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• Kisi specific topic ke baare mein poochh sakte hain (e.g., heart failure, eclampsia, nephrology cases)
• Main clinical scenarios ke jawab in books se dhoondh ke de sakta hoon
• Step 2 CK style questions ke liye relevant content extract kar sakta hoon

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🩺 Hypercalcemia - Mukammal Urdu Roman Mein Tafseeli Wazahat

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📌 Hypercalcemia Kya Hai? (Definition)

• Normal serum calcium: 8.2 - 10.2 mg/dL
• Hypercalcemia: > 10.2 mg/dL
• Severe / Symptomatic: > 13-14 mg/dL
• Hypercalcemic crisis: > 14 mg/dL (emergency!)

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🔬 Calcium Regulation Ka Mechanism (Normal Physiology)

1. Bone se calcium release karta hai (osteoclast activate karke)
2. Kidney mein calcium reabsorb karta hai
3. Kidney mein Vitamin D ko activate karta hai (25-OH-D ko 1,25-OH-D banata hai)
4. 1,25-OH-D intestine se calcium absorb karata hai

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⚡ Causes of Hypercalcemia (Asbab)

Mnemonic yaad rakhein: "CHIMPANZEES"

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🔴 DO SABSE IMPORTANT CAUSES (USMLE ke liye):

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1. PRIMARY HYPERPARATHYROIDISM (PHPT)

• 80% cases: Solitary parathyroid adenoma
• 15% cases: Parathyroid hyperplasia (especially MEN-1, MEN-2A mein)
• <1% cases: Parathyroid carcinoma

• Serum Ca: 10.7 mg/dL (high)
• PTH: 119 pg/mL (normal: 10-65) - HIGH
• Phosphorus: 2.8 mg/dL (low-normal)
• Alkaline phosphatase: slightly elevated

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2. MALIGNANCY-ASSOCIATED HYPERCALCEMIA

• Tumor ek fake PTH banata hai jo PTHrP kehlata hai
• Yeh PTH ki tarah kaam karta hai - bone resorption badhata hai, renal calcium reabsorption badhata hai
• BUT - Intestinal calcium absorption nahi badhata (PTH se fark)
• Breast cancer, lung cancer (squamous cell) mein common
• PTH: LOW, PTHrP: HIGH

• Cancer seedha bone mein grow karta hai
• IL-1, IL-6, TNF release hote hain jo osteoclasts activate karte hain
• Bone destroy hoti hai, calcium blood mein aata hai
• Multiple myeloma, breast cancer, lymphoma mein common
• Skeletal X-ray mein: lytic bone lesions

• Lymphoma cells 1,25-OH-D (active Vit D) banate hain
• Intestinal calcium absorption badhti hai
• PTH: LOW, 1,25-OH-D: HIGH

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3. SARCOIDOSIS / GRANULOMATOUS DISEASES

• Granuloma cells (macrophages) Vitamin D ko activate kar deti hain
• 1,25-OH-D level HIGH hota hai
• PTH: LOW

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4. MEDICATIONS

• Thiazide diuretics: Kidney mein calcium retention badhate hain
• Lithium: PTH secretion badh jaati hai
• Calcium carbonate + Vitamin D (excess): Milk-Alkali syndrome
• Agar asymptomatic hai aur Ca < 14 mg/dL - medication band karo, 1 hafte baad dobara check karo

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😣 Symptoms of Hypercalcemia

Classic Mnemonic: "Bones, Stones, Moans, Abdominal Groans" (+ Psychic Overtones!)

1. Calcium kitna high hai
2. Kitni tezi se badha hai

>13 mg/dL wale patients usually symptomatic hote hain.

