Recurrent endobronchial occlusion and aorto-bronchial fistula formation in Behcet's disease.

BACKGROUND: Behcet's disease is a multi-system inflammatory disorder. A small subset of patients with Behcet's develop relapsing polychondritis which is classified as a separate disease known as Mouth and Genital ulcers with inflamed cartilage (MAGIC syndrome). It has previously been observed that this condition can also affect the cartilaginous tissue in the tracheobronchial tree. CASE PRESENTATION: We present the case of a 44-year-old lady with Behcet's Disease, Mouth and Genital ulcers with inflamed cartilage (MAGIC) syndrome and an aortic Frozen Elephant Trunk (FET) who presented to hospital with recurrent episodes of left lobar collapse of the lung. During bronchoscopy, we found the presence of multiple inflammatory endobronchial webs occluding segments of the left bronchial tree. Repeated examinations showed evidence that these inflammatory webs were progressing in size, density and location. Furthermore, we noticed herniation of her descending aortic FET into her left bronchial tree forming an aorto-bronchial fistula which was complicated by a graft infection. Her descending aortic FET section was surgically replaced with an open procedure and bronchoscopic interventions attempted to remove the occlusions in her bronchial tree. Despite optimisation of medical management and surgical correction, this patient continued to develop progressive occlusion of her left bronchial tree, resulting in a chronically collapsed left lung. CONCLUSIONS: A multi-disciplinary team approach is of paramount importance in order to optimally manage patients with Behcet's disease, balancing immunosuppressive regimens that need close monitoring and titration in the context of potential surgical intervention and the risk for intercurrent infection.

Nucleus Isthmi Is Required to Sustain Target Pursuit during Visually Guided Prey-Catching.

Animals must frequently perform a sequence of behaviors to achieve a specific goal. However, the neural mechanisms that promote the continuation and completion of such action sequences are not well understood. Here, we characterize the anatomy, physiology, and function of the nucleus isthmi (NI), a cholinergic nucleus thought to modulate tectal-dependent, goal-directed behaviors. We find that the larval zebrafish NI establishes reciprocal connectivity with the optic tectum and identify two distinct types of isthmic projection neuron that either connect ipsilaterally to retinorecipient laminae of the tectum and pretectum or bilaterally to both tectal hemispheres. Laser ablation of NI caused highly specific deficits in tectally mediated loom-avoidance and prey-catching behavior. In the context of hunting, NI ablation did not affect prey detection or hunting initiation but resulted in larvae failing to sustain prey-tracking sequences and aborting their hunting routines. Moreover, calcium imaging revealed elevated neural activity in NI following onset of hunting behavior. We propose a model in which NI provides state-dependent feedback facilitation to the optic tectum and pretectum to potentiate neural activity and increase the probability of consecutive prey-tracking maneuvers during hunting sequences.