iiinova — where your digital self keeps evolving

David Warner (he/him) @davidwarner2.bsky.social · 07/03/2025

AOA induction dinner! Congratulations to my amazing classmates; can’t wait to see where you end up in 2 weeks and hear about your future accomplishments! #Match2025 #UCCOMClassof2025

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David Warner (he/him) @davidwarner2.bsky.social · 07/03/2025

Rades et. al published a validated scoring system to predict prognosis within 6 months to guide radiotherapy. 🧠 Score 20-30 = poor prognosis (short-course recommended) 🧠 Score 30-35 = intermediate prognosis 🧠 Score 36-45 = favorable prognosis (longer course recommended, as more likely to recur)

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David Warner (he/him) @davidwarner2.bsky.social · 07/03/2025

Workup: 🧠 MRI w/in 24 hrs: sagittal T1 and T2-weighted sequence of whole spine + axial imaging of detected lesions 🧠 CT + myelogram if MRI contraindicated 🧠 Bladder scan if relevant + Foley if needed 🧠 Assess for spinal instability (e.g. Spinal Instability Neoplastic Score)

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David Warner (he/him) @davidwarner2.bsky.social · 07/03/2025

Clinical features: Back pain is the most common symptom. 🧠 Severe and localized 🧠 Worse when coughing, sneezing, defecating or lying down 🧠 Progressive worsening 🧠 Disturbs sleep Other features 🧠 Weakness 🧠 Sensory disturbance 🧠 Autonomic dysfunction 🧠 Paralysis 🧠 Cauda equina syndrome

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David Warner (he/him) @davidwarner2.bsky.social · 28/02/2025

Scoring systems have been created to guide management: 🫀 The Kishi scoring system - Score >3 indicates need for stenting 🫀 The Yu grading system - Score of 3 or 4 indicates need for stenting 🫀The Stanford Method - Venography used to identify patients at risk for airway or brain involvement

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David Warner (he/him) @davidwarner2.bsky.social · 28/02/2025

🫀 The drainage of dilated chest wall veins to the left portal vein via the veins of Sappey can lead to perfusion changes and a "hot quadrate sign" around the falciform ligament, seen on this CT.

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David Warner (he/him) @davidwarner2.bsky.social · 28/02/2025

Review of anatomy: 🫀SVC drains blood from the brachiocephalic veins, which receive blood from the head and upper extremities 🫀Collateral supply is important in SVC syndrome 🫀Upper/mid esophageal veins drain into the esophagus, causing "downhill esophageal varices"

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David Warner (he/him) @davidwarner2.bsky.social · 21/02/2025

Summary: 🩸Leukostasis = symptomatic hyperleukocytosis (WBC >100,000) 🩸Clinical features = respiratory and neurological symptoms 🩸May cause falsely high K, low O2, and high platelets 🩸Definitive treatment = induction chemo but perform bone marrow bx first 🩸Use hydroxurea while awaiting studies

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David Warner (he/him) @davidwarner2.bsky.social · 21/02/2025

Leukostasis is a clinical diagnosis that should be suspected in patients with leukemia who develop 🩸Respiratory distress 🩸Neurological changes 🩸Other end organ damage 🩸Hyperleukocytosis Novotny et. al (2005) created the attached grading score to predict the probability of leukostasis.

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David Warner (he/him) @davidwarner2.bsky.social · 14/02/2025

When to stop abx: 🌡️ Known source: usual duration + ANC is improving and >500 🌡️ Unknown source: no fever for >2 days + ANC is improving and >500 Prophylaxis: 🌡️ IDSA guidelines regarding prophylaxis are outlined in the attached table.

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David Warner (he/him) @davidwarner2.bsky.social · 14/02/2025

If hemodynamically unstable: 🌡️ Meropenem/imipenem 🌡️ Vancomycin 🌡️ Aminoglycoside or ciprofloxacin Only use vancomycin if: 🌡️ Skin/soft tissue infection 🌡️ Catheter-related infection 🌡️ Pneumonia 🌡️ Hemodynamically unstable Add antifungal if no response within 3-7 days.

