South African Medical Journal - Volume 105, Issue 1, 2015
Volumes & issues
Volume 105, Issue 1, 2015
Hearing loss in the developing world : evaluating the iPhone mobile device as a screening tool : researchSource: South African Medical Journal 105, pp 35 –39 (2015) http://dx.doi.org/http://dx.doi.org/10.7196/SAMJ.8338More Less
Background. Developing countries have the world's highest prevalence of hearing loss, and hearing screening programmes are scarce. Mobile devices such as smartphones have potential for audiometric testing.
Objectives. To evaluate the uHear app using an Apple iPhone as a possible hearing screening tool in the developing world, and to determine accuracy of certain hearing thresholds that could prove useful in early detection of hearing loss for high-risk populations in resource-poor communities.
Methods. This was a quasi-experimental study design. Participants recruited from the Otolaryngology Clinic, Groote Schuur Hospital, Cape Town, South Africa, completed a uHear test in three settings - waiting room (WR), quiet room (QR) and soundproof room (SR). Thresholds were compared with formal audiograms.
Results. Twenty-five patients were tested (50 ears). The uHear test detected moderate or worse hearing loss (pure-tone average (PTA) >40 dB) accurately with a sensitivity of 100% in all three environments. Specificity was 88% (SR), 73% (QR) and 68% (WR). It was highly accurate in detecting high-frequency hearing loss (2 000, 4 000, 6 000 Hz) in the QR and SR with 'good' and 'very good' kappa values, showing statistical significance (p< 0.05). It was moderately accurate in low-frequency hearing loss (250, 500, 1 000 Hz) in the SR, and poor in the QR and WR.
Conclusion. Using the iPhone, uHear is a feasible screening test to rule out significant hearing loss (PTA >40 dB). It is highly sensitive for detecting threshold changes at high frequencies, making it reasonably well suited to detect presbycusis and ototoxic hearing loss from HIV, tuberculosis therapy and chemotherapy. Portability and ease of use make it appropriate to use in developing world communities that lack screening programmes.
The Vaccine and Cervical Cancer Screen (VACCS) project : acceptance of human papillomavirus vaccination in a school-based programme in two provinces of South Africa : researchSource: South African Medical Journal 105, pp 40 –43 (2015) http://dx.doi.org/http://dx.doi.org/10.7196/SAMJ.8419More Less
Background. The incidence of cervical cancer in South Africa (SA) remains high, and the current screening programme has had limited success. New approaches to prevention and screening tactics are needed.
Objectives. To investigate acceptance of school-based human papillomavirus (HPV) vaccination, as well as the information provided, methods of obtaining consent and assent, and completion rates achieved.
Methods. Information on cervical cancer and HPV vaccination was provided to 19 primary schools in Western Cape and Gauteng provinces participating in the study. Girls with parental consent and child assent were vaccinated during school hours at their schools.
Results. A total of 3 465 girls were invited to receive HPV vaccine, of whom 2 046 provided written parental consent as well as child assent. At least one dose of vaccine was delivered to 2 030 girls (99.2% of the consented cohort), while a total of 1 782 girls received all three doses. Sufficient vaccination was achieved in 91.6% of the vaccinated cohort. Of all invited girls, 56.9% in Gauteng and 50.7% in the Western Cape were sufficiently vaccinated.
Conclusion. This implementation project demonstrated that HPV vaccination is practical and safe in SA schools. Political and community acceptance was good, and positive attitudes towards vaccination were encountered. During the study, which mimicked a governmental vaccine roll-out programme, high completion rates were achieved in spite of several challenges encountered.
High concentrations of natural rubber latex allergens in gloves used by laboratory health personnel in South Africa : researchSource: South African Medical Journal 105, pp 43 –46 (2015) http://dx.doi.org/http://dx.doi.org/10.7196/SAMJ.8082More Less
Introduction. Gloves made of natural rubber latex (NRL) are commonly used by healthcare workers because of their good qualities. However, allergic reactions to latex allergens are still commonly reported.
Objective. To measure the concentrations of Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02 allergens in gloves used by a large laboratory service in South Africa.
Methods. NRL gloves as well as non-latex gloves supplied by various suppliers that were used by the laboratory personnel during the period June 2009 - May 2010 were obtained from various suppliers on the vendor list. Proteins were extracted from the gloves and Hev b 1, Hev b 3, Hev b 5 and Hev b 6.02 allergens were quantified using the FITkit assay.
Results. Twenty NRL gloves from 13 different brands were analysed. Only four (20%) of the 20 NRL gloves analysed had a total allergen content < 0.15 µg/g, the suggested threshold limit for low allergenicity for the sum of these four allergens.
