Doctor reviews: Neonatal Thrombocytopenia// Causes and diagnosis

Good afternoon, my name is Dr. Tala and I am a neonatologist. We are starting a YouTube channel dedicated to all things NICU. Hopefully you'll find it educational as well as entertaining. So welcome to Tala Talks NICU. Today we're going to be starting with platelets. So let's start first of all with discussing what platelets actually do. So hopefully anybody watching this knows what platelets do and if you don't know what platelets do then I really don't know why you're watching this. Go watch something more interesting. So what platelets do is they are responsible for the primary step of haemostasis. So you cut yourself, platelets are the first tiny little parts of cells because they're not entire cells themselves, and then they go stick on the bleeding area to stop that from bleeding. And then the secondary part of haemostasis is that the little clot is formed with all the factors and then the fibrin comes and sticks on top of that, right? So imagine that you are in a river and there's a dam and a part of the wall breaks and the dam breaks. The beavers literally standing there holding the water from it coming through the dam are the platelets until all the other beavers come with like the sticks and the stones and the cement or whatever beavers use to like properly cement up that area in the dam. So the platelets are the first step in haemostasis. So obviously with a low platelet count what we'd be most worried about is, yes, bleeding. Very good. So that's one of the reasons why obviously we follow platelets. We always want to make sure that babies are not in a state where they or anybody could just bleed to death. The good thing about platelets is that they are very redundant which means that we have a lot of them but we don't need a lot of them, okay? It's not like your red blood cells where your hematocrit could be 40, right? And you need the blood to carry the oxygen around the body. So say you just lose half your blood, you bleed out, something horrible happens, you bleed out and you lose half your blood and your hematocrit is now 20. That is not enough blood to carry oxygen around the body, right? Same thing with all your factors. So if you have 50 percent of the factor eight that you're supposed to have, so one of the clotting proteins, you are literally diagnosed with hemophilia. Whereas platelets, if your normal platelet count is 300,000 and you lose like nearly all of them, you lose and you end up with 75,000 platelets, you're still not suddenly going to start bleeding. In fact with 75,000 platelets there's a really good chance that even if you do cut yourself it will still go and form a nice clot. So in that way platelets are very redundant. The other thing about platelets is that they have a much shorter half-life, like seven to ten days as compared to the red blood cells, which is really two to three months, or white blood cells. So platelets kind of go up and down much faster in blood. So for us it's very helpful as a lab to look at because they're constantly changing. So it gives you a really good idea about exactly how the baby is doing at that second. What's interesting in babies is that when babies are stressed, platelets normally go down. So very often in adults or kids, older kids, if they get stressed for whatever reason, there's a trauma or infection or something, platelets very often can go up. They're a good inflammatory marker. Whereas in babies, platelets very often go down. So what is thrombocytopenia considered in babies? The number is 150,000. So very often babies have higher numbers than that, but less than 150,000 is considered thrombocytopenia. So anytime any baby, in fact anytime any human, or any animal, or anybody has an abnormal, including beavers, has an abnormal cell count, you have to follow up on it. So two things, you have to one, figure out why they have an abnormal count and two, you have to follow it and make sure it gets normal or act on it if necessary. So less than 150,000 is considered thrombocytopenia in a baby. That's mild thrombocytopenia. Less than 100 is moderate, less than 50 is severe thrombocytopenia. So again, baby has a lowish platelet count and where do you get the platelet count from? Generally it's on the CBC, right? So when you order the CBC, which is the complete blood count, you'll get the white blood cells, the red blood cells, and the platelet count. So the platelet count is the little number at the end. Hopefully it's not little. If it's little, then you've got thrombocytopenia. Again, if it's less than 150,000, so it's the number at the end of your CBC. Obviously you can also order the platelet count separately. So you've got a low platelet count in a baby. Your next step is to figure out why do they have a low platelet count? Eventually we'll talk about what we need to do about it, but obviously like everything in medicine, you have to figure out why do they have a low platelet count? Again, something's a little bit different in neonates versus older kids and adults. In older kids and adults, the way that people generally differentiate thrombocytopenia is in whether the platelets are not being formed enough, whether they're getting used up too quickly, or whether the platelets are hiding somewhere. Normally if somebody has a huge spleen, the platelets can all kind of hide in the spleen