Beyond Spirometry: Linking Wasted Ventilation to Exertional Dyspnea in the Initial Stages of COPD.

Exertional dyspnea, a key complaint of patients with chronic obstructive pulmonary disease (COPD), ultimately reflects an increased inspiratory neural drive to breathe. In non-hypoxemic patients with largely preserved lung mechanics - as those in the initial stages of the disease - the heightened inspiratory neural drive is strongly associated with an exaggerated ventilatory response to metabolic demand. Several lines of evidence indicate that the so-called excess ventilation (high ventilation-CO2 output relationship) primarily reflects poor gas exchange efficiency, namely increased physiological dead space. Pulmonary function tests estimating the extension of the wasted ventilation and selected cardiopulmonary exercise testing variables can, therefore, shed unique light on the genesis of patients' out-of-proportion dyspnea. After a succinct overview of the basis of gas exchange efficiency in health and inefficiency in COPD, we discuss how wasted ventilation translates into exertional dyspnea in individual patients. We then outline what is currently known about the structural basis of wasted ventilation in "minor/trivial" COPD vis-à-vis the contribution of emphysema versus a potential impairment in lung perfusion across non-emphysematous lung. After summarizing some unanswered questions on the field, we propose that functional imaging be amalgamated with pulmonary function tests beyond spirometry to improve our understanding of this deeply neglected cause of exertional dyspnea. Advances in the field will depend on our ability to develop robust platforms for deeply phenotyping (structurally and functionally), the dyspneic patients showing unordinary high wasted ventilation despite relatively preserved FEV1.

Non-ECG-gated cardiac CT angiography in acute stroke is feasible and detects sources of embolism.

BACKGROUND: A significant portion of cryptogenic stroke is hypothesized to be secondary to cardiac embolism. However, transthoracic echocardiogram is usually delayed after stroke, and more detailed cardiac imaging is not routinely done. AIMS: This study aimed to determine whether non-ECG-gated cardiac CT angiography (cCTA) during hyperacute stroke would provide diagnostic quality images and act as an adjunct modality of cardiac imaging to detect sources of emboli. METHODS: In this single-center prospective cohort study, modified Code Stroke imaging was implemented with a 64-slice CT scanner, where the longitudinal axis of CT angiography was extended from the carina to the diaphragm. The primary outcomes of image quality, recruitment feasibility, impact on hyperacute time metrics, and additional radiation dose were assessed. Secondary outcomes consisted of detection of high-risk cardiac sources of embolism, mediastinal or lung pathology, and impact on etiologic classification. RESULTS: One hundred and twenty eligible patients were enrolled, of which 105 (87.5%) had good/moderate quality images for motion artifact and 119 (99.2%) for contrast opacification. Total CT time, door-to-needle time, and door-to-groin puncture time were unchanged with the addition of cCTA. Eighty-nine patients received a final diagnosis of ischemic stroke, of which 12/89 (13.5%) had high-risk cardioembolic findings on cCTA. Incidental findings, such as pulmonary embolism (PE) (7/89, 7.9%) and malignancy (6/89, 6.7%), were observed. cCTA led to changes in management for 19/120 (15.8%) of all patients, and reclassification of stroke etiology for 8/89 (9%) of patients. CONCLUSIONS: Non-ECG-gated cCTA can be feasibly incorporated into Code Stroke and provide diagnostic quality images without delays in hyperacute time metrics. It can detect high-risk cardiac sources, and other findings impacting patient care. This may help reclassify a subset of cryptogenic stroke cases and improve secondary prevention.

Atypical Polycystic Kidney Disease as defined by Imaging.

