Eleven subjects with non-paralytic and 10 with paralytic kyphoscoliosis and nine normal control subjects were studied during sleep. The Cobb angle of those with kyphoscoliosis varied from 600 to 1400 (median 100°) and the vital capacity varied from 17% to 56% (median 28%) of the value predicted on the basis of span. Recordings made during sleep included expired carbon dioxide tension at the nose, gas flow at the mouth, arterial oxygen saturation, chest wall movement, and the electroencephalogram, electro-oculogram, and electrocardiogram. In three subjects transcutaneous carbon dioxide tension was measured simultaneously. Patients with kyphoscoliosis hypoventilated during sleep, particularly in rapid eye movement sleep, resulting in a rise in end tidal and transcutaneous carbon dioxide tension, and a reduction in oxygen saturation to a degree not observed in normal subjects. Reduced chest wall movement was the major cause of these episodes, which were more frequent and occupied a greater proportion of sleep time in those with kyphoscoliosis than in normal subjects. Serious cardiac arrhythmias were rarely associated. It is concluded that disturbances of respiration during sleep occur in patients with kyphoscoliosis and that these may be important in the pathogenesis of cardiorespiratory failure.Severe kyphoscoliosis may lead to cardiorespiratory failure and premature death.1 Factors contributing to the onset of respiratory failure are thought to include reduced surface area for diffusion, ventilationperfusion inequality, alveolar hypoventilation, increased respiratory work, and an abnormal increase in pulmonary artery pressure during exercise.2 3 Recent work by Mezon et al4 and Guilleminault et al! has suggested that sleep related disturbances of respiration may also contribute. Discrepancies between their findings, which were based on only a few subjects, prompted this larger study to identify the major abnormality and mechanism of disturbances of respiration during sleep in patients with kyphoscoliosis, to distinguish any differences between non-paralysed and paralysed subjects, and to try to assess the importance of these abnormalities in the pathogenesis of cor pumonale. MethodsPatients with thoracic kyphoscoliosis were selected if they had a forced vital capacity (FVC) less than 30% predicted on the basis of span, or gave a history of Address for reprint requests: Dr E H Sawicka, Department of Thoracic Medicine, London SW3 6HP.Accepted 25 February 1987 801 sleep disturbance or early morning headache for which no non-respiratory cause could be found. None had had an episode of illness of any type during the preceding month. Control subjects were within five years of age of at least one patient of the same sex, although there were no controls for the patients below 20 years of age. None had a history of chest disease, sleep disturbance, recent upper respiratory tract infection, or rhinitis, but those with a history of occasional snoring were accepted. Ethical approval was obtained from the ethics co...

Sniff esophageal pressure (Pes) is a useful measurement of global inspiratory muscle strength, although it does require passage of an esophageal balloon. We investigated the relationship between nasopharyngeal pressure (Pnp) or pressure within the mouth (Pmo) and Pes during a maximal sniff from FRC without a noseclip. We measured Pes, Pnp, and Pmo simultaneously in 10 normal volunteers, and in 12 patients with inspiratory muscle weakness. In both groups, Pnp and Pmo were slightly less but very close to Pes. In normal volunteers, the mean ratio Pnp/Pes was 0.92 +/- 0.006 (mean +/- SE) and Pmo/Pes was 0.95 +/- 0.006. Regression analysis showed Pes = 4.57 + 1.05 Pnp (r = 0.995, p less than 0.001) and Pes = 0.74 + 1.05 Pmo (r = 0.994, p less than 0.001). Similar relationships between Pnp, Pmo, and Pes were found over a wide range of pressures generated by submaximal sniffs in normal subjects. In patients, the mean ratio Pnp/Pes was 0.90 +/- 0.02 and Pmo/Pes was 0.87 +/- 0.03. Regression analysis showed Pes = 5.12 + 1.0 Pnp (r = 0.949, p less than 0.001) and Pes = 11.2 + 0.882 Pmo (r = 0.936, p less than 0.001). We conclude that Pnp and Pmo predict Pes during a maximal sniff in both normal subjects and in patients with inspiratory muscle weakness. Sniff Pnp and/or Pmo may provide a useful and less invasive method of measuring maximal inspiratory pressures during a sniff.

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A 70-year-old man was referred for the investigation of fevers, sweats and neutropenia. Full blood count showed a haemoglobin concentration 120 g/l, white blood cell count (WBC) 2AE1 · 10 9 /l, neutrophils 0AE9 · 10 9 /l, monocytes 0AE0 · 10 9 /l and platelets 195 · 10 9 /l. Blood film, bone marrow biopsy and immunophenotyping confirmed hairy cell leukaemia (HCL). A computerized tomography (CT) scan showed normal lung fields, small volume mediastinal and right hilar lymphadenopathy (1AE5 cm) and a bulky spleen. He was initially treated with alpha interferon to increase his WBC but this was discontinued due to deranged liver function tests. Subsquently, because he was still neutropenic, four weekly infusions of rituximab (375 mg/m 2 ) were given.A few weeks later, he was admitted with neutropenic sepsis, which was unresponsive to broad-spectrum antibiotics and antifungals. A bone marrow biopsy (left) showed complete remission but non-caseating granulomas. A CT chest scan revealed bilateral pleural effusions, enlarged mediastinal and right hilar lymph nodes and a pulmonary infiltrate in the right apex. The findings were consistent with infection and highly suspicious of tuberculosis. A bronchoscopy with bronchial washings and aspiration of pleural fluid was performed, but unfortunately he died acutely of severe sepsis.Post mortem examination (right) showed extensive central necrosis of a mediastinal node. Ziehl-Neelson staining revealed numerous acid-fast bacilli of atypical morphology (right). Subsequently the pleural fluid and bronchial washings confirmed the diagnosis of Mycobacterium kansasii infection.Mycobacterium kansasii is an environmentally acquired microorganism, which usually causes infection in patients with pre-existing chronic lung disease or those with immunodeficiency. This case demonstrates that environmental mycobacteria can cause acute infection in patients with haematological conditions such as HCL who are severely immunosuppressed. Therefore one should investigate these patients with pyrexia of unknown origin for evidence of atypical mycobacterial infection.