Rectus sheath hematoma (RSH) is an uncommon but significant cause of acute abdominal pain in pregnancy, challenging in both diagnosis and treatment. It often arises from ruptured epigastric vessels ...and is associated with factors like anticoagulation therapy and previous abdominal surgery. Misdiagnosis, due to nonspecific symptoms, frequently leads to unnecessary surgeries, posing substantial risks to maternal and fetal health.
We present a case of a 32-year-old multiparous woman at 31 weeks of gestation, experiencing right-sided abdominal pain and irregular contractions. With a history of four full-term deliveries and no recent trauma, her examination showed hemodynamic stability but featured pain upon movement and a notable blue discoloration in the left abdominal area. Moderate anemia was observed in lab tests. The diagnosis of RSH was confirmed via ultrasound and MRI. The treatment approach shifted from conservative to surgical due to deteriorating symptoms and falling hemoglobin levels.
This case highlights the rarity and seriousness of RSH in pregnancy. Its non-specific symptoms complicate differential diagnosis, underscoring the need for prompt and precise diagnosis to avoid unwarranted surgical interventions. While conservative management is preferred in stable cases, surgical action is required in situations of instability or hematoma growth.
RSH is a critical consideration in pregnant patients with acute abdominal pain. Early detection and tailored management are essential to mitigate surgical risks and ensure the safety of mother and child. This case reinforces the importance of vigilant and systematic patient evaluation to improve outcomes and minimize unnecessary surgical procedures.
•Rare case of spontaneous rectus sheath hematoma in a 32-year-old pregnant woman.•Initial symptoms: irregular contractions, right-sided abdominal pain.•Diagnosis via MRI after initial ultrasound showed no abnormalities.•Treatment shifted to surgery due to worsening symptoms, falling hemoglobin.•Case emphasizes the importance of considering rectus sheath hematoma in pregnancy abdominal pain diagnosis.
We consider the problem of best arm identification in the multi-armed bandit model, under fixed confidence. Given a confidence input \(\delta\), the goal is to identify the arm with the highest mean ...reward with a probability of at least 1 -- \(\delta\), while minimizing the number of arm pulls. While the literature provides solutions to this problem under the assumption of independent arms distributions, we propose a more flexible scenario where arms can be dependent and rewards can be sampled simultaneously. This framework allows the learner to estimate the covariance among the arms distributions, enabling a more efficient identification of the best arm. The relaxed setting we propose is relevant in various applications, such as clinical trials, where similarities between patients or drugs suggest underlying correlations in the outcomes. We introduce new algorithms that adapt to the unknown covariance of the arms and demonstrate through theoretical guarantees that substantial improvement can be achieved over the standard setting. Additionally, we provide new lower bounds for the relaxed setting and present numerical simulations that support their theoretical findings.
We consider the problem of ranking n experts based on their performances on d tasks. We make a monotonicity assumption stating that for each pair of experts, one outperforms the other on all tasks. ...We consider the sequential setting where in each round, the learner has access to noisy evaluations of actively chosen pair of expert-task, given the information available up to the actual round. Given a confidence parameter \(\delta\) \(\in\) (0, 1), we provide strategies allowing to recover the correct ranking of experts and develop a bound on the total number of queries made by our algorithm that hold with probability at least 1 -- \(\delta\). We show that our strategy is adaptive to the complexity of the problem (our bounds are instance dependent), and develop matching lower bounds up to a poly-logarithmic factor. Finally, we adapt our strategy to the relaxed problem of best expert identification and provide numerical simulation consistent with our theoretical results.
We investigate the problem of cumulative regret minimization for individual sequence prediction with respect to the best expert in a finite family of size K under limited access to information. We ...assume that in each round, the learner can predict using a convex combination of at most p experts for prediction, then they can observe a posteriori the losses of at most m experts. We assume that the loss function is range-bounded and exp-concave. In the standard multi-armed bandits setting, when the learner is allowed to play only one expert per round and observe only its feedback, known optimal regret bounds are of the order O(\(\sqrt\) KT). We show that allowing the learner to play one additional expert per round and observe one additional feedback improves substantially the guarantees on regret. We provide a strategy combining only p = 2 experts per round for prediction and observing m \(\ge\) 2 experts' losses. Its randomized regret (wrt. internal randomization of the learners' strategy) is of order O (K/m) log(K\(\delta\) --1) with probability 1 -- \(\delta\), i.e., is independent of the horizon T ("constant" or "fast rate" regret) if (p \(\ge\) 2 and m \(\ge\) 3). We prove that this rate is optimal up to a logarithmic factor in K. In the case p = m = 2, we provide an upper bound of order O(K 2 log(K\(\delta\) --1)), with probability 1 -- \(\delta\). Our strategies do not require any prior knowledge of the horizon T nor of the confidence parameter \(\delta\). Finally, we show that if the learner is constrained to observe only one expert feedback per round, the worst-case regret is the "slow rate" \(\Omega\)(\(\sqrt\) KT), suggesting that synchronous observation of at least two experts per round is necessary to have a constant regret.