Using age- and height-adjusted total kidney volume, the Mayo Clinic Imaging Classification provides a validated approach to assess the risk of chronic kidney disease (CKD) progression in autosomal dominant polycystic kidney disease (ADPKD), but requires excluding patients with atypical imaging patterns, whose clinical characteristics have been poorly defined. We report an analysis of the prevalence, clinical and genetic characteristics of patients with atypical polycystic kidney disease by imaging. Patients from the extended Toronto Genetic Epidemiology Study of Polycystic Kidney Disease recruited between 2016 and 2018 completed a standardized clinical questionnaire, kidney function assessment, genetic testing, and kidney imaging by magnetic resonance or computed tomography. We compared the prevalence, clinical features, genetics, and renal prognosis of atypical versus typical polycystic kidney disease by imaging. Forty-six of the 523 (8.8%) patients displayed atypical polycystic kidney disease by imaging; they were older (55 vs. 43 years; P < 0.001), and less likely to have a family history of ADPKD (26.1% vs. 74.6%; P < 0.001), a detectable PKD1 or PKD2 mutation (9.2% vs. 80.4%; P < 0.001), or progression to CKD stage 3 or stage 5 (P < 0.001). Patients with atypical polycystic kidney disease by imaging represent a distinct prognostic group with a low likelihood of progression to CKD.

V̇/Q̇ Mismatch: A Novel Target for COPD Treatment.

In people with COPD, pulmonary gas-exchange efficiency may be impaired because of abnormal alveolar ventilation (V˙A), capillary perfusion (Q˙c), or both. Both have been reported in early and mild stages of the disease. Such derangements often accompany significant clinical consequences such as activity-related dyspnea and exercise intolerance. Although much attention has been paid to pharmacologic treatment of mechanical abnormalities in COPD (eg, bronchodilators to deflate the lungs), increasing neurochemical afferent activity, secondary to gas-exchange inefficiency, has remained elusive as a therapeutic target. Hence, in this invited review, we first summarize how dyspnea, leading to poor exercise tolerance in COPD, may be explained by an increased venous admixture resulting from low V˙A/Q˙c, or wasted ventilation related to high V˙A/Q˙c, or both. We review the conflicting evidence supporting current treatments for gas-exchange inefficiency and exercise tolerance that act primarily on V˙A (bronchodilators, antiinflammatory medications) or Q˙c (oral and inhaled vasodilators, almitrine, and supplemental oxygen). Finally, to address the current knowledge and health care gaps, we propose two independent clinical research foci that may lead to a better understanding of the role of pulmonary gas-exchange inefficiency and activity-related dyspnea in COPD: (1) enhanced and deeper phenotyping of patients with COPD with V˙A/Q˙c abnormalities and (2) evaluation of existing and novel pharmacologic treatments to improve gas-exchange inefficiency, exertional dyspnea, and exercise tolerance across the spectrum of COPD severity.

Patients with Protein-Truncating PKD1 Mutations and Mild ADPKD.

BACKGROUND AND OBJECTIVES: Progression of autosomal dominant polycystic kidney disease (ADPKD) is highly variable. On average, protein-truncating PKD1 mutations are associated with the most severe kidney disease among all mutation classes. Here, we report that patients with protein-truncating PKD1 mutations may also have mild kidney disease, a finding not previously well recognized. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: From the extended Toronto Genetic Epidemiologic Study of Polycystic Kidney Disease, 487 patients had PKD1 and PKD2 sequencing and typical ADPKD imaging patterns by magnetic resonance imaging or computed tomography. Mayo Clinic Imaging Classification on the basis of age- and height-adjusted total kidney volume was used to assess their cystic disease severity; classes 1A or 1B were used as a proxy to define mild disease. Multivariable linear regression was performed to test the effects of age, sex, and mutation classes on log-transformed height-adjusted total kidney volume and eGFR. RESULTS: Among 174 study patients with typical imaging patterns and protein-truncating PKD1 mutations, 32 (18%) were found to have mild disease on the basis of imaging results (i.e., Mayo Clinic Imaging class 1A-1B), with their mutations spanning the entire gene. By multivariable analyses of age, sex, and mutation class, they displayed mild disease similar to patients with PKD2 mutations and Mayo Clinic Imaging class 1A-1B. Most of these mildly affected patients with protein-truncating PKD1 mutations reported a positive family history of ADPKD in preceding generations and displayed significant intrafamilial disease variability. CONCLUSIONS: Despite having the most severe mutation class, 18% of patients with protein-truncating PKD1 mutations had mild disease on the basis of clinical and imaging assessment. PODCAST: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2021_02_18_CJN11100720_final.mp3.

Convolutional neural networks versus radiologists in characterization of small hypoattenuating hepatic nodules on CT: a critical diagnostic challenge in staging of colorectal carcinoma.