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🔍 Diagnosis / Workup

Step 1: Confirm Hypercalcemia

• Serum ionized calcium measure karo (total calcium albumin se adjust hota hai)
• Albumin correction: Total Ca + 0.8 × (4.0 - serum albumin)

Step 2: PTH measure karo - YEH SABSE PEHLA AUR ZAROORI TEST HAI

• 24-hour urine calcium/creatinine ratio check karo
  • Ratio > 0.03 → Primary Hyperparathyroidism (PHPT)
  • Ratio < 0.02 → FHH (Familial Hypocalciuric Hypercalcemia) - benign condition

• PTHrP aur Vitamin D levels check karo:
  • PTHrP HIGH → Malignancy (most likely)
  • 1,25-OH-D HIGH → Lymphoma, Sarcoidosis, Granulomatous disease
  • 25-OH-D HIGH → Vitamin D intoxication
  • Sab normal → Myeloma, Vitamin A toxicity, Thyrotropin

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Lab Summary Table:

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💊 Treatment (Ilaj)

🚨 Acute / Severe Hypercalcemia (Emergency Treatment):

• 2-4 L/day aggressive rehydration
• Hypercalcemia se nephrogenic DI hoti hai → polyuria → dehydration
• Calcium sensing receptor loop of Henle mein natriuresis karta hai → aur dehydration
• Isliye pehle fluid do!

• Fluid overload prevent karne ke liye
• Elderly patients aur cardiac/renal disease mein especially
• Note: Thiazide diuretics KABHI NAHI dena - yeh calcium badhate hain!

• Zoledronate (Zometa): 4 mg IV over 15 min - most potent
• Pamidronate: 60-90 mg IV over 2-4 hrs
• Onset: 2-4 din mein effect shuru, 4-7 din mein peak
• Renal function monitor karo - nephrotoxic ho sakta hai

• Fastest action (4-6 ghante mein kaam karta hai)
• Calcium ~1-2 mg/dL kam karta hai
• Tachyphylaxis develop hoti hai (2-3 din baad effect khatam)
• Bisphosphonate ke sath milake use karo (bridge therapy)

• RANKL antibody - osteoclasts ko block karta hai
• Renal insufficiency mein safe (dose adjust nahi chahiye)
• Malignancy mein use hota hai

• Specifically: Sarcoidosis, Lymphoma, Vitamin D toxicity mein
• Vitamin D activation block karte hain

• Severe refractory hypercalcemia mein last resort

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💊 Long-term / Definitive Treatment:

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🎯 USMLE Step 2 CK High-Yield Points (Yaad rakho!)

1. Outpatients mein #1 cause = Primary Hyperparathyroidism (parathyroid adenoma)
2. Inpatients mein #1 cause = Malignancy (squamous cell lung cancer, breast cancer, myeloma)
3. Mnemonic: "Bones, Stones, Groans, Psychic Moans"
4. ECG finding: Short QT interval
5. First step in workup: Measure iPTH
6. First step in TREATMENT: IV Normal Saline (aggressive hydration)
7. PTHrP: Cancer mein hota hai, PTH LOW rahta hai
8. FHH: PTH high lekin urine calcium LOW - benign, surgery NAHI chahiye
9. Sarcoidosis mein: 1,25-OH-D high, PTH low - treat with steroids
10. Calcitonin: Fastest acting but tachyphylaxis hoti hai
11. Bisphosphonates: Serum creatinine monitor karo - nephrotoxic!
12. MEN-1: Hyperparathyroidism + Pituitary tumor + Pancreatic tumor
13. Thiazide diuretics: Hypercalcemia BADHATE hain (urine mein calcium retention)
14. Loop diuretics (Furosemide): Treatment mein use karte hain (calcium excretion badhata hai)

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📊 Quick Comparison: PTH vs PTHrP

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🩺 Hyperparathyroidism - Mukammal Urdu Roman Wazahat

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📌 Hyperparathyroidism Kya Hai?