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David Warner (he/him) @davidwarner2.bsky.social · 14/02/2025

Treatment: 🌡️ Once blood cultures are drawn, start empiric antibiotics within 1 hr Inpatient: 🌡️ Empiric cefepime, pip-tazo, or meropenem is recommended 🌡️ Severe penicillin allergy: ciprofloxacin + clindamycin 🌡️ Broaden if suspected MDRO Outpatient: 🌡️ Ciprofloxacin + Augmentin

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David Warner (he/him) @davidwarner2.bsky.social · 14/02/2025

A few risk scores have also been adopted in society guidelines: 1. MASCC Scoring System 📋 Score <21 = inpatient 2. Talcott's rules 📋 Groups I-III = inpatient 📋Group IV low-risk = outpatient 3. CISNE 📋 Used for stable pts receiving mild-mod chemo for solid malignancy 📋 Score >2 = inpatient

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David Warner (he/him) @davidwarner2.bsky.social · 07/02/2025

Clinical presentation: 🦀 Stones (nephrolithiasis) 🦀 Groans (abdominal pain, N/V, pancreatitis) 🦀 Bones (bone pain, muscle weakness) 🦀 Psychiatric overtones (depression, anxiety) 🦀 Cardiac manifestations (short QT, bradycardia, AVN blockade) 🦀 Nephrogenic DI (polyuria, thirst)

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David Warner (he/him) @davidwarner2.bsky.social · 31/01/2025

Hyperuricemia Options: 🦀 Rasburicase 🦀 Allopurinol 🦀 Febuxostat 🦀 Dialysis 🦀 Rasburicase is preferred over allopurinol - Faster acting - Allopurinol does not remove existing uric acid and leads to buildup of xanthine (also nephrotoxic) 🦀 But, rasburicase is contraindicated in G6PD deficiency

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David Warner (he/him) @davidwarner2.bsky.social · 31/01/2025

The work-up for TLS includes: 🦀 BMP (Cr, BUN, K, Phos, and Ca) 🦀 CBC (WBC, may also have anemia/thrombocytopenia) 🦀 Uric Acid 🦀 EKG 🦀 LDH 🦀 Urinalysis + urine microscopy TLS is diagnosed via the Cairo-Bishop Classification: 🦀 Laboratory (asymptomatic) 🦀 Clinical (symptomatic)

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David Warner (he/him) @davidwarner2.bsky.social · 24/01/2025

So what is the physiologic basis underlying the use of glucagon in BB/CCB overdose? 🫀Cardiac myocytes have glucagon receptors 🫀These receptors also act through Gs proteins to activate PKA, providing the above benefits even in the setting of BB or CCB toxicity

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David Warner (he/him) @davidwarner2.bsky.social · 24/01/2025

To start, let's review myocardial contractility to understand how glucagon works. 🫀L-type Ca channels open ➡️ Ca binds RyR ➡️ Ca released from sarcoplasmic reticulum 🫀Ca binds troponin C ➡️ exposes myosin-binding site of actin 🫀SERCA2 pumps Ca back into SR 🫀Phospholamban inhibits SERCA2

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David Warner (he/him) @davidwarner2.bsky.social · 17/01/2025

What are the risk factors for BRASH Syndrome? 📝Elderly patients 📝Pts with underlying kidney disease 📝Volume depletion (dehydration, diuretic use) 📝Use of ACEi or ARBs 📝Use of K-sparing diuretics (spironolactone)

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David Warner (he/him) @davidwarner2.bsky.social · 17/01/2025

📝 AV node blockers (esp. beta blockers, verapamil, and diltiazem) are renally cleared 📝 In patients with CKD, renal clearance of AVN blockers is impaired 📝 Underlying CKD + AVN blockade (+ARB in this case) ➡️ HyperK 📝 HyperK + AVN blockade ➡️ bradycardia + shock

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David Warner (he/him) @davidwarner2.bsky.social · 10/01/2025

Hyperlipidemia in hypothyroidism is both mediated by low T3 and high TSH T3 🫀⬇️FFA beta-oxidation 🫀⬇️CYP7A1, leading to impaired cholesterol clearance 🫀⬇️Lipoprotein Lipase, decreasing hydrolysis of VLDL TSH 🫀⬇️CYP7A1 🫀⬆️PCSK9 🫀⬆️HMG CoA reductase 🫀⬆️Hormone-Sensitive lipase

