The development of paranasal sinuses in patients with cystic fibrosis: sinuses volume analysis.

BACKGROUND: Cystic fibrosis (CF) is a severe systemic disease that affects many aspects of patients' lives. It is known that the progression of the disease adversely affects lower and upper airways including the paranasal sinuses. However, its impact on sinus development in the pediatric population is not fully examined. The purpose of this study was to evaluate the development of the paranasal sinuses in a pediatric population with CF and compare it to a control group consisting of healthy children. METHODS: The results of computed tomography (CT) scans of children with the disease and the control group were evaluated. The study included 114 CT images of children in the study group and 126 images of healthy children aged 0-18 years. The volumes of maxillary, frontal, and sphenoid sinuses were analyzed. The obtained results were compared with those of the control group and analyzed statistically. RESULTS: The volume and the development of the paranasal sinuses in both groups increased with age, but statistically significant differences were found between the study and the control group. CONCLUSIONS: The obtained results provide valuable knowledge regarding the impact of the CF on sinuses development. Also, they may be important in understanding the progression of the disease and its influence on the quality and length of life of patients. The results may contribute to enhanced diagnostics and have implications for improving therapy for patients with chronic sinusitis associated with CF.

Autoimmune Thyroiditis Induced by Bartonella henselae (Cat-Scratch Disease) Might Be Reversible.

INTRODUCTION: Bartonella henselae infection leads to development of cat-scratch disease (CSD) but may also trigger of autoimmune thyroiditis (AIT). CASE PRESENTATION: We describe a 4-year-old boy with a severe fever of unknown etiology, disseminated neck lymphadenopathy, and a headache. Treatment with antibiotics was employed, but finally a left tonsillectomy, selective left lymphadenectomy, and immunophenotyping were performed to exclude lymphoma. Histologic examination excluded lymphoma but revealed CSD. IgG against B. henselae and Bartonella quintana was positive. A goiter was also found and positive anti-thyroid antibodies confirmed AIT. Two months later, the thyroid was not palpable, normal on ultrasound, and both anti-thyroid antibodies were negative. The full reversibility was documented, and 6-year follow-up showed that the patient remains disease free. CONCLUSION: This is the first report that AIT triggered by B. henselae/B. qunitana might be reversible if the pathogenetic factor is eliminated at an early stage of disease.

Applications of the Grading Scales for the Detection of Ototoxicity in Children after Treatment of Neuroblastoma and Extracranial Germinal Tumor.

INTRODUCTION: Advances in treatment have resulted in a significant increase in survival rates for patients cured of malignant diseases such as neuroblastoma (NBL) and extracranial germ cell tumor (GCT). NBL is one of the pediatric cancers during which potentially ototoxic cytostatic drugs (cisplatin and carboplatin) are used for treatment. Other cancers include germinal tumors, hepatoblastoma, sarcomas, and brain tumors. Often, this very aggressive treatment has a high risk of causing long-term side effects, including hearing loss. Hence, the present study aimed to evaluate the usefulness of the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE), Brock, Chang, and International Society of Pediatric Oncology (SIOP) Boston scales in terms of detecting the high-frequency nature of hearing loss induced by ototoxic drugs and monitoring hearing status in children after completion of oncological treatment. Additionally, the frequency of hearing loss in children treated for NBL and extracranial GCT was assessed, and the principles of monitoring hearing in these patients were indicated. METHODS: The study group consisted of 78 patients diagnosed with NBL (n = 47) and GCT (n = 31). There were 23 boys and 24 girls in the NBL group, aged 0-16 years, and 21 boys and 10 girls in the GCT group, aged 0-18 years. The control group consisted of 54 patients who had never received oncological treatment, were not taking potentially ototoxic drugs, and appeared socially efficient in the subjective audiological assessment. Audiometric examinations and DP-acoustic otoemission measurements were performed. Additionally, impedance audiometry tests were done to exclude a possible conductive component of the hearing loss. RESULTS: The analysis shows that ototoxicity-induced hearing loss was observed in 13.8-65.5% of children. 75.9% of patients showed hearing loss in the 16 kHz frequency range, and at least 56.8% of patients showed hearing loss in the frequency range above 12.5 kHz. Hearing impairment, relevant to speech understanding, was displayed by more than 40% of children treated for NBL and GCT. CONCLUSIONS: The confirmation of hearing loss in nearly 65% of cases in both patients indicates the necessity to monitor the long-term side effects of anticancer treatment. Acoustic otoemission measurements, the adoption of articulatory indices based on an audiogram, or the use of arbitrary ototoxicity assessment scales such as Brock, Chang, or SIOP Boston are fully justified techniques for studying ototoxicity induced by cytostatic drugs. However, they all require continuous improvement to increase their sensitivity and specificity, especially in the pediatric group.