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🔢 Hyperparathyroidism ke 3 Types

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1️⃣ PRIMARY HYPERPARATHYROIDISM (PHPT)

Epidemiology:

• 1000 adults mein se 3 mein hoti hai
• Females mein 3 guna zyada (males se)
• Age: 40-65 saal mein peak
• Asymptomatic hypercalcemia ki #1 cause hai

Causes (Etiology):

• MEN-1 gene mutation - 35-50% sporadic adenomas mein
• Cyclin D1 (CCND1) overexpression - 15% mein
• CDC73 mutation - 70% parathyroid carcinomas mein
• Wnt/β-catenin pathway abnormality - 85% mein

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Microscopic Appearance (Histology):

• Chief cells se bani hoti hai (uniform, monotonous)
• Fat cells: kam ya nahi ke barabar (normal gland mein hote hain)
• Adenoma ke edge par normal parathyroid tissue ki rim hoti hai
• Mitoses rare hote hain
• Dusri glands: normal ya choti (feedback inhibition se)

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Pathophysiology (Kaise hota hai nuksaan):

PTH barh jaata hai
       ↓
1. BONE: Osteoclasts activate → RANKL expression badh jaata hai
         → Bone resorption → Calcium blood mein aata hai
         → Osteitis fibrosa cystica, brown tumors

2. KIDNEY: Calcium reabsorption BADHTA hai
           Phosphate excretion BADHTA hai
           → Hypercalcemia + Hypophosphatemia

3. INTESTINE: PTH → Vitamin D activate karta hai
              → 1,25-OH-D badhta hai
              → Intestinal calcium absorption badhti hai

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Clinical Features (Symptoms):

🦴 BONES (Haddiyon mein changes):

• Osteitis fibrosa cystica - PTH se bone buri tarah resorb hoti hai
• Brown tumors - bone cysts (hemorrhage se brown rang aata hai) - long bones mein
• Subperiosteal bone resorption - X-ray mein radial border of middle phalanx par
• Salt and pepper skull - khopri ki X-ray mein pattern
• Distal clavicle tapering (clavicle ka end ghis jaata hai)
• Osteoporosis - especially cortical bone mein (radius, hip)
• Pathologic fractures

Note: Aaj kal early detection ki wajah se classic bone changes sirf <5% patients mein milte hain!

🪨 STONES (Kidney mein):

• Nephrolithiasis (kidney stones) - 20% patients mein
• Nephrocalcinosis - kidney mein calcium deposits
• Hypercalciuria - 30% patients mein
• Polyuria aur polydipsia (nephrogenic DI)

🤢 ABDOMINAL GROANS:

• Peptic ulcers (gastrin secretion badhti hai)
• Pancreatitis (calcium pancreatic enzymes activate karta hai)
• Nausea, vomiting
• Constipation
• Gallstones

😔 PSYCHIC MOANS (Neuropsychiatric):

• Depression, anxiety
• Lethargy, fatigue
• Proximal muscle weakness (neuromuscular)
• Confusion
• Seizures (severe mein)
• Aortic/mitral valve calcification (cardiac)

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Diagnosis (PHPT ki):

• PTH HIGH ya inappropriately normal = Primary Hyperparathyroidism

• Sestamibi scintigraphy (Tc-99m MIBI) + CT (SPECT) - PREFERRED (3D image deta hai)
• Ultrasound neck
• MRI
• (Note: Do modalities milake confirm karte hain - false positives hote hain)

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Surgery ke Guidelines (Parathyroidectomy kab karein?):

1. Nephrolithiasis ya bone erosions (complications) hain
2. Life-threatening hypercalcemia ka episode aaya ho
3. Serum Ca > 1 mg/dL above normal limit
4. Urinary Ca > 400 mg/24 hr (men) ya >300 mg/24 hr (women)
5. Creatinine clearance < 60 mL/min
6. Bone mineral density T-score < -2.5 (osteoporosis)
7. Age < 50 years

• 98% cases mein biochemical cure hoti hai (skilled surgeon ke haath se)
• Bone mineral density 6-12 mahine mein badh jaati hai, 10 saal tak improve hoti rehti hai
• Complications: Recurrent laryngeal nerve damage, permanent hypoparathyroidism

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Asymptomatic PHPT Management:

• Sirf 25% progressive hoti hai (10 saal mein)
• Watchful waiting kaafi hai agar surgery criteria na milen
• Medical therapy: Cinacalcet (calcimimetic) - calcium-sensing receptor ko activate karta hai, PTH aur calcium dono kam karta hai
• Bisphosphonates - bone density maintain karte hain

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2️⃣ SECONDARY HYPERPARATHYROIDISM

Kya hota hai:

Causes:

• Chronic Renal Failure (#1 cause) - sabse common
• Vitamin D deficiency
• Malabsorption / steatorrhea
• Inadequate calcium intake

Mechanism (Renal Failure mein):

Chronic Renal Failure
       ↓
Phosphate excretion kam → Hyperphosphatemia
       ↓
Phosphate calcium ko seedha depress karta hai → Hypocalcemia
       ↓
PLUS: Kidney mein α1-hydroxylase kam → 1,25-OH-D kam
       ↓
Intestinal calcium absorption kam → Aur zyada hypocalcemia
       ↓
Parathyroid gland stimulate hoti hai → PTH BARH JAATA HAI
       ↓
Bone resorption → Renal Osteodystrophy

Lab Findings (Secondary HPT):

Treatment:

• Underlying cause treat karo
• Active Vitamin D analog (Calcitriol / Paricalcitol)
• Cinacalcet (calcimimetic) - PTH suppress karta hai
• Phosphate binders (calcium carbonate, sevelamer)
• Parathyroidectomy (subtotal) - severe persistent cases mein

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3️⃣ TERTIARY HYPERPARATHYROIDISM

• Secondary hyperparathyroidism bahut lambe arse tak rahe
• Parathyroid gland autonomous ho jaati hai (calcium levels ki parvah nahi karti)
• Calcium HIGH hone ke bawajood PTH HIGH rehta hai
• Najdi misaal: Renal transplant ke baad bhi PTH elevated rehta hai

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⚖️ Comparison Table (USMLE Exam ke liye)

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🎯 USMLE Step 2 High-Yield Points:

1. PHPT = #1 cause of asymptomatic hypercalcemia (outpatients mein)
2. Solitary parathyroid adenoma = 80-85% PHPT cases
3. Classic triad: Bones, Stones, Groans, Moans
4. X-ray clue: Subperiosteal bone resorption at radial aspect of middle phalanx
5. PTH HIGH + Calcium HIGH = Primary HPT (ya FHH)
6. FHH se farq: Urine Ca/Cr ratio - PHPT mein HIGH (>0.03), FHH mein LOW (<0.01)
7. Surgery criteria yaad karo: Ca >1 mg/dL above normal, age <50, T-score <-2.5, CrCl <60, stones
8. Cinacalcet: Medical therapy - calcium sensing receptor agonist - PTH aur Ca dono kam karta hai
9. MEN-1: HPT + Pituitary tumor + Pancreatic tumor (Zollinger-Ellison)
10. MEN-2A: HPT + Pheochromocytoma + Medullary thyroid cancer
11. Secondary HPT mein: Calcium LOW, Phosphate HIGH (renal failure)
12. Chloride:Phosphate ratio >33 = PHPT ka hint
13. Brown tumors = PHPT mein bone cysts - malignancy se confuse mat karna!
14. Sestamibi scan = preoperative localization ki best test

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🩺 Hypocalcemia - Mukammal Urdu Roman Wazahat

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📌 Definition (Tarif)

Important: Symptoms ionized calcium se relate hote hain, total calcium se nahi. Aur jitni tezi se calcium gire, utne zyada symptoms hote hain.