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David Warner (he/him) @davidwarner2.bsky.social · 10/01/2025

The Osborn waves are secondary to hypothermia from the slower metabolic rate in hypothyroidism and are caused by 🫀Slow conduction speeds 🫀Delayed and prolonged repolarization phase 🫀Hypothermia may also block the transient outward current responsible for Phase 1 of the cardiac AP

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David Warner (he/him) @davidwarner2.bsky.social · 10/01/2025

Hypothyroidism also leads to the following arrhythmias: 🫀Bradycardia 🫀Long PQ segment 🫀Diffuse flattened or inverted T waves 🫀Low voltage QRS 🫀AV blockage 🫀Acquired long QT syndrome, which can lead to TdP 🫀Osborn waves

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David Warner (he/him) @davidwarner2.bsky.social · 10/01/2025

Hypothyroidism has various cardiovascular manifestations including arrhythmias, high blood pressure, dyslipidemia, heart failure, and pericardial effusion. What are the physiologic mechanisms underlying these associations? Welcome to another #PhysiologyFriday! A 🧵 #MedSky #CardioSky

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David Warner (he/him) @davidwarner2.bsky.social · 03/01/2025

How does TH cause AFib? 🫀The shortened cardiac AP can cause increased afterdepolarizations in the pulmonary vein and cardiomyocytes 🫀TH also increases spontaneous activity in the pulmonary vein cardiomyocytes 🫀This creates the perfect storm (no pun intended) for the development of AFib

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David Warner (he/him) @davidwarner2.bsky.social · 03/01/2025

How does TH cause increased heart rate? 🫀TH upregulates beta-1 adrenergic receptors and downregulates M2 receptors 🫀TH downregulates L-type calcium channels, shortening Phase 2 of the cardiac AP 🫀TH upregulates KCNA5 K channels, shortening Phase 3 of the cardiac AP

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David Warner (he/him) @davidwarner2.bsky.social · 03/01/2025

Let's start with a review of heart contractility. 🫀L-type Ca channels open ➡️ Ca binds ryanodine receptor ➡️ Ca released from sarcoplasmic reticulum (SR) 🫀Ca binds troponin C ➡️ exposes myosin-binding site of actin 🫀SERCA2 pumps Ca back into SR 🫀Phospholamban inhibits SERCA2

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David Warner (he/him) @davidwarner2.bsky.social · 03/01/2025

The role of hyperthyroidism in cardiovascular disease is well-documented. What are the pathophysiologic mechanisms underlying thyroid hormone's role in arrhythmias, hypertrophy, and heart failure? Welcome to #PhysiologyFriday! A 🧵 #MedSky #CardioSky

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David Warner (he/him) @davidwarner2.bsky.social · 01/01/2025

Happy new year!! 🎉 The year I become a doctor!! #Match2025 🩺

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David Warner (he/him) @davidwarner2.bsky.social · 27/12/2024

🍫 Interference with these inhibitory pathways in IDA may lead to an increased desire to smell specific odors (desiderosmia) 🍫Desiderosmia is most commonly reported in pregnancy, which can cause harm to mom/baby 🍫Tx: treat underlying IDA Other clinical applications of iron's role in smell:

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David Warner (he/him) @davidwarner2.bsky.social · 27/12/2024

🧠 Tyrosine hydroxylase (requires iron) 👃There are juxtaglomerular neurons that release dopamine and modulate the release of glutamate from olfactory receptor neurons, inhibiting smell 👃Dopamine is made from tyrosine via tyrosine hydroxylase

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David Warner (he/him) @davidwarner2.bsky.social · 27/12/2024

🧠 TDO, IDO, and 3-HAO (requires iron) 👃 These enzymes are involved in the kynurenine pathway, which converts tryptophan into quinolinic acid 👃Quinolinic acid then activates NMDA on the granule cells, triggering release of GABA and inhibition of smell as above

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David Warner (he/him) @davidwarner2.bsky.social · 27/12/2024

🧠 Nitric Oxide Synthase (requires heme) 👃 Depolarization of mitral cell ➡️ voltage-gated Ca channel opens ➡️ NOS activated ➡️ activation of cGMP ➡️ exocytosis of glutamate which binds NMDA on granule cells ➡️ release of GABA which binds GABA receptor on mitral cells ➡️ inhibits smell

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David Warner (he/him) @davidwarner2.bsky.social · 27/12/2024

👃 Odorant exposed to olfactory receptor ➡️ action potential in the olfactory receptor cell is transferred to the olfactory bulb (which consists of mitral and tufted cells) via the olfactory glomerulus Yes you heard that right #NephSky, the nose has glomeruli as well!

