Lemierre's Syndrome Associated With Papillary Thyroid Cancer and Cerebellar Stroke.

A 53-year-old woman with no past medical history presented to the Emergency Department with right frontal headache and ipsilateral neck pain. She was found to have right internal jugular vein thrombosis, right cerebellar stroke, meningitis, septic pulmonary emboli, and fusobacterium bacteremia, all consistent with a severe presentation of Lemierre's syndrome (LS). While LS is often preceded by nasopharyngeal infection, no such history was elicited from our patient. Instead, concomitant papillary thyroid cancer with extension to her right internal jugular vein was implicated. Prompt recognition of these multiple related processes led to a timely initiation of appropriate therapy for infection, stroke, and malignancy.

Determinants of point-of-care ultrasound lung sliding amplitude in mechanically ventilated patients.

BACKGROUND: Although lung sliding seen by point-of-care ultrasound (POCUS) is known to be affected to varying degrees by different physiologic and pathologic processes, it is typically only reported qualitatively in the critical care setting. Lung sliding amplitude quantitatively expresses the amount of pleural movement seen by POCUS but its determinants in mechanically ventilated patients are largely unknown. METHODS: This was a single-center, prospective, observational pilot study examining 40 hemithoraces in 20 adult patients receiving mechanical ventilation. Each subject had lung sliding amplitude measured in both B-mode and by pulsed wave Doppler at their bilateral lung apices and bases. Differences in lung sliding amplitude were correlated with anatomical location (apex vs base) as well as physiologic parameters including positive end expiratory pressure (PEEP), driving pressure, tidal volume and the ratio of arterial partial pressure of oxygen (PaO2) to fraction of inspired oxygen (FiO2). RESULTS: POCUS lung sliding amplitude was significantly lower at the lung apex compared to the lung base in both B-mode (3.6 ± 2.0 mm vs 8.6 ± 4.3 mm; p < 0.001) and the pulsed wave Doppler mode (10.3 ± 4.6 cm/s vs 13.9 ± 5.5 cm/s; p < 0.001) corresponding to expected distribution of ventilation to the lung bases. Inter-rater reliability of B-mode measurements was excellent (ICC = 0.91) and distance traversed in B-mode had a significant positive correlation with pleural line velocity (r2 = 0.32; p < 0.001). There was a non-statistically significant trend towards lower lung sliding amplitude for PEEP ≥ 10 cmH2O, as well as for driving pressure ≥ 15 cmH2O in both ultrasound modes. CONCLUSION: POCUS lung sliding amplitude was significantly lower at the lung apex than the lung base in mechanically ventilated patients. This was true when using both B-mode and pulsed wave Doppler. Lung sliding amplitude did not correlate with PEEP, driving pressure, tidal volume or PaO2:FiO2 ratio. Our findings suggest that lung sliding amplitude can be quantified in mechanically ventilated patients in a physiologically predictable way and with high inter-rater reliability. A better understanding of POCUS derived lung sliding amplitude and its determinants may aid in the more accurate diagnosis of lung pathologies, including pneumothorax, and could serve as a means of further reducing radiation exposure and improving outcomes in critically ill patients.

Community-acquired Pneumonia and Hospital-acquired Pneumonia.

Pneumonia is among the leading causes of morbidity and mortality worldwide. Although Streptococcus pneumoniae is the most likely cause in most cases, the variety of potential pathogens can make choosing a management strategy a complex endeavor. The setting in which pneumonia is acquired heavily influences diagnostic and therapeutic choices. Because the causative organism is typically unknown early on, timely administration of empiric antibiotics is a cornerstone of pneumonia management. Disease severity and rates of antibiotic resistance should be carefully considered when choosing an empiric regimen. When complications arise, further work-up and consultation with a pulmonary specialist may be necessary.

Advantages of Cardiopulmonary Ultrasound in Post-Cardiopulmonary Resuscitation Tension Pneumothorax.

Tension pneumothorax is a life-threatening condition that frequently occurs in the setting of cardiopulmonary resuscitation as a result of positive pressure ventilation and chest compressions. Developing crepitus due to subcutaneous air can severely limit pleural ultrasound (US) views and hinder the diagnosis of pneumothorax by pleural US. Physicians trained in the use of point-of-care US must be familiar with the subcostal cardiac and inferior vena cava views associated with tension pneumothorax. These include a dilated, nondistensible inferior vena cava and hyperdynamic right heart as a result of a reduced preload.

Primary Laryngotracheal Amyloidosis With Bilateral Vocal Cord Involvement and Associated Bronchiectasis.

Localized tracheobronchial amyloidosis is a rare disease that results from submucosal deposition of insoluble amyloid proteins in the large airways. Amyloidosis affecting the larynx and subglottic space typically results in unilateral, nodular vocal cord infiltration. It rarely can present with bilateral vocal cord involvement and can progress to lifethreatening respiratory failure due to upper airway obstruction. In these patients, typical treatment modalities such as CO2 laser ablation are often ineffectual. Bronchiectasis is a predisposing risk factor associated with the secondary (AA) form of disease. We present a patient with the primary (AL) form of localized laryngotracheal amyloidosis with pre-existing bronchiectasis, and also review the existing literature on this disease.

Molecular mechanism for the regulation of human mitochondrial NAD(P)+-dependent malic enzyme by ATP and fumarate.

The regulation of human mitochondrial NAD(P)+-dependent malic enzyme (m-NAD-ME) by ATP and fumarate may be crucial for the metabolism of glutamine for energy production in rapidly proliferating tissues and tumors. Here we report the crystal structure at 2.2 A resolution of m-NAD-ME in complex with ATP, Mn2+, tartronate, and fumarate. Our structural, kinetic, and mutagenesis studies reveal unexpectedly that ATP is an active-site inhibitor of the enzyme, despite the presence of an exo binding site. The structure also reveals the allosteric binding site for fumarate in the dimer interface. Mutations in this binding site abolished the activating effects of fumarate. Comparison to the structure in the absence of fumarate indicates a possible molecular mechanism for the allosteric function of this compound.