Normal Pressure Hydrocephalus (NPH) - Urinary Incontinence, Ataxia, Dementia (memory loss) - Neuro

What is going on wonderful people, it's Medicosis Perfect, Schneider's World, medicine makes perfect sense. Welcome back to my neurology playlist. In previous videos we talked about neuroanatomy and neurophysiology, as well as neuropharmacology. Then we started talking about diseases or pathology. We talked about the levels of consciousness and the galascocoma scale. We talked about strokes, whether ischemic or hemorrhagic. We talked about multiple sclerosis and Guillain-Barré syndrome. We talked about myasthenia gravis and Lambert-Eaton myasthenic syndrome. We talked about cerebral abscess and the intracranial pressure. We talked about intracranial hypertension and brain herniation. The last video was about hydrocephalus in general. Today we'll talk about a special type of hydrocephalus known as normal pressure hydrocephalus. So just because I have hydrocephalic symptoms doesn't necessarily mean that my intracranial pressure is high. Because it could be normal. Click the like button, click the subscribe button and let's get started. I've got two playlists concerning this matter. One is just for anatomy called neuroanatomy and one for everything called neurology. This is your brain from the outside. This is the lateral aspect. Now let's dig deeper into the brain. What do you find? You find the ventricles. This is the lateral ventricle and then this is the third ventricle and then this is the fourth ventricle. Between the lateral ventricle and the third ventricle we have the interventricular foramen of Monroe. Between the third ventricle and the fourth ventricle we have the cerebral aqueduct of Silvius. Then after the fourth ventricle you have many options. You can continue straight ahead downwards to be continuous with the central canal of the spinal cord or you can leave the fourth ventricle and go outside via the midline foramen of Mizandi or the lateral foramina of Lushka. If you follow them you're gonna enter into the subarachnoid space which will surround the brain and the spinal cord. All of this green is cerebrospinal fluid. Who makes the cerebrospinal fluid? The ependymal cells that line the choroid plexus which invades the ventricles. But who drains the CSF? Arachnoid granulation which drained the CSF from the subarachnoid space into the dural venous sinuses such as the famous superior sagittal sinus. Remember that the subarachnoid space is under the arachnoid mater but is above the pia mater. If you wish to see more videos like this in the future drop a brain emoji in the comments. Here is a coronal section. Right lateral ventricle and the left lateral ventricle and then the interventricular foramina of Monroe. Then you are in the third ventricle through the cerebral aqueduct of Silvius. Now you are in the fourth ventricle and then you have options. You can continue straight ahead to become continuous with the central canal of the spinal cord or you can leave the fourth ventricle and go to the subarachnoid space through the foramina of Mijandi and this is one in the midline or the foramina of Luska and these are two, one on the right and one on the left. Then you are in the subarachnoid space to surround the brain and the spinal cord. Please keep in mind that the lateral ventricles are the ventricles of the telencephalon whereas the third ventricle is the ventricle of the diencephalon. The cerebral aqueduct of Silvius is the ventricle of the midbrain. It's not literally a ventricle, it's just a duct but it's the cavity of the midbrain and then the fourth ventricle is the cavity of the hindbrain. Keep it neat, keep it simple, keep it organized. If you want to download these doozy colorful notes go to medicosusperfectionitis.com I help you learn, understand and pass exams. If you want me to personally tutor you reach out to me on my website. This is the lateral ventricle. It has an anterior horn, it has a body, it has a posterior horn and an inferior horn. Between the lateral ventricle and the third ventricle this is the interventricular foramen of Monroe. Then the third ventricle will continue as the cerebral aqueduct of Silvius and then the fourth ventricle. If you continue downstairs this is the central canal of the spinal cord or you can leave and go to the subarachnoid space around the brain and the spinal cord. Again, who makes the cerebrospinal fluid? Ependymal cells that line the choroid plexus. But who drains the CSF arachnoid granulations? Drain the CSF from the subarachnoid space into the dural venous sinuses such as the superior sagittal sinus. So basically the CSF is just like the lymph. It came from the blood. Choroid plexus is a plexus of capillaries and is returned back to blood. In this case it's venous blood. The lymph was a very similar idea. It starts from capillaries and then ends up in veins from the blood and back to the blood. Today we're talking about normal pressure hydrocephalus. Now what happens in these patients? Well, it's not an obstruction because if there is