorrhagic fever with renal syndrome

The objective of this study was to determine the prevalence and clinical significance of acute pancreatitis in patients in whom hemorrhagic fever with renal syndrome (HFRS) has been diagnosed. We retrospectively reviewed all patients with a diagnosis of HFRS at our institution from 1994 to 1998. The review included medical records, laboratory results, radiologic examinations, and one autopsy report. From 1994 to 1998, 13 patients received diagnoses of HFRS that were confirmed by serology. In 9 patients (69%), serum amylase, serum lipase, or both were assessed during hospitalization. Seven (78%) of the 9 patients had pancreatitis. Four (57%) of these 7 patients with HFRS and pancreatitis had associated pulmonary edema, and 1 patient had rhabdomyolysis. In our small retrospective case series, acute pancreatitis in patients with HFRS was much more common than previously recognized. Patients with HFRS and pancreatitis had increased morbidity. However, the treatment for the associated pancreatitis was conservative.

[Respiratory manifestations of hemorrhagic fever with renal syndrome. Retrospective study of 129 cases in Champagne-Ardenne and Lorraine]

OBJECTIVES

The contradiction between airborne transmission of Puumala virus and the low rate of airway manifestations reported in hemorrhagic fever with renal syndrome (HFRS) caused by this virus led us to conduct this study to check whether the incidence of respiratory manifestations may have been underestimated.

PATIENTS AND METHODS

We retrospectively reviewed 129 consecutive cases of HFRS diagnosed between 1983 and 1995 in the eastern France.

RESULTS

Clinical manifestations of airway involvement and chest X-ray abnormalities were observed in 30% and 50% of the patients respectively. Analysing the radiological anomalies by serum creatinine level showed that in two-thirds of the cases (33% of all the HFRS cases) they were concomitant with acute renal failure and probably related to pulmonary edema, and that in one-third (17% of the HFRS cases) they were compatible with pneumonia. These cases of pneumonia could correspond to specific manifestations of the hantavirus Puumala at the site of penetration.

CONCLUSION

Although minimally expressive, respiratory manifestations were found to be more frequent than expected in hemorrhagic fever with renal syndrome. Incidence may have been formerly underestimated.

Fatal pulmonary edema in white-tailed deer (Odocoileus virginianus) associated with adenovirus infection

Sporadic sudden deaths in adult white-tailed deer occurred from November 1997 through August 1998 on an Iowa game farm. Three of the 4 deer necropsied had severe pulmonary edema, widespread mild lymphocytic vasculitis, and amphophilic intranuclear inclusion bodies in scattered endothelial cells in blood vessels in the lung and abdominal viscera. Immunohistochemistry with bovine adenovirus 5 antisera and transmission electron microscopy demonstrated adenoviral antigen and nucleocapsids, respectively, within endothelial cells. Adenovirus was isolated in cell culture from 1 of the affected deer. The isolate was neutralized by California black-tailed deer adenovirus antiserum. These findings indicate that adenovirus should be considered in the differential diagnosis of both black-tailed and white-tailed deer with pulmonary edema and/or hemorrhagic enteropathy.

Decreased expression of aquaporin (AQP)1 and AQP5 in mouse lung after acute viral infection