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⚠️ Ek Zaroori Concept: Albumin Correction

• Bound calcium (albumin se binda hua) - 40%
• Ionized/Free calcium (active form) - 50%

Corrected Ca = Measured Ca + 0.8 × (4.0 - serum albumin)

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🔢 Causes of Hypocalcemia (Asbab)

🔵 GROUP 1: PTH LOW hai (Hypoparathyroidism)

1. Post-Surgical Hypoparathyroidism (#1 Most Common Cause Overall)

• Thyroid surgery ya parathyroid surgery ke baad parathyroid glands accidentally nikal jaati hain
• Symptoms 12-24 ghante ke andar shuru
• Specially: Total thyroidectomy, radical neck dissection

2. Autoimmune Hypoparathyroidism

• Immune system parathyroid glands ko destroy kar deta hai
• Autoimmune Polyglandular Syndrome (APS type 1) = Hypoparathyroidism + Adrenal insufficiency + Mucocutaneous candidiasis (APECED syndrome)

3. DiGeorge Syndrome

• 22q11.2 deletion - chromosome 22 ka deletion
• 3rd/4th pharyngeal pouch develop nahi hote
• Parathyroid glands + Thymus ka agenesis
• Tetralogy of Fallot + Hypocalcemia + Immune deficiency (T cell) - classic triad
• Neonatal period mein hypocalcemia present hoti hai

4. Hypomagnesemia (#1 Reversible cause)

• Magnesium < 0.4 mmol/L ho to PTH ki release block ho jaati hai
• Aur PTH ke action ka resistance bhi aata hai
• Causes: Crohn disease, renal tubular disorders, alcoholism, malabsorption
• Key point: Hypocalcemia tab tak theek nahi hogi jab tak Mg correct na karo!

5. Infiltrative Diseases

• Hemochromatosis (iron deposits), Wilson disease (copper deposits)
• Amyloidosis, sarcoidosis - parathyroid glands mein infiltrate

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🟠 GROUP 2: PTH HIGH hai (Secondary HPT - body compensate kar rahi hai)

1. Chronic Renal Failure (CRF) - #1 Most Common Cause Overall

• Kidney phosphate nahi nikal sakti → Hyperphosphatemia
• Hyperphosphatemia directly calcium ko suppress karta hai
• Kidney mein α1-hydroxylase kam → 1,25-OH-D (active Vit D) kam → intestinal Ca absorption kam
• PTH reactive taur par badh jaata hai (Secondary HPT)

2. Vitamin D Deficiency

• Inadequate diet ya sun exposure
• Malabsorption (celiac disease, Crohn's)
• Liver disease (25-hydroxylation nahi ho sakti)
• 25-OH-D low → calcium absorption kam → PTH badh jaata hai

3. Acute Pancreatitis

• Fat necrosis hoti hai, calcium fat ke sath "soap" bana leta hai (saponification)
• Calcium intra-abdominal fat necrosis mein chali jaati hai
• PTH normally HIGH hoti hai (compensatory)

4. Tumor Lysis Syndrome

• Cancer treatment ke baad rapidly phosphate release → hyperphosphatemia → hypocalcemia

5. Rhabdomyolysis (Early phase)

• Muscle breakdown → phosphate release → hypocalcemia

6. Bisphosphonates / Denosumab

• Bone resorption block karte hain → calcium release kam hoti hai

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🔴 GROUP 3: PTH HIGH hai lekin kaam nahi kar raha (Pseudohypoparathyroidism)

Pseudohypoparathyroidism (PHP) - Albright Hereditary Osteodystrophy

• PTH banata hai, lekin target organs (kidney, bone) PTH ko respond nahi karte
• Cause: Gs-alpha protein (adenylyl cyclase) mein defect → cAMP nahi banta
• Lab: Ca LOW, Phosphate HIGH, PTH very HIGH (kyunki parathyroid zyada banane ki koshish karta hai)
• Clinical features:
  • Chota qad (short stature)
  • Mote/round face
  • Shortened 4th/5th metacarpals (haath mein choti ungliyan)
  • Mental retardation
  • Calcifications (basal ganglia, subcutaneous)
  • Cataracts

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😣 Symptoms & Signs (Alamat)

🔴 Neuromuscular Irritability (Sabse Important)

👆 2 Classic Physical Signs (USMLE favorite!)

