MLT WITH OSAMA

4 Types of THYROID CANCER USMLE Will Test on Step 1, Step 2, & Step 3

1️⃣ Papillary Carcinoma
🔬 Most common (80%). best prognosis
They’ll give you young woman with painless nodule, history of childhood radiation, cervical lymphadenopathy.
⚠️ Spreads via LYMPHATICS but still excellent prognosis.
Histology: “Orphan Annie” eyes (clear nuclei), nuclear grooves, psammoma bodies.
🔍 Dx: Ultrasound → FNA shows characteristic nuclear features.
🏥 Tx: Total thyroidectomy + radioactive iodine (I-131) ablation + TSH suppression. >95% survival.

2️⃣ Follicular Carcinoma
🔬 Second most common. spreads via BLOOD
They’ll give you middle-aged patient with nodule.
FNA says “follicular neoplasm”. cannot distinguish adenoma from carcinoma on FNA.
⚠️ Spreads hematogenously to bone and lungs, NOT lymph nodes.
Need surgical excision to see capsular/vascular invasion.
🔍 Dx: FNA indeterminate → lobectomy required to diagnose.
🏥 Tx: Total thyroidectomy + radioactive iodine + TSH suppression.
🎯 FNA “follicular neoplasm” + need surgery to diagnose + mets to bone/lung = Follicular

3️⃣ Medullary Carcinoma
🔬 Parafollicular C cells. CALCITONIN
They’ll give you thyroid mass + elevated calcitonin + diarrhea.
Ask about MEN2A (pheo, hyperparathyroidism) or MEN2B (marfanoid, mucosal neuromas).
⚠️ 25% familial (RET mutation).
Histology shows amyloid deposits.
Screen for pheo BEFORE surgery in MEN2.
🔍 Dx: Elevated calcitonin. RET genetic testing. FNA with calcitonin stain.
🏥 Tx: Total thyroidectomy + lymph node dissection.
NO radioactive iodine. C cells don’t take it up.
🎯 Calcitonin elevated + amyloid + MEN2 = Medullary

4️⃣ Anaplastic Carcinoma
🔬 Undifferentiated. WORST PROGNOSIS
They’ll give you elderly patient (>60) with rapidly enlarging, rock-hard fixed mass causing dysphagia, hoarseness, stridor.
⚠️ Median survival 6 months.
Does NOT respond to radioactive iodine or TSH suppression.
🔍 Dx: FNA shows undifferentiated cells. CT for invasion.
🏥 Tx: Surgery if resectable + radiation + che

Blood cell formation explained in one view.

From a single stem cell in bone marrow, all blood cells are formed.
Red cells handle oxygen transport.
Platelets control clotting.
Myeloid cells drive innate immunity and inflammation.
Lymphoid cells build adaptive immunity.

One process. Many functions. All critical for survival.

Total Bilirubin vs Direct Bilirubin vs Indirect Bilirubin, How Labs Interpret Jaundice

Why bilirubin fractions matter 🧪
Total bilirubin alone cannot explain jaundice. Fractionation into direct and indirect bilirubin helps identify the underlying cause.

Total Bilirubin 🟡
• Sum of direct and indirect bilirubin
• Routine part of liver function tests
• Elevated in hemolysis, liver disease, and obstruction

Direct Bilirubin (Conjugated) 🟢
• Water soluble and excreted in bile
• Reflects hepatocellular function and bile flow
• Appears in urine when elevated

Indirect Bilirubin (Unconjugated) 🟠
• Water insoluble, albumin bound
• Elevated in hemolysis and impaired conjugation
• Does not appear in urine

Key lab takeaway 📌
Indirect rise points to hemolysis or Gilbert syndrome.
Direct rise points to cholestasis or liver injury.
Always interpret total bilirubin with fractions.

🩺Nursing Calculation :-

1️⃣ Always check the units
Convert mg ↔ g, mL ↔ L, hours ↔ minutes carefully. Unit mistakes are very common in exams.

2️⃣ Write the formula before solving
Even if the final answer is wrong, writing the correct formula can help you get partial marks.

3️⃣ Convert time into minutes for IV flow rate
Always multiply hours by 60. Many students lose marks here.

4️⃣ Be careful with weight-based dosage
Use the correct formula:
Dose (mg/kg) × Patient weight (kg)
Very important for pediatric questions.

5️⃣ Re-check your answer logically
If the dose or flow rate looks too high or too low, recheck your calculation