A population-based study of the incidence, cause, and severity of anaphylaxis in the United Kingdom

BACKGROUND

Anaphylaxis is an acute and potentially fatal systemic reaction usually caused by mast cell-mediated release of histamine. Symptoms can vary in onset, appearance, and severity. Some common symptoms include weakness, dizziness, flushing, angioedema, urticaria, nasal congestion, and sneezing. Severe symptoms include upper respiratory tract obstruction, hypotension, vascular collapse associated with angioedema and urticaria, gastrointestinal distress, cardiovascular arrhythmias, and/or arrest.

METHODS

We conducted an observational follow-up study encompassing approximately 8 million person-years based on the UK General Practice Research Database for the period January 1, 1994, to December 31, 1999, which quantified the frequency, type, and severity of a clinical diagnosis of anaphylaxis.

RESULTS

Based on 675 cases of anaphylaxis, we estimate the incidence to be 8.4 per 100 000 person-years. Approximately 10% of cases had hypotension and shock that required urgent treatment. The most common causes were insect stings and oral medicines.

CONCLUSION

Anaphylaxis is an uncommon illness that has multiple causes and can be life-threatening.

The natural history of primary first-degree atrioventricular heart block

The long-term prognosis of first-degree heart block in the absence of organic heart disease has not been clearly defined. We addressed this question in a 30-year longitudinal study of 3983 healthy men. We identified 52 cases that were present on entry into the study and 124 incident cases during follow-up. The incidence rose steadily after age 40 and was 1.13 per 1000 person-years over the entire period. Two thirds of the cases had only moderate prolongation of the PR interval (0.22 to 0.23 second). We compared four age-matched controls with each case for histories of scarlet fever, rheumatic fever, diphtheria, smoking, blood pressure, and body-mass index. No significant differences (P greater than 0.05) were found. Likewise, mortality from all causes did not differ between cases and controls. Although somewhat higher rates of morbidity and mortality from ischemic heart disease were observed in the cases than in the controls, the differences were not significant. Progression to higher grades of heart block occurred in only two cases. In view of the prognostic findings and the rare occurrence of advanced degrees of heart block, we conclude that primary first-degree heart block with moderate PR prolongation is a benign condition. This conclusion may not apply, however, to persons with more marked prolongation of the PR interval, a very rare condition.

Antitoxin antibody levels and the outcome of illness during an outbreak of diphtheria among alcoholics

During an outbreak of diphtheria among alcoholics in Göteborg, Sweden, a study was made of the diphtheria-antitoxin antibodies in serum samples from 8 clinical cases and 36 carriers of toxin-producing Corynebacterium diphtheriae. 33/36 carriers were antibody-positive and had antitoxin titres greater than 0.01 IU/ml, a level which is regarded as relative protective, while only 1/8 clinical cases had such a titre. This patient presented a mild illness with no complications. The results of the study of this outbreak stress the importance of maintaining adequate antibody levels against diphtheria in highly developed societies.

Penicillin vs. erythromycin in the treatment of diphtheria

In an open-label, randomized trial, 44 Vietnamese children with diphtheria were given penicillin therapy (intramuscular benzylpenicillin, 50,000 U/[kg.d] for 5 days and then oral penicillin, 50 mg/[kg.d] for 5 days), and 42 were given erythromycin therapy (50 mg/[kg.d] orally for 10 days). There were no differences in times to membrane clearance or bacteriologic clearance, but median times to fever clearance were 27 hours (95% confidence interval [CI], 19-30; range, 0-124 hours) for penicillin recipients and 46 hours (95% CI, 34-54; range, 0-148 hours) for erythromycin recipients (P = .0004). In the penicillin group, acute treatment failed for one patient, and one patient relapsed. Three patients in the penicillin group developed diphtheritic myocarditis as evidenced by abnormal electrocardiograms. Erythromycin did not cause prolongation of the QT interval corrected for heart rate. Cultures of specimens from 15 patients (17.4%) were positive for toxigenic Corynebacterium diphtheriae. All isolates were susceptible to penicillin, but for isolates (27%), all of which were from patients who received penicillin treatment, were resistant to erythromycin (minimum inhibitory concentrations, > 64 mg/L). Penicillin is recommended as first-line treatment for diphtheria in Vietnam.

