Trending Topics in Gastroenterology | GastroAGI

Dopamine Beyond Reward. JAMA| May 2026

This review redefines dopamine (DA) signaling beyond its classical role in reward processing, positioning dopaminergic circuits as central regulators of feeding behavior, metabolic sensing, and energy homeostasis. The authors describe how distributed dopamine ensembles across mesocorticolimbic and hypothalamic networks integrate both hedonic and homeostatic information to coordinate adaptive feeding responses. Midbrain ventral tegmental area (VTA) dopamine neurons dynamically respond to nutrient availability, metabolic state, and peripheral hormonal signals such as leptin, insulin, and ghrelin. These signals are further integrated within dopaminoceptive circuits in the nucleus accumbens and hypothalamus, where dopamine modulates food-seeking behavior, caloric intake, glucose regulation, and energy expenditure. Importantly, the review emphasizes the remarkable cellular and circuit heterogeneity of dopamine systems. Distinct neuronal populations and receptor-specific pathways enable context-dependent regulation of feeding under physiological and pathological conditions, including obesity, metabolic syndrome, binge eating, and anorexia-related disorders. Rather than functioning as isolated reward pathways, dopamine circuits are conceptualized as highly interconnected metabolic networks translating internal physiological states into behavioral outputs. This evolving framework has major translational implications, suggesting that selective modulation of specific dopaminergic nodes may provide novel therapeutic strategies for metabolic and eating disorders.

Gut–Heart Axis: Gut | May 2026

Introduction Atherosclerosis has traditionally been viewed as a lipid-driven disease. However, emerging evidence highlights a critical role of chronic inflammation and immune activation, with the gut microbiota now recognised as a key modulator of vascular health. The concept of a gut–heart axis is reshaping our understanding of cardiovascular disease. Problem Statement Despite optimal lipid control, many patients continue to develop atherosclerosis, suggesting lipid-independent mechanisms. The challenge lies in identifying novel pathways contributing to vascular inflammation. The gut microbiota, through its interaction with host metabolism and immunity, has emerged as a potential contributor—but its exact role and therapeutic relevance remain incompletely defined. Summary This review highlights the growing evidence linking gut microbiota to atherosclerosis. Patients with cardiovascular disease exhibit gut dysbiosis, including increased translocation of oral bacteria into the intestine. Microbial-derived metabolites play a central role: harmful metabolites such as trimethylamine N-oxide (TMAO), endotoxins, and imidazole propionate promote vascular inflammation and plaque formation, whereas other metabolites, like certain tryptophan derivatives, may have protective effects. The microbiota also interacts closely with lipid metabolism, influencing lipid absorption, storage, and systemic inflammation. Additionally, it contributes to vascular ageing, further accelerating atherosclerosis. Therapeutic modulation of the microbiome—through diet, prebiotics, probiotics, or antibiotics—has shown promising results in preclinical models, though human data remain limited. Overall, the gut microbiota functions as a biological rheostat regulating vascular inflammation, offering a novel target for future cardiovascular therapies.

Bleeding Risk with Apixaban vs. Rivaroxaban: NEJM March 2026

Clinical Summary In this randomized international trial (COBRRA), investigators compared the bleeding risk of apixaban vs. rivaroxaban in patients with acute venous thromboembolism (VTE), including pulmonary embolism and proximal deep-vein thrombosis. A total of 2,760 patients were randomized to receive either apixaban (10 mg twice daily for 7 days followed by 5 mg twice daily) or rivaroxaban (15 mg twice daily for 21 days followed by 20 mg daily) for 3 months. The primary endpoint—clinically relevant bleeding (major or clinically relevant nonmajor bleeding)—occurred significantly less often with apixaban (3.3%) compared with rivaroxaban (7.1%), corresponding to a 54% relative risk reduction (RR 0.46; 95% CI 0.33–0.65; P<0.001). Mortality rates were low and similar between groups. Clinical implication: Apixaban demonstrated a substantially lower bleeding risk than rivaroxaban while maintaining similar clinical outcomes, suggesting it may be the safer first-line direct oral anticoagulant for treatment of acute VTE in routine clinical practice.