Our objective was to compare the diagnostic performance and diagnostic confidence of convolutional neural networks (CNN) to radiologists in characterizing small hypoattenuating hepatic nodules (SHHN) in colorectal carcinoma (CRC) on CT scans. Retrospective review of CRC CT scans over 6-years yielded 199 patients (550 SHHN) defined as < 1 cm in diameter. The reference standard was established through 1-year stability/MRI for benign or nodule evolution for malignant nodules. Five CNNs underwent supervised training on 150 patients (412 SHHN). The remaining 49 patients (138 SHHN) were used as testing-set to compare performance of 3 radiologists to CNN, measured through ROC AUC analysis of confidence rating assigned to each nodule by the radiologists. Multivariable modeling was used to compensate for radiologist bias from visible findings other than SHHN. In characterizing SHHN as benign or malignant, the radiologists' mean AUC ROC (0.96) was significantly higher than CNN (0.84, p = 0.0004) but equivalent to CNN adjusted through multivariable modeling for presence of synchronous ≥ 1 cm liver metastases (0.95, p = 0.9). The diagnostic confidence of radiologists and CNN were analyzed. There were significantly lower number of nodules rated with low confidence by CNN (19.6%) and CNN with liver metastatic status (18.1%) than two (38.4%, 44.2%, p < 0.0001) but not a third radiologist (11.1%, p = 0.09). We conclude that in CRC, CNN in combination with liver metastatic status equaled expert radiologists in characterizing SHHN but with better diagnostic confidence.

New cardiac manifestation of IgG4-related disease: a case report.

(IgG4-RD) is a systemic fibro-inflammatory immune-mediated disease, which has been defined in the past few years. IgG4-RD affects various organs and leads to a variety of clinical manifestations. As it is a relatively newly defined entity, new manifestations are now being recognised and reported. We describe a case involving the cardiovascular system.

Prognostic Performance of Kidney Volume Measurement for Polycystic Kidney Disease: A Comparative Study of Ellipsoid vs. Manual Segmentation.

Total kidney volume (TKV) is a validated prognostic biomarker for risk assessment in autosomal dominant polycystic kidney disease (ADPKD). TKV by manual segmentation (MS) is the "gold standard" but is time-consuming and requires expertise. The purpose of this study was to compare TKV-based prognostic performance by ellipsoid (EL) vs. MS in a large cohort of patients. Cross-sectional study of 308 patients seen at a tertiary referral center; all had a standardized MRI with typical imaging of ADPKD. An experienced radiologist blinded to patient clinical results performed all TKV measurements by EL and MS. We assessed the agreement of TKV measurements by intraclass correlation(ICC) and Bland-Altman plot and also how the disagreement of the two methods impact the prognostic performance of the Mayo Clinic Imaging Classification (MCIC). We found a high ICC of TKV measurements (0.991, p < 0.001) between EL vs. MS; however, 5.5% of the cases displayed disagreement of TKV measurements >20%. We also found a high degree of agreement of the individual MCIC risk classes (i.e. 1A to 1E) with a Cohen's weighted-kappa of 0.89; but 42 cases (13.6%) were misclassified by EL with no misclassification spanning more than one risk class. The sensitivity and specificity of EL in distinguishing low-risk (1A-B) from high-risk (1C-E) MCIC prognostic grouping were 96.6% and 96.1%, respectively. Overall, we found an excellent agreement of TKV-based risk assessment between EL and MS. However, caution is warranted for patients with MCIC 1B and 1C, as misclassification can have therapeutic consequence.

Foam Sclerotherapy for Cyst Volume Reduction in Autosomal Dominant Polycystic Kidney Disease: A Prospective Cohort Study.

