Bodytemperature changes Heat stroke, malignant hyperthermia, malignant neuroleptic syndrome, hypothermia Metabolic and electrolyte disorders Hypokalemia, hypophosphatemia, hypocalcemia, nonketotic hyperosmotic conditions, diabetic ketoacidosis Drugs and toxins Lipidlowering drugs (fibrates, statins), alcohol, heroin, cocaine Idiopathic (sometimes recurrent) * Rhabdomyolysis from this cause is associated with a crush syndrome-like mechanism. † CoA denotes coenzyme A. ‡ In most cases, the mechanism is unclear.

CTA-defined LVV occurs in two-thirds of patients with GCA at the time of diagnosis and aortic dilation is already present in 15%. Previous corticosteroid treatment may decrease CTA-detected LVV.

GCA patients with a strong systemic inflammatory response, who have been previously shown to be more resistant to corticosteroid therapy, have elevated tissue expression of proinflammatory cytokines IL-1beta, TNFalpha and IL-6. High production of TNFalpha is associated with longer corticosteroid requirements.

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Background— Patients with giant-cell arteritis (GCA) who develop a strong acute-phase response are at low risk of disease-related ischemic events. Methods and Results— To assess the potential protective role of proinflammatory cytokines in the development of ischemic events in GCA, we measured tissue expression (66 individuals) and/or circulating levels (80 individuals) of interleukin (IL)-1β, tumor necrosis factor-α (TNF-α), and IL-6 in patients with biopsy-proven GCA. Tissue expression was determined by quantitative real-time polymerase chain reaction and immunohistochemistry. Circulating cytokines were determined by enzyme-linked immunoassay. We found that patients with disease-related ischemic events had lower IL-6 mRNA levels (5.9±2.1 versus 27.6±7.8 relative units, P =0.013), lower IL-6 immunohistochemical expression scores (1.5±0.9 versus 2.7±1, P =0.001), and lower circulating levels of IL-6 (13.6±2.1 versus 24±2.4 pg/mL, P =0.002) than patients without ischemic complications. No significant differences were found for either IL-1β or TNF-α. We subsequently investigated direct effects of IL-6 on vessel wall components. We found that IL-6 stimulates endothelial cell proliferation and differentiation into capillary-like structures and induces full angiogenic activity in both ex vivo (aortic ring) and in vivo (chick chorioallantoic membrane) assays. Conclusions— GCA patients with ischemic complications have lower tissue expression and circulating levels of IL-6 than patients with no ischemic events. IL-6 has relevant direct effects on vascular wall components that might be protective: IL-6 activates a functional program related to angiogenesis that may compensate for ischemia in patients with GCA.

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We studied 7 patients with an acute motor axonal Guillain-Barré syndrome (GBS), manifested 5 to 15 days after parenteral injection of a commercial ganglioside preparation given for nonspecific pain syndromes. The serum IgG and IgM antibody response to ganglioside was studied serially and the recognition of epitopes on the peripheral nerves and motor end-plates was examined using biotinylated IgG extracted from the patient's serum. Sera from 8 patients treated with the same ganglioside preparation who did not develop neuropathy and from 25 patients with classic GBS never treated with gangliosides were studied concurrently. All patients with ganglioside-related GBS had a rather severe axonal degeneration, incomplete recovery, and high IgG, but not IgM, antiganglioside antibody titers, ranging from 1:320 to 1:10,240. Seven (28%) of the 25 GBS patients had IgG antibody titers, ranging from 1:160 to 1:10,240. None of the ganglioside-treated patients who did not develop GBS and none of the 50 disease control subjects had IgG GM1 antibodies. Purified IgG from the patients with high GM1, antibodies, but not from the others, recognized epitopes at the nodes of Ranvier and the distal motor nerve terminals at the end-plate. We conclude that exogenous ganglioside injections can be immunogenic, triggering IgG antiganglioside antibodies with specificity for motor nerve-terminals. In some patients with axonal GBS such antibodies may be markers or mediators of axonal involvement.

Pleural effusion (PE) often causes abnormal pulmonary gas exchange. Thoracentesis is commonly used to relieve dyspnea in patients with PE, but its effect upon arterial oxygenation is varied and poorly understood. This investigation sought to: (1) characterize the distribution of ventilation-perfusion (VA/Q) ratios in patients with PE and (2) assess the effects of PE drainage by thoracentesis upon pulmonary gas exchange. We studied nine patients (two females) with a mean age of 39+/-20 (SD) yr. All of them had PE of recent clinical onset (< 2 wk of symptoms), without other apparent medical conditions. Before thoracentesis, PaO2 was 82.3+/-10.2 mm Hg and AaPO2 was 28.7+/-10.0 mm Hg. Patients had broadened unimodal VA/Q distributions with small amounts of blood flow perfusing lung units with low VA/Q ratios (< 0.1) (1.4+/-2.2%) and mild intrapulmonary shunt (6.9+/-6.7%). PaO2 was significantly related to the amount of shunt (rho = -0.82; p < 0.01) but not to the percentage of blood flow perfusing low VA/Q units. While thoracentesis drained 693+/-424 ml of fluid and caused a significant fall in mean pleural pressure (by -10.7 +/- 7.1 mm Hg; p < 0.01), PaO2, AaPO2, and shunt remained unchanged; only the amount of blood flow perfusing low VA/Q ratios increased slightly (2.4+/-2.6%; p < 0.05). This study shows that: (1) intrapulmonary shunt is the main mechanism underlying arterial hypoxemia in patients with PE and (2) effective thoracentesis has minor short-term effects upon pulmonary gas exchange. These findings are in accord with delayed (> 30 min) pulmonary volume re-expansion after thoracentesis with or without the coexistence of mild ex vacuo pulmonary edema.