ACG 2025

The American College of Gastroenterology (ACG) 2025 meeting is a prominent annual event where groundbreaking research, clinical studies, and advancements in gastroenterology are presented. At the ACG 2025 meeting, several impactful studies were showcased, providing significant insights into the prevention, diagnosis, and treatment of gastrointestinal disorders. Below are the highlights of four major studies presented at the meeting: ### 1. **Sessile Serrated Lesion Detection Rate (SSLDR) and Colon Cancer Prevention** - Researchers analyzed data from over **115,000 colonoscopies** to evaluate the Sessile Serrated Lesion Detection Rate (SSLDR). - Findings revealed that a **higher SSLDR is strongly associated with a reduced risk of post-colonoscopy colorectal cancer**. - Key results: - SSLDR between **4.5–8%** reduced the cancer risk by **62%**. - SSLDR of **≥8%** reduced the risk by nearly **80%**. - This study suggests that endoscopists should aim for SSLDR rates **higher than the current guideline minimum of 6%** to improve colon cancer prevention efforts. ### 2. **Inadequate Bowel Preparation (IABP) in Colonoscopies** - This study analyzed data from **16.7 million colonoscopies** to assess the prevalence and consequences of inadequate bowel preparation (IABP). - Despite guidelines recommending fewer than **10%** inadequate preps, real-world adherence was poor. - Key findings: - Only **32%** of patients with IABP underwent a repeat colonoscopy within a year. - **57%** of patients with IABP were lost to follow-up for more than five years. - Even high-risk patients rarely returned for follow-up, and many had **another inadequate preparation** during repeat exams. - The study highlights the need for improved strategies, including **better bowel preparation selection, enhanced patient education, and navigation support** to ensure adequate preparation and follow-up care. ### 3. **Translumbosacral Neuromodulation Therapy (TNT) for Fecal Incontinence** - Researchers evaluated the efficacy of **translumbosacral neuromodulation therapy (TNT)** in managing fecal incontinence. - The study involved **109 patients** and demonstrated significant improvements in symptoms: - Weekly incontinence episodes decreased from **7.7 to 2.8** and **8.3 to 3.5**, depending on the dose. - TNT also improved nerve function, suggesting its potential to **regenerate neural pathways**. - While the results are promising, TNT remains an **investigational therapy** at this stage. ### 4. **Resmetirom for Advanced Liver Disease** - Resmetirom, a medication approved for managing **Metabolic Associated Steatohepatitis (MASH) with fibrosis**, was studied in patients with cirrhosis. - Over a two-year period, the study revealed significant improvements: - **20–28%** of patients no longer met the criteria for clinically significant portal hypertension. - **35%** of patients improved from **F4 fibrosis (cirrhosis)** to **F3 fibrosis**, indicating a regression of liver disease severity. - These findings represent a significant advance in the treatment of **advanced liver disease**, offering hope for patients with cirrhosis. ### Conclusion The ACG 2025 meeting presented critical advancements in gastroenterology, highlighting the importance of: - Improving detection rates for sessile serrated lesions to reduce colorectal cancer risk. - Addressing challenges in bowel preparation and follow-up care for colonoscopies. - Investigating innovative therapies like TNT for fecal incontinence. - Expanding the use of resmetirom for patients with advanced liver disease and cirrhosis. These studies underscore the ongoing efforts in the medical community to enhance patient outcomes and address significant gaps in care.

Alcohol Use Disorder (AUD) with Alcohol-Related Liver Disease (ArLD) - Pharmacology

