Orotic Aciduria (Heme/Onc) - USMLE Step 1

MadMedicine

4 Dec 201907:33

Summary

TLDRIn this episode of Mad Medicine, the discussion focuses on erythrocytic aciduria and its link to anemia, particularly microcytic and megaloblastic anemias. The video explains the role of UMP synthase and its impact on DNA synthesis, leading to macrocytic anemia characterized by hypersegmented neutrophils and elevated erythrocytic acid levels. It emphasizes diagnosis through exclusion of other causes and highlights treatment options, including UMP supplementation. Viewers are encouraged to engage with the channel for further educational content.

Takeaways

😀 Microcytic anemias are defined by an MCV greater than 100, indicating macrocytic characteristics.
😀 Megaloblastic anemias are caused by impaired DNA synthesis, with two main types: megaloblastic and non-megaloblastic.
😀 Erotic acid urea is an autosomal recessive disorder primarily due to a deficiency in uridine monophosphate synthase (UMP synthase).
😀 The deficiency of UMP synthase leads to low levels of UMP, causing decreased synthesis of thymine and cytosine.
😀 Patients with erotic acid urea will present with macrocytic megaloblastic anemia and hyper-segmented neutrophils.
😀 Erotic acid crystals can be found in the urine of affected individuals, serving as a diagnostic marker.
😀 Diagnosis of erotic acid urea is a process of exclusion, particularly when treatments with folate and vitamin B12 do not alleviate symptoms.
😀 Children with erotic acid urea may experience failure to thrive and developmental delays due to ineffective erythropoiesis.
😀 Treatment options include direct supplementation of UMP, which can bypass the defective pathway and improve symptoms.
😀 Even with treatment, patients may continue to exhibit erotic acid crystals in their urine, indicating persistent metabolic issues.

Q & A

What is the main topic of the video?
-The video discusses erotic acid urea and its relation to macrocytic anemias.
What defines microcytic anemias?
-Microcytic anemias are classified by a mean corpuscular volume (MCV) greater than 100, indicating large red blood cell size.
What causes megaloblastic anemia?
-Megaloblastic anemia is caused by issues in DNA synthesis, often due to deficiencies in folate or vitamin B12.
What is erotic acid urea?
-Erotic acid urea is an autosomal recessive disorder characterized by a deficiency in uridine monophosphate (UMP) synthase, leading to elevated levels of erotic acid.
What happens when UMP synthase is not functioning properly?
-When UMP synthase is impaired, erotic acid cannot be converted to UMP, resulting in low levels of UMP and subsequent deficiencies in thymine and cytosine.
How does erotic acid urea present in terms of anemia?
-Patients typically exhibit macrocytic megaloblastic anemia due to decreased DNA synthesis, leading to hypersegmented neutrophils and failure to thrive in children.
What are hypersegmented neutrophils?
-Hypersegmented neutrophils are neutrophils that have more than the normal number of nuclear lobes, indicating a problem with DNA synthesis.
What is the significance of finding erotic acid crystals in urine?
-The presence of erotic acid crystals in urine is a key diagnostic marker for erotic acid urea.
How can erotic acid urea be treated?
-Treatment may involve administering UMP directly to bypass the dysfunctional enzyme pathway.
What should be considered if macrocytic anemia does not improve with folate or vitamin B12?
-If there is no improvement with folate or vitamin B12 supplementation, erotic acid urea should be considered as a diagnosis of exclusion.