RATIONALE & OBJECTIVE: Autosomal dominant polycystic kidney disease (ADPKD) is the most common inherited kidney disorder. Progressive increase in cyst number and size leads to kidney failure in a majority of patients. Large kidney cysts, although few, can be especially deleterious by impeding kidney blood flow and obstructing urine flow over a large region. Foam sclerotherapy is a minimally invasive procedure that may be used to ablate large cysts. We examined the effectiveness and safety of foam sclerotherapy for kidney volume reduction in patients with ADPKD. STUDY DESIGN: Prospective cohort study. SETTING & PARTICIPANTS: Adults with ADPKD at a tertiary referral center in Toronto. PREDICTOR: Foam sclerotherapy. OUTCOMES: Volume of treated kidneys and adverse events. ANALYTICAL APPROACH: Treated and nontreated kidney volume, kidney function, tolerability, and symptoms were analyzed within each patient. RESULTS: We performed 77 foam sclerotherapy treatment sessions in 66 patients. Foam sclerotherapy was associated with a 21.8% volume reduction of the treated kidneys (n = 95; median, 1,138 [IQR, 801-1,582] mL before vs 891 [IQR, 548-1,450] mL after; P < 0.001), while the volume of the nontreated kidneys increased by 3.4% during the same time frame (n = 37; median, 655 [IQR, 352-998] mL before vs 677 [IQR, 371-1,164] mL after; P < 0.001). 4 (6%) patients had a higher measured creatinine clearance by at least 10 mL/min at least 12 months after foam sclerotherapy. 9 (14%) patients experienced self-limiting pain at the procedure site and 2 (3%) had cyst or urinary tract infection. Most patients with flank/back pain, abdominal pain, and abdominal distension had improvement in their symptoms. LIMITATIONS: Small sample, observational data. CONCLUSIONS: Foam sclerotherapy is a safe and effective procedure for kidney volume reduction and amelioration of compressive symptoms in select patients with ADPKD. Further studies are needed to assess its effects on kidney blood flow and kidney function and determine the subgroups of patients most likely to benefit.

Polycystic Kidney Disease without an Apparent Family History.

The absence of a positive family history (PFH) in 10%-25% of patients poses a diagnostic challenge for autosomal dominant polycystic kidney disease (ADPKD). In the Toronto Genetic Epidemiology Study of Polycystic Kidney Disease, 210 affected probands underwent renal function testing, abdominal imaging, and comprehensive PKD1 and PKD2 mutation screening. From this cohort, we reviewed all patients with and without an apparent family history, examined their parental medical records, and performed renal imaging in all available parents of unknown disease status. Subsequent reclassification of 209 analyzed patients revealed 72.2% (151 of 209) with a PFH, 15.3% (32 of 209) with de novo disease, 10.5% (22 of 209) with an indeterminate family history, and 1.9% (four of 209) with PFH in retrospect. Among the patients with de novo cases, we found two families with germline mosaicism and one family with somatic mosaicism. Additionally, analysis of renal imaging revealed that 16.3% (34 of 209) of patients displayed atypical PKD, most of which followed one of three patterns: asymmetric or focal PKD with PFH and an identified PKD1 or PKD2 mutation (15 of 34), asymmetric and de novo PKD with proven or suspected somatic mosaicism (seven of 34), or focal PKD without any identifiable PKD1 or PKD2 mutation (eight of 34). In conclusion, PKD without an apparent family history may be due to de novo disease, missing parental medical records, germline or somatic mosaicism, or mild disease from hypomorphic PKD1 and PKD2 mutations. Furthermore, mutations of a newly identified gene for ADPKD, GANAB, and somatic mosaicism need to be considered in the mutation-negative patients with focal disease.

The Diagnostic Accuracy of Gluteal Trigger Points to Differentiate Radicular From Nonradicular Low Back Pain.

OBJECTIVES: Low back pain (LBP) is highly prevalent and costly to the society. Previous studies have shown an association between radicular LBP and trigger points (TrPs) in the superior-lateral quadrant of the gluteal area (GTrP). The objective of current study was to evaluate the diagnostic value of GTrP to predict nerve root involvement among patients with LBP. MATERIALS AND METHODS: In a prospective, diagnostic accuracy study 325 consecutive patients with LBP were recruited. At first step, patients were evaluated for the presence or absence of the GTrP. A different investigator, blinded to the GTrP findings, then performed history taking and physical examination. Subsequently, all patients underwent a lumbar spine magnetic resonance imaging and, when indicated, electrodiagnostic tests. On the basis of the clinical and ancillary tests findings, a multidisciplinary panel of experts (the "reference standard"), blinded to the GTrP evaluation, allocated patients to radicular versus nonradicular LBP groups. The agreement between the GTrP findings, as a diagnostic test and the reference standard allocation was evaluated in a 2 by 2 contingency table. RESULTS: The specificity of the GTrP test was 91.4% and its sensitivity was 74.1%. The area under the receiver operating characteristic curve was 0.827 (0.781 to 0.874). Positive likelihood ratio was 8.62 and negative likelihood ratio was 0.28. Positive and negative predictive values were 91.9% and 72.7%, respectively. DISCUSSION: As a clinical finding, TrPs in superior-lateral quadrant of gluteal area are highly specific indicators for radicular LBP. Incorporating these TrPs evaluation in routine physical examination of patients with LBP could decrease the need for more costly, time-consuming, and invasive diagnostic tests.