Alcohol Use Disorder (AUD) and Alcohol-Related Liver Disease (ArLD) often coexist, presenting a complex clinical challenge that requires careful consideration of pharmacological treatment. Below is a detailed explanation starting from definitions, the need for pharmacological treatment, and how liver disease severity impacts drug toxicity and treatment choices. --- ### **Definitions** 1. **Alcohol Use Disorder (AUD):** - AUD is a medical condition characterized by an impaired ability to stop or control alcohol consumption despite adverse social, occupational, or health consequences. It is classified as mild, moderate, or severe based on criteria outlined in the DSM-5 (Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition). - Symptoms of AUD include strong cravings for alcohol, inability to reduce alcohol intake, withdrawal symptoms upon cessation, and continued use despite harm. 2. **Alcohol-Related Liver Disease (ArLD):** - ArLD refers to liver damage caused by chronic alcohol consumption. It encompasses a spectrum of liver conditions, including: - **Alcoholic Fatty Liver Disease:** Excess fat accumulation in liver cells due to alcohol consumption. - **Alcoholic Hepatitis:** Inflammation and damage to liver cells, often accompanied by jaundice and elevated liver enzymes. - **Alcoholic Cirrhosis:** End-stage liver disease characterized by extensive scarring and irreversible damage, leading to liver dysfunction. --- ### **Why Pharmacological Treatment is Needed** 1. **AUD Management:** - Pharmacological treatment for AUD aims to reduce alcohol cravings, prevent relapse, and support abstinence. Behavioral therapies alone may not be sufficient for many patients, especially those with moderate-to-severe AUD. - Alcohol cessation is critical for halting the progression of ArLD and improving liver function, as continued alcohol use accelerates liver injury. 2. **ArLD Management:** - In patients with ArLD, stopping alcohol consumption is the cornerstone of treatment. However, withdrawal symptoms and cravings can make it difficult for patients to achieve abstinence without pharmacological support. - Pharmacological interventions must be tailored to avoid exacerbating liver damage or worsening symptoms of hepatic encephalopathy. --- ### **Toxicity and Severity of Liver Disease** The severity of liver disease significantly impacts drug metabolism, toxicity, and treatment choices. Patients with ArLD often have impaired liver function, leading to altered drug clearance, increased risk of toxicity, and heightened sensitivity to medications. 1. **Hepatic Metabolism in ArLD:** - The liver is responsible for metabolizing many drugs. In ArLD, liver enzyme activity is reduced, leading to accumulation of drugs that are hepatically metabolized. - Decompensated cirrhosis (advanced liver disease with complications like ascites, jaundice, or hepatic encephalopathy) further impairs drug metabolism. 2. **Hepatic Encephalopathy Considerations:** - Hepatic encephalopathy is a neuropsychiatric complication of advanced liver disease caused by the accumulation of toxins (e.g., ammonia) due to impaired liver function. - Drugs with CNS depressant effects (e.g., benzodiazepines, baclofen, gabapentin) can exacerbate hepatic encephalopathy and must be used cautiously. 3. **Renal Function in ArLD:** - Patients with advanced liver disease often develop renal impairment (hepatorenal syndrome), which affects drug excretion. Renal function must be assessed before prescribing medications that are renally excreted. --- ### **Pharmacological Treatment Options for AUD with ArLD** #### 1. **Disulfiram**: - **Mechanism:** Disulfiram inhibits aldehyde dehydrogenase, causing acetaldehyde accumulation when alcohol is consumed, leading to unpleasant effects (e.g., flushing, nausea, vomiting). - **Contraindication:** Disulfiram is contraindicated in patients with liver disease due to its potential for hepatotoxicity and risk of worsening liver injury. It should not be used in patients with ArLD. #### 2. **Naltrexone**: - **Mechanism:** Naltrexone is an opioid antagonist that reduces alcohol cravings and the rewarding effects of alcohol. - **Caution:** Naltrexone is metabolized by the liver and should be avoided in decompensated cirrhosis due to impaired metabolism and increased toxicity risk. It can be considered in patients with mild liver dysfunction but requires close monitoring. #### 3. **Acamprosate**: - **Mechanism:** Acamprosate modulates glutamatergic neurotransmission to reduce alcohol cravings and support abstinence. - **Safety:** Acamprosate is considered the safest pharmacological agent for AUD in patients with liver disease as it is not hepatically metabolized. However, it is renally excreted and requires dose adjustment in renal impairment. #### 4. **Benzodiazepines**: - **Use:** Benzodiazepines are often used for managing alcohol withdrawal symptoms, which can include seizures, agitation, and delirium tremens. - **Preferred Agents:** Short-acting benzodiazepines like **lorazepam** and **oxazepam** are safer choices in patients with liver disease as they are less dependent on hepatic metabolism. - **Avoid Long-Acting Benzodiazepines:** Long-acting agents such as diazepam and chlordiazepoxide should be avoided in decompensated cirrhosis due to increased risk of toxicity. #### 5. **Baclofen**: - **Mechanism:** Baclofen is a GABA-B receptor agonist that reduces alcohol cravings and promotes abstinence. - **Caution:** Baclofen can exacerbate hepatic encephalopathy due to its CNS depressant effects. It should be used cautiously in patients with advanced liver disease. #### 6. **Gabapentin and Topiramate**: - **Mechanism:** Gabapentin and topiramate are anticonvulsant medications that have shown efficacy in reducing alcohol cravings. - **Caution:** Both drugs can worsen hepatic encephalopathy and require careful monitoring in patients with ArLD. --- ### **Key Considerations** 1. **Individualized Treatment:** - Treatment must be tailored to the severity of liver disease, renal function, and the presence of complications like hepatic encephalopathy. - Non-pharmacological interventions (e.g., counseling, support groups) should be integrated into the treatment plan. 2. **Monitoring:** - Regular monitoring of liver and kidney function is essential to avoid drug toxicity and ensure safe use of medications. 3. **Abstinence as the Goal:** - Complete alcohol cessation is critical for improving liver function and preventing progression of ArLD. - Pharmacological agents should be used as adjuncts to support abstinence and reduce relapse risk. --- ### **Summary** Patients with AUD and ArLD require careful pharmacological management due to altered drug metabolism, toxicity risks, and potential exacerbation of hepatic encephalopathy. While acamprosate is the safest option for AUD in liver disease, other medications like naltrexone, baclofen, and benzodiazepines may be considered with appropriate precautions. Disulfiram is contraindicated in liver disease, and long-acting benzodiazepines should be avoided. Renal function and liver disease severity must be evaluated before prescribing any medication.