Conclusion. This study demonstrated that a very low proportion of gloves tested had a total allergen content below the threshold for low allergenicity.
Severe blunt thoracic trauma : differences between adults and children in a level I trauma centre : researchSource: South African Medical Journal 105, pp 47 –51 (2015) http://dx.doi.org/http://dx.doi.org/10.7196/SAMJ.8499More Less
Background. Trauma is a leading cause of death in the developing world. Blunt thoracic trauma represents a major burden of disease in both adults and children. Few studies have investigated the differences between these two patient groups.
Objective. To compare mechanism of injury, presentation, management and outcome in children and adults with blunt thoracic trauma.
Methods. Patients were identified from the database of the trauma intensive care unit at Inkosi Albert Luthuli Central Hospital, Durban, South Africa. Demographics and relevant data were extracted from a pre-existing database.
Results. Of 415 patients admitted to the unit, 331 (79.7%) were adults and 84 (20.2%) children aged < 18 years. The median injury severity score (ISS) was similar for both age groups (32 v. 34; p=0.812). Adults had a higher lactate level at presentation (3.94 v. 2.60 mmol/L; p=0.001). Of the children, 96.4% were injured in motor vehicle collisions, 75.0% as pedestrians. Compared with adults, children had significantly fewer rib fractures (20.2% v. 42.0%; p< 0.001), flail chests (2.4% v. 26.3%; p< 0.001) and blunt cardiac injuries (BCIs) (9.5% v. 23.6%; p=0.004), but sustained more lung contusions (79.8% v. 65.6%; p=0.013). Mortality in children was significantly lower than in adults (16.7% v. 27.8%; p=0.037).
Conclusion. Thoracic injuries in children are the result of pedestrian collisions more often than in adults. They suffer fewer rib fractures and BCIs, but more lung contusions. Despite similar ISSs, children have significantly lower mortality than adults. More effort needs to be concentrated on child safety and preventing pedestrian injury.
Author B. PoreauSource: South African Medical Journal 105, pp 52 –55 (2015) http://dx.doi.org/http://dx.doi.org/10.7196/SAMJ.8866More Less
Background. Since 1994, South Africa (SA) has faced up to the challenge of building a strong economy, to which public health provides an important underpinning.
Objectives. To map the scientific research in public health in SA after the end of apartheid and to present the links between the different financing/funding systems.
Methods. Bibliographic analyses utilising the Web of Science of papers published during the period 1975 - 2014, analyses of journals, most cited articles, authors, publication years, organisations, funding agencies, countries and keywords, and mapping of the relations between countries involved in public health research and of the Web of Science Categories using VOSviewer.
Results. I accessed 2 246 articles published between 1975 and 2014, the majority of which were published after 2007. The main countries of research were the USA, SA, Switzerland and the UK, representing the main network collaborations. The relevant keywords were HIV, woman, child, program/programme, rural, tuberculosis, district and sex.
Conclusions. Public health research in SA reached a high level 16 years after the end of apartheid. The chief field that emerged was the spread of HIV, including mother-to-child transmission, and the policies applied to all districts of SA, through a network of institutions between the USA and SA.
Regulation of HIV receptor expression in cervical epithelial cells by Gram-negative bacterial lipopolysaccharide : researchSource: South African Medical Journal 105, pp 56 –61 (2015) http://dx.doi.org/http://dx.doi.org/10.7196/SAMJ.8185More Less
Background. Sexually transmitted infections (STIs) caused by the Gram-negative bacteria Chlamydia trachomatis and Neisseria gonorrhoeae are associated with an increased risk of HIV acquisition in South African women. HIV infection involves binding of the virus to CD4+ receptors on host cells and subsequent binding to a chemokine co-receptor that mediates fusion with the host target cell membrane.
Objective. To investigate the potential impact of STIs on HIV receptor expression in cervical epithelial cells, and the molecular pathways mediating this effect.
Methods. Expression of Toll-like receptor 4 (TLR4), CD4+ and CCR5 was investigated in HPV type 18-positive (HeLa) and HPV-negative (C33A) cervical epithelial cells, uterine adenocarcinoma cells (Ishikawa), cervical squamous cell carcinoma tissue and normal cervical tissue by real-time polymerase chain reaction (RT-PCR) analysis. HIV receptor expression in HeLa cells was investigated in the presence/absence of 10 µg/mL bacterial lipopolysaccharide (LPS) and chemical inhibitors of epidermal growth factor receptor (EGFR), extracellular signal-regulated kinase (ERK1/2) or cyclo-oxygenase-2 (COX-2) by RT-PCR analysis.