Stridor in pediatric patients

We have presented a classification scheme to help in evaluating the diagnosis of stridor in the pediatric patient. The correct diagnosis can usually be arrived at on the basis of a careful and complete history, physical examination, appropriate radiographic studies and bronchoscopy. The anesthesiologist should be aware of the problems associated with all these conditions. In every instance prompt establishment of an adequate airway is imperative.

An outbreak of nontoxigenic Corynebacterium diphtheriae infection: single bacterial clone causing invasive infection among Swiss drug users

From 1990 to 1996, a total of 65 patients from whom Corynebacterium diphtheriae had been isolated were reported to the Swiss Federal Office of Public Health. A retrospective review of medical and microbiological records as well as results of ribotyping of available isolates was performed. Twenty-seven patients had acquired their infection without evidence of use of illicit drugs, mostly as a skin infection imported from subtropical areas (20 patients); 38 isolations were associated with intravenous drug use (IVDU) (skin, 15; respiratory tract, 10; blood, 13). Endocarditis was documented in nine patients with bloodstream infection, four of whom died. There were two additional deaths due to overwhelming sepsis. The same ribotype of nontoxigenic C. diphtheriae was found in 31 of the 32 examined isolates associated with IVDU. All non-IVDU isolates had different ribotypes. Among Swiss drug users, a single clone of nontoxigenic C. diphtheriae was found over a period of several years with a high potential to cause severe invasive infection.

Parkinson's disease and the environment in early life

To explore a possible relationship between environmental factors encountered during fetal life and infancy and the later risk of developing Parkinson's disease, a case-control study (172 cases, 343 age- and sex-matched controls) was carried out in 42 general practices in the eastern part of Hertfordshire, England. Information about birthweight and growth during the first year of life was obtained for subjects who had been born in Hertfordshire from records made by health visitors in the first part of the century. Information concerning size of sibship, position in the birth order, type of housing, other features of the environment in early life and experience of the common infections of childhood was obtained by questionnaire. Neither birthweight, weight at 1 year of age nor any aspect of the childhood domestic environment were associated with an altered risk of Parkinson's disease. Cases were more likely to recall suffering from croup (odds ratio 4.1, 95% CI 1.1 to 16.1) or diphtheria (odds ratio 2.3, 95% CI 1.2 to 4.7) in childhood than controls but no other infection was associated with an increased relative risk for Parkinson's disease. Cases were more likely than controls never to have smoked cigarettes (odds ratio 2.0, 95% CI 1.1 to 3.6). The results of this study do not suggest that poor growth in fetal life or infancy is important in the aetiology of Parkinson's disease but they hint that early infection might partly determine susceptibility to the disease.

Diphtheritic polyneuropathy: clinical analysis of severe forms

BACKGROUND

Diphtheritic polyneuropathy (DP) is a dangerous complication of diphtheria, especially its severe forms with bulbar, respiratory tract, and circulatory disturbances. However, the clinical picture of severe forms of DP is practically unknown.

OBJECTIVE

To investigate the clinical features and peculiarities of the course of severe forms of DP.

PATIENTS

Thirty-two patients with severe forms of DP.

RESULTS

The first symptoms of DP developed in most patients 3 to 5 weeks after the onset of diphtheria. The cranial nerves were involved in all patients, most frequently nerves IX and X (32 patients); VII (28 patients); III, IV, and VI (27 patients); and XI (27 patients). One third of the patients had quadriplegia. The remaining patients had quadripareses. Of the 32 patients, 24 underwent artificial ventilation. All patients had sensory signs, proprioceptive more often than superficial. Autonomic disturbances were observed also in all patients. Only 2 of the 32 patients died.

CONCLUSIONS

A direct indication for tracheotomy and artificial ventilation in patients with DP is a decrease of the vital capacity of the lungs below the traditional 16 mL/kg body weight or the development of the paralytic closure of the larynx against the background of the increasing weakness of the respiratory muscles. Characteristic of severe forms of DP is the phenomenon of the oppositely directed change in the neurological symptoms in the second month of the disease: the restoration of the function of the cranial nerves against the background of the further increase of the motor disturbances in the extremities and trunk. Special attention and care should be taken of patients during the period of the appearance of the episodes of vascular collapses-between the fourth and seventh weeks of DP.

Clinical and electrophysiological studies of diphtheritic neuritis in Jordan

Eleven patients with acute diphtheritic neuritis were studied clinically and electrophysiologically. Decreased conduction velocity and increased distal motor latency were present in most patients within two weeks of the onset of neurological symptoms. Velocities later fell to approximately 45% of mean normal values. Wasting with electrophysiological evidence of denervation was present in 3 patients. Nerve conduction studies had returned to normal within 3 months in 8 patients. There was a striking dissociation between the time course of the clinical and the neurophysiological abnormalities: early in the illness, peripheral nerve conduction was normal in some patients despite the presence of severe weakness, and later, the maximum electrophysiological abnormalities were sometimes found after clinical recovery had commenced. The nature and sequence of the clinical and electrophysiological changes are in accord with the known pattern and distribution of the pathological changes in the disease.

Corynebacterium diphtheriae endocarditis

Two patients with Corynebacterium diphtheriae endocarditis have been observed in the past ten years. Both cases occurred sporadically. In one case toxigenic C. diphtheriae caused endocarditis in an immunized child with congenital heart disease. The second patient developed rapidly progressive valve destruction caused by a nontoxigenic strain of C. diphtheriae. These cases illustrate that C. diphtheriae may produce endocarditis in addition to its previously described diseases spectrum.

Misidentification of toxigenic Corynebacterium diphtheriae as a Corynebacterium species with low virulence in a child with endocarditis

A 6-year-old boy presented to a university hospital in Malaysia with infective endocarditis complicating cyanotic congenital heart disease. Blood cultures showed a gram-positive, aerobic, coryneform-like bacillus identified by the hospital laboratory as Corynebacterium xerosis, but a reference laboratory identified the organism as a toxigenic strain of Corynebacterium diphtheriae. The two laboratories concurred on all biochemical test results except for sucrose fermentation.

Failure of corticosteroid therapy to prevent diphtheritic myocarditis or neuritis

The efficacy of corticosteroid therapy for the prevention of diphtheritic myocarditis and neuritis was studied. Sixty-six patients with diphtheria were divided into two groups. Steroid therapy was given in addition to specific treatment for diphtheria in one group, while the other group was given only specific treatment. The groups were comparable regarding age, duration of illness and extent of exudate. The result shows that steroid therapy does not prevent the occurrence of electrocardiographic changes and of neuritis in the patient with diphtheria.

Dexamethasone in laryngeal diphtheritic croup

Eighteen children diagnosed as having laryngeal diphtheria with various degrees of respiratory obstruction were treated with intravenous dexamethasone in addition to penicillin and anti-diphtheritic serum. Reduction in the severity of laryngeal obstruction was assessed 12-hourly. Eleven of 12 children with mild-to-moderate obstruction responded within 24 hours. The 12th child died of toxaemia and renal failure following tracheostomy. Four of six with severe obstruction also responded within 24 hours. The remaining two underwent tracheostomy, one of whom died. Dexamethasone appears to have a role to play in obviating tracheostomy in laryngeal diphtheria.

Autonomic dysfunction in diphtheritic neuropathy

Sympathetic and parasympathetic function and somatic nerve conduction were assessed in ten patients with diphtheritic neuropathy and 28 controls. None of the patients had postural hypotension. The Valsalva ratio was abnormal in two patients who also had myocarditis, but it was normal in five cases. Cardiac vagal dysfunction was found in five patients. One case showed cardiac parasympathetic denervation despite normal conduction velocity in the limbs.

Prognostic significance of electrocardiographic abnormalities in diphtheritic myocarditis after hospital discharge: a long-term follow-up study

OBJECTIVE

We aimed to investigate the long-term cardiac mortality and the relationship between cardiac mortality and electrocardiographic abnormalities in patients with diphtheritic myocarditis who survived after hospital discharge.

MATERIALS AND METHODS

Between 1991 and 1996, 32 patients (all males, mean age 21.00 +/- 3.77 years) surviving diphtheritic myocarditis were included in the study and they were followed up for an average of 16.3 months (range 10.3-26.8 months) after hospital discharge. Clinical evaluation, ECG, and echocardiography were performed on admission, daily while in hospital and at the time of discharge. ECG changes were permanent during the follow-up period. The causes of death of the patients during follow-up period were inferred from the death records of the patients and talking to the people witnessing cardiac arrest.

RESULTS

We observed that the patients with left bundle branch block (LBBB) and T wave inversion at hospital discharge had lower survival rates than that of the patients without these ECG changes in the long term. Although univariate Cox regression analysis identified LBBB (P = 0.001) and T wave inversion (P = 0.014) as the predictors of survival, only LBBB was an independent predictor of survival in multivariate Cox regression analysis. Adjusted hazard ratio was calculated as 13.67 for LBBB (P = 0.001; CI = 2.81-66.28).

CONCLUSION

Diphtheritic myocarditis does not only demonstrate a malignant clinical course during acute phase of the disease, but also during the long-term follow-up period, especially in patients with LBBB and T wave inversion. Besides, T wave inversion and LBBB can help us to predict survival rate of the patients in long term. Moreover, LBBB is an independent predictor of long-term survival in diphtheritic myocarditis.

Prognosis in patients with diphtheric myocarditis and bradyarrhythmias: assessment of results of ventricular pacing

OBJECTIVE

To determine the prognosis in patients with diphtherial myocarditis and bradyarrhythmias and to assess the results of ventricular pacing in those with third degree atrioventricular block.

DESIGN

Case series.

SETTING

Referral department of cardiology in a teaching hospital.

PATIENTS

Twenty four out of 46 patients admitted with diphtherial myocarditis over 10 years had bradyarrhythmias. Six had sinus bradycardia, 15 atrioventricular or intraventricular conduction disturbances, and three atrioventricular dissociation.

MAIN OUTCOME MEASURE

Death rate.

RESULTS

Eleven patients died (46%): all seven patients with third degree atrioventricular block, the patient with bifascicular block, and three of the six patients with bundle branch block. Seven died of cardiogenic shock and four of ventricular fibrillation. All nine patients with sinus bradycardia or atrioventricular dissociation survived.

CONCLUSION

Conduction system disturbances in patients with diphtherial myocarditis are markers of severe myocardial damage and a poor prognosis. In addition, ventricular pacing does not improve survival.

An outbreak of diphtheria among Swedish alcoholics

After 25 years without any indigenous cases of diphtheria in Sweden, an outbreak occurred in the city of Göteborg, during 1984 to 1986. A group of alcoholics constituted the reservoir of Corynebacterium diphtheriae. The outbreak included 13 clinical cases and 65 carriers. The death-to-case ratio and the complication rate among the clinical cases was high, with three fatal cases and six patients developing reversible paralyses. The fatal cases had no history of previous immunization. The outbreak demonstrates the necessity of a good vaccination status to diphtheria, also in countries where the disease was thought to have been eradicated.

The effect of local pressure in diphtheritic neuropathy

Images

Complete heart block as a consequence of atriondal discontinuity

We have recently studied a case of complete heart block in which there was considerable difficulty in deciding whether it was of congenital or acquired origin. This was because the heart block was first discovered at the age of 2 years in the course of acute diphtheria. Though diphtheritic infections are known to affect the cardiac conduction system, authenticated cases of post-diphtheritic block persisting after the infection are rare, and, furthermore, histopathological study in this case revealed discontinuity between the atrial tissues and the more peripheral parts of the atrioventricular conduction tissues. This has been more commonly observed in congenital cases of complete heart block and it has been postulated on theoretical grounds that this could be thebasis for congenital heart block; on the other hand, it has been noted in a single casethought to be of acquired origin. Review of the evidence available failed to allow accurate classification of the case into either congenital or acquired categories. Thenormal, segmental development of the atrioventricular node, each segment being of different embryological origin, is discussed and the case presented is understandable in thelight of this.

Treatment of severe diphtheritic myocarditis by temporary insertion of a cardiac pacemaker

Vietnamese children and adolescents with diphtheritic myocarditis and severe conduction abnormalities were treated prospectively with temporary insertion of a cardiac pacemaker. Five of 32 patients died before the procedure could be performed; the remaining 27 patients underwent successful pacemaker insertion. In children and adolescents with diphtheritic myocarditis and severe conduction defects, temporary insertion of a cardiac pacemaker may improve the outcome.