The role of copper dysregulation in Wilson disease

Copper dysregulation plays a central role in the pathogenesis of Wilson disease (WD). The disease arises from the body’s inability to regulate copper levels, leading to its accumulation and subsequent toxicity. Below is a detailed explanation of how copper dysregulation contributes to WD: ### 1. **Dysfunctional Copper Regulation:** - In healthy individuals, copper homeostasis is tightly regulated. Excess copper is excreted into bile via the ATP7B protein, encoded by the ATP7B gene. However, in Wilson disease, mutations in the ATP7B gene impair the function of this protein, disrupting copper excretion. - This dysfunction results in copper accumulation in hepatocytes (liver cells), as the body cannot eliminate the excess copper effectively. ### 2. **Pathogenic Mechanism:** - The inability to excrete copper into bile leads to copper buildup in the liver. Over time, hepatocellular copper storage exceeds the liver's capacity, causing lysosomal toxicity and liver damage. - As hepatocytes become damaged, free copper is released into the bloodstream, leading to systemic toxicity. This free copper is highly reactive and harmful to various tissues. ### 3. **Copper Toxicity and Free Radicals:** - The cuprous ion (Cu⁺), the reduced form of copper, is highly reactive and generates free radicals. These free radicals cause oxidative stress and cellular damage unless copper is safely bound to intracellular chaperones. - In Wilson disease, the lack of proper copper regulation allows free copper to accumulate, leading to oxidative damage in the liver, brain, and other organs. ### 4. **Systemic Effects of Copper Dysregulation:** - Once free copper is released from damaged liver cells, it enters the bloodstream and causes toxicity in other tissues: - **Red Blood Cells:** Free copper damages red blood cells, leading to hemolysis (destruction of red blood cells). - **Brain:** Copper deposition in the brain, particularly in the basal ganglia, leads to neurological and psychiatric symptoms, such as movement disorders, tremors, and mood changes. - The systemic effects of copper dysregulation are responsible for the multi-organ manifestations of Wilson disease. ### 5. **Diagnostic Indicators of Copper Dysregulation:** - Key diagnostic markers of copper dysregulation in Wilson disease include: - **Decreased ceruloplasmin levels:** Ceruloplasmin is the major copper-binding protein in plasma, but its levels are low in WD. However, it plays no direct role in copper metabolism. - **Elevated non-ceruloplasmin-bound copper (free copper):** This form of copper is toxic and contributes to tissue damage. - **Increased urinary copper excretion:** Urinary copper levels exceeding 100 μg/day are a hallmark of Wilson disease. - **Exchangeable copper (CuEXC):** This is a newer diagnostic marker that measures the bioavailable, toxic form of copper. A ratio of exchangeable copper (REC) >18.5% is highly indicative of WD. ### 6. **Clinical Consequences of Copper Dysregulation:** - The inability to regulate copper leads to two major patterns of organ damage: - **Liver Damage:** Chronic copper accumulation in the liver causes inflammation, fibrosis, cirrhosis, and, in severe cases, fulminant hepatic failure. Fulminant Wilson disease is a rare, rapidly progressive form of the disease that can lead to death without emergency liver transplantation. - **Neurological and Psychiatric Symptoms:** Copper deposition in the brain, particularly in the basal ganglia, results in movement disorders (e.g., tremors, dystonia, and rigidity), cognitive impairment, and psychiatric disturbances. ### 7. **Therapeutic Implications:** - The cornerstone of Wilson disease management is reducing toxic free copper levels to prevent irreversible organ damage. This is achieved through: - **Chelation Therapy:** Medications like D-penicillamine and trientine bind to free copper, facilitating its excretion through urine. - **Zinc Therapy:** Zinc induces the production of intestinal metallothionein, which blocks copper absorption from the diet and reduces the amount of free copper in the body. - **Combination or Sequential Therapy:** Depending on disease severity and side effects, chelators and zinc can be used together or alternated. - **Liver Transplantation:** In cases of fulminant liver failure or advanced liver disease, transplantation may be the only life-saving option. - **Gene Therapy:** Experimental ATP7B gene therapy offers hope for restoring copper transport in the future, although it is still in early stages of development. ### 8. **Importance of Early Detection:** - Early detection of copper dysregulation is critical to prevent severe and irreversible damage to the liver and brain. Family screening and biochemical testing can identify at-risk individuals, enabling early intervention and treatment. ### Core Message: The primary defect in Wilson disease is a failure of copper excretion due to ATP7B gene mutations, leading to copper dysregulation. This results in toxic copper accumulation in the liver, release into the bloodstream, and subsequent damage to multiple organs, including the liver, brain, and red blood cells. Early diagnosis and treatment aimed at reducing toxic free copper are essential to prevent life-threatening complications and improve outcomes for individuals with Wilson disease.

Molecular basis of alcohol abstinence and relapse in alcohol-associated liver disease