Micro RNAs and Circular RNAs in Different Forms of Otitis Media.

The aim of this comprehensive review was to present the current knowledge on the role of microRNAs (miRNAs) in acute, recurrent, and chronic forms of otitis media. Special attention was focused on cholesteatoma of the middle ear. MicroRNAs modulate gene expression, which, in turn, influences the development and likelihood of the recurrence of acute and aggressive chronic middle ear inflammatory processes. Moreover, this study discusses the modulating role of a specific subgroup of noncoding RNA, circular RNA (circRNA). Recognizing the precise potential pathways and the mechanisms of their function may contribute to a better understanding of the molecular bases of middle ear diseases and identifying novel methods for treating this demanding pathology. Articles published between 2009 and 2022 were used in this analysis. In this review, we provide a complete overview of the latest progress in identifying the role and mechanisms of particular miRNAs and circRNAs in acute, recurrent and chronic forms of otitis media.

Fecal Fat Concentration and Excretion in the First 2 Years of Life: a Cross-Sectional Study.

OBJECTIVES: Data on pancreatic exocrine secretion in the youngest children are scarce. The aim of the study was to determine the range of normal values for fecal fat concentration (FFC) and fecal fat excretion (FFE) in infants and toddlers up to 2 years of age. METHODS: A total of 160 subjects aged 1 to 24 months (8 groups of 20: aged 1-3, 4-6 months, etc) were included in the study. In all children, FFC (%) and FFE (g/day) were assessed in 3-day stool collection. RESULTS: FFC correlated with age (r = -0.50, P < 0.0001). Of infants aged 1 to 3 months 65% had FFC higher than the <5% norm proposed for older children. The values of 90th/95th FFC percentile ranged from 9.7/13.0% at 1 month to 3.1/3.2% at 24 months. FFE did not differ between age groups. It was, however, higher than 4 and 3 g/day in 7.5% and 15.0% infants, respectively. The first detailed nomogram for the assessment of FFC and FFE in children aged 1 to 24 months was created. CONCLUSIONS: Healthy infants may have higher FFC and FFE than older children. We provide reference values, which should allow for both precise and facile FFC and FFE interpretation in clinical practice.

The Acute Phase Proteins Reaction in Children Suffering from Pseudocroup.

The aim of the study was to evaluate the inflammatory reaction in children with pseudocroup and compare it with other laryngological diseases according to the available literature data. The study group included 51 children hospitalized because of pseudocroup. The measurements of the acute phase proteins (APP), such as C-reactive protein (CRP), alpha-1-antitrypsin (AT), alpha-1-antichymotrypsin (ACT), alpha-1-acid glycoprotein (AGP), ceruloplasmin (Cp), transferrin (Tf), alpha-2-macroglobulin (A2M), and haptoglobin (Hp) were obtained at 3 time points. The glycosylation profiles of AGP, ACT, and Tf were completed. An increased AGP level was observed in girls. The AGP glycosylation revealed the advantage of the W0 variant over the W1 variant. W1 and W2 were decreased in boys. W3 emerged in boys. The Tf concentration and T4 variant were lower compared to the control group. The A2M level was lower after treatment. The Hp and AT levels were decreased a few weeks later. The ACT glycosylation revealed a decrease of the A4 variant in boys. In conclusion, the inflammatory reaction during pseudocroup was of low intensity. The APP glycosylation suggested a chronic process. In a follow-up investigation, no normalization of the parameters was noted, but signs of persistent inflammation were observed.

Impact of Nutritional Status of Patients with Head and Neck Squamous Cell Carcinoma on the Expression Profile of Ghrelin, Irisin, and Titin.