Ectopic Cushing's syndrome secondary to lung and mediastinal tumours -- report from a tertiary care centre in Iran.

INTRODUCTION: Ectopic Cushing`s syndrome (ECS) secondary to neuroendocrine tumours (NETs) of the lung and mediastinum are rarely encountered. In this study, we present our experience in Iran on 15 patients with ECS secondary to lung and mediastinal tumours over a period of 27 years. MATERIAL AND METHODS: Since 1985, 15 patients with ECS secondary to lung and mediastinal tumours have been diagnosed and prospectively followed by the endocrinology team of Taleghani Hospital, Tehran, Iran. The clinical signs and symptoms, laboratory findings, radiological features, immunohistochemical characteristics, management strategies and outcome data are here presented. RESULTS: There were six women and nine men, aged 26-70 years, all presenting with typical features of Cushing's syndrome. Based on histopathologic evaluations, four patients had small cell lung cancer (SCLC) and seven patients had pulmonary NETs, one patient had a thymic NET, and one case was diagnosed as a lung tumourlet. The mean ± SD serum cortisol, 24h urine free cortisol and plasma ACTH were 47.2 ± 20.5 µg/dL, 2,702 ± 5,439 µg/day, and 220 ± 147 pg/mL, respectively. Pulmonary lesions ranged in diameter from 1.1 to 4 cm (mean 1.9 ± 1.1 cm). One patient had a 10 cm mediastinal mass. The duration of follow up in these cases was between one month and seven years (mean 29.9 ± 27.5 months). The four patients with SCLC died within three months of diagnosis. CONCLUSION: Our data demonstrates the protean clinical and laboratory manifestations of ECS secondary to lung and mediastinal tumours, the problems encountered in diagnosis, and the need for a multidisciplinary approach. This study confirms other series from Western Europe and North America that, unlike the SCLC patients who show a poor outlook, ECS secondary to lung carcinoids has a more favourable prognosis.

Multiple endocrine neoplasia type 2A in an Iranian family: clinical and genetic studies.

Multiple endocrine neoplasia (MEN) type 2A, a dominant inherited syndrome caused by germline activating mutations in the RET protooncogene, is characterized by association of medullary thyroid carcinoma, pheochromocytoma and primary hyperparathyroidism. There is limited data on this disease in the Middle East region. In this paper, we present clinical and genetic studies of an Iranian patient and her family members. The patient was a 49-year old Iranian woman who presented with hypertension due to bilateral pheochromocytoma. She had history of a medullary carcinoma of thyroid which had been operated 28 years ago. Analysis of the RET gene in the family revealed a C634R mutation in codon 11 and 3 polymorphisms, G691S, S836S and S904S in codons 11, 14 and 15, respectively, that might have been important in modifying the clinical picture. Due to paucity of information on MEN type 2 in the area, this study can be helpful in portraying the clinical and cytogenetic characteristics of the disease in the region.

Ectopic acromegaly due to growth hormone releasing hormone.

Acromegaly secondary to extra-pituitary tumors secreting growth hormone releasing hormone (GHRH) is rarely encountered. We review the literature on ectopic acromegaly and present the index report of ectopic acromegaly secondary to GHRH secretion from a mediastinal paraganglioma. Clinical and pathological manifestations and therapeutic management of 99 patients with ectopic acromegaly are reviewed. Acromegaly secondary to ectopic GHRH secretion is usually caused by a neuroendocrine tumor in the lung and pancreas. We report an additional cause of ectopic acromegaly from a mediastinal paraganglioma. Diagnostic criteria of ectopic GHRH syndrome include biochemical and pathologic tumoral confirmation of GHRH secretion and expression. Management of ectopic acromegaly consists of surgical resection of the primary tumor and biochemical normalization, with possible adjuvant use of somatostatin analogs. The review demonstrates that there are several tumor types, including paragangliomas which may secrete GHRH, leading to acromegaly. Clinical and laboratory manifestations of the syndrome and challenges in diagnosis and management of these rarely encountered patients require early diagnosis and appropriate treatment to prevent long-term morbidity and mortality with ectopic acromegaly.