Intratracheal infection of mice with adenovirus is associated with subsequent pulmonary inflammation and edema. Water movement through the air space-capillary barrier in the distal lung is facilitated by aquaporins (AQPs). To investigate the possibility that distal lung AQPs undergo altered regulation under conditions of aberrant fluid handling in the lung, we analyzed messenger RNA (mRNA) and protein expression of AQPs 1 and 5 in the lungs of mice 7 and 14 d after infection with adenovirus. Here, we demonstrate that AQP1 and AQP5 show decreased expression following adenoviral infection. Northern blot analysis showed significantly decreased mRNA levels of AQP1, which is expressed in the capillary endothelium, and AQP5, which is expressed in alveolar epithelium, in the lungs of mice both 7 and 14 d after infection. Immunoblotting studies demonstrated significantly reduced levels of AQP1 and AQP5 protein after infection as well. In addition, mRNA expression of the alpha subunit of the epithelial sodium channel was reduced in the lungs of mice 7 and 14 d after adenoviral infection. In contrast, mRNA expression of the alpha1 subunit of the Na,K-adenosine triphosphatase in the lung was unaltered. Immunohistochemical analysis demonstrated that the decreases in AQP1 and AQP5 expression were not localized to regions of overt inflammation but were found throughout the lung. Thus, this study provides the first report of AQP gene regulation in an in vivo model of pulmonary inflammation and edema. Decreased AQP1 and AQP5 levels during adenoviral infection suggest a role for AQP1 and AQP5 in the abnormal fluid fluxes detected during pulmonary inflammation.

Clinical features and risk factors of pulmonary oedema after enterovirus-71-related hand, foot, and mouth disease

BACKGROUND

In Taiwan, from April to July, 1998, an epidemic of hand, foot, and mouth disease associated with enterovirus 71 (EV71) occurred with fatal complications. We did a clinical study of EV71-related diseases in Taiwan.

METHODS

We studied 154 children with virus-culture confirmed EV71 infection. Children were divided into three groups: 11 patients with pulmonary oedema; 38 patients with central nervous system (CNS) involvement and no pulmonary oedema; and 105 children without complications. We compared the clinical features, laboratory findings, risk factors, and outcome among these three groups.

FINDINGS

Nine children with pulmonary oedema had hand, foot, and mouth disease, one had herpangina, and one had febrile illness with eight children with limb weakness and one with limb hypesthesia. All children had had sudden onset of tachycardia, tachypnoea, and cyanosis 1-3 days after onset of the disease. Nine of 11 children died within 12 h of intubation; one child was braindead within 15 h and died 17 days after intubation; one child was in deep coma and died 3 months later. In children with CNS complication and no pulmonary oedema, one child died of pneumonia after 4 months of ventilator support and four children had sequelae. All 105 children without complications recovered. There was a significant association between CNS involvement and pulmonary oedema (odds ratio 12.4 [95% CI 2.6-60.1], p=0.001). Risk factors for pulmonary oedema after CNS involvement were hyperglycaemia, leucocytosis, and limb weakness. Hyperglycaemia was the most significant prognostic factor for pulmonary oedema (odds ratio 21.5 [3-159], p=0.003).

INTERPRETATION

EV71 can cause hand, foot, and mouth disease, CNS involvement with severe sequelae, and fatal pulmonary oedema. Hyperglycaemia is the most important prognostic factor.

Spectrum of hantavirus infection: hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome

Hantaviruses chronically infect rodents without apparent disease, but when they are spread by aerosolized excreta to humans, two major clinical syndromes result: hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). Both diseases appear to be immunopathologic, and inflammatory mediators are important in causing the clinical manifestations. In HPS, T cells act on heavily infected pulmonary endothelium, and it is suspected that gamma interferon and tumor necrosis factor are major agents of a reversible increase in vascular permeability that leads to severe, noncardiogenic pulmonary edema. HFRS has prominent systemic manifestations. The retroperitoneum is a major site of vascular leak and the kidneys suffer tubular necrosis. Both syndromes are accompanied by myocardial depression and hypotension or shock. HFRS is primarily a Eurasian disease, whereas HPS appears to be confined to the Americas; these geographic distinctions correlate with the phylogenies of the rodent hosts and the viruses that coevolved with them.

Fatal enterovirus 71 encephalomyelitis

During an outbreak of hand-foot-mouth disease caused by enterovirus 71 (EV-71) in 1997, 4 children presented with sudden cardiopulmonary collapse and minimal neurologic features. All children received cardiopulmonary resuscitation but died within a few hours of admission. Postmortem studies showed infection by EV-71 with extensive damage to the medulla and pons. We postulate an etiologic link between EV-71 and brainstem encephalomyelitis as the cause of pulmonary edema and death.

