🩸 Understanding Upper vs Lower GI Bleeding: Pathophysiology & Clinical Clues

Gastrointestinal (GI) bleeding is a common and potentially serious problem in medicine. Some cases involve chronic, slow blood loss, leading to anaemia, while others can result in massive haemorrhage, requiring urgent intervention.

To effectively manage GI bleeding, doctors need to identify the source, which falls into two broad categories:

• Upper GI Bleeding (UGIB): 

• The bleeding comes from areas above the ligament of Treitz, meaning it starts in the oesophagus, stomach, or first part of the small intestine (duodenum).

• Lower GI Bleeding (LGIB): 

• The bleeding originates from below the ligament of Treitz, meaning it occurs in the jejunum, ileum, colon, or rectum.

Recognising whether the bleeding is from the upper or lower part of the digestive tract is critical for choosing the right treatment.

Understanding Lymphoma 🧬

 Lymphoma is a malignancy of lymphoid tissue, encompassing a diverse group of blood cancers originating in B cells, T cells, or (rarely) natural killer (NK) cells. Though primarily arising within lymph nodes, lymphomas can also involve the spleen, liver, bone marrow, gastrointestinal tract, or skin.

Acute and Chronic Leukaemias – A Clinical and Pathophysiological Guide 🩸

 Leukaemia refers to a group of blood cancers arising from abnormal proliferation of white blood cell precursors. The problem begins in the bone marrow, where mutations in haematopoietic stem or progenitor cells allow one clone to escape normal checks on growth and differentiation.

While the term leukaemia may sound singular, it actually encompasses a group of distinct diseases, each with its own biological behaviour, clinical features, and management principles. Chronic and acute leukemias are completely different diseases, and they progress at different speeds.

Over time — sometimes over days, sometimes years — these abnormal cells crowd out normal blood production, leading to anaemia, immunosuppression, and bleeding. Clinical presentations vary depending on which blood line is affected and how fast the disease progresses.

Understanding Anaemia: Types, Causes, and Pathophysiology

Anaemia is one of the most frequently encountered clinical problems, yet its underlying mechanisms are diverse. Defined as a reduction in haemoglobin concentration, red blood cell (RBC) count, or haematocrit below normal for age and sex, anaemia reflects a failure of oxygen delivery rather than a singular disease.

Understanding the Pathophysiology of Inflammatory Bowel Disease (IBD)

 Inflammatory bowel disease (IBD) consists of Crohn’s disease (CD) and ulcerative colitis (UC)—two chronic, immune-mediated disorders of the gastrointestinal tract. While their clinical presentations may overlap, their underlying mechanisms, immune responses, and structural involvement differ significantly.

The Lower Gastrointestinal Tract: Structure & Function in Nutrient Absorption

 The lower gastrointestinal (GIT) tract plays a critical role in nutrient absorption, fluid balance, and waste excretion. It includes the small intestine (jejunum, ileum), large intestine (colon), rectum, and anus—each with unique structural and functional adaptations that optimise digestion and absorption.

Let’s explore the detailed mechanisms at work throughout this system.

Measles: A Primer for Medical Students 🦠

 Measles cases in the US are now over 1,000 cases across 30 states. 3 people have died in this outbreak and 130 have been hospitalised. And it is not slowing down. 

There is currently much discussion about measles worldwide, and most of you will have never seen a case of it  - but that certainly doesn't mean you can ignore it. Do so at your peril! 

Measles is a highly contagious viral disease that can cause severe complications and, in some cases, death - particularly in young children, immunocompromised individuals, and unvaccinated populations. Although now rare in Australia due to successful vaccination programs, measles remains a global health threat, with imported cases continuing to cause small outbreaks here.

Upper GI pharmacology - important classes of drugs to know

 Acid suppression therapy

Acid suppression therapy plays a central role in the management of a range of upper gastrointestinal conditions, including gastro-oesophageal reflux disease (GORD), peptic ulcer disease, and dyspepsia. By reducing gastric acid secretion, these therapies help relieve symptoms, promote mucosal healing, and prevent complications such as bleeding or strictures. 