The molecular basis of alcohol abstinence and relapse in alcohol-associated liver disease (ALD) involves complex interactions between the gut-liver-brain axis, immune system, neurotransmitters, and signaling pathways. Here is an in-depth explanation: ### **1. Alcohol Abstinence and Its Molecular Benefits** Sustained alcohol abstinence is critical for improving survival and reducing the progression of ALD. Molecular mechanisms underlying the benefits of abstinence include: #### **Gut Health and Microbiota Restoration** - **Microbiota Composition:** Alcohol disrupts the gut microbiota, leading to dysbiosis, increased intestinal permeability, and systemic inflammation. Abstinence allows the gut microbiota to recover, restoring microbial diversity and reducing harmful bacterial translocation. - **Bile Acid Metabolism:** Abstinence improves bile acid metabolism, which is essential for maintaining liver and gut health. #### **Barrier Function** - **Intestinal Barrier:** Ethanol damages the intestinal barrier, increasing bacterial translocation and systemic inflammation. Abstinence helps repair the intestinal epithelial lining and reduces endotoxemia. - **Blood-Brain Barrier:** Abstinence improves the integrity of the blood-brain barrier, reducing neuroinflammation and protecting brain health. #### **Reduction in Inflammation** - Chronic alcohol consumption triggers immune activation, including Kupffer cell activation, Toll-like receptor (TLR) signaling, and cytokine release (e.g., IL-1, IL-6, TNF-α). Abstinence reduces these inflammatory pathways, decreasing hepatic fibrosis and neuroinflammation. #### **Extracellular Vesicles (EVs):** - Abstinence reduces the release of extracellular vesicles (EVs) that carry inflammatory and fibrotic signals, mitigating liver injury and systemic inflammation. #### **Neuroendocrine Regulation** - Abstinence helps normalize dysregulated neuroendocrine signals, such as ghrelin and glucagon-like peptide-1 (GLP-1), which influence alcohol craving and consumption. --- ### **2. Molecular Basis of Relapse** Relapse in ALD is influenced by dysregulated reward and stress circuits, immune activation, and gut-liver-brain interactions. Key molecular mechanisms include: #### **Neurobiology of Addiction** - **Maladaptive Reward Circuits:** AUD involves alterations in reward pathways mediated by neurotransmitters like dopamine, GABA, and glutamate. Chronic alcohol use sensitizes these circuits, making individuals more prone to relapse. - **Stress Circuits:** Dysregulated stress responses mediated by the hypothalamic-pituitary-adrenal (HPA) axis contribute to relapse, especially during periods of emotional distress. #### **Gut-Liver-Brain Axis** - **Microbiota Dysbiosis:** Persistent gut microbiota disruption and systemic inflammation increase the risk of relapse by interfering with brain signaling and promoting alcohol cravings. - **Bile Acid Signaling:** Altered bile acid metabolism may impact brain reward pathways, sustaining cravings. #### **Immune Activation** - Chronic alcohol use primes the innate and adaptive immune system, leading to persistent inflammation even after abstinence. Cytokines like IL-1, IL-6, and TNF-α, as well as TLR4 signaling, are implicated in relapse risk. #### **Extracellular Vesicles (EVs):** - EVs released during chronic alcohol use may persist and act as mediators of relapse by carrying signals that promote inflammation and liver injury. #### **Neuroendocrine Dysregulation** - **Ghrelin Receptor Activation:** Ghrelin, a hunger hormone, is implicated in alcohol craving and relapse. Dysregulation of ghrelin signaling can drive alcohol-seeking behavior. - **GLP-1 Dysregulation:** Impaired GLP-1 signaling may reduce the ability to suppress alcohol consumption. --- ### **3. Therapeutic Molecular Targets** Emerging therapies aim to modulate the molecular pathways involved in abstinence and relapse: #### **Gut-Based Therapies** - **Probiotics:** Probiotics help restore gut microbiota composition, reduce systemic inflammation, and improve gut barrier integrity, which may lower relapse risk. - **Fecal Microbiota Transplantation (FMT):** Preliminary studies suggest that FMT can reduce alcohol cravings and improve liver health. #### **Immune Modulation** - **Targeting Inflammatory Pathways:** Toll-like receptors (e.g., TLR4), cytokines (IL-1, IL-6, TNF-α), and phosphodiesterase inhibitors are potential therapeutic targets for reducing inflammation and relapse risk. - **PPARs (Peroxisome Proliferator-Activated Receptors):** PPAR agonists show promise in reducing liver inflammation and fibrosis. #### **Neuroendocrine Pathways** - **Ghrelin Receptor Antagonists:** Blocking ghrelin receptors may help reduce alcohol cravings and relapse. - **GLP-1 Agonists:** Drugs like semaglutide and exenatide are being tested for their ability to suppress alcohol consumption and improve metabolic health. #### **Mineralocorticoid Receptor Modulation** - **Spironolactone:** Traditionally used for cirrhosis management, spironolactone shows potential in lowering alcohol intake by modulating stress circuits. --- ### **4. Implications for Liver Transplantation** - **Pre-Transplant Abstinence:** Abstinence before liver transplantation reduces systemic inflammation and improves outcomes by lowering relapse risk. - **Post-Transplant Abstinence:** Sustained abstinence post-transplant is critical for preventing graft injury and improving long-term survival. - **Reevaluation of “6-Month Rule”:** Rigid abstinence periods before transplantation are being reconsidered, emphasizing individualized approaches based on molecular and clinical markers. --- ### **5. Future Directions** Advancing the understanding of molecular mechanisms underlying alcohol abstinence and relapse in ALD requires: - **Integrative Management:** Combining psychological, pharmacological, and gut-based therapies for precision medicine. - **Early Detection:** Identifying at-risk individuals through biomarkers like EVs, cytokines, and microRNAs. - **Genetic Studies:** Exploring genetic predispositions to AUD and ALD for personalized interventions. - **Rigorous Randomized Controlled Trials (RCTs):** Testing novel therapies targeting gut-liver-brain axis, immune pathways, and neuroendocrine systems. In summary, alcohol abstinence improves gut, liver, and brain health at the molecular level by reducing inflammation, restoring barrier function, and normalizing neuroendocrine signaling. Relapse, on the other hand, is driven by dysregulated reward circuits, immune activation, and gut-liver-brain interactions. Targeting these pathways through innovative therapies holds promise for improving outcomes in ALD and AUD management.