Distribution of bluetongue virus in tissues of experimentally infected pregnant dogs as determined by in situ hybridization

Six female dogs (four pregnant and two nonpregnant) were inoculated with bluetongue virus (BTV), serotype 11. Pregnant animals and one nonpregnant dog received 5.5-6.3 log10 of cell culture-adapted virus. The other nonpregnant dog received a modified live vaccine contaminated with bluetongue virus. The non-pregnant animals never became clinically ill and were euthanatized 35 days post-inoculation. Three of the four pregnant dogs aborted, and all four died or were euthanatized 5-10 days post-inoculation. The predominant pathologic feature in the adults was severe pulmonary edema. Various tissues from the bitches and fetuses were examined by in situ hybridization using a digoxigenin-labeled probe corresponding to the nonstructural protein-1 gene of BTV-17. By this technique, viral nucleic acid was detected predominantly in endothelial cells of lung of all four dogs, with lesser amounts in capillaries of uterus, spleen, and kidney in some of the dogs. In two adult dogs, bluetongue viral nucleic acid was detected in mononuclear cells of the periarteriolar lymphoid sheaths of spleen. There was minimal staining of capillaries in placenta in three of the five fetuses examined. There was no viral nucleic acid detected in any of the other fetal tissues.

Cardiopulmonary manifestations of hantavirus pulmonary syndrome

OBJECTIVE

To describe the clinical characteristics of a group of patients infected with the newly recognized hantavirus in the Southwestern United States.

DESIGN

Case series.

SETTING

Tertiary referral center.

PATIENTS

All patients with confirmed hantavirus infection admitted to the University of New Mexico Hospital between May 1, 1993 and January 1, 1994.

INTERVENTIONS

Records of patients with hantavirus infection were reviewed to collect all pertinent clinical data.

MEASUREMENTS AND MAIN RESULTS

Pulmonary disease in these patients was characterized by hypoxemia covering a wide range of severity. The cause of hypoxemia was an increased permeability (noncardiac) pulmonary edema which could be differentiated from hydrostatic (cardiac) pulmonary edema by its association with low pulmonary artery occlusion pressures and increased protein content of edema fluid. Hemodynamic measurements in severe cases showed a shock state characterized by a low cardiac index (range 1.6 to 3.0 L/min/min2), a low stroke volume index (range 10.5 to 29 mL/m2), and high systemic vascular resistance index (range 1,653 to 2,997 dyne.sec/cm5.m2). Progression to death was associated with worsening cardiac dysfunction unresponsive to treatment and causing oxygen debt and lactic acidosis.

CONCLUSIONS

The two major life-threatening pathophysiologic changes in Hantavirus Pulmonary Syndrome are increased permeability pulmonary edema, and an atypical form of septic shock caused by myocardial depression and hypovolemia.

Hantavirus pulmonary syndrome in Florida: association with the newly identified Black Creek Canal virus

Hantavirus pulmonary syndrome (HPS) is a recently recognized viral zoonosis. The first recognized cases were caused by a newly described hantavirus. Sin Nombre virus (previously known as Muerto Canyon virus), isolated from Peromyscus maniculatus (deer mouse). We describe a 33-year-old Floridian man who resided outside the ecologic range of P maniculatus but was found to have serologic evidence of a hantavirus infection during evaluation of azotemia associated with adult respiratory distress syndrome. Small mammal trapping conducted around this patient's residence demonstrated the presence of antihantaviral antibodies in 13% of Sigmodon hispidus [cotton rat). Serologic testing using antigen derived from the Black Creek Canal hantavirus subsequently isolated from this rodent established that this patient was acutely infected with this new pathogenic American hantavirus. HPS is not confined to the geographical distribution of P maniculatus and should be suspected in individuals with febrile respiratory syndromes, perhaps associated with azotemia, throughout the continental United States.