RESUMO
A 59-year-old male with past medical history significant for non-Hodgkin's lymphoma status after chemotherapy presented with acute onset of neck pain, odynophagia, and dysphagia associated with subjective fever, chills, and dyspnea. Physical findings included a temperature of 38.4°C, hypertension, and tachycardia. Patient was found to have anterior neck tenderness. Laboratory evaluation revealed neutropenia. The patient was started on empiric antibacterial and antiviral therapy and continued on home prophylactic antifungal treatment. Thyroid function tests revealed overt hyperthyroidism. A thyroid ultrasound showed heterogeneous echotexture without discrete nodules. Subacute thyroiditis was treated with methylprednisolone, metoprolol, and opiate analgesics. Patient's antibacterial, antifungal, and antiviral treatments were broadened. A fine needle aspiration was not conducted. The patient's condition deteriorated rapidly over his brief hospital course and he expired. Autopsy showed fungal thyroiditis secondary to disseminated invasive Aspergillus. This report describes the presentation of fungal thyroiditis secondary to disseminated invasive Aspergillus originating from the respiratory tract. The authors review the diagnostic challenges, pathophysiology, and treatment of this condition.
RESUMO
Schaffer collateral excitatory synapses onto CA1 pyramidal cells are subject to significant modulation by short-term plasticity. This presynaptic, history-dependent modulation of neurotransmitter release causes synaptic transmission to be sensitive to the frequency of the input. As a result, temporally irregular input patterns, such as those observed in vivo, produce synaptic responses over a very wide dynamic range that reflect a balance of short-term facilitation and short-term depression. The neonatal period is an important developmental period in the hippocampus, when functional representations of an animal's environment are being established through exploratory behavior. The strength of excitatory synapses and their modulation by short-term plasticity are critical to this process. One form of short-term plasticity, paired-pulse facilitation, has been shown to decrease as juvenile rats mature into young adults. However, little is known about the neonatal modulation of other forms of short-term plasticity, including the responses to temporally complex stimuli. We examined developmental modulation of the short-term dynamics of Schaffer collateral excitatory synapses onto CA1 pyramidal cells in acute hippocampal slices, using both constant frequency stimuli and natural stimulus patterns that were taken from in vivo recording of spike patterns of hippocampal cells. In response to constant frequency stimulation, synapses in slices from young adult rats (P28-P35) showed less short-term depression than did those in slices from juveniles (P12-P18). However, when the natural stimulus pattern (containing a wide mix of frequencies) was used, synapses from young adults instead showed more short-term depression and less short-term facilitation than did juveniles. Comparing the natural stimulus pattern responses with constant frequency stimulation of a similar frequency, we found that the average responses were similar in young adults (both showed modest depression). However, in juveniles, the natural pattern produced robust facilitation while constant frequency stimulation caused a large short-term depression. Our results reveal that there are developmental changes both in individual forms of short-term plasticity and in the relative balance between short-term facilitation and short-term depression that will alter the signal transfer characteristics of these synapses.
