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Published in Samar Razaq, Difficult Cases in Primary Care, 2021
CF is the commonest genetic inherited disease in the white population and is the commonest cause of severe chronic lung disease in children. It is inherited in an autosomal recessive fashion. Despite its major impact on the lungs, it is a multisystem disease and requires management by multidisciplinary teams in secondary and tertiary centres. Early recognition is vital to prevent a prolonged period of recurrent infections, malabsorption, stunted growth and terminal lung disease. Early, aggressive and multidisciplinary management of CF has lead to a huge improvement in quality of life and longevity. Neonatal screening has helped with this. All neonates have a Guthrie blood test. Neonates with positive results are referred for genetic tests looking for mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CFTR gene defects (more than 400 have been identified) may lead to defective sodium and chloride transport across epithelial cells, resulting in increased levels of the two ions in surface sweat. This forms the basis of the sweat test. However, some individuals with rarer CF genotypes may have a negative sweat test. These individuals are likely to have milder disease expression also. There is a high incidence of CFTR mutations in men with congenital bilateral absence of the vas deferens, leading to the idea that this condition may be a variant presentation of CF. It is important to note that not all polymorphisms in the CFTR gene cause disease.
Chest
Published in Keith Hopcroft, Vincent Forte, Symptom Sorter, 2020
SMALL PRINT: Pertussis serology, sweat test, secondary care investigations (e.g. for interstitial lung disease or immune deficiency). FBC, ESR/CRP: WCC raised in infection – marked lymphocytosis in pertussis; ESR/CRP elevated in any inflammatory process.CXR: May be helpful in LRTI, TB, inhaled foreign body, cystic fibrosis.Serial peak flow or spirometry: To help confirm a diagnosis of asthma (guidance recommends, in children over the age of 5, testing fractional exhaled nitric oxide in suspected asthma but this may not be practical, or available).Pertussis serology: If a clinical suspicion of pertussis needs confirming.Sweat test: For cystic fibrosis.Other secondary care investigations: May be required after referral (e.g. for interstitial lung disease or immune deficiency).
Chest
Published in Keith Hopcroft, Vincent Forte, Symptom Sorter, 2020
SMALL PRINT: pertussis serology, sweat test, secondary care investigations (e.g. for interstitial lung disease or immune deficiency). FBC, ESR/CRP: WCC raised in infection – marked lymphocytosis in pertussis; ESR/CRP elevated in any inflammatory process.CXR: may be helpful in LRTI, TB, inhaled foreign body, cystic fibrosis.Serial peak flow or spirometry: to help confirm a diagnosis of asthma.Pertussis serology: if a clinical suspicion of pertussis needs confirming.Sweat test: for cystic fibrosis.Other secondary care investigations: may be required after referral (e.g. for interstitial lung disease or immune deficiency).
Signs and symptoms of pediatric complex regional pain syndrome - type 1: A retrospective cohort study
Published in Canadian Journal of Pain, 2023
Giulia Mesaroli, Logan McLennan, Yvonne Friedrich, Jennifer Stinson, Navil Sethna, Deirdre Logan
Differences in the prevalence rates of symptoms versus signs may be related several factors. First, clinical features of CRPS are episodic in nature, and patients may be able to self-report symptoms experienced in the prior days that are not present during the time of the physical examination. Perhaps some clinical features such as color changes, swelling, and temperature are more episodic—that is, dynamic regional autonomic nervous system dysregulation due to immobilization of the limb—than others (e.g., skin texture, nail and hair growth changes) due to chronic poor circulation to deliver nutrition over time, explaining this difference in prevalence rates across symptoms vs. signs. Second, patients may be able to report symptoms that have resolved and are not present on physical exam. Third, some symptoms may be difficult for patients to report because of persistent pain and immobilization of the affected limb (e.g., sweating changes, temperature changes, weakness) that may be more easily detected as a sign on physical exam using objective measures (e.g., skin thermometer, sweat test, manual muscle testing).
Assessing accuracy of testing and diagnosis in cystic fibrosis
Published in Expert Review of Respiratory Medicine, 2023
Malina Barillaro, Tanja Gonska
To overcome the challenge of establishing a CF diagnosis genetically, tests that assess CFTR function are also found in the CF diagnostic algorithm. Among them, the sweat chloride test serves as the gold standard CFTR functional test. However, the experience that the sweat test can be falsely negative or positive in some individuals, particularly for those along the CF disease spectrum, led to the development of additional CFTR functional sweat tests that have ultimately also been included in the CF diagnostic algorithm [3]. These additional tests are the nasal potential difference (NPD) measurements as well as the intestinal current measurements (ICM) [4]. The NPD test assesses transepithelial bioelectrical properties across the in vivo nasal epithelium and the ICM, across ex vivo rectal biopsies [6]. However, in contrast to the sweat chloride test, reference values for NPD and ICM tests are not well-defined, which can lead to variability in result interpretation.
A second case of liraglutide-type localised amyloidosis
Published in Amyloid, 2023
Sara Muhammad, Ellen D. McPhail, W. Oliver Tobin, Surendra Dasari, Jason Theis, Julie A. Vrana, Elie Naddaf
Neurological examination was remarkable for decreased pinprick sensation from the mid-shin down to the toes, and mildly decreased hot temperature sensation in the right foot. Reflexes were decreased at the right patella, absent at the left patella and bilateral ankles. Motor and gait examination were normal. Nerve conduction studies/electromyography demonstrated mild bilateral old or chronic L5 radiculopathies with no evidence of ongoing denervation, and no evidence of a large fibre peripheral neuropathy. Thermoregulatory sweat test showed no evidence of a small fibre neuropathy either. However, serologic evaluation, performed to screen for potential peripheral neuropathy causes prior to our evaluation, showed a triclonal gammopathy of uncertain significance (IgG κ, IgG λ and IgA κ). Congo red stain performed on an abdominal fat aspirate was positive for amyloid (Figure 1), raising the possibility of systemic amyloidosis. The patient had TTR sequencing which revealed no mutation.