This review focuses on the newest data on mechanistic aspects of chemotherapy-induced peripheral neuropathy (CIPN), its assessment and the current status of neuroprotection and treatment options.
...Several anticancer drugs are associated with CIPN. Rodent models showed that axons, dorsal root ganglia and terminal trees are affected, whereas myelin remains unaffected. Oxidative stress and mitochondrial damage, as well as the role of nerve growth factor, have been highlighted in CIPN. Candidate genes, single nucleotide polymorphisms, were correlated with a higher incidence of CIPN in patients receiving a combination of chemotherapies. CIPN assessment mainly relies on patient-oriented questionnaires, nevertheless an international effort is ongoing to access reliable and objective means to assess small and large fiber impairment.To date, dose modification is the most effective strategy to prevent CIPN, whereas duloxetine is recommended for patients with painful CIPN.
CIPN is a common, potentially severe and dose-limiting adverse effect of cancer treatment. Chemotherapies mainly target axons, dorsal root ganglia and terminal trees of intraepidermal nerve fibers. A quick and noninvasive method allowing the assessment of CIPN should be developed, although no treatment prevents CIPN or improves its long-term course. Furthermore, symptomatic therapy is often largely ineffective in reducing CIPN symptoms.
We investigate the problem of minimizing the excess generalization error with respect to the best expert prediction in a finite family in the stochastic setting, under limited access to information. ...We assume that the learner only has access to a limited number of expert advices per training round, as well as for prediction. Assuming that the loss function is Lipschitz and strongly convex, we show that if we are allowed to see the advice of only one expert per round for T rounds in the training phase, or to use the advice of only one expert for prediction in the test phase, the worst-case excess risk is \(\Omega\)(1/ \(\sqrt\) T) with probability lower bounded by a constant. However, if we are allowed to see at least two actively chosen expert advices per training round and use at least two experts for prediction, the fast rate O(1/T) can be achieved. We design novel algorithms achieving this rate in this setting, and in the setting where the learner has a budget constraint on the total number of observed expert advices, and give precise instance-dependent bounds on the number of training rounds and queries needed to achieve a given generalization error precision.
Online Orthogonal Matching Pursuit El Mehdi Saad; Blanchard, Gilles; Arlot, Sylvain
arXiv (Cornell University),
02/2021
Paper, Journal Article
Odprti dostop
Greedy algorithms for feature selection are widely used for recovering sparse high-dimensional vectors in linear models. In classical procedures, the main emphasis was put on the sample complexity, ...with little or no consideration of the computation resources required. We present a novel online algorithm: Online Orthogonal Matching Pursuit (OOMP) for online support recovery in the random design setting of sparse linear regression. Our procedure selects features sequentially, alternating between allocation of samples only as needed to candidate features, and optimization over the selected set of variables to estimate the regression coefficients. Theoretical guarantees about the output of this algorithm are proven and its computational complexity is analysed.
Background
Radiation-induced leukoencephalopathy (RIL) is the most threatening delayed complication of cerebral radiotherapy (RT) and remains roughly defined by cognitive dysfunction associated with ...diffuse FLAIR MRI white matter hyperintensities after brain irradiation. We documented clinical, neuropsychological, and radiological aspects of RI in order to refine diagnostic criteria.
Methods
Patients referred to our center for deterioration in cognitive complaint at least 6 months after completing a focal or whole brain RT underwent a systematic cross-sectional assessment including clinical examination, neuropsychological tests, and a standardized MRI protocol. Patients with progressive tumor were excluded.
Results
Forty patients were prospectively enrolled. Of these, 26 had received a focal RT, median dose of 53 Gy (range 50 to 60), and 14 had received a whole brain RT, median dose of 30 Gy. Cognitive complaints, gait apraxia, and urinary troubles were reported in 100, 67, and 38% of cases, respectively. On neuropsychological examination, patients displayed a global and severe cognitive decline through a subcortical frontal mode. The cognitive changes observed were not hippocampic, but related to executive dysfunction. On MRI, 68% of the patients had extensive FLAIR hyperintensities with anterior predominance, 87% had brain atrophy, and 21% had intraparenchymal cysts. T2*-weighted MRI showed small asignal areas in 53% of the patients. These abnormalities are evocative of cerebral small vessel disease. Fractional anisotropy in the corpus callosum correlated with the cognitive evaluation. No differentiation in terms of cognitive and MRI features could be made between patients treated with focal brain RT (glioma) and patients treated with WBRT (for brain metastases or PCNSL).
Conclusions
RIL can be defined by clinical symptoms (subcortical frontal decline, gait apraxia, urinary incontinence) and MRI criteria (cortico-subcortical atrophy, spread FLAIR HI, T2* asignals). This condition mimics a diffuse progressive cerebral small vessel disease triggered by RT, independent of RT protocol.
