Rapid Glomerulotubular Nephritis as an Initial Presentation of a Lethal Diquat Ingestion.

INTRODUCTION: Diquat is an herbicide that can lead to rapid multiorgan system failure upon toxic ingestion. Although Diquat shares a similar chemical structure with paraquat, diquat is still readily available to the general population, and in contrast to paraquat, it is not regulated. We present a case of an intentional diquat poisoning which emphasizes the necessity of the early recognition due to atypical symptoms within the first 24 hours and certainly enhanced regulatory restrictions on this very toxic compound. CASE: A 60-year-old male with a history of severe depression presented to the emergency department after intentional ingestion of a commercial herbicide containing diquat dibromide 2.30%. The earliest manifestations of this acute diquat intoxication comprised a glomerulonephritis and proximal tubular dysfunction. Progressive multiorgan system failure then developed with a significant delay (24-38 hours) including acute renal, liver failure, and then respiratory failure with refractory hypoxemia. Despite maximal supportive care, the end organ failure was lethal. Discussion. Diquat intoxication should be suspected in patient presenting an acute glomerulonephritis with coma. Diquat should undergo the same regulatory restrictions as paraquat-containing compounds.

Evidence for the emergence of an opioid-resistant respiratory rhythm following fentanyl overdose.

Breathing resumes within one to two minutes following fentanyl overdose induced apnea in spontaneously breathing rats. As this regular rhythm is produced at a time wherein fentanyl concentrations and receptor occupancy are likely to be extremely high, the mechanisms initiating and sustaining such a respiratory activity remain unclear. Forty-four un-anesthetized adult rats were studied in an open-flow plethysmograph. Regardless of the dose of fentanyl that was used, i.e. 50 µg.kg-1 (n = 8), 100 µg.kg-1 (n = 8) or 300 µg.kg-1 (n = 7), all rats developed an immediate central apnea followed by a depressed regular rhythm that was produced 118, 97 and 81 s (median) later, respectively. Only one rat did not recover. This inspiratory and regular activity consisted of a low frequency and tidal volume pattern with a significant reduction in V̇E/V̇CO2 ratio, which persisted for at least 30 min and that was not different between 100 or 300 µg.kg-1. The time at which this respiratory rhythm emerged, following the highest dose of fentanyl, was not affected by 100 % O2 or 8% CO2/15 % O2. The absolute level of ventilation was however higher in hypercapnic and moderately hypoxic conditions than in hyperoxia. When a second injection of the highest dose of fentanyl (300 µg.kg-1) was performed at 10 min, ventilation was not significantly affected and no apnea was produced in major contrast to the first injection. When a similar injection was performed 30 min after the first injection, in a separate group of rats, an apnea and breathing depression was produced in 30 % of the animals, while in the other rats, ventilation was unaffected. We conclude that the depressed regular respiratory activity emerging during and following fentanyl overdose is uniquely resistant to fentanyl.

Severe Hypoxemia Prevents Spontaneous and Naloxone-induced Breathing Recovery after Fentanyl Overdose in Awake and Sedated Rats.

BACKGROUND: As severe acute hypoxemia produces a rapid inhibition of the respiratory neuronal activity through a nonopioid mechanism, we have investigated in adult rats the effects of hypoxemia after fentanyl overdose-induced apnea on (1) autoresuscitation and (2) the antidotal effects of naloxone. METHODS: In nonsedated rats, the breath-by-breath ventilatory and pulmonary gas exchange response to fentanyl overdose (300 µg · kg · min iv in 1 min) was determined in an open flow plethysmograph. The effects of inhaling air (nine rats) or a hypoxic mixture (fractional inspired oxygen tension between 7.3 and 11.3%, eight rats) on the ability to recover a spontaneous breathing rhythm and on the effects of naloxone (2 mg · kg) were investigated. In addition, arterial blood gases, arterial blood pressure, ventilation, and pulmonary gas exchange were determined in spontaneously breathing tracheostomized urethane-anesthetized rats in response to (1) fentanyl-induced hypoventilation (7 rats), (2) fentanyl-induced apnea (10 rats) in air and hyperoxia, and (3) isolated anoxic exposure (4 rats). Data are expressed as median and range. RESULTS: In air-breathing nonsedated rats, fentanyl produced an apnea within 14 s (12 to 29 s). A spontaneous rhythmic activity always resumed after 85.4 s (33 to 141 s) consisting of a persistent low tidal volume and slow frequency rhythmic activity that rescued all animals. Naloxone, 10 min later, immediately restored the baseline level of ventilation. At fractional inspired oxygen tension less than 10%, fentanyl-induced apnea was irreversible despite a transient gasping pattern; the administration of naloxone had no effects. In sedated rats, when PaO2 reached 16 mmHg during fentanyl-induced apnea, no spontaneous recovery of breathing occurred and naloxone had no rescuing effect, despite circulation being maintained. CONCLUSIONS: Hypoxia-induced ventilatory depression during fentanyl induced apnea (1) opposes the spontaneous emergence of a respiratory rhythm, which would have rescued the animals otherwise, and (2) prevents the effects of high dose naloxone.

Bilateral spontaneous pneumothoraces with spontaneous pneumomediastinum: An intravenous methamphetamine complication.

OBJECTIVE: To present an unusual case and proposed mechanism of bilateral spontaneous pneumothoraces with pneumomediastinum in a patient with intravenous methamphetamine use. CASE REPORT: Thin white man presented with confusion and chest pain after intravenous methamphetamine use. Initial workup found bilateral pneumothoraces with pneumomediastinum. Conservative management was initiated and subsequent radiographs and physical examination revealed subsequent improvement in pneumothoraces and pneumomediastinum. CONCLUSION: Intravenous methamphetamine use increases a wide number of inflammatory markers that can increase the risk of spontaneous pneumothoraces and pneumomediastinum. In patients with known risk factors, methamphetamine use can promote an increased incidence of spontaneous pneumothorax and pneumomediastinum.