Delirium: Acute Brain Failure and How to Reason Through It

 Delirium is not “confusion”. It is acute failure of the brain’s ability to maintain homeostasis, usually triggered by illness elsewhere in the body. When attention collapses, the cortex is signalling that its metabolic, inflammatory, or neurotransmitter environment has become unsafe.

Unlike dementia, which reflects slow structural decline, delirium develops over hours to days, fluctuates, and is usually reversible when the underlying insult is corrected.

Delirium is common, dangerous, and frequently missed — especially the quiet forms.

Dementia: When Cognitive Networks Begin to Fail

 Mrs K is a 72-year-old retired teacher who presents to her GP after becoming lost while driving home from the supermarket she has visited weekly for 20 years.

Her daughter reports that:

• she repeats questions within the same conversation
• she has stopped attending social activities
• she struggles to organise meals she previously prepared routinely

Her neurological examination is normal.

Her blood tests are normal.

Her CT scan is reported as “age-appropriate”.

So what is actually going wrong?

Structure and Function of CNS Motor and Sensory Tracts 🧠

 👋 Ready to dive into the highways of the nervous system? Buckle up, because today we’re exploring the Structure and Function of CNS Motor and Sensory Tracts! 💨

Your brain and spinal cord are like a highly-organized city, and these tracts are the express lanes that carry critical information to and from your body. Let’s break it down in detail:

Stroke: Risk Factors, Epidemiology 🧠

Let’s dive deeper into stroke — a major global health burden and one of the leading causes of death and disability. Its impact spans acute care, rehabilitation, and long-term health outcomes, making it a cornerstone topic in medical education and public health.

Understanding the epidemiology, risk factors, and pathophysiology of stroke is essential not only for diagnosis and treatment but also for effective prevention strategies. Stroke is not a single disease but a spectrum of vascular events with diverse presentations, underlying mechanisms, and prognoses.

Here’s a structured breakdown to guide your understanding:

• Stroke affects over 15 million people annually worldwide, with rising incidence in low- and middle-income countries.

• In Australia, stroke is a leading cause of adult disability, with over 400,000 people living with its effects.

• Ischaemic strokes account for ~85% of cases, while haemorrhagic strokes (intracerebral and subarachnoid) make up the remainder.

• Age is the strongest predictor: risk doubles with each decade after 55.

• Rural and remote populations often face delayed access to acute stroke care and rehabilitation services, contributing to worse outcomes.

Read on for risk factors and more !

Part 2: Brain Blood Supply – Clinical Correlations & Stroke Syndromes!

Now that you’ve explored the intricate anatomy of the brain’s blood supply — from the Circle of Willis to the branching cerebral arteries — it’s time to connect that knowledge to clinical practice. Understanding which regions are perfused by each artery allows you to localise neurological deficits with precision, especially in acute stroke presentations.

Each arterial territory corresponds to distinct functional areas of the brain, so when blood flow is disrupted, the resulting symptoms offer vital clues. Whether it’s a sudden onset of aphasia, hemianopia, or ataxia, recognising the vascular pattern behind these signs helps clinicians rapidly identify the affected region, initiate appropriate imaging, and guide timely intervention.

Let’s walk through the major cerebral arteries and examine how their territories shape the clinical picture in stroke and other vascular syndromes.

Clinical Presentation of Stroke: Pathophysiology & Key Differences 🧠💥

Stroke is one of the leading causes of death and disability worldwide — a true medical emergency where every minute counts. Whether due to vascular occlusion or haemorrhage, the resulting neurological injury demands timely intervention and a solid understanding of underlying mechanisms. 

We'll explore the key concepts behind stroke presentation and mechanisms — from FAST signs to cellular cascades — to illuminate what’s happening beneath the surface. 🧠⚡

Part 1: Brain Blood Supply – The Anatomy Behind the Magic! 🧠

Today we’re exploring the vascular anatomy of the brain—because the brain may run the show, but without blood, it’s lights out! 💡 

Here’s some basics

🧠 Seeing the Brain in Action: A Beginner’s Guide to Neuroimaging

You’ve learned to listen to the brain’s electrical activity with EEG — now it’s time to see it. Neuroimaging gives us a window into the brain’s structure, guiding diagnosis, understanding, and treatment. 

But no single scan tells the full story. Each modality sees the brain differently — some reveal anatomy, others show activity — and choosing the right one means knowing what you’re asking, and what the scan can answer. This is just a primer to get you started - imaging is a long journey of learning to come !

🧠 How Do We Listen to the Brain? A Beginner’s Guide to EEG

 Electroencephalography (EEG) is like eavesdropping on a conversation happening in your cerebral cortex. But instead of words, it uses electrical signals—and the patterns those signals make can tell us a lot about how the brain is functioning… or misfiring.

