Background/Objectives: Anti-MAG polyneuropathy is a demyelinating peripheral neuropathy associated with IgM monoclonal gammopathies, particularly MGUS (monoclonal gammopathy of undetermined significance) and Waldenström macroglobulinemia. It is characterized by a subacute onset of distal sensory symptoms, with distal motor dysfunction typically appearing only in the later stages of the disease. The condition is caused by the presence of autoantibodies directed against myelin-associated glycoprotein, a structural protein of myelin. This leads to abnormalities in electrophysiological studies, such as markedly delayed distal latencies without conduction blocks or temporal dispersion of potentials. While rituximab (RTX) is the primary treatment, its efficacy is limited, with improvement seen in only 30–50% of patients. Recently, acute worsening of symptoms after RTX treatment has been increasingly reported. Methods: This systematic review compiles case reports and series from inception to June 2024 published on Scopus, PubMed or Cochrane, documenting acute exacerbations after RTX treatment in patients with anti-MAG polyneuropathy. Additionally, we present a case report from our institution that highlights this phenomenon. Results: We identified 13 clinical cases of acute deterioration in patients with anti-MAG polyneuropathy. Among these, eight patients (62%) achieved full recovery following additional treatment, while five patients (38%) did not return to their previous level of function. Plasmapheresis led to complete recovery in all four patients who received this intervention. Interestingly, many patients also experienced recovery after discontinuation of rituximab (RTX) treatment without the need for further therapeutic intervention. Conclusions: Acute clinical deterioration following RTX treatment in anti-MAG polyneuropathy is a possible occurrence. However, to date, no studies have assessed the true prevalence of this phenomenon. Further research is warranted to identify potential predictors of worsening following RTX treatment in this patient population.

Background/Objectives: The benefits of liberal transfusion strategies for neurological outcomes in critically ill patients with acute brain injuries (ABIs) remain uncertain due to conflicting evidence and potential risks. This study aimed to evaluate the efficacy and safety of a liberal transfusion strategy in adults with ABI. Methods: A systematic review of PubMed, Scopus, and the Cochrane Library was conducted from inception until 18 December 2024. Randomized clinical trials (RCTs) comparing liberal and restrictive transfusion strategies in adult patients admitted to intensive care units with ABI were included. The primary outcome was unfavorable neurological function at the last follow-up, defined as Glasgow Outcome Scale (GOS) score <4, Extended GOS score 3. Results: Among 5859 screened records, five RCTs (2385 patients) met the inclusion criteria. Liberal transfusion significantly reduced unfavorable neurological outcomes (RR, 0.88; 95% CI, 0.82–0.95; p = 0.0009) without affecting mortality (RR, 0.97; 95% CI, 0.84–1.11; p = 0.66). A meta-analysis of two studies (n = 1465 patients) showed improved functional independence with liberal strategies (MD, 6.70; 95% CI, 2.07–11.33; p = 0.005) but no difference in quality of life (p = 0.30). Sepsis or septic shock occurred less frequently in the liberal group (RR, 0.68; 95% CI, 0.50–0.92; p = 0.01). Subgroup analysis indicated that liberal strategies improved neurological outcome in traumatic brain injury (TBI) patients (RR, 0.89; 95% CI, 0.82–0.97; p = 0.01) but did not yield significant differences in spontaneous subarachnoid hemorrhage (p = 0.09). Conclusions: Liberal transfusion strategies safely improve neurological outcomes in adults with ABI, specifically in the subgroup of TBI, whereas further studies are needed in patients with SAH.