Early stages of chemotherapy-induced peripheral neurotoxicity (CIPN) are poorly investigated due to the lack of simple tool. SUDOSCAN is a simple, quick (<3 minutes), non-invasive and quantitative ...method to assess small fiber neuropathy, based on an electrochemical reaction between sweat chlorides and stainless-steel electrodes. This study aimed to evaluate SUDOSCAN in the detection and follow-up of early CIPN. 15 patients receiving Oxaliplatin (12 males, mean age: 60 plus or minus 10years) and 16 Paclitaxel (6 males, mean age: 64 plus or minus 15 years) were involved in the study. At each chemotherapy infusion cumulative dose of chemotherapy was calculated, Total Neuropathy Score (TNSc) was performed and Electrochemical Skin Conductances (ESC) of hands and feet expressed in microSiemens ( mu S) were assessed by SUDOSCAN. For patients receiving Oxaliplatin hands ESC changed from 78 plus or minus 9 to 68 plus or minus 14 mu S (p < 0.0001) and feet ESC from 82 plus or minus 10 to 75 plus or minus 14 mu S (p = 0.0005) while TNSc changed from 3.3 plus or minus 4.3 to 3.6 plus or minus 2.6 (p = 0.001) for mean cumulative dose changing from 250 plus or minus 264 to 429 plus or minus 248 (mg/m2). In patients receiving Paclitaxel hands ESC changed from 62 plus or minus 20 to 44 plus or minus 18 mu S (p < 0.0001) and feet ESC from 72 plus or minus 18 to 60 plus or minus 20 mu S (p = 0.0005) while TNSc changed from 5.8 plus or minus 2.2 to 6.3 plus or minus 2.4 (p = 0.001) for mean cumulative dose changing from 1180 plus or minus 1255 to 1507 plus or minus 1380 (mg/m2). When looking at asymptomatic patients mean TNSc changed from 3 plus or minus 3 to 4 plus or minus 3 (p = 0.0002). Mean hands ESC changed from 66 plus or minus 20 mu S to 55 plus or minus 21 mu S (p < 0.0001), while mean feet ESC changed from 71 plus or minus 21 mu S to 64 plus or minus 23 mu S (p < 0.0001), suggesting that SUDOSCAN could help detect and quantify CIPN even in asymptomatic patients. This preliminary study demonstrated that small fiber neuropathy can be followed using SUDOSCAN in patients receiving chemotherapy. These preliminary results observed during on-going chemotherapy must be confirmed in a larger population with measurements performed before the initiation of chemotherapy and during its follow-up.
Early stages of chemotherapy-induced peripheral neurotoxicity (CIPN) are poorly investigated due to the lack of simple tool. SUDOSCAN is a simple, quick (<3 minutes), non-invasive and quantitative ...method to assess small fiber neuropathy, based on an electrochemical reaction between sweat chlorides and stainless-steel electrodes. This study aimed to evaluate SUDOSCAN in the detection and follow-up of early CIPN. 15 patients receiving Oxaliplatin (12 males, mean age: 60 ± 10years) and 16 Paclitaxel (6 males, mean age: 64 ± 15 years) were involved in the study. At each chemotherapy infusion cumulative dose of chemotherapy was calculated, Total Neuropathy Score (TNSc) was performed and Electrochemical Skin Conductances (ESC) of hands and feet expressed in microSiemens (µS) were assessed by SUDOSCAN. For patients receiving Oxaliplatin hands ESC changed from 78 ± 9 to 68 ± 14 µS (p < 0.0001) and feet ESC from 82 ± 10 to 75 ± 14 µS (p = 0.0005) while TNSc changed from 3.3 ± 4.3 to 3.6 ± 2.6 (p = 0.001) for mean cumulative dose changing from 250 ± 264 to 429 ± 248 (mg/m
2
). In patients receiving Paclitaxel hands ESC changed from 62 ± 20 to 44 ± 18 µS (p < 0.0001) and feet ESC from 72 ± 18 to 60 ± 20 µS (p = 0.0005) while TNSc changed from 5.8 ± 2.2 to 6.3 ± 2.4 (p = 0.001) for mean cumulative dose changing from 1180 ± 1255 to 1507 ± 1380 (mg/m
2
). When looking at asymptomatic patients mean TNSc changed from 3 ± 3 to 4 ± 3 (p = 0.0002). Mean hands ESC changed from 66 ± 20 µS to 55 ± 21 µS (p < 0.0001), while mean feet ESC changed from 71 ± 21 µS to 64 ± 23 µS (p < 0.0001), suggesting that SUDOSCAN could help detect and quantify CIPN even in asymptomatic patients. This preliminary study demonstrated that small fiber neuropathy can be followed using SUDOSCAN in patients receiving chemotherapy. These preliminary results observed during on-going chemotherapy must be confirmed in a larger population with measurements performed before the initiation of chemotherapy and during its follow-up.
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