The article is a thorough treatise on the dreaded disease ‘Cystic Fibrosis’ which occurs due to a genetic defect, largely in people of Caucasian origin, although it is not exclusive for this particular race (3). It includes systematically collected information about the disease from past as well as the latest reviews available at Medline, Google Scholar and the Cochrane Library, besides those from Johns Hopkins University in the US.
The historical prevalence, therapeutic interventions employed for its treatment, the recently identified mechanisms of the disease have been thoroughly elaborated upon and the latest guidelines for handling the disease have been suggested. The treatise follows a lucid, easy to read style which is comprehensible even for a non technical person, except for certain sections which explain the genetic basis of the disease.
The flow of the article is built in an appropriate manner by first elucidating the mechanisms of the disease, followed by the latest diagnostic methods employed to detect its presence, the symptoms and clinical manifestations, the effects in different organ systems of the body and finally rounded off by treatment modalities available to handle its various manifestations.
The article closes with a peek at the latest endeavours in research on cystic fibrosis. The article however, has more academic than clinical relevance as it is too elaborate to focus on one particular facet of the disease.
In the introduction, the author has highlighted the contribution of research on cystic fibrosis, which has enabled a person suffering from this disease to have a better life expectancy due to the recent advances in diagnosis and treatment. The disease aetiology has been explained extensively with explanations about the genetic defect which precipitates it.
The cause of the disease has been attributed due to mutation in the gene that encodes for the CFTR (cystic fibrosis transmembrane conductance regulator) protein which is expressed in many epithelial and blood cells (3). The finer molecular mechanisms, mutations and effects of CFTR are tabulated on the first page with appropriate detail.
According to the author, CFTR primarily functions as a chloride channel besides it multifarious functions in the regulation of sodium transportation and ATP channels. Despite the occurrence of more than 1500 mutations in the CFTR gene, class II mutation has been identified as the most common in European and North American populations (3).
Manifestations of cystic fibrosis are variable depending upon the particular mutation and specific organ systems are affected accordingly. The variations are so extensive that symptoms and characteristics of the disease can vary, even between siblings. Polymorphisms in non-CFTR genes and gene-gene interactions have been suggested as the basis of these variations.
According to the author, a number of hypotheses have been suggested for the occurrence of cystic fibrosis, out of which four have been elaborated in the article. The first hypothesis suggests that loss of inhibition of epithelial sodium channels results in excessive sodium and water reabsorption with the resultant dehydration of airway surface materials.
This results in drying up of the airway mucous membranes and the formation of plaques which harbour pathogenic bacteria. Another hypothesis, the high-salt hypothesis suggests that due to the absence of functional CFTR, excess sodium and chloride retained in the airway surface liquid increases concentration of chloride in periciliary layers which does not allow innate antibiotic molecules to function.
The third hypothesis suggests a dysregulation of the host inflammatory response is responsible for the characteristic molecular changes observed in cystic fibrosis. Yet another hypothesis suggests a primary predisposition to infection as the main cause due to the defective CFTR gene (3).
After this thorough introduction the author shifts the focus onto diagnosis of cystic fibrosis in which investigations are recommended to be initiated if the characteristic symptoms are observed in any child or adult.
The general symptoms include family history of the disease, salty-tasting skin, clubbing of fingers and toes, cough accompanied with sputum, hypochloraemic metabolic alkalosis and isolation of Pseudomonas aeruginosa bacterium from the airway (3). Chloride concentration in sweat is a good marker for the diagnosis of cystic fibrosis.
The author has comprehensively tabulated a list of diseases which might give a false positive/negative result in the sweat test and hence are vital for making a differential diagnosis. Diagnosis in infants and children can also be made by observing characteristic signs and symptoms as well as with the assistance of molecular biology techniques such as CFTR mutation detection and measurement of immunoreactive trypsinogen in blood spots, particularly in infants (3).
Clinical manifestations of the disease have been thoroughly explained in the following paragraphs which are addressed according to the organ systems involved. Gastrointestinal symptoms include obstruction in the gastrointestinal tract, pancreatic insufficiency, steatorrhoea and generalized malnutrition (3).
The displayed symptoms include greasy stools, flatulence, abdominal bloating and poor weight gain. Biliary cirrhosis and jaundice are also observed in some cases. The respiratory system is also profoundly affected by cystic fibrosis and manifestations are in the form of chronic airway infection, bronchiectasis, gas trapping, hypoxaemia and hypercarbia (3).
Characteristic bacterial infections with specific organisms are observed in the pulmonary system which includes P. aeruginosa, S. aureus and methycillin resistant S. aureus (MRSA) (3). Besides these major system infections, endocrine disturbances are observed in the patients and men particularly suffer from azoospermia leading to infertility.
Treatment approaches available and recommended have been comprehensively described in the article and include primarily the modes employed to handle pulmonary infection and enhance lung functioning. Lung function tests involve elaborate procedures and equipment which has to be sterile. Moreover, a patient in acute respiratory distress may not be able to comply with the demands of such tests which involve breathing through equipment for a particular duration and with some effort.
Inhaled hypertonic saline, macrolide antibiotics and anti-inflammatory drugs such as ibuprofen have particularly been recommended. Corticosteroids have been contraindicated in the treatment of cystic fibrosis due to their prominent side effects which can deteriorate the condition. However in emergency situations they may have to be resorted to depending upon the level of distress being experienced by a patient at a particular moment.
Airway clearance techniques currently available have been recommended with the final resort as lung transplantation in cases where there have been pulmonary exacerbations due to this disease. Maintenance of appropriate nutrition is vital in patients with cystic fibrosis and supplement use, specifically pancreatic enzymes have been recommended to aid the digestive process. Regular maintenance of BMR (basal metabolic rate) has been suggested for patients so that appropriate corrective measure can be employed in a timely manner.
The article has great pertinence for Ireland in particular, where the incidence of Cystic fibrosis is the highest in the world (4). The Cystic Fibrosis Registry of Ireland (CFRI) maintains a registry of all the patients diagnosed with the disease which has been made online from July, 2002 (2).
Around 30-40 children with the genetic defect are born in Ireland each year with a very poor life expectancy (15-25 years) (1). There is therefore a need for providing the most appropriate therapy at the right stages in such patients to make their life comfortable. The article covers most recent guidelines for treatment comprehensively which can be adopted depending upon the clinical symptoms encountered.
The article rounds off with the current advances in gene therapy due to the development of advanced molecular biology techniques, which might yield some new therapeutic intervention strategy to handle this dreaded disease. In Ireland, a number of deficiencies in the current health services exist which complicate the treatment of cystic fibrosis.
These include inadequate staff, lack of as well as below par physical resources and deficiencies in provision of adult services (4). These issues need to be handled appropriately if any meaningful therapeutic measures as suggested in this study can be actually employed.
Annual Report, 2007, available online at: http://www.cfri.ie/docs/annual_reports/annual_report_2007_registry.pdf, Accessed Dec. 8, 2009
Bowers F, Over 1,080 Cystic fibrosis cases here, online article available at: http://www.irishhealth.com/article.html?id=5514. Accessed Dec. 9, 2009. 2004 January 13
O’Sullivan BP, Freedman SD. Cystic Fibrosis, Seminar. Lancet 2009 April 28 373;1891-904
Rainey C, Blueprint for The Future, online article available at: http://www.cfireland.ie/publications/booklets/cf_rep_inside.pdf, Accessed Dec. 8, 2009. 2005 February