Pulmonary histiocytosis X: pulmonary function and exercise pathophysiology.

Abstract

Pulmonary histiocytosis X (PHX) is a diffuse, smoking-related lung disease characterized pathologically by bronchocentric inflammation, cyst formation, and widespread vascular abnormalities and physiologically by exercise limitation. The major mechanism underlying exercise impairment in this disease has not been previously defined. Spirometry, lung volumes, lung mechanics, and exercise physiology were performed on 23 patients with PHX. Two subgroups were identified on the basis of elastic recoil: 12 subjects had an elevated coefficient of elastic recoil with 11 demonstrating a predominant pattern of restriction, and 10 subjects had normal elastic recoil and relatively normal lung function. Exercise performance was severely limited in both subgroups (workload 53 +/- 3%). Abnormalities of ventilatory function and gas exchange were present but did not appear to be exercise-limiting in the majority of subjects. Indices reflecting pulmonary vascular function (DLCO, baseline VD/VT, exercise VD/VT) were abnormal. Strong correlations between overall exercise performance (% predicted VO2max) and indices of vascular involvement were present: DLCO (r = 0.68, p = 0.0004), baseline VD/VT (-0.65, 0.001), exercise VD/VT (-0.67, 0.0004). Similar correlations were found when exercise performance was measured by maximal workload achieved. We conclude that (1) subjects with PHX present with either normal or predominantly restrictive pulmonary physiology and that (2) exercise impairment is common and appears to reflect pulmonary vascular dysfunction.

Histiocitosis de células de Langerhans pulmonar: Caso clínico

“…Las principales alteraciones funcionales descritas son la disminución de la DLCO (70-90%), atribuible al engrosamiento de la membrana alveolo-capilar y compromiso vascular pulmonar 4,7 . El patrón espirométrico puede ser normal u obstructivo y la curva fl ujo volumen es anormal en la mitad de los casos; el patrón obstructivo, raro en enfermedad pulmonar difusa, orienta al diagnóstico cuando está presente [4][5][6][7][14][15][16] . En los volúmenes pulmonares destaca la disminución de las capacidades vital y pulmonar total (CPT), con aumento del volumen residual (VR) y relación VR/CPT 7 .…”

Pulmonary Langerhans'-Cell Histiocytosis

“…Up to 20% of patients have normal pulmonary function tests at the time of diagnosis [5,82]. Approximately 70% of patients have low diffusing capacity to carbon monoxide (DLCO), which is the most common abnormality observed on physiologic testing [5,82].…”

“…Up to 20% of patients have normal pulmonary function tests at the time of diagnosis [5,82]. Approximately 70% of patients have low diffusing capacity to carbon monoxide (DLCO), which is the most common abnormality observed on physiologic testing [5,82]. Reduction in DLCO may occur in isolation or accompany restrictive, obstructive or mixed abnormality and is primarily a reflection of pulmonary vascular dysfunction [5,82].…”

“…Approximately 70% of patients have low diffusing capacity to carbon monoxide (DLCO), which is the most common abnormality observed on physiologic testing [5,82]. Reduction in DLCO may occur in isolation or accompany restrictive, obstructive or mixed abnormality and is primarily a reflection of pulmonary vascular dysfunction [5,82]. A restrictive pattern is more frequently observed in earlier stages of disease while an obstructive pattern is more common as disease advances, and is the predominant pattern as disease progresses [12,83].…”

“…A significant proportion of patients develop progressive decline in DLCO and Forced Expiratory Volume in 1 s (FEV 1 ) within the first few years following diagnosis, and develop severe airflow obstruction [83]. Crausman and colleagues reported either normal or restrictive physiology on lung function testing in 23 patients with early disease [82]. In a study including 102 adults, restriction was present in 46% of cases at the time of diagnosis [5].…”