Primary ciliary dyskinesia: age at diagnosis and symptom history

Age at diagnosis and the symptom history of children with primary ciliary dyskinesia (PCD) are described by reviewing the case notes in the paediatric PCD clinic. Mean age at diagnosis was 4.4 y despite a history of neonatal respiratory distress in 37/55 cases, situs inversus in 38/55 cases and early onset troublesome rhinitis in 42/55.

CONCLUSION

Diagnosis of PCD is often delayed despite the presence of typical symptoms early in life. The key clinical features of unexplained neonatal respiratory distress, early onset rhinitis, situs inversus and a productive cough are highlighted, which, especially when occurring in combination, makes early referral for specific testing for PCD mandatory.

Predicting hypoxaemia during flights in children with cystic fibrosis

BACKGROUND

We have previously suggested that it is possible to predict oxygen desaturation during flight in children with cystic fibrosis and chronic lung disease by non-invasive measurement of oxygen saturation following inhalation of 15% oxygen--the pre-flight hypoxic challenge. This study reports on the results of measurements over 5 years.

METHODS

The study comprised a pre-flight hypoxic challenge measuring oxygen saturation by finger tip pulse oximetry (SpO(2)) during tidal breathing of 15% oxygen in nitrogen and spirometric testing 1 month before the flight followed by SpO(2) measurements during intercontinental flights to and from holidays abroad with children in wake and sleep states.

RESULTS

Pre-flight tests were completed on 87 children with cystic fibrosis. Desaturation of <90% occurred in 10 children at some stage during the flight, three of whom received supplementary oxygen. Using a cut off SpO(2) of 90%, the pre-flight hypoxic challenge correctly predicted desaturation in only two of these children. The sensitivity and specificity of the pre-flight hypoxic challenge were 20% and 99%, respectively, compared with 70% and 96% for spirometric tests (using a cut off for forced expiratory volume in 1 second (FEV(1)) of <50% predicted). Overall, pre-flight spirometric tests were a better predictor of desaturation during flight with the area under the Receiver Operating Characteristic (ROC) curve of 0.89 compared with 0.73 for the hypoxic challenge test.

CONCLUSIONS

In this group of subjects pre-flight spirometric testing was a better predictor of desaturation during flight than the pre-flight hypoxic challenge.

Imaging and laboratory investigation in herpes simplex encephalitis

A 14 day old baby presented with signs of an acute encephalitis. Clinically, herpes simplex encephalitis (HSE) was suspected. Early MRI and EEG were normal and there was rapid clinical improvement. A negative polymerase chain reaction (PCR) result on the initial CSF sample seemed to make HSE most unlikely. This diagnosis was subsequently proved after demonstration of specific antibody production using immunoelectrophoresis of the CSF. The child had extensive damage to brain tissue. The need for sequential analysis of CSF in making or refuting this diagnosis is illustrated.

Prediction of hypoxaemia at high altitude in children with cystic fibrosis

OBJECTIVE

To assess the usefulness of a hypoxic challenge in a laboratory at sea level in predicting acute desaturation at altitude in children with lung disease.

DESIGN

Comparison of responses to hypoxic challenge in different settings.

SUBJECTS

22 children (12 boys) aged 11 to 16 years with cystic fibrosis in whom the mean forced expiratory volume in one second was 64% (range 24-100%).

SETTING

Lung function laboratory, the Alps, and aboard commercial jet aircraft.

MAIN OUTCOME MEASURES

Spirometric lung function at sea level and finger probe oximetry with air and 15% oxygen. Oximetry during high altitude flight and on a mountain at altitude of 1800 m.

RESULTS

Significant desaturation (range 0 to 12%) occurred with all hypoxic challenges (P < 0.002). The best predictor of hypoxic response from a single reading was the laboratory test (r2 = 76% for flight and r2 = 47% for mountain altitude), but the mean errors of prediction were not clinically significantly different. In six children who showed the greatest desaturation the laboratory test overestimated desaturation, but other predictors underestimated desaturation in three by up to 5%.