• Facial nerve ko cheek par tap karo (tragus ke saamne)
• Positive = Ipsilateral facial muscle twitch/contraction
• (Note: 10-15% normal logon mein bhi positive ho sakta hai - low specificity)

• BP cuff arm par lagao, systolic se 20 mmHg zyada inflate karo, 3 minute raho
• Positive = Carpal spasm - wrist flexion, thumb adduction, finger extension
• Ischemia se neuromuscular irritability unmask hoti hai

❤️ Cardiac Changes:

• Prolonged QT interval - most important ECG finding!
• Dysrhythmia, cardiac dysfunction
• Aortic/mitral valve calcification (chronic mein)
• Generally reversible when calcium normalize hota hai

🧠 Neuropsychiatric:

• Anxiety, depression, confusion, psychosis
• Dementia (chronic mein)
• Extrapyramidal symptoms (basal ganglia calcification se - PHP mein)
• Papilledema (raised ICP)
• Seizures

👁️ Chronic Hypocalcemia ke Extra Features:

• Subcapsular cataracts (aankhon mein)
• Ectopic calcification (basal ganglia, subcutaneous)
• Abnormal dentition (daant mein problems)
• Dry skin, brittle nails, coarse hair (hypoparathyroidism mein)

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🔍 Diagnosis Algorithm

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Lab Findings Summary:

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💊 Treatment (Ilaj)

🚨 Acute / Symptomatic Hypocalcemia (Emergency):

• 10% calcium gluconate, 10 mL → 50 mL 5% dextrose mein dilute karo
• Slow IV injection: 5 minute se zyada waqt mein do (tezi se dena dangerous hai - cardiac arrest!)
• Repeat kar sakte hain zaroorat par
• Phir IV calcium infusion: 10 ampoules 1L dextrose mein - 50 mL/hr se shuru karo

Calcium Chloride vs Calcium Gluconate:

• Gluconate prefer karo peripheral line mein (less irritating)
• Chloride zyada elemental calcium contain karta hai (cardiac arrest mein prefer)

• Hypomagnesemia - pehle Mg theek karo warna Ca theek nahi hogi!
• Hyperphosphatemia
• Alkalosis (alkalosis mein ionized calcium aur bhi kam ho jaata hai)

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💊 Chronic Hypocalcemia (Long-term Treatment):

• 10-20 mmol calcium har 6-12 ghante mein
• Calcium carbonate (khaane ke sath - acid chahiye absorb hone ke liye)
• Calcium citrate (khaali pet bhi de sakte hain)

• Calcitriol (1,25-OH-D) - DRUG OF CHOICE for:
  • Hypoparathyroidism
  • Chronic renal failure
  • Dose: 0.25 - 2 mcg/day
  • Kidney mein 1-hydroxylation ki zaroorat nahi hoti
• Cholecalciferol (Vit D3) / Ergocalciferol (Vit D2): Vitamin D deficiency ke liye (10,000-50,000 units/day)
• Alfacalcidol (1α-OH-D3): Hepatic 25-hydroxylation chahiye

• Hypoparathyroidism mein use ho sakti hai
• Urinary calcium kam karte hain (hypercalciuria aur nephrolithiasis prevent karte hain)
• Note: Hypercalcemia mein BILKUL NAHI!

• Chronic hypoparathyroidism mein - skeletal aur biochemical indices improve karta hai

• Pehle 1-2 hafte mein serum aur urine calcium check karo
• Phir stable hone ke baad har 3-6 mahine
• Goal: Hypercalcemia, hypercalciuria, nephrolithiasis aur renal failure AVOID karna

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📊 Hypocalcemia vs Hypercalcemia - Quick Comparison

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🎯 USMLE Step 2 High-Yield Points:

1. #1 cause overall: Postsurgical hypoparathyroidism (thyroidectomy ke baad)
2. #1 cause in CKD patients: Chronic renal failure
3. Hypomagnesemia: Hypocalcemia theek karne se pehle Mg