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David Warner (he/him) @davidwarner2.bsky.social · 13/12/2024

🌰 Natural latex rubber is made from a milky emulsion from the rubber tree Hevea brasiliensis 🌰After processing, latex contains 250 proteins, 60 that bind to IgE, and 15 that are identified as allergens by the WHO 🌰Some of these proteins are homologous with proteins found in other foods:

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David Warner (he/him) @davidwarner2.bsky.social · 13/12/2024

🥑 ~30% of people with latex allergies also have allergies to certain fruits, which is known as latex-fruit syndrome 🥑 Latex-fruit syndrome can present as a Type I or Type IV hypersensitivity reaction 🥑 Avocados, bananas, kiwis, and chestnuts in particular have high cross-reactivity with latex

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David Warner (he/him) @davidwarner2.bsky.social · 08/12/2024

My Anki Wrapped was this email I received yesterday 😅 #ItGetsBetter

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David Warner (he/him) @davidwarner2.bsky.social · 02/12/2024

You have to make mistakes in order to learn from them #GrowthMindset📈 @duolingoverde.bsky.social

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David Warner (he/him) @davidwarner2.bsky.social · 01/12/2024

I'm writing about an intervention to enforce medical school workload policies, and this paragraph sums up my concerns about the future of medical education. Be kind to your med students. #MedStudentSky #MedSky @aamctoday.bsky.social

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David Warner (he/him) @davidwarner2.bsky.social · 29/11/2024

🦃 That is until 1989 when the FDA banned tryptophan supplements due to a rare side effect called eosinophilia-myalgia syndrome that affected 1500 people and killed 30 people in a 6-month period.

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David Warner (he/him) @davidwarner2.bsky.social · 29/11/2024

🦃 Tryptophan is an essential amino acid that was discovered in 1901 and first synthesized in 1906. 🦃 Tryptophan is metabolized into serotonin and melatonin, which is why OTC tryptophan has historically been used to treat depression and insomnia.

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David Warner (he/him) @davidwarner2.bsky.social · 25/11/2024

One last topic is the role of Mg in the renal handling of K. 🍫 Mg inhibits ROMK and Na/K ATPase in the TAL and collecting duct 🍫 Inhibiting ROMK and Na/K ATPase decreases secretion of K

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David Warner (he/him) @davidwarner2.bsky.social · 25/11/2024

Onto Mg handling, which mostly occurs in the TAL. Mg handling is mostly regulated by the calcium-sensing receptor (CaSR), which when activated by Ca or Mg, lowers Mg via 2 mechanisms: 🍫Inhibiting NKCC2 and ROMK, which decreases the positive lumen voltage 🍫Decreases claudin 16/19 activity

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David Warner (he/him) @davidwarner2.bsky.social · 25/11/2024

1. PTH Big picture: 🥤The goal of PTH is to increase calcium when serum calcium is low 🥤Phos works against this goal by binding Ca, lowering free serum Ca 🥤Thus PTH (aka Phosphate Trashing Hormone) wants to reabsorb Ca and excrete phosphate! PTH does this by promoting NaPi2a/2c endocytosis.

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David Warner (he/him) @davidwarner2.bsky.social · 25/11/2024

Starting with Phos, there is only one transporter you need to worry about in the kidney, the Na/Phos cotransporter (NaPi2a/2c) in the PCT. There are 3 hormones that regulate this cotransporter:

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David Warner (he/him) @davidwarner2.bsky.social · 25/11/2024

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David Warner (he/him) @davidwarner2.bsky.social · 25/11/2024

Starting with Phos, there is only one transporter you need to worry about in the kidney, the Na/Phos cotransporter (NaPi2a/2c) in the PCT. There are 3 hormones that regulate this cotransporter:

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