The goal of this paper was the evaluation of the changes in the expression profile of irisin, ghrelin, and titin in the carcinoma tissue and in the blood of patients with head and neck squamous cell carcinoma (HNSCC), including determining the profile of their expression in relation to patient nutrition. The study included 56 patients with diagnosed squamous cell carcinoma of HNSCC in the T3 and T4 stages of the disease. Healthy control tissue specimens were collected from an area 10 mm outside the histologically negative margin. In turn, the blood and serum from the control group came from healthy volunteers treated for non-oncologic reasons (n = 70). The molecular analysis allowed us to determine the profile of irisin, ghrelin, and titin methylation, evaluate their expression on the level of mRNA (quantitative Reverse Transcription Polymerase Chain Reaction; qRT-PCR) and protein (Enzyme-Linked Immunosorbent Assay Reaction; ELISA) in the carcinoma tissue and the margin of healthy tissue, as well as in serum of patients in the study and control groups. At the start of our observations, a Body Mass Index (BMI) < 18.5 was noted in 42 of the patients, while six months after the treatment a BMI < 18.5 was noted in 29 patients. We also noted a decrease in the expression of irisin, ghrelin, and titin both on the level of mRNA and protein, as well as a potential regulation of their expression via DNA methylation. There is no convincing evidence that the proteins assayed in the present work are specific with regard to HNSSC.

Vitamin K Status Based on K1, MK-4, MK-7, and Undercarboxylated Prothrombin Levels in Adolescent and Adult Patients with Cystic Fibrosis: A Cross-Sectional Study.

The available evidence on vitamin K status in cystic fibrosis (CF) is scarce, lacking data on vitamin K2 (menaquinones-MK). Therefore, we assessed vitamin K1, MK-4 and MK-7 concentrations (LC-MS/MS) in 63 pancreatic insufficient and modulator naïve CF patients, and compared to 61 healthy subjects (HS). Vitamin K1 levels did not differ between studied groups. MK-4 concentrations were higher (median <1st-3rd quartile>: 0.778 <0.589-1.086> vs. 0.349 <0.256-0.469>, p < 0.0001) and MK-7 levels lower (0.150 <0.094-0.259> vs. 0.231 <0.191-0.315>, p = 0.0007) in CF patients than in HS. MK-7 concentrations were higher in CF patients receiving K1 and MK-7 supplementation than in those receiving vitamin K1 alone or no supplementation. Moreover, vitamin K1 concentrations depended on the supplementation regime. Based on multivariate logistic regression analysis, we have found that MK-7 supplementation dose has been the only predictive factor for MK-7 levels. In conclusion, vitamin K1 levels in CF are low if not currently supplemented. MK-4 concentrations in CF patients supplemented with large doses of vitamin K1 are higher than in HS. MK-7 levels in CF subjects not receiving MK-7 supplementation, with no regard to vitamin K1 supplementation, are low. There do not seem to be any good clinical predictive factors for vitamin K status.

First Brachial Cleft Anomalies in Children: An Innovative Surgical Technique Preventing External Auditory Canal Stenosis.

First branchial cleft anomalies (FBCAs) are rare congenital malformations that require complete surgical removal. A stenosis of the external auditory canal (EAC) may be the consequence of the disease and its treatment. The aim of this study is to present the details and results of an innovative surgical technique using part of the abnormality for reconstruction purposes. This study covered 28 surgically treated children with FCBA between 2014 and 2021. The analysis included the clinical manifestation form of the abnormality, presence of the EAC deformity, histopathological results, complications, and distant results. On the basis of Work's classification system, 15 pediatric patients with type II FBCA and 13 children with type I FBCA were included in the further study. One child with type II FBCA and two with type I FBCA had a normal EAC. The preoperative appearance of the EAC was classified into three main types, each potentially accompanied by a skin ostium of the sinus/fistula in the EAC. Reconstruction with our technique was performed in 14 children (1 with type I FBCA and 13 with type II FBCA). Wound healing was uncomplicated in all cases. No recurrences were observed. This innovative surgical technique of the subtotal resection of FBCAs with simultaneous reconstruction is safe and prevents postoperative EAC stenosis. Despite the deliberate use of part of the abnormality wall for reconstructive purposes, it remained free of recurrences.

Isolated Sphenoid Sinus Disease in Children.

The rarity of isolated sphenoid sinus disease (ISSD) and the specificity of pediatric populations meant that a separate analysis was required in this study. This study aimed to present and discuss the results of an analysis of clinical manifestations, radiological findings and surgical methods based on a large series of exclusively pediatric patients. The study group covered 28 surgically treated children (aged 5.5-17.5 years). The medical data were retrospectively analyzed and meticulously discussed with regards to presenting signs and symptoms, radiographic findings, surgical approaches, complications, post-op care, histopathological results and follow-ups. The dominant symptom was a persistent headache (78%). Four children presented visual symptoms, diplopia in two cases, visual acuity disturbances in one case and both of these symptoms in one patient. Sixteen children presented chronic isolated rhinosinusitis without nasal polyps, six suffered from mucocele and one presented chronic sphenoiditis with sphenochoanal polyp. Four patients turned out to exhibit neoplastic lesions and developmental bony abnormality was diagnosed in one case. No fungal etiology was revealed. The transnasal approach was used in 86% of patients. A transseptal approach with concurrent septoplasty was used in four patients. The patient with visual acuity disturbances completely recovered after the surgery. All children with visual symptoms reported improvement in the vision immediately after surgery. No postoperative complications were observed. Fungal etiology was extremely rare in the pediatric population with ISSD. The surgical treatment should be a minimally invasive procedure regarding a limited range of the pathology in ISSD. Emergency surgery should be performed if ISSD produces any visual loss.

