Pathological laughter and crying in patients with pontine lesions.
Pathological laughter and crying (PLC) has been widely documented in the medical literature in association with various pathological processes in the brainstem, particularly infarction. However, it remains poorly understood. The authors present a case report and analyze all the cases in the literature to try to localize a putative faciorespiratory center. This 13-year-old girl developed a pontine abscess subsequent to sphenoid sinusitis. This increased in size despite antibiotic treatment, and she developed PLC. The abscess was then stereotactically aspirated, with resolution of the symptoms.   A PubMed search of the term "pathological laughter and crying" was performed. From these papers all reported cases of PLC were identified. Cases without neuroimaging were excluded. The remaining cases were categorized as small lesions permitting accurate localization within the pons, or large nonlocalizing lesions. All images of localizing lesions were magnified to the same size and placed on a grid. From this an area of maximal overlap was identified. The authors identified 7 cases of small localizing lesions with adequate imaging. The area of maximal overlap was in the region of the anterior paramedian pons. All the lesions involved this region of the pons. There were 28 further reports of large lesions that either resulted in gross compressive distortion of the pons or diffusely infiltrated it, and thus, although implicating involvement of a pontine center, did not allow for localization of a specific region of the pons.   The authors report a case of PLC caused by a pontine abscess. Symptoms were reversible with stereotactically assisted aspiration and antibiotic administration. Analysis of the lesions reported in the literature showed a pattern toward a regulatory center in the pons. The most consistently involved region was in the anterior paramedian pons, and this may be the site of a faciorespiratory center.