Epstein-Barr Virus-Associated Atraumatic Spleen Laceration Presenting with Neck and Shoulder Pain

BACKGROUND

Infectious mononucleosis, caused by the Epstein-Barr virus (EBV), is a common infection with worldwide distribution; more than 90% of people have been infected by adulthood. One of the most feared, albeit rare, complications, occurring in less than 0.5% of those infected, is splenic injury or rupture.

CASE REPORT

A febrile 15-year-old male presented to the emergency department with the chief compliant of headache, neck pain, and upper shoulder pain. He did not recall any specific traumatic injury. His abdomen was soft, nondistended, and was tender in the right and left lower quadrants. Right lower quadrant ultrasound demonstrated non-visualization of the appendix, moderate right lower quadrant free fluid, and positive McBurney's sign. CT of the abdomen and pelvis was ordered, which demonstrated moderate splenomegaly, with findings compatible with laceration through the anterior aspect of the spleen, with moderate hemoperitoneum. Monospot was negative and EBV panel demonstrated IGG negative, IGM positive, and, IGG negative. The patient was transferred to interventional radiology for a splenic angiogram and proximal splenic artery embolization. The angiogram demonstrated grade 3 laceration with moderate hemoperitoneum and no active extravasation or evidence of pseudoaneurysm. The patient was admitted and made a prompt recovery without any other sequelae.

CONCLUSIONS

The presentation of splenic injury or rupture can vary; the patient may complain of abdominal pain or left upper quadrant pain, may exhibit referred left shoulder pain when the LUQ is palpated (Kehr's Sign), or may exhibit hemodynamic instability. Given the spectrum of non-specific symptoms, diagnosing EBV-induced splenic laceration can be difficult.

Injuries Following Segway Personal Transporter Accidents: Case Report and Review of the Literature

The Segway® self-balancing personal transporter has been used as a means of transport for sightseeing tourists, military, police and emergency medical personnel. Only recently have reports been published about serious injuries that have been sustained while operating this device. This case describes a 67-year-old male who sustained an oblique fracture of the shaft of the femur while using the Segway® for transportation around his community. We also present a review of the literature.

Methemoglobinemia: a systematic review of the pathophysiology, detection, and treatment

Methemoglobin is the oxidized form of hemoglobin which does not bind to oxygen efficiently. An increased level of methemoglobin can be attributed to congenital enzymatic defects, alterations in the hemoglobin molecule, or as a result of medications and toxins. The main clinical characteristic of the disease include cyanosis which is unresponsive to oxygen therapy and blood that is chocolate color when drawn. Co-oximetry is the gold standard for diagnosis but arterial blood gas paired with pulse oximetry and serum methemoglobin levels can confirm the diagnosis clinically. Treatment is aimed at removal of the offending agent, if medication induced, and is directed at aggressive oxygen therapy and treatment with the antidote, methylene blue.

Unilateral papilledema: a case of optic neuritis diagnosed with bedside ocular sonography

Optic neuritis is a demyelinating inflammatory condition that causes acute loss of vision, especially color vision, and eye pain. Magnetic resonance imaging and fundoscopy have traditionally aided the diagnosis of what largely remains a clinical diagnosis. We report a case of optic neuritis diagnosed in the emergency department with the aid of bedside ocular sonography. The pathophysiology, diagnosis and management of acute optic neuritis will be reviewed.

The DNA sequence and comparative analysis of human chromosome 20

The finished sequence of human chromosome 20 comprises 59,187,298 base pairs (bp) and represents 99.4% of the euchromatic DNA. A single contig of 26 megabases (Mb) spans the entire short arm, and five contigs separated by gaps totalling 320 kb span the long arm of this metacentric chromosome. An additional 234,339 bp of sequence has been determined within the pericentromeric region of the long arm. We annotated 727 genes and 168 pseudogenes in the sequence. About 64% of these genes have a 5' and a 3' untranslated region and a complete open reading frame. Comparative analysis of the sequence of chromosome 20 to whole-genome shotgun-sequence data of two other vertebrates, the mouse Mus musculus and the puffer fish Tetraodon nigroviridis, provides an independent measure of the efficiency of gene annotation, and indicates that this analysis may account for more than 95% of all coding exons and almost all genes.

Stuttering: neuropsychiatric features measured by content analysis of speech and the effect of risperidone on stuttering severity

