When you order a serum alcohol level, what does the lab measure? An answer and a quick #Medtweetorial on false elevations in #ETOH
If you guessed NADH, you would be correct.
Most lab assays for serum alcohol utilize a reagent containing alcohol dehydrogenase & NAD+
This is used to convert all present ethanol to acetaldehyde
Thereby reducing present NAD+ to NADH.
NADH is then measured via spectrophotometry
It is theoretically proportional to the amount of serum ethanol that was present in the sample.
Which of the following conditions can cause a false elevation in alcohol despite not drinking any?
If you guessed lactic acidosis, you are CORRECT
In states of lactic acidosis, lactate & LDH present in a patient's sample can interfere by metabolizing lactate to pyruvate and reducing NAD+ to NADH, thereby causing a false elevation in the measurement.
Most of the research suggests the interference is minimal or requires significant lactic acidosis like after someone who presents in status.
With that being said, which of the following overdoses can plausibly cause a false rise in serum alcohol?
If you guessed acetaminophen then you would be correct!!
Experimental evidence from studies in whole animals, perfused liver slices & cell cultures has shown that the toxic metabolite of paracetamol, N-acetyl-p-benzo-quinone imine...cont
cont... inhibits electron transfer in the mitochondrial respiratory chain and thus inhibits aerobic respiration.
This occurs only at very high concentrations of paracetamol & precedes cellular injury by several hours."
This interruption of aerobic respiration causes an increase in anaerobic respiration which of course can lead to lactic acidosis.
Maybe it is a stretch but we used our knowledge base and foundation to link some plausible cases.
I learned this from a wonderful student in the ER this past month who had some lab experience.
It is awesome to learn from my learners! Thanks Jordan
westgard.com/lesson12.htm Review of statistical measures used in laboratory quality control. Dr. Westgard is essentially the founding father of laboratory QC techniques
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Hematogenous dissemination then can occur typically 4 to 10 weeks later, giving rise to secondary syphilis. <40% of pts w/ syphilis have primary syphilis diagnosed. These “Secondary” lesions last for several weeks before spontaneously resolving. Coined “early, latent infection”
What does late infection mean? When syphilitic lesions recur after 1 year from the initial eruption, or seropositivity is detected more than 1 year after the initial eruption, it is termed late latent syphilis.
Some optics neuritis pearls in a short #Medtweetorial 🧵…. We all know that optic neuritis is frequently associated with multiple sclerosis (MS). But optic nerve inflammation can exist from autoimmunity, infection, granulomatous disease, paraneoplastic disorders, & demyelination
Classical ON from MS is unilateral, moderate, painful color vision loss with an afferent pupillary defect & normal fundus examination.
In those with ON, 95% of patients showed unilateral vision loss & 92% had associated retroorbital pain that frequently worsened w/ eye movement.
If you have not listened to the @CuriousClinPod most recent podcast (Episode 10: Why does metronidazole treat both bacterial and parasitic infections?) then I suggest you tune in.
I'll summarize their show notes here in short #medtweetorial
First a question:
Was metronidazole first used as an antibiotic or as an antiparasitic?
If you guessed antiparasitic, then you would be correct!
It was developed in the 1950s to treat the parasite trichomonas & then was used in the 1960s to treat other parasitic infections, like giardia and amoebiasis.
A 31-year-old M born and raised in Brazil w/ no PMH presented with a 3 mon history of worsening DOE, orthopnea, 7kg weight loss, abdominal distention, dry cough, and syncope
An interesting fact from @3owllearning : Depending on the clinical problems, the studies of disease probability for differential diagnosis often show 10 - 25% of cases are unexplained, even after careful examination and testing.