an obstruction let's say obstruction in the cerebral aqueduct of Silvius we will call it non-communicating hydrocephalus and it will have high intracranial pressure. But in normal pressure hydrocephalus it's a different story. What's happening is that the ventricles are enlarging and the areas around the ventricles we call them the periventricular matter and its white matter is being distorted. Moreover, the sulci which are these tiny grooves between the gyri of the brain are also atrophying. Oh, so there is atrophy in the sulci. There is enlargement of the ventricles and distortion of the periventricular white matter. However, the enlargement of the ventricles is out of proportion to the atrophy of the sulci. So who is winning the race? The ventriculomegaly is winning the race. What is the normal intracranial pressure? It's about 7 to 13 millimeters of mercury in the normal adult because in infants it's slightly lower. Then if I want to measure it in millimeters of water since the density of mercury is 13.6 times greater than that of water you simply multiply the first number by 13.6 and multiply the second number by 13.6 and this is the range if you want to measure it in millimeters of water. How can we measure the intracranial pressure? We do so via lumbar puncture and you connect the needle to a manometer. Does anyone remember the Monroe-Cayley hypothesis that we talked about in previous videos? Well, well, well, the skull is like a box which is 100% full, packed and stacked and stuffed. There is not a single inch of empty space in the skull. Therefore, anything that will happen in the skull for example, developing a brain tumor or a brain abscess or something like this will have to take the space of something else which means that the pressure has to rise. However, in patients with normal pressure hydrocephalus there is no space occupying lesion in the brain. There is no tumor. There is no abscess. You said that normal pressure hydrocephalus patients do not have an obstruction. Yeah, how can we tell that there is no obstruction? You can do an MRI or you can do this. The Quickenstead test. Basically, remember that the CSF drains into the superior sagittal sinus which will then become right transverse sinus and then right sigmoid sinus and then right internal jugular vein. If you compress the jugulars, what's going to happen? Well, the fluid will build up in the veins and then back pressure, back pressure, back pressure back up into the arachnoid and then back up, back up, back up into the subarachnoid space. And remember that the subarachnoid space surrounds the brain and the spinal cord and you are performing a lumbar puncture below the spinal cord inside the subarachnoid space. So when I compress the jugulars the pressure on the manometer rises. And this is a normal response. This is expected. This is normal. This means that there is no obstruction. But what if I have a tumor about here, for example? Oh, then you're gonna press. The pressure will rise until the tumor but the pressure will not rise past the tumor which means you can compress the jugular veins all you want. The pressure on the lumbar puncture will not rise. And if it did not rise there could be an obstruction or a fibrosis or some kind of malformation or something. And that's not normal. But in patients with normal pressure hydrocephalus since they do not have an obstruction if you compress the jugulars the pressure will rise on the lumbar puncture. If you want to learn about the causes of intracranial hypertension and the consequences of intracranial hypertension please refer to my previous video titled intracranial hypertension. Recall that hydrocephalus has many types. There is non-communicating. There is communicating. There is normal pressure hydrocephalus which is today's topic. And there is hydrocephalus exvacuo also known as exvacuo ventriculomegaly. We've talked about all of these in my video titled hydrocephalus which you can find in this neurology playlist but today we'll focus on NPH. NPH or normal pressure hydrocephalus. It's more common in older patients. You'll see it in patients in their 70s, 80s, 90s, etc. It is sex congruent meaning it's as likely in females as males. Symptoms and physical exam findings include a classic clinical triad of three Ws. I am wet. I am wobbly. I am wacky. What do I mean by wet? Urinary incontinence. Usually with urgency. So it's an urge type of incontinence or urge incontinence. Can you mention three causes of urge incontinence? Please comment below. And by the way in many patients it's urinary incontinence but few patients have fecal incontinence as well. Nocturia is a very common symptom in patients with NPH. If you do urodynamic studies for the urinary bladder you will find an overactive bladder. Why is the bladder super duper duper overactive? Why is it acting out like this? Because there is no one to inhibit it. And why is there no one inhibiting it? Because we disrupted the descending cortical tract. The cerebral cortex used to inhibit the bladder. And that's how if you're