Results. TLR4, CD4+ and CCR5 expression was elevated in HeLa, C33A and Ishikawa cell lines and carcinoma tissue, compared with normal cervical tissue. Treatment of HeLa cells with LPS increased expression of the primary HIV chemokine co-receptor CCR5 (p< 0.01) and several alternative HIV receptors including CCR2b (p< 0.01), CXCR6 (p< 0.05) and GPR1 (p< 0.05), but not CD4+. We found that LPS- mediated CCR5 expression occurred via induction of the EGFR, ERK1/2 and COX-2 signalling pathways.
Conclusion. Our findings suggest that STIs have the potential to enhance susceptibility to HIV infection in women by regulating expression of HIV receptors in cervical epithelial cells.
Source: South African Medical Journal 105, pp 62 –65 (2015) http://dx.doi.org/http://dx.doi.org/10.7196/SAMJ.9098More Less
The prevalence of food allergy is increasing worldwide and is an important cause of anaphylaxis. There are no local South African food allergy guidelines. This document was devised by the Allergy Society of South Africa (ALLSA), the South African Gastroenterology Society (SAGES) and the Association for Dietetics in South Africa (ADSA). Subjects may have reactions to more than one food, and different types and severity of reactions to different foods may coexist in one individual. A detailed history directed at identifying the type and severity of possible reactions is essential for every food allergen under consideration. Skin-prick tests and specific immunoglobulin E (IgE) (ImmunoCAP) tests prove IgE sensitisation rather than clinical reactivity. The magnitude of sensitisation combined with the history may be sufficient to ascribe causality, but where this is not possible an incremental oral food challenge may be required to assess tolerance or clinical allergy. For milder non-IgE-mediated conditions a diagnostic elimination diet may be followed with food re-introduction at home to assess causality. The primary therapy for food allergy is strict avoidance of the offending food/s, taking into account nutritional status and provision of alternative sources of nutrients. Acute management of severe reactions requires prompt intramuscular administration of adrenaline 0.01 mg/kg and basic resuscitation. Adjunctive therapy includes antihistamines, bronchodilators and corticosteroids. Subjects with food allergy require risk assessment and those at increased risk for future severe reactions require the implementation of risk-reduction strategies, including education of the patient, families and all caregivers (including teachers), the provision of a written emergency action plan, a MedicAlert necklace or bracelet and injectable adrenaline (preferably via auto-injector) where necessary.
Source: South African Medical Journal 105 (2015) http://dx.doi.org/http://dx.doi.org/10.7196/SAMJ.9104More Less
Non-imunoglobulin E (IgE)-mediated conditions include combined IgE and cell-mediated conditions such as atopic dermatitis and eosinophilic oesophagitis, and pure T-cell-mediated conditions such as food protein-induced enterocolitis syndrome, allergic proctocolitis and enteropathy syndromes. Diagnosing mixed or non-IgE-mediated allergy is challenging. A clear cause-effect relationship between exposure to the suspected food and symptoms is not always possible, as symptoms develop over time and are more chronic in nature. Skin-prick tests and specific IgE to the allergen are usually negative. An elimination diet may be necessary to diagnose non-IgE-mediated type food allergy. The suspected allergen should be excluded from the diet for 2 - 6 weeks under dietetic guidance to assess for improvement of symptoms. After symptom improvement, a rechallenge is necessary to definitively prove causal relation.
Source: South African Medical Journal 105, pp 67 –68 (2015) http://dx.doi.org/http://dx.doi.org/10.7196/SAMJ.9101More Less
Instituting an exclusion diet for 2 - 6 weeks, and following it up with a planned and intentional re-introduction of the diet, is important for the diagnosis of a food allergy when a cause-and-effect relationship between ingestion of food and symptoms is unclear. Food may be re-introduced after (short-term) exclusion diets for mild-to-moderate non-immunoglobulin E (IgE)-mediated conditions in a safe clinical environment or cautiously at home. However, patients who have had an IgE-mediated immediate reaction to food, a previous severe non-IgE-mediated reaction or a long period of food exclusion should not have a home challenge, but rather a formal incremental food challenge protocol in a controlled setting. An incremental oral food challenge (OFC) test is the gold standard to diagnose clinical food allergy or demonstrate tolerance. It consists of gradual feeding of the suspected food under close observation. It should be done by trained practitioners in centres that have experience in performing the procedure in an appropriate setting. An OFC must be performed in a setting where resuscitation equipment is available in the event of a severe anaphylactic reaction. OFCs are terminated when a reaction becomes apparent. Standardised and pre-set criteria are available on when to discontinue challenges. Patients who tolerate the full dose 'pass' the challenge and are advised to eat a full portion of the food at least twice a week to maintain tolerance. Those who have reactions have 'failed' the challenge, should avoid the food, receive education and implement risk-reduction strategies where appropriate. Patients should be observed for a minimum of 2 hours following a negative challenge and for 4 hours after a positive one.