and it looks like you've got a low platelet count. In babies, generally that can be used, but it's not as helpful to differentiate low platelets in that way. So in babies, very much like everything else we do in neonates, we divide thrombocytopenia into two big categories. Thrombocytopenia in a baby that looks sick and thrombocytopenia in a baby that looks healthy. I don't know how much time you've spent in the NICU, whether as a parent or as a nurse or as a doctor, but that is probably the most important thing that we do in the unit, being able to look at a baby and immediately get that like gestalt, a little bit of German there everybody, I think it's German, about how sick the baby is. So you're looking at signs like the baby's activity level. Is the baby lethargic? Is the baby not moving? If you speak to the baby or touch the baby, is it responsive? Is it breathing too fast? Does it have that scary grayish greenish color? Are the blood pressures borderline? Is the perfusion down? All these other kind of subtle signs that you can look at a baby immediately and be like, that is a sick baby. So we differentiate thrombocytopenia into babies that are sick and babies with thrombocytopenia that are healthy. So let's go over the sicker ones first. So the first differential diagnosis always in the NICU, always is sepsis. Like if you don't know the answer to a question and somebody's asking you a question on rounds or you're a brand new nurse in the NICU and a doctor asks you a question, what is the differential? Whatever the question is, even if you didn't hear the question and you hear them ask, you know, go up at the end of the sentence, the answer is sepsis. You are always worried about sepsis in the unit. If you ever have any abnormal lab value, if the baby does anything abnormal, the first thing you worry about is sepsis because their immune system is so weak. They're basically like little chemotherapy patients because their immune system is so weak. So you're always worried that an infection is going to overtake them. So the first thing to worry about is sepsis. A low platelet count and a sick looking baby, you really don't start thinking about anything else. You just get the blood culture, start antibiotics and the spinal tap or whatever else you need. So again, sepsis is always number one in any differentiator. The second one is TORCH infections. So TORCH, again, are infections, but mostly viral. And TORCH for, I'm sure you've heard this term before, but it stands for toxoplasmosis is the T. O is other. It includes, for example, syphilis, which obviously is a R, rubella, C, CMV, H, herpes and HIV. So it's kind of enlarged to include a whole bunch of other abnormal viruses and bacteria that babies can get normally transmitted from the mummy. So vertical transmission from the mummy. But a TORCH infection in a sick looking baby also is very possible is going to show up with thrombocytopenia. So number one, sepsis. So sepsis is like up here. Again, I can't emphasize this enough. And then TORCH. Hypoxemia. So baby came out extremely stressed, didn't get oxygen at the time of birth, whether it was a huge shoulder disturbance, a huge baby trying to squeeze out through the vaginal canal and got stuck there for ages, didn't get enough oxygen. And so baby gets extremely stressed. The platelets can plummet in that situation. Or for example, the baby's cord got compressed on the way out. Whatever reason, mummy had a placental abruption. So right before delivery, the placenta tore off the mother's uterus and the baby didn't get enough blood or oxygen for a certain period of time before birth. Then all of these things are going to cause low oxygen to the baby, which could then translate into thrombocytopenia in the baby. The fourth one is necrotizing enterocolitis. So this mostly is a disease that happens in preemie babies. And it's a horrible, horrible disease of the gut where babies really are normally kind of trucking along, getting bigger and growing, tolerating feeds. When suddenly they start puking green, pooping out blood, and they can end up with very, very sick intestines that sometimes end up surgery and sometimes end up with the baby's dying. They can also present with pretty profound thrombocytopenia. So obviously with the other symptoms in a sick baby with low platelets, think of neck. And then the other kind of big category, which is really much more rare as well, is an inborn error of metabolism. And that is a genetic issue. Most of the time, these are recessive. So recessive would be that both parents are probably carriers and the baby ended up getting this inborn error of metabolism. So they're kind of also associated with like acidosis or high ammonia. But a whole group of them, especially the organic acidiness can be associated with thrombocytopenia. So just something to think of, especially with kind of abnormal acidosis and stuff, especially when the baby does not look, and I'm going to say it again, septic. So sick baby with thrombocytopenia, sepsis, torch infections, hypoxemia, neck, inborn errors of metabolism. So stay tuned for all the thrombocytopenia with a healthy appearing baby. So if you have any comments or suggestions, then please write something below. Otherwise, please like and subscribe so that you can stay up to date with all the absolutely fascinating making talks that we shall have. Thank you.