an adult and not an infant you can control your urges. As an adult you do not pee on the couch in your mother's house because this is socially unacceptable. You wait until you arrive at the restroom or the bathroom. How are you able to control your urges like this unlike an infant? Because you, unlike an infant, has a very robust well-myelinated and well-developed cerebral cortex capable of inhibiting your bladder. But as my ventricles grow bigger and bigger and bigger they're going to disrupt the periventricular white matter which contains what? White means myelinated. Yes, these descending cortical tracts are indeed myelinated or at least they should be myelinated but now they are being disrupted which means I can no longer control my urges and that's why I have urge incontinence. See, medicine makes so much sense once you understand what the french toast you're talking about. You can learn more about the micturition reflex by referring to my physiology playlist. The next W is wobbly. Ataxia. Abnormal gait. Usually described as magnetic gait. What does that mean? Just like the magnet stuck to your refrigerator. It's hard to remove from the refrigerator at first. You can do it eventually but when you start pulling it's hard at the beginning. Similarly, if you ask the patient to Hey, hey, hey, start walking right now. I'm gonna count to three and then you walk. One Two Three The patient does not start at three. Instead, the patient starts at five or six or seven. Why is the patient slow at initiating ambulation? That's one of the symptoms of the magnetic gait. Just like the magnet on your fridge. It's hard to remove at first. So the patient has difficulty initiating the movement at first. But that's not it. When the patient starts walking both feet do not leave the floor. The patient shuffles back and forth back and forth like the sound of the friction rub. If you know what I'm saying. So the feet are stuck to the floor. The feet are not elevated from the floor before the next step. So it's as if the patient's feet are stuck to the floor like a magnet. That's why we call it the magnetic gait. Whoever termed this phenomenon magnetic gait is pure genius. The third W is wacky. Why? Why do I have cognitive decline? Well, we have ventriculomegaly. You have sulcal atrophy. You have atrophy or distortion of the periventricular white matter. There is thinning of the corpus callosum which connects the right hemisphere with the left hemisphere. And other features that you can see on MRI or CT scan. Usually MRI is better for these cases. How can I make the diagnosis? Clinically. And you perform lumbar puncture. In many patients there is dramatic improvement in the symptoms especially the gait symptoms once you tap the fluid out of the subarachnoid space. And if this happens, this means that the patient is likely to respond to a surgical intervention known as ventriculoperitoneal shunting. What does that mean? What does ventriculo mean? The ventricles. Of my heart? No, of your brain. Oh, okay. Remember that the ventricles of the brain are basically continuous with the central canal of the spinal cord. I got that. Then you're gonna take the subarachnoid space which surrounds the spinal cord and you're going to connect it to the patient's belly. The peritoneum. Hence, ventriculoperitoneal shunt. Why is this? Because the ventricles are big. The ventricles have had enough. So let's just remove some of that fluid and drain it towards the peritoneum. So anytime the ventricles are sick and tired of being sick and tired, they can give their CSF to the peritoneum. And that's the main course of treatment for these patients. However, just like any intervention, it has some complications. If you want me to make another video on the ventriculoperitoneal shunting, its procedure and complications, please let me know in the comments. So let's summarize. What is NPH? NPH is symptomatic hydrocephalus despite normal intracranial pressure measurement. I know that patients with normal pressure hydrocephalus have normal intracranial pressure. But let's say that we have another patient for another reason has intracranial hypertension. Can you mention five different methods, whether medical or surgical, by which we can lower this patient's intracranial pressure? Let me know your answer in the comments. You will find the answer key in my video titled Hydrocephalus, which is in my neurology playlist. Don't forget to take a look at my neuroanatomy playlist and my neurology playlist. If you want to learn about strokes, myocardial infarctions, cardiac arrhythmias, ARGS, acute limb ischemia, drowning, lots of toxidromes, download my emergency medicine high yields course at medicosisperfectionist.com. My courses come with videos, notes, and cases. To learn about the alphas, the betas, the adrenergics, the cholinergics, the nicotinics, the muscarinics, the sympathomimetics, lytics, parasympathomimetics, lytics, etc. Download my autonomic pharmacology course at medicosisperfectionist.com. 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