Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0034067 (emphysema)
 11,506 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ventilation may bypass obstructed airways through collateral channels, including interalveolar pores of Kohn, bronchiole-alveolar communications of Lambert, and interbronchiolar pathways of Martin. Resistance through these channels, like resistance through small airways, increases with decreasing lung volume and with hypocapnia. But whereas the distention of collateral channels and small airways by a variety of factors is similar, the efficiency of ventilation through collateral channels is less than the efficiency through airways. Gas inspired through collateral channels is contaminated with alveolar gas from surrounding lung so that the dead space for collateral ventilation is increased. When one part of the lung ventilates out of phase with the surrounding lung, pulmonary interdependence promotes more homogeneous ventilation. In the presence of airways obstruction, interdependence may be a primary factor governing the rate of collateral ventilation. In man, collateral ventilation is unimportant in normal lungs. However, with disease, it may be critical in producing or compensating for abnormalities. For example, the long time constant for collateral ventilation in the middle lobe may be responsible for atelectasis, which results in the middle lobe syndrome. On the other hand, the short time constant for collateral ventilation in emphysema may be essential for the distribution of ventilation beyond obstructed airways.
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PMID:Collateral ventilation. 75 33

A patient with pronounced dyspnoea and cyanosis was found to have severe hypoxaemia with normal spirographic values. His past history included arterial hypertension, myocardial infarction and phlebitis of the lower limb. Airways resistance was normal, but maximal expiratory flow rates at low lung volume (Flow-volume curves) were reduced, suggesting "peripheral" airways obstruction. This was confirmed by the presence of pulmonary hyperinflation and mechanical non-homogeneity accompanied by unevenly distributed ventilation, as shown by alveolar nitrogen gradient. There was marked hyperventilation with hypocapnia. Since transfer values (measured by the CO single-breath method) and lung distensibility values were normal, emphysema could be ruled out as a cause of obstruction. Analysis of pressure-flow relationship confirmed that the obstruction of peripheral airways was "intrinsic" in character. It could be due to an increase in lung extravascular fluid (interstitial oedema due to left cardiac failure), or to repeated micro-emboli in the lungs, or to hypocapnia, these three mechanisms possibly being associated.
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PMID:[Peripheral airway obstruction involving cardiovascular factors. A case report (author's transl)]. 677 51

We describe the case of a 61-year-old male patient, in which the search for the cause of chronic respiratory failure, severe pulmonary hypertension and secondary erythrocytosis resulted in a diagnosis of combined pulmonary fibrosis and emphysema (CPFE). This is a unique, recently characterised syndrome with upper-lobe emphysema and pulmonary fibrosis of the lower lungs. The cause is unknown, but one of the main risk factor remains smoking. The patient was a heavy smoker (over 40 pack-years). He complained of dyspnoea on exertion and cough. Physical examination revealed basal crackles and cyanosis. The patient had severe reduction in diffusing capacity, out of proportion to his lung volumes (DLCO 27% of predicted value, FEV1 2.95 l (100%), FVC 4.41 l (118%), FEV1/FVC (66%). The blood gas showed hypoxemia (pO2 37 mm Hg), hypocapnia and respiratory alkalosis. Diagnosis was based on chest computer tomography, which revealed upper lobe emphysema and lower lobe ground glass changes and honeycombing. Severe pulmonary hypertension (SPAP 80 mm Hg) was confirmed by echocardiography and right cardiac catherisation. The patient received long-term oxygen therapy, inhaled corticosteroid and Ca-blocker.
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PMID:[Combined pulmonary fibrosis and emphysema - case report and literature review]. 1946 58