Congenital midline upper lip sinuses with intracranial extension - A variant of nasal dermoid? An embryology-based concept.

OBJECTIVE: The study aimed to present the comparative analysis of midline congenital upper lip sinuses (MCULS) and nasal dermoids (NDs). The clinical similarity of congenital midline pathologies of the midface was interesting subject for further studies. Therefore, histopathological, and embryological background were also analyzed to verify a hypothesis that NDs and MCULSs are the different variants of the same entity. MATERIAL AND METHODS: The study group included 27 surgically treated pediatric cases with the congenital midline sinus of the nose (n = 25) or upper lip (n = 2). Seven children presented intraoperatively confirmed intracranial extension of the abnormality, 6 in NDs group and 1 in MCULS group. Apart from clinical characteristics also histopathological results were compared in both groups. An analysis of the literature concerning the proposed theories of origin of NDs as well as the current classification systems of MCULSs and NDs were conducted. RESULTS: The analysis revealed that MCULSs present the same clinical characteristics as NDs. No differences were noticed in the histopathological results. The embryological theories presented so far are insufficient to convincingly explain the precise process of origin of abnormalities such as ND and MCULS. Nevertheless, the developmental embryological processes of the midface shed a new light on the common origin of NDs and MCULSs. The proposal of an update of the existing classification of midline congenital midface sinuses was presented. CONCLUSIONS: The comparative analysis of clinical, histopathological, and embryological characteristics confirms that NDs and MCULSs are different forms of the same entity. Embryological implications result in the possibility of intracranial extension in each case of MCULS. Therefore, CT and MR imaging which provide irreplaceable information are recommended for all patients with MCULS. The updated classification of midline congenital midface sinuses should be taken into consideration.

Otogenic Cerebral Sinus Thrombosis in Children: A Narrative Review.

Cerebral venous thrombosis (CVT) is a rare entity that remains a diagnostic challenge due to various clinical manifestations and a wide variety of causative agents. Local infections, such as acute (AOM) or chronic otitis media, can play a role in the pathogenesis of CVT. The proximity of the tympanic cavity and temporal bone air cells to the dural venous sinuses predisposes them to secondary thrombosis. The release of inflammatory cytokines and activation of the coagulation pathway in the middle ear space in response to infection may trigger the thrombotic mechanism in venous sinuses of the central nervous system. There is no consensus in the literature concerning the treatment of otogenic cerebral venous sinus thrombosis (CVST). Both the extent of the surgery and the use of anticoagulants are disputable. The aim of the study was to provide a thorough analysis of the literature concerning CVST in patients with AOM and acute mastoiditis (AM). The current surgical and conventional treatment strategies are presented. Special attention has been attached to the predisposing factors, the extent of the surgery, and the role of anticoagulants in the treatment of septic otogenic CVST.

Characteristics of Patients with Laryngomalacia: A Tertiary Referral Center Experience of 106 Cases.

Laryngomalacia (LM) is the most common airway congenital anomaly and the main cause of stridor in infants. Some patients with severe airway symptoms or with feeding difficulties require surgical intervention. Synchronous airway lesions (SALs) may influence the severity and course of the disease. This study aimed to determine the prevalence of various types of LM and SALs and their influence on surgical intervention decisions and feeding difficulties. Moreover, the study focused on the interrelations between SALs and the type of LM or the presence of feeding difficulties. A retrospective analysis of 106 pediatric patients revealed a significant relationship between type 2 LM and the necessity of surgical treatment. We also found a significant effect of LM type 2 on feeding difficulty. Type 1 LM is significantly more characteristic in premature children. Among different comorbidities, SALs are suspected of modification of the course and severity of LM. This study did not find a significant effect of SALs on the incidence of supraglottoplasty or feeding difficulty.