Differential Diagnosis of Intestinal Tuberculosis (ITB) vs Crohn’s Disease (CD)

Differentiating Intestinal Tuberculosis (ITB) from Crohn’s Disease (CD) is one of the most challenging diagnostic dilemmas in clinical practice, particularly in tuberculosis (TB)-endemic regions. Both disorders share overlapping clinical, imaging, endoscopic, and histological features, but several distinct differences can guide the differential diagnosis. Below is a comprehensive breakdown of the key aspects for distinguishing ITB from CD: --- ### 1. **Epidemiological Context** - **ITB**: More common in TB-endemic regions such as India, China, South Korea, Latin America, and South Africa. - **CD**: Predominates in Western countries but is increasingly being reported in Asia, leading to overlap in these regions. --- ### 2. **Clinical Features** - **Common Symptoms**: Both ITB and CD present with abdominal pain, obstruction, fever, anorexia, weight loss, and anemia, making symptoms alone insufficient for diagnosis. - **Distinct Clues**: - **ITB**: Ascites and pulmonary symptoms (e.g., cough, hemoptysis) are more common. - **CD**: Diarrhea, rectal bleeding, perianal disease, and extraintestinal manifestations (e.g., skin, joints, eyes, hepatobiliary involvement) are more suggestive of CD. - **Disease Duration**: ITB typically has a relatively acute course, while CD tends to have a more chronic and relapsing course. --- ### 3. **Imaging Features (CT Enterography)** - **ITB**: - Necrotic lymph nodes (central low attenuation with peripheral rim enhancement). - Ileocecal involvement (most common site). - Ascites and omental thickening. - **CD**: - Skip lesions (discontinuous areas of inflammation). - Long-segment disease. - Comb sign (engorged vasa recta). - Mesenteric fat proliferation ("creeping fat"). - **Quantitative Biomarker**: - A visceral-to-subcutaneous fat ratio >0.63 on CT favors CD with ~80% sensitivity and specificity. --- ### 4. **Chest Imaging** - **ITB**: CT chest can double diagnostic sensitivity by identifying miliary lesions or necrotic mediastinal lymph nodes. Chest radiographs alone are insufficient. - **CD**: Normal chest imaging; no specific findings. --- ### 5. **Endoscopic Findings** - **ITB**: - Transverse ulcers. - Gaping ileocecal valve. - **CD**: - Longitudinal ulcers. - Cobblestoning. - Aphthous ulcers. - Skip lesions. - **Granuloma Distribution**: - **ITB**: Granulomas are localized to the ileocecal region. - **CD**: Granulomas can occur in any bowel segment, often involving the rectosigmoid region, which is rarely affected in ITB. --- ### 6. **Histopathology** - **ITB**: - Caseating granulomas (highly specific but low sensitivity, 13–40%). - **CD**: - Non-caseating granulomas that are small, poorly organized, or isolated. - **Key Difference**: - Caseating granulomas are a hallmark of ITB, while non-caseating granulomas are more typical of CD. --- ### 7. **Microbiological Tests** - **ITB**: - Acid-Fast Bacilli (AFB) stain and culture, GeneXpert, and PCR are specific but have low sensitivity (<25%). - GeneXpert MTB/RIF is preferred for rapid detection. - **CD**: - No specific microbiological test available. --- ### 8. **Serological and Immune Markers** - **ITB**: - Interferon-Gamma Release Assay (IGRA) and Tuberculin Skin Test (TST) detect latent TB, not active ITB. - **CD**: - Limited utility of IGRA and TST in distinguishing CD from ITB in TB-endemic regions. - **Emerging Markers**: - Novel biomarkers like FOXP3+ Tregs and metabolomics show promise but remain experimental. --- ### 9. **Therapeutic Anti-TB Therapy (ATT) Trial** - In TB-endemic regions, when diagnostic uncertainty persists, a therapeutic trial of anti-TB therapy (ATT) is initiated to avoid the risk of giving immunosuppressants to undiagnosed ITB patients. - **Response to ATT**: - **ITB**: Clinical improvement and mucosal healing after 8–12 weeks strongly suggest ITB. - **CD**: May show temporary symptom relief but no endoscopic healing. - **Non-Response to ATT**: - If no healing is observed after 8–12 weeks and multidrug-resistant TB (MDR-TB) is excluded, the diagnosis should shift toward CD, and CD-specific therapy (immunosuppressants/biologics) should be initiated. --- ### 10. **Follow-Up and Monitoring** - **ITB**: - Fecal calprotectin decline at 2 months and definitive mucosal healing at 6 months confirm the diagnosis. - **CD**: - Persistent ulcers or high fecal calprotectin levels favor CD. --- ### 11. **Surgical or Laparoscopic Biopsies** - Considered in cases where endoscopic or imaging-guided sampling fails, especially before initiating biologic therapy or in cases of inaccessible lesions. --- ### 12. **Role of Artificial Intelligence (AI) and Predictive Models** - Machine learning models combining clinical, imaging, and histological data (e.g., Limsrivilai Bayesian model, Crohn’s Aid app) have achieved up to 92% diagnostic accuracy and show promise in aiding diagnosis in TB-endemic settings. --- ### Summary Table: Key Differences Between ITB and CD | Feature | ITB | CD | |-----------------------------|-------------------------------------------|------------------------------------------| | **Epidemiology** | TB-endemic regions | Western countries, increasing in Asia | | **Disease course** | Acute | Chronic | | **Symptoms** | Pulmonary symptoms, ascites | Diarrhea, rectal bleeding, perianal disease, extraintestinal manifestations | | **Endoscopic findings** | Transverse ulcers, gaping ileocecal valve | Longitudinal ulcers, cobblestoning, skip lesions | | **Histopathology** | Caseating granulomas | Non-caseating granulomas | | **Imaging (CTE)** | Necrotic lymph nodes, ascites, ileocecal involvement | Skip lesions, comb sign, mesenteric fat proliferation | | **Microbiological tests** | AFB stain, GeneXpert, PCR (low sensitivity) | Not applicable | | **Response to ATT** | Mucosal healing | No healing | | **Fecal calprotectin** | Decline supports ITB | Persistent elevation favors CD | --- ### Conclusion: The differential diagnosis of ITB and CD requires a multimodal approach that integrates clinical, imaging, endoscopic, histological, and microbiological findings. In cases of diagnostic uncertainty, a therapeutic trial of ATT and close follow-up with fecal calprotectin levels or repeat colonoscopy can help clarify the diagnosis. Emerging biomarkers and AI-based predictive models hold promise for improving diagnostic accuracy in the future.

