Diagnosing peripheral neuropathy in South‐East Asia: A focus on diabetic neuropathy

Burning and stabbing pain in the feet and lower limbs can have a significant impact on the activities of daily living, including walking, climbing stairs and sleeping. Peripheral neuropathy in particular is often misdiagnosed or underdiagnosed because of a lack of awareness amongst both patients and physicians. Furthermore, crude screening tools, such as the 10‐g monofilament, only detect advanced neuropathy and a normal test will lead to false reassurance of those with small fiber mediated painful neuropathy. The underestimation of peripheral neuropathy is highly prevalent in the South‐East Asia region due to a lack of consensus guidance on routine screening and diagnostic pathways. Although neuropathy as a result of diabetes is the most common cause in the region, other causes due to infections (human immunodeficiency virus, hepatitis B or C virus), chronic inflammatory demyelinating polyneuropathy, drug‐induced neuropathy (cancer chemotherapy, antiretrovirals and antituberculous drugs) and vitamin deficiencies (vitamin B₁, B₆, B₁₂, D) should be actively excluded.     

Syndrome of inappropriate antidiuretic hormone caused by continuous lumbar spinal fluid drainage after transphenoidal surgery

A 53-year-old acromegalic woman had cerebrospinal fluid rhinorrhoea following transphenoidal surgery for a pituitary microadenoma. A continuous lumbar spinal fluid drainage catheter was inserted and on the sixth postoperative day, she developed hyponatremia with features of syndrome of inappropriate antidiuretic hormone (SIADH) requiring hypertonic saline administration. Over-drainage is potentially hazardous and close biochemical monitoring is required. To our knowledge, this is the first reported case of SIADH caused by continuous lumbar drainage in an adult.     

Signal quality measures for pulse oximetry through waveform morphology analysis

Pulse oximetry has been extensively used to estimate oxygen saturation in blood, a vital physiological parameter commonly used when monitoring a subject's health status. However, accurate estimation of this parameter is difficult to achieve when the fundamental signal from which it is derived, the photoplethysmograph (PPG), is contaminated with noise artifact induced by movement of the subject or the measurement apparatus. This study presents a novel method for automatic rejection of artifact contaminated pulse oximetry waveforms, based on waveform morphology analysis. The performance of the proposed algorithm is compared to a manually annotated gold standard. The creation of the gold standard involved two experts identifying sections of the PPG signal containing good quality PPG pulses and/or noise, in 104 fingertip PPG signals, using a simultaneous electrocardiograph (ECG) signal as a reference signal. The fingertip PPG signals were each 1 min in duration and were acquired from 13 healthy subjects (10 males and 3 females). Each signal contained approximately 20 s of purposely induced artifact noise from a variety of activities involving subject movement. Some unique waveform morphology features were extracted from the PPG signals, which were believed to be correlated with signal quality. A simple decision-tree classifier was employed to arrive at a classification decision, at a pulse-by-pulse resolution, of whether a pulse was of acceptable quality for use or not. The performance of the algorithm was assessed using Cohen's kappa coefficient (κ), sensitivity, specificity and accuracy measures. A mean κ of 0.64 ± 0.22 was obtained, while the mean sensitivity, specificity and accuracy were 89 ± 10%, 77 ± 19% and 83 ± 11%, respectively. Furthermore, a heart rate estimate, extracted from uncontaminated sections of PPG, as identified by the algorithm, was compared with the heart rate derived from an uncontaminated simultaneous ECG signal. The mean error between both heart rate readings was 0.49 ± 0.66 beats per minute (BPM), in comparison to an error value observed without using the artifact detection algorithm of 7.23 ± 5.78 BPM. These results demonstrate that automated identification of signal artifact in the PPG signal through waveform morphology analysis is achievable. In addition, a clear improvement in the accuracy of the derived heart rate is also evident when such methods are employed.     

Chemotherapy-associated recurrent pneumothoraces in lymphangioleiomyomatosis

Lymphangioleiomyomatosis is a rare cause of pneumothorax in women. We present the case of a 48-year-old woman with lymphangioleiomyomatosis, who had never had a pneumothorax prior to commencing chemotherapy for breast cancer. During chemotherapy she developed 3 pneumothoraces and 2 episodes of pneumomediastinum. We suggest that the pneumothoraces were caused by the chemotherapy. To our knowledge, this is the first reported case of chemotherapy triggering pneumothoraces in a woman with lymphangioleiomyomatosis.     

Real-World Experience of Palbociclib-Induced Adverse Events and Compliance With Complete Blood Count Monitoring in Women With Hormone Receptor–Positive/HER2-Negative Metastatic Breast Cancer

Background

The cyclin-dependent kinase 4/6 inhibitor palbociclib has emerged as a novel therapeutic agent in metastatic breast cancer. Neutropenia is commonly observed, and thus stringent treatment guidelines regarding complete blood count (CBC) monitoring have been developed. The aim of this study was to provide a real-world experience of the toxicities associated with palbociclib therapy and to evaluate compliance with CBC monitoring.