Polish national guidelines for the diagnosis and treatment of chronic otitis media with effusion in children.

Otitis media with effusion (OME), is a common childhood disease and is characterized by long-term fluid retention in the middle ear spaces without signs of acute infection. Surgical treatment of OME in the form of a tympanostomy is one of the most commonly performed medical procedures by pediatric ENT surgeons worldwide. In February 2022, the Journal of Otolaryngology - Head and Neck Surgery published updated guidelines from the American Academy of Otolaryngology - Head and Neck Surgery for tympanostomy tuba in children between 6 months and 12 years of age. They are aimed at both otolaryngologists and pediatricians, as well as other medical personnel who are directly involved in the care of patients with tympanostomy tuba or are candidates for the procedure. The previous version of the guidelines was developed in 2013. With the cooperation of the Board of Expert chaired by the National Consultant in Pediatric Otorhinolaryngology, Prof. Wieslaw Konopka, PhD, during the VII International Conference "Otology, 2022" which took place on September 15-17, 2022 in Torun, the previously published recommendations and consensuses from other countries, both European and non-European, were analyzed and the task of developing new national diagnostic and therapeutic recommendations for OME was undertaken.

Nasal Dermoids in Children: Factors Influencing the Distant Result.

The aim of the study was to present a single institution's treatment strategy for nasal dermoids and to identify factors influencing distant results. The study covered 24 surgically treated pediatric patients with nasal dermoids (NDs). The medical data concerning demographics, preoperative local inflammations and surgical procedures, form of the abnormality, imaging, surgical techniques, and a role of osteotomies and reconstructions were analyzed. The recurrence rates and distant aesthetic outcomes were assessed. The surgical approach included vertical incision in 21 patients, the external rhinoplasty approach in 2 cases, and bicoronal incision in 1 child. The intracranial extension was confirmed in 6 patients. Seven out of 8 cases with preoperative local inflammations and 3 out of 4 with secondary fistulization were < 4 years old. Nine patients required osteotomies. Three children required reconstruction of the nasal skeleton. None of the distant cosmetic results was described as hideous or unsatisfactory. The incidence of local inflammatory complications is unrelated to the age of the patients. The distant aesthetic result depends on both the initial extent of the disease and preoperative local conditions or interventions. Prompt surgical intervention is highly recommended.

Diagnostic Challenges in Neonatal Respiratory Distress-Congenital Surfactant Metabolism Dysfunction Caused by ABCA3 Mutation.

Surfactant is a complex of phospholipids and proteins produced in type II pneumocytes. Its deficiency frequently occurs in preterm infants and causes respiratory distress syndrome. In full-term newborns, its absence results from mutations in the SFTPC, SFTPB, NKX2-1, or ABCA3 genes involved in the surfactant metabolism. ABCA3 encodes ATP-binding cassette, which is responsible for transporting phospholipids in type II pneumocytes. We present a case of a male late preterm newborn with inherited surfactant deficiency in whom we identified the likely pathogenic c.604G>A variant in one allele and splice region/intron variant c.4036-3C>G of uncertain significance in the second allele of ABCA3. These variants were observed in trans configuration. We discuss the diagnostic challenges and the management options. Although invasive treatment was introduced, only temporary improvement was observed. We want to raise awareness about congenital surfactant deficiency as a rare cause of respiratory failure in term newborns.

Multispecialty Approach to a Very Large Congenital Head and Neck Cystic Lymphatic Malformation in an Infant Born by SARS-CoV-2 Positive Mother-A Case Report.

Masses of the head and neck are often diagnosed prenatally and require special care due to the risk of airway obstruction. The EXIT procedure is a preferable mode of delivery. A congenital cystic lymphatic malformation is one of the most common lesions of the cervical region described in neonates. The treatment consists of different strategies and involves the cooperation of multiple specialists. Up to now, no guidelines or protocols are available. We report a case of a congenital cystic lymphatic malformation of the head and neck delivered during the EXIT procedure by a mother who was SARS-CoV-2 positive. We analyzed clinical characteristics, radiologic features, and treatment with injections of sclerotic agents and orally administrated sirolimus. Sirolimus seems a valuable and safe therapeutic option for treating lymphatic malformations, especially with adjunct therapies.

Radiological diagnostics in nasal dermoids: Pitfalls, predictive values and literature analysis.