Albumin-corrected anion gap (ACAG) and mortality in GI bleeding

The **albumin-corrected anion gap (ACAG)** is a calculated laboratory parameter that adjusts the traditional anion gap (a measure of the difference between measured cations and anions in the blood) for serum albumin levels. Albumin is a negatively charged protein that significantly contributes to the anion gap; therefore, low albumin levels (commonly seen in critically ill patients) can lead to an underestimation of the anion gap. Correcting the anion gap for albumin levels provides a more accurate reflection of a patient's acid-base status, which is crucial for assessing critical illnesses, including gastrointestinal bleeding (GIB). ### Role of ACAG in Mortality in GI Bleeding: Recent research, including a retrospective cohort study analyzing data from the **Medical Information Mart for Intensive Care IV (MIMIC-IV)** database, has demonstrated that ACAG is a **powerful prognostic biomarker** for predicting mortality in critically ill patients with gastrointestinal bleeding (GIB). #### Key Findings: 1. **Association with Mortality**: - Elevated ACAG levels (≥20) were found to be **independently associated** with increased all-cause mortality in both short- and long-term follow-ups. This was confirmed through multivariable Cox proportional hazards regression analysis, with all results showing statistical significance (P < .001). - Patients with higher ACAG levels had significantly lower survival rates compared to those with lower ACAG levels, as shown by Kaplan-Meier survival curves. 2. **Optimal Cutoff for Mortality Prediction**: - Using X-tile analysis, researchers identified an **ACAG value of ≥20** as the optimal threshold for predicting 28-day mortality in GIB patients. This cutoff point allows clinicians to stratify patients into high-risk and low-risk categories. 3. **Predictive Accuracy**: - The study demonstrated that ACAG has **moderate discriminative ability** for mortality prediction, as evidenced by receiver operating characteristic (ROC) curves. - A predictive nomogram model incorporating ACAG achieved strong performance, with area under the curve (AUC) values for 30-, 90-, 180-, and 365-day mortality all approximately 0.80. This indicates robust predictive accuracy for both short- and long-term outcomes. 4. **Consistency Across Subgroups**: - Subgroup analyses revealed that the prognostic value of ACAG remained consistent across diverse patient populations, further supporting its reliability as a universal risk marker in critically ill GIB patients. 5. **Linear Relationship with Mortality Risk**: - Restricted cubic spline models confirmed a linear relationship between increasing ACAG levels and higher mortality risk. This suggests that as ACAG rises, the likelihood of mortality increases proportionally. #### Clinical Implications: - **Prognostic Biomarker**: ACAG can serve as a reliable and independent biomarker for identifying critically ill GIB patients at higher risk of mortality. - **Risk Stratification**: Incorporating ACAG into clinical risk assessment tools can enhance early identification of high-risk patients, allowing for timely and targeted interventions. - **Guidance for Treatment**: By identifying patients with elevated ACAG, clinicians can prioritize aggressive management strategies to address underlying metabolic disturbances and improve patient outcomes. #### Summary: The albumin-corrected anion gap (ACAG) has emerged as a critical tool for predicting mortality in gastrointestinal bleeding. Elevated ACAG (≥20) is strongly associated with worse outcomes, including both short- and long-term mortality. Its integration into clinical practice could significantly improve risk stratification and guide the management of critically ill GIB patients.