Inguinal herniation of a transplant kidney ureter: a case report.

Ureteral obstruction is relatively common after renal transplantation. A rare cause is the inguinal herniation of the transplant ureter. We report a case of late allograft renal transplant failure due to ureteral herniation as well as ureterovesical junction stenosis.

Cushing syndrome secondary to a thymic carcinoid tumor due to multiple endocrine neoplasia type 1.

OBJECTIVE: To present an Iranian patient with a nonclassic form of multiple endocrine neoplasia type 1 (MEN 1) who presented with ectopic Cushing syndrome (CS) secondary to a corticotropin (ACTH)-producing thymic neuroendocrine tumor (NET), recurrent renal stones, and a giant cell granuloma of the jaw due to primary hyperparathyroidism (PHPT) without involvement of the pituitary or pancreas. METHODS: Relevant imaging and hormonal evaluations were performed. The patient was operated on 2 occasions for a thymic NET and on 3 occasions for PHPT. DNA from a peripheral blood sample was extracted for sequencing of the MEN1 gene. RESULT: Histopathologic evaluation of the thymic tumor removed during the first surgery showed an atypical carcinoid tumor with a Ki-67 labeling index of 5%. Evaluation after the second surgery revealed an invasive carcinoid tumor with a Ki-67 labeling index of 30%. Parathyroid pathology was suggestive of glandular hyperplasia. Menin gene sequencing revealed a novel frameshift mutation c.1642_1648dup in exon 10. CONCLUSION: This case of MEN 1 is unusual because most thymic NETs in MEN 1 are nonfunctional, and secretion of ACTH or other ectopic hormones rarely occurs. In patients presenting with thymic NETs, the possibility of MEN 1 should be considered, especially in the presence of hyperparathyroidism. This case also demonstrates that the behavior of thymic NETs can change over time from slow-growing tumors to highly invasive neoplasia, and that ectopic ACTH can be produced by these tumors in the context of MEN 1.

Postpartum hypercalcemia secondary to a neuroendocrine tumor of pancreas; a case report and review of literature.

Parathyroid hormone-related protein producing pancreatic neuroendocrine tumors have been infrequently reported. Herein, we report a case of an Iranian woman who had such a tumor during pregnancy, and gave birth to a female neonate with esophago-tracheal fistula and imperforated anus. Hypercalcemia was diagnosed at postpartum because of elevated serum calcium levels in the neonate and neurologic deterioration of the mother. Extensive literature review revealed 42 cases with pancreatic neuroendocrine tumors and hypercalcaemia. The clinical and laboratory findings of such patients are reviewed in this manuscript.

Abdominal inflammatory myofibroblastic tumor: report on four cases and review of literature.

BACKGROUND: The Abdominal Inflammatory Myofibroblastic Tumor (AIMT) is a rare tumor with unknown etiology which usually occurs in children and adolescents. It is composed of myofibroblastic spindle cells intermixed with inflammatory cells. We present four cases of AIMT. CASES PRESENTATION: WE HEREIN PRESENT FOUR CASES OF AIMT IN DIFFERENT AGES (RANGE: 3.5 to 13 years) and in different organs (stomach, periduodenal, mesenteric, and colon). There were two females and two males. The main symptoms were abdominal pain/mass/obstruction, vomiting, and weight loss. In all four patients, diagnosis was made by laparatomy and pathologic examination of excised mass lesion. Three patients underwent complete excision and no residual disease was present, one patient received chemotherapy due to tumor recurrences. The patients were followed up in average for four years. CONCLUSION: As the imaging and laboratory tests are non-specific, the diagnosis of AIMT is rarely made before surgery. AIMT should, therefore, be considered when a mass arises in an unusual location in the pediatric age group. Complete surgical resection should be performed whenever possible and the child should be kept on long-term follow-up.