OBJECTIVE: The study aimed to present the accuracy of radiological diagnostics in pediatric patients with nasal dermoids and to discuss the potential factors influencing the radiological pitfalls on imaging in these cases. MATERIAL AND METHODS: The patient's cohort included 25 surgically treated pediatric cases with nasal dermoid. The results of preoperative imaging studies were analyzed regarding intraoperative findings. A review of the literature concerning a series of cases with nasal dermoid was performed in order to evaluate the possible radiological pitfalls and the accuracy of radiological imaging. The following statistical parameters for the particular radiological tools was determined: sensitivity, specificity, predictive positive values and predictive negative values. RESULTS: Total number of 18 CT and 14 MRI were performed. 6 out of 32 radiological examinations occurred to be inconsistent with operative findings. Potential pitfalls were identified and discussed. All the patients with false radiological results were below the age of 5 and 83% were below the age of 3 y.o. The overall sensitivity (S), specificity (SP), predictive positive value (PPV) and predictive negative value (PNV) for CT vs. MRI were 68% vs. 79%, 90% vs. 95%, 65% vs. 86% and 90% vs. 92%, respectively. CONCLUSIONS: MRI technique characterizes with higher predictive values in terms of identifying intracranial extension of nasal dermoid on imaging. Further analysis of radiological methods' accuracy should be conducted based on the detailed data concerning age distribution. The combination of CT and MRI should become a gold standard in diagnostics of nasal dermoids in children under the age of 5.

Decreased miRNA-320e correlates with allergy in children with otitis media with effusion.

OBJECTIVE: Otitis media with effusion (OME) is a common childhood disease and the main cause of conductive hearing loss in this age group. Many factors predispose to OME but allergy is still widely disputed. The answer may lay in the molecular mechanisms of ear exudate formation and the recent studies showed miRNAs might take part in it. MiRNAs are also potent regulators of allergic response. As miRNAs are present in the middle ear, we hypothesized their expression differs between allergic and non-allergic patients and reflects the difference in pathomechanism of effusion formation between these two groups. MATERIALS AND METHODS: This study aimed to establish the expression of 5 different miRNAs (miR-223-3p, miR-451a, miR-16-5p, miR-320e, miR-25-3p) in ear exudates in children diagnosed with OME. The allergy group consisted of 18 patients whereas the non-allergic group had 36 patients. MicroRNA was isolated from the middle ear fluid collected during myringotomy and transcribed into cDNA. MiRNA expression was measured with TaqMan™ MicroRNA Assays and analyzed with DataAssist software. The comparative CT method was used for calculating the relative quantification of gene expression based on the endogenous control gene expression (U6 snRNA-001973). RESULTS: MiR-320e expression was significantly decreased in allergic children with OME. Other studied miRNAs also showed reduced expression in allergic children, but the decrease was not significant. CONCLUSIONS: MiRNA expression differs between children with and without allergy in the course of OME, but further studies are needed to explain the exact role of miR-320e and its target genes in OME pathology in allergic patients.

Small intestine bacterial overgrowth does not correspond to intestinal inflammation in cystic fibrosis.

INTRODUCTION: Small intestine bacterial overgrowth (SIBO) has been reported in cystic fibrosis (CF) patients. However, the potential link to intestinal inflammation has not been studied so far. Therefore, we aimed to assess whether SIBO correlates with intestinal inflammation in CF patients. MATERIAL AND METHODS: As a preliminary study, we assessed whether calprotectin is detectable in sputum expectorated by 10 CF patients. Since significant immunoreactivity was documented, in the major study we have included exclusively CF subjects not expectorating sputum for at least two weeks. Fecal calprotectin was measured in 25 CF patients and 30 healthy subjects (HS). All CF subjects were tested for the presence of SIBO using the hydrogen-methane breath test (BT). According to obtained results CF patients were divided into SIBO positive and negative subgroups. Subsequently, the intensity of intestinal inflammation in both subgroups was compared. RESULTS: Fecal calprotectin concentrations in CF patients (range: 1.8-302.5; median 80.0 mg/L) were significantly higher (p < 0.00001) than in HS (not detectable-15.5; 2.5 mg/L). Calprotectin levels were abnormal in 21 (84%) studied CF subjects and none of HS. Abnormal BT results were found in 10 (40.0%) of CF patients. Calprotectin concentrations in SIBO positive and negative patients did not differ. CONCLUSIONS: Gastrointestinal inflammation is a frequent finding in cystic fibrosis patients. However, small intestine bacterial overgrowth does not seem to be the major or at least not the only determinant of intestinal inflammation. Indirect measures of intestinal inflammation in CF patients may give false positive results.