Positron-emission tomographic (PET) studies and genetic research of stuttering have recently revealed underlying cerebral neurobiologic contributing factors in this disorder. We aimed to assess whether cognitive impairment and other neuropsychiatric dimensions could be detected through computerized content analysis of short samples of speech from stutterers, and whether administration of risperidone in a double-blind placebo-controlled study could decrease the severity of stuttering, as well as any of the neuropsychiatric features of these stutterers. A group of 21 stutterers with the developmental form of stuttering, an onset before age of 6 years, aged 20 to 74 years, and who were otherwise free of major medical or psychiatric problems, initially gave a 5-minute tape-recorded speech sample in response to purposely ambiguous instructions to talk about any interesting or dramatic life experiences. Then, half of these subjects (n = 10) were randomly selected to receive 6 weeks of risperidone treatment up to 2.0 mg/d and the other half (n = 11) were administered a placebo. Both groups of subjects gave a second verbal sample after 6 weeks of treatment. Significantly elevated cognitive impairment and social alienation-personal disorganization scores, derived from the computerized content of the initial 5-minute speech samples, were found. After 6 weeks, the risperidone group improved significantly on a measure of severity of stuttering but did not improve on the percentage of time spent stuttering. The placebo group did not improve on either measure of stuttering. The psychopathological processes of subjects who received risperidone treatment, including those with elevated cognitive impairment and social alienation-personal disorganization, did not change significantly. However, stutterers who had lower scores on verbal content analysis-derived shame anxiety, guilt anxiety, or hostility inward measures improved significantly more with risperidone than stutterers with higher scores on these measures. The findings of elevated cognitive impairment and social alienation-personal disorganization scores of adult stutterers with the early developmental form of stuttering are consistent with the neurobiologic abnormalities found in PET-scan and genetic research involving stutterers. Risperidone (< or =2.0 mg/d) can reduce the severity of stuttering while not significantly affecting the magnitude of neuropsychiatric dimensions such as cognitive impairment or social alienation-personal disorganization. The less the inward shame, guilt, or hostility of the stutterers, the better the beneficial effect of risperidone on the severity of stuttering.

Specific interactions between the syntrophin PDZ domain and voltage-gated sodium channels

Syntrophins are modular proteins belonging to the dystrophin associated glycoprotein complex and are thought to be involved in the regulation of the muscular system. Screening of peptide libraries revealed selectivity of the synotrophin PDZ domain toward the motif R/K/Q-E-S/T-X-V-COO- found to be highly conserved in the alpha-subunit C-terminus of vertebrate voltage gated sodium channels (VGSCs). The solution structure of the domain in complex with the peptide G-V-K-E-S-L-V shows specific interactions between the conserved residues in the peptide and syntrophin-characteristic residues in the domain. We propose that syntrophins localize VGSCs to the dystrophin network through its PDZ domain.

Characterization of pheophytin ground states in Rhodobacter sphaeroides R26 photosynthetic reaction centers from multispin pheophytin enrichment and 2-D 13C MAS NMR dipolar correlation spectroscopy

The electronic ground states of pheophytin cofactors potentially involved in symmetry breaking between the A and B branch for electron transport in the bacterial photosynthetic reaction center have been investigated through a characterization of the electron densities at individual atomic positions of pheophytin a from 13C chemical shift data. A new experimental approach involving multispin 13C labeling and 2-D NMR is presented. Bacterial photosynthetic reaction centers of Rhodobacter sphaeroides R26 were reconstituted with uniformly 13C biosynthetically labeled (plant) Pheo a in the two pheophytin binding sites. From the multispin labeled samples 1-D and 2-D solid-state 13C magic angle spinning NMR spectra could be obtained and used to characterize the pheophytin a ground state in the Rb. sphaeroides R26 RCs, i.e., without a necessity for time-consuming selective labeling strategies involving organic synthesis. From the 2-D solid state 13C-13C correlation spectra collected with spinning speeds of 8 and 10 kHz, with mixing times of 1 and 0.8 ms, many 13C resonances of the [U-13C]Pheo a molecules reconstituted in the RCs could be assigned in a single set of experiments. Parts of the pheophytins interacting with the protein, at the level of 13C shifts modified by binding, could be identified. Small reconstitution shifts are detected for the 17(2) side chain of ring IV. In contrast, there is no evidence for electrostatic differences between the two Pheo a, for instance, due to a possibly strong selective electrostatic interaction with Glu L104 on the active branch. The protonation states appear the same, and the NMR suggests a strong overall similarity between the ground states of the two Pheo a, which is of interest in view of the asymmetry of the electron transfer.

Night-to-night variability in sleep apnea and sleep-related periodic leg movements in the elderly

The amount of night-to-night variability in sleep apnea (SA) and sleep-related periodic leg movements (PLMs) is largely unknown but, despite this, clinical decisions are based on single-night studies in many clinical sleep laboratories. We examined variability in SA and PLMs over three nights in 46 community-resident seniors. No evidence was found for either a first-night effect or a directional trend across nights in either the Respiratory Disturbance Index (RDI) or the Movement Index (MI), despite a prominent first-night effect on pattern of sleep. Duration of apneas/hypopneas and degree of associated heart rate change and oxygen desaturation in subjects with SA and intermovement interval in subjects with PLMs also failed to show systematic change across nights. However, if a cut-off score of 5/h for RDI and MI was used, the classification recorded on the first night did differ from the classification given on at least one of the other nights in 43% of the subjects. The magnitude of fluctuation in RDI or MI from night to night was large enough in some subjects that, in a clinical situation, decisions based on one night would have been entirely different had the subject been studied on a different night. Night-to-night variability in RDI and MI within subjects also was associated with significant alterations in the sleep pattern. We conclude that caution should be taken in drawing conclusions from single-night studies, especially in individuals with relatively mild forms of SA and PLMs where nightly variations could easily place them above or below an arbitrary cut-off score.