With the widespread use of proton pump inhibitors (PPIs) and H2-receptor antagonists, it’s important for medical students and clinicians alike to understand their mechanisms, appropriate indications, and potential risks—especially given rising concerns about long-term use.

The symphony of digestion: Gastric acid, enzymes & cellular interplay

 The digestive system functions as a well-orchestrated biochemical network, where secretions from various cell types work in harmony to break down food, absorb nutrients, and regulate gastrointestinal function.

From parietal cells producing hydrochloric acid (HCl) to pancreatic acinar cells secreting digestive enzymes, each step of digestion stimulates and modulates the next, ensuring efficient processing of nutrients.

Mastering OSCEs and other clinical assessments: your mindset helps!

It's the beginning of "OSCE season" at UOW and for the next 2 months we will be evaluating the clinical skills of our medical students in these high stakes assessments. Clinical exams, especially OSCEs, challenge more than just knowledge—they also can test your ability to think under pressure, communicate effectively, and maintain composure in high-stress scenarios. They require students to perform procedures and demonstrate clinical skills, interact dynamically with patients, and showcase medical understanding along with confidence, competence and professionalism.

However, the pressure of being watched, the fear of forgetting key details, and the worry of making clinical errors can all contribute to performance anxiety. But the good news? These feelings are normal—and entirely manageable with the right approach. 

Helicobacter pylori: the microbe that changed Gastroenterology

 Helicobacter pylori (H.pylori) is a gram-negative, spiral-shaped bacterium that resides in the gastric mucosa, affecting nearly half the global population. While many infections remain asymptomatic, H. pylori is a key driver of gastritis, peptic ulcer disease, and even gastric cancer.

Haemostasis: Balancing Bleeding and Clotting in the Human Body 🩸

 Haemostasis is the body's finely tuned process of maintaining blood flow while preventing excessive bleeding or clot formation. It operates through a delicate equilibrium of pro-coagulant and anti-coagulant proteins, ensuring that blood remains fluid under normal conditions but can rapidly clot when injury occurs.

Pathophysiology of GORD: The Science Behind Acid Reflux

 

Gastro-oesophageal reflux disease (GORD) occurs due to chronic reflux of gastric contents into the oesophagus, leading to mucosal irritation, inflammation, and potential long-term complications.

 The key defect? Lower oesophageal sphincter (LOS) dysfunction, but several additional mechanisms contribute.

Barrett’s Oesophagus: Pathophysiology & Clinical Implications

Barrett’s oesophagus is a pre-malignant condition characterised by intestinal metaplasia of the normal stratified squamous epithelium in the oesophagus. 

This transformation occurs as a defensive response to chronic acid exposure, but paradoxically increases the risk of oesophageal adenocarcinoma.

NSAIDs & Your Stomach: What Every Med Student Should Know

Nonsteroidal anti-inflammatory drugs (NSAIDs)—such as ibuprofen, naproxen, and aspirin—are essential in clinical practice, but their effects on the gastric mucosa are often underestimated. A common belief is that taking NSAIDs with food reduces stomach irritation. But is this actually true? 

We have discussed this earlier in the week, so thought I would provide a bit more explanation ... featuring my favourite biochemical pathway!!! IYKYK 😁

Upper GI Bleeding: Causes, Investigations & Clinical Considerations

Upper gastrointestinal (GI) bleeding is a high-priority emergency that presents as haematemesis (vomiting blood) or melaena (black, tarry stools). Severity ranges from minor mucosal bleeds to life-threatening haemorrhages, requiring urgent assessment and intervention.

Social Determinants of Mental Health: Beyond Biology!

Mental health is shaped by far more than individual choices or biology—it’s profoundly influenced by the social determinants of health.   🧠🌏

Mastering the Upper Gastrointestinal Tract: Structure & Function

The upper GI tract plays a pivotal role in digestion, absorption, and gastrointestinal regulation. A thorough understanding of its anatomy and physiology is essential for diagnosing conditions ranging from GORD to pernicious anaemia.