This post will outline the major important features of the EEG and how it can help us to understand the function, and dysfunction, of the brain. 

💊 Neurotransmitters on drugs: How alcohol, medications & other substances affect the CNS

Every action in the brain - whether catching a ball, calming a panic attack, or waking from anaesthesia - starts at the synapse. In physiology, you’ve already met the major neurotransmitters: GABA, glutamate, dopamine, serotonin, acetylcholine, and noradrenaline.

Now it’s time to see these in clinical action. If you haven't already read it, go back and check out the Neurotransmitters 101 post, it will help it all make sense. 

Many drugs and substances - from prescription medications to recreational drugs - alter the brain’s electrochemical balance. They dial neurotransmitter signalling up or down, leading to effects that are therapeutic, recreational, harmful, or all three. Understanding how they work builds your clinical intuition - and helps you spot mechanisms behind both therapeutic effects and side effects.

 We’ll explore how each class works, what effects they trigger, and where they act in the neural circuit. Consider this your pharmacological map of the CNS - designed for clarity, clinical context, and curiosity.

🧠 Principles of Seizure Management

 Seizures are a common clinical presentation—but behind each episode lies a nuanced web of causes, classifications, and considerations. Effective care begins with pattern recognition, cause exploration, and clinical prioritisation. 

This guide walks through how clinicians approach seizure care—from the first event to long-term planning—by connecting symptoms to anatomy, treatment, and safety.

Clinical Cases in Seizure Localisation

 Recognising seizure types isn't just about memorising lists — it's about observing patterns, interpreting subtle clues, and linking symptoms to functional neuroanatomy. The ability to reason clinically, even from brief descriptions, is one of the most important skills you’ll develop as a future doctor. 

In this post, we’ll walk through a series of realistic case vignettes that should be a challenge for not just first years, but clinical second and third years as well. 

Take your time with each one — some may seem straightforward, others more ambiguous. That’s okay. Clinical reasoning is a skill, not an instinct — and every case you puzzle through builds it.

🧠 CONSCIOUSNESS (and how we can lose it)

 Consciousness might seem like something “obvious”—you know when you’re awake, alert, and aware. But understanding what consciousness is (from a medical perspective), and why it can be disrupted, is fundamental to learning clinical neurology and emergency medicine. Let’s build the foundation.

🧠 NEUROTRANSMITTERS 101: The Basics of Neurotransmission

 Ready to dive into the fascinating world of neurotransmitters? These tiny molecules are the chemical messengers that keep your nervous system humming—coordinating thoughts, movements, moods, and memories.

 Let’s explore how these molecules work and why they’re clinically meaningful. 🩺

Localisation of seizures 🧠

 When someone has a seizure, the symptoms can tell us more than just what happened — they give clues about where in the brain it happened. Seizure localisation is the art and science of mapping signs and behaviours to specific cortical regions. From staring spells to sudden muscle jerks, each presentation points to a unique neural epicentre. 

Understanding where seizures begin helps us decode the circuitry behind them, guides diagnosis, and even shapes treatment decisions. Let’s explore how brain geography becomes clinical insight.

Understanding Seizure Classification 🧠

Hey future doctors! 👋 Let's dive into the fascinating world of seizure classification. 🩺✨

Seizures reflect abnormal electrical activity in the brain, but they don't all look alike. Some involve convulsions, others just subtle lapses in awareness. Classification matters—not just for tidy documentation, but for tailoring treatment and understanding prognosis.

🔬 Pathophysiology of Seizures: What’s Going Wrong?

 Seizures are caused by abnormal, excessive, synchronous electrical activity in groups of neurons. Seizures are like a power surge in the brain. Instead of orderly, purposeful neural signals, you get a storm of chaotic, excessive firing across neuron groups. 

This hyperactivity disrupts normal function — from movement and sensation to awareness and behaviour.

🧠 From Cortex to Brainstem: Mapping the Machinery of Thought and Function

 The central nervous system (CNS) isn’t just a bundle of grey and white matter—it’s the command centre for sensation, movement, cognition, and survival. Understanding its architecture sets the stage for recognising how neurological damage unfolds in real patients.

Let’s take a tour through the cortex, subcortex, and brainstem—with just enough anatomical and functional depth to make it stick.

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.   🧠🌏

Back Pain: Chronic, Complex & Concerning (Part 2)

  

Welcome to Part 2 – let's move beyond the acute setting to focus on the challenges of chronic low back pain, the impact of psychosocial factors (yellow flags), and how to recognise red flags that may signal serious underlying pathology.