Recent advances in the treatment of chronic hepatitis C

Recent advances in the treatment of chronic hepatitis C (HCV) have transformed the landscape of care for this disease. The introduction of direct-acting antivirals (DAAs) has been the cornerstone of this revolution, offering highly effective, well-tolerated, and simplified treatment options for patients across all HCV genotypes. Below is a detailed overview of the most recent advances and their implications: --- ### **1. Direct-Acting Antivirals (DAAs): A Game-Changer** DAAs target specific steps in the HCV life cycle, such as viral replication, and have demonstrated cure rates exceeding 95% in most patient populations. The key advancements include: #### **Pan-Genotypic Regimens** - **Sofosbuvir/Velpatasvir**: Approved as a once-daily combination pill, it is effective against all six major HCV genotypes. This regimen has streamlined therapy, reducing the need for genotype testing prior to treatment initiation. - **Glecaprevir/Pibrentasvir**: Another pan-genotypic regimen, this combination is particularly advantageous for patients with chronic kidney disease, as it does not require renal dose adjustment. It also offers an 8-week treatment duration for most patients, making it highly convenient. #### **Retreatment Options** For patients who fail initial DAA therapy, **Sofosbuvir/Velpatasvir/Voxilaprevir** has emerged as an effective retreatment option. It provides high cure rates even in cases of prior treatment failure, including those with resistance-associated variants. #### **Shortened Treatment Durations** Recent trials have explored ultra-short regimens (e.g., 6 weeks) for certain patient populations with low baseline viral loads and no cirrhosis. While not yet widely adopted, these studies highlight the potential for further simplification of therapy. --- ### **2. Individualized Treatment Strategies** Special populations, such as those with advanced liver disease or comorbidities, require tailored approaches. Recent guidelines, including those from the **American Association for the Study of Liver Diseases (AASLD)** and the **European Association for the Study of the Liver (EASL)**, emphasize individualized care: #### **Decompensated Cirrhosis** - Patients with decompensated cirrhosis (Child-Pugh B or C) benefit from regimens such as **Sofosbuvir/Velpatasvir**, often combined with ribavirin. DAAs are preferred over interferon-based therapies due to their superior safety profile. #### **Chronic Kidney Disease** - Glecaprevir/Pibrentasvir is the regimen of choice for patients with end-stage renal disease, as it is not renally excreted and does not require dose adjustment. #### **HIV/HCV Coinfection** - DAAs are highly effective in HIV/HCV coinfected individuals, achieving similar cure rates as in HCV-monoinfected patients. Drug-drug interactions with antiretroviral therapy must be carefully managed. #### **Post-Liver Transplant Patients** - DAAs are safe and effective in patients post-liver transplant, with regimens tailored to avoid drug-drug interactions with immunosuppressive medications. #### **Hepatocellular Carcinoma (HCC)** - Patients with HCC undergoing curative therapies (e.g., resection or ablation) can benefit from DAA treatment to prevent reinfection and reduce liver-related morbidity. --- ### **3. Addressing Special Populations and Challenges** Despite the success of DAAs, vulnerable populations remain challenging to treat: - **People Who Inject Drugs (PWID)**: This group faces barriers such as stigma, lack of access to care, and reinfection risk. Expanding harm reduction strategies (e.g., needle exchange programs) and providing integrated care models are essential. - **Migrants and Underserved Groups**: Screening and linkage to care are often inadequate in these populations. Community-based interventions and culturally sensitive approaches are critical. - **Patients with Poor Hepatic Function**: Advanced liver disease may limit the use of certain regimens, requiring careful monitoring and adjunctive therapies. --- ### **4. Advances in Screening and Diagnosis** Improving screening and diagnosis is vital to achieving global eradication goals. Recent developments include: - **Point-of-Care Testing**: Rapid diagnostic tests (RDTs) enable on-the-spot detection of HCV antibodies, facilitating immediate linkage to care. - **Non-Invasive Biomarkers**: Tools like transient elastography (FibroScan) and serum biomarkers (e.g., APRI, FIB-4) are increasingly used to assess liver fibrosis and eliminate the need for invasive biopsies. --- ### **5. Global Eradication Goals** The World Health Organization (WHO) has set a target to eliminate HCV as a public health threat by 2030. This requires: - **Strengthening Screening Programs**: Universal screening, particularly in high-risk populations, is critical for early detection. - **Expanding Access to DAAs**: Cost reduction and inclusion of DAAs in national health programs are essential for widespread treatment availability. - **Optimizing Retreatment Strategies**: For patients who fail initial therapy, retreatment regimens such as Sofosbuvir/Velpatasvir/Voxilaprevir are crucial. --- ### **6. Recent Clinical Trials** Several landmark clinical trials have shaped the current treatment paradigm: - **POLARIS-1 and POLARIS-4 Trials**: Demonstrated the efficacy of Sofosbuvir/Velpatasvir/Voxilaprevir in retreatment scenarios. - **EXPEDITION-1 Trial**: Highlighted the safety and efficacy of Glecaprevir/Pibrentasvir in patients with severe renal impairment. - **ASTRAL Trials**: Validated the pan-genotypic efficacy of Sofosbuvir/Velpatasvir across diverse patient populations. --- ### **7. Future Directions** Ongoing research aims to further improve HCV therapy: - **Development of Vaccines**: Although no approved vaccine exists, efforts are underway to develop preventive vaccines targeting conserved viral epitopes. - **Ultra-Short Regimens**: Studies are exploring shorter treatment durations for select patients, potentially reducing costs and improving adherence. - **Combination Therapies**: Investigating DAAs in combination with immune modulators to enhance cure rates in difficult-to-treat populations. --- ### **Conclusion** The treatment of chronic hepatitis C has advanced significantly with the advent of DAAs, offering hope for global eradication. However, challenges such as treatment access, reinfection in high-risk groups, and optimizing care for special populations persist. Addressing these gaps through comprehensive screening, individualized treatment strategies, and continued innovation is essential to achieving the WHO’s 2030 elimination goals.