CONCLUSIONS

The laboratory hypoxic challenge directly predicted the worst case of desaturation during flight and at equivalent high altitude. Spirometry and baseline oxygen saturations may underestimate individual hypoxic response. The test may have wider applications to other patients with stable chronic lung diseases, particularly in determining who needs supplementary oxygen during air travel and who should be advised against holidays at high altitude.

Conservative management of foetal lung lesions

Routine antenatal ultrasound screening has identified a variety of malformations which may present as hyperechogenic or cystic lung lesions. Knowledge of the natural history of these lesions in utero and after birth is incomplete, and an exact diagnosis is not always possible. Despite this, an increasing number of interventions and terminations of pregnancy are being undertaken. We advocate a more conservative approach in the management of these lesions. We describe three cases and review the current literature to demonstrate the uncertain natural history of these lesions, the diagnostic difficulties, and some of the medical and ethical problems of intervention.

Energy and nutrient intakes in cystic fibrosis

The diets of 20 children with cystic fibrosis were analysed for energy and nutrient content with simultaneous measurement of energy losses in stools. Median energy intakes were in excess of the WHO estimated daily requirements (118.2%) when expressed as MJ/kg/24 hours, the excess almost accounted for by energy losses in the stools. When expressed as MJ/24 hours, however, median energy intakes were 98.7% of that estimated for normal children of median weight for age. Compared with recently published data for normal school children the fat content of the diet was reduced (30.0%) as were intakes of iron and zinc. Children whose whole milk intakes were high had the greatest amount of fat and energy in their diets and were able to absorb energy in excess of that recommended. We conclude that many children with cystic fibrosis are still on low fat diets and whole milk is the single most useful food for the provision of extra dietary fat and energy.

Increased resting energy expenditure in cystic fibrosis

To explore the hypothesis that there is an increased metabolic rate in cystic fibrosis, resting energy expenditure was measured by indirect calorimetry in 23 subjects with cystic fibrosis in a stable clinical state and in 42 normal control subjects. Resting energy expenditure was found to be elevated by an average of 0.45 MJ/24 h [95% confidence interval (CI) = 0.26-0.64, t = 4.91, P less than 0.001] (108 kcal/24 h), or 9.2% above expected values derived from the regression relating resting energy expenditure to whole body weight and sex in control subjects. When related to lean body mass, values were still elevated by 0.36 MJ/24 h (95% CI = 0.18-0.53, t = 4.15, P less than 0.001) (86 kcal/24 h), or 7.2%. The increased values were found to be independent of age, sex, or body size. There were significant correlations between increased values and poor pulmonary function as measured by the ratio of the forced expiratory volume in 1 s to forced vital capacity (r = -0.44, P less than 0.05) and subclinical infection as indicated by the blood leukocyte count (r = 0.40, P less than 0.05). However, the correlations were low, suggesting that other factors may contribute to the increased resting energy expenditure, possibly including the putative metabolic defect in cystic fibrosis.

Ciliary abnormalities in respiratory disease

One hundred and sixty seven children, ranging in age from 5 weeks to 16 years, with chronic upper or lower respiratory tract problems, or both, were investigated for ciliary dyskinesia. Abnormal ciliary function was found in 18 cases all of whom had chronic lower respiratory disease and most of whom also had upper respiratory problems. Fifteen of the 18 cases had reduced ciliary beat frequencies (less than 10 Hz) associated with dyskinesia and the other three showed apparent absence of ciliated cells. Of the 15 cases with reduced ciliary beat frequencies, ciliary ultrastructure was normal in seven cases but abnormal with missing dynein arms and occasional abnormalities of microtubular arrangement in eight. Respiratory symptoms in the perinatal period were more common in children with abnormal ciliary function and present in all those with ultrastructural abnormalities or absence of ciliated cells compared with 34 (26%) of 132 children, in whom symptoms were recorded, with normal ciliary function. This study would suggest that all children with unexplained chronic respiratory disease, in particular those with symptoms starting in the perinatal period, should be investigated for ciliary dyskinesia.