Source: South African Medical Journal 105, pp 68 –69 (2015) http://dx.doi.org/http://dx.doi.org/10.7196/SAMJ.9103More Less
Despite the large number of foods that may cause immunoglobulin E (IgE)-mediated reactions, most prevalence studies have focused on the most common allergenic foods, i.e. cow's milk, hen's egg, peanut, tree nut, wheat, soya, fish and shellfish. Food allergy peaks during the first two years of life, and then diminishes towards late childhood as tolerance to several foods develops. Based on meta-analyses and large population-based studies, the true prevalence of food allergy varies from 1% to >10%, depending on the geographical area and age of the patient. The prevalence of food allergy in South Africa (SA) is currently being studied. The prevalence of IgE-mediated food allergy in SA children with moderate-to-severe atopic dermatitis is 40%; however, this represents a high-risk population for food allergy. Preliminary data from the South African Food Sensitisation and Food Allergy (SAFFA) study, which is investigating food allergy in an unselected cohort of 1 - 3-year olds, show a prevalence of 11.6% sensitisation to common foods. Food allergy was most common to egg (1.4%) and peanut (1.1%). Food allergy appears to be the most common trigger of anaphylactic reactions in the community, especially in children, in whom food is responsible for ≥85% of such reactions. In adults, shellfish and nut, and in children, peanut, tree nut, milk and egg, are the most common triggers of food-induced anaphylaxis.
Diagnosis of food allergy : history, examination and in vivo and in vitro tests : continuing medical educationSource: South African Medical Journal 105, pp 69 –70 (2015) http://dx.doi.org/http://dx.doi.org/10.7196/SAMJ.9100More Less
One cannot depend on one single test to diagnose food allergy. A detailed history is an essential initial step in cases of suspected food allergy. Aspects of the history should be gathered separately for each food being considered, as a patient may experience different types of reactions with various foods, each of which requires individual diagnostic and management strategies. History alone is not diagnostic and additional measures of sensitisation or food challenges are often required. In suspected immunoglobulin E (IgE)-mediated allergy, skin-prick tests (SPTs) and/or measurement of serum specific IgE antibodies (ImmunoCAP) to suspected foods is used to prove sensitisation. Sensitisation does not, however, confirm clinical food allergy as these tests indicate an immunological response to the specific allergen, but the diagnosis requires a clear correlation between the test result and clinical reaction (by positive history or food challenge). The magnitude of the test result (SPT mean wheal size or ImmunoCAP level in kU/L) correlates with the likelihood of clinical allergy, but not the severity of a reaction. Choice of the allergens tested should be guided by the history, but limited to the lowest necessary number to avoid false-positive results. Tests for sensitisation to foods should not be performed when the history indicates that such foods are tolerated. Ninety-five per cent positive predictive values (where a clinical reaction can be predicted in 95% of cases) have been described for immediate reactions, but may be population specific. There are no validated tests to confirm non-IgE- or mixed IgE- and non-IgE-mediated food allergies. Diagnosis of this group of allergies depends on elimination of the suspected food, clearance of symptoms, and recurrence of symptoms on re-introduction of the food.
Elimination diets and dietary interventions for the management of food allergies : continuing medical educationSource: South African Medical Journal 105, pp 71 –72 (2015) http://dx.doi.org/http://dx.doi.org/10.7196/SAMJ.9102More Less
The primary therapy for food allergy is strict avoidance of the offending food or foods. Dietary restriction should be tailored to meet the nutritional requirements of each patient. Patients should be educated on how to avoid allergens safely by understanding terminology for common ingredients and how to read food labels. Information regarding safe, cost-effective and freely available substitutes for the avoided foods should be provided. Patients should be re-evaluated at regular intervals to see if they have developed tolerance. Mothers of infants with cow's milk protein allergy (CMPA) who are breastfeeding should be supported and encouraged to continue breastfeeding. Partially hydrolysed infant formulas are not hypoallergenic (tolerated by 90% of subjects with proven CMPA) and are therefore not recommended for the treatment of CMPA, but may have a role in prevention of eczema or CMPA in high-risk individuals. Some extensively hydrolysed and amino-acid-based formulas are truly hypoallergenic. The recommended feed of choice for the dietary management of mild-to-moderate CMPA in infants not breastfed is an extensively hydrolysed cow's milk formula. The recommended formula for the dietary management of non-breastfed infants and children with known severe CMPA is an amino-acid-based formula. Soya-based formulas may be useful in infants with immunoglobulin E (IgE)-mediated CMPA with proven tolerance to soya, and some cases of mild-to-moderate non-IgE-mediated CMPA, bearing in mind the increased risk of co-reactivity between CMPA and soya allergy in non-IgE-mediated conditions. Other mammalian milks and plant-based milks, including rice and oat milks, are not suitable as sole nutrition for cow's milk protein allergic individuals.
Severe food allergy and anaphylaxis : treatment, risk assessment and risk reduction : continuing medical educationSource: South African Medical Journal 105, pp 72 –73 (2015) http://dx.doi.org/http://dx.doi.org/10.7196/SAMJ.9099More Less
An anaphylactic reaction may be fatal if not recognised and managed appropriately with rapid treatment. Key steps in the management of anaphylaxis include eliminating additional exposure to the allergen, basic life-support measures and prompt intramuscular administration of adrenaline 0.01 mg/kg (maximum 0.5 mL). Adjunctive measures include nebulised bronchodilators for lower-airway obstruction, nebulised adrenaline for stridor, antihistamines and corticosteroids. Patients with an anaphylactic reaction should be admitted to a medical facility so that possible biphasic reactions may be observed and risk-reduction strategies initiated or reviewed after recovery from the acute episode. Factors associated with increased risk of severe reactions include co-existing asthma (and poor asthma control), previous severe reactions, delayed administration of adrenaline, adolescents and young adults, reaction to trace amounts of foods, use of non-selective β-blockers and patients who live far from medical care. Risk-reduction measures include providing education with regard to food allergy and a written emergency treatment plan on allergen avoidance, early symptom recognition and appropriate emergency treatment. Risk assessment allows stratification with provision of injectable adrenaline (preferably via an auto-injector) if necessary. Patients with ambulatory adrenaline should be provided with written instructions regarding the indications for and method of administration of this drug and trained in its administration. Patients and their caregivers should be instructed about how to avoid foods to which the former are allergic and provided with alternatives. Permission must be given to inform all relevant caregivers of the diagnosis of food allergy. The patient must always wear a MedicAlert necklace or bracelet and be encouraged to join an appropriate patient support organisation.
Source: South African Medical Journal 105 (2015) http://dx.doi.org/http://dx.doi.org/10.7196/SAMJ.9106More Less
Important potential food allergens in vaccines include egg and gelatin. Rare cases of reactions to yeast, lactose and casein have been reported. It is strongly recommended that when vaccines are being administered resuscitation equipment must be available to manage potential anaphylactic reactions, and that all patients receiving a vaccine are observed for a sufficient period. Children who are allergic to egg may safely receive the measles-mumps-rubella (MMR) vaccine; it may also be given routinely in primary healthcare settings. People with egg allergy may receive influenza vaccination routinely; however, some authorities still perform prior skinprick testing and give two-stage dosing. The purified chick embryo cell culture rabies vaccine contains egg protein, and therefore the human diploid cell and purified verocell rabies vaccines are preferred in cases of egg allergy. Yellow fever vaccine has the greatest likelihood of containing amounts of egg protein sufficient to cause an allergic reaction in allergic individuals. This vaccine should not be routinely administered in egg allergic patients and referral to an allergy specialist is recommended, as vaccination might be possible after careful evaluation, skin-testing and graded challenge or desensitisation.
Novel therapies in the management of food allergy : oral immunotherapy and anti-IgE : continuing medical educationSource: South African Medical Journal 105 (2015) http://dx.doi.org/http://dx.doi.org/10.7196/SAMJ.9105More Less
The process of oral immunotherapy (OIT) consists of a series of dose escalations with the immediate goal of inducing desensitisation and ultimately achieving a state of tolerance. Owing to the limitations of OIT, including side-effects and lack of proven efficacy in long-term tolerance induction, it is not yet recommended in routine clinical practice and should be restricted to the research setting. Studies using anti-immunoglobulin E (IgE) antibody in food allergy management are limited, but show promising results. The possible applications are for increasing the sensitivity threshold to certain foods such as peanut, and also for use in combination with OIT to enhance safety and rapidity of the OIT process; however, anti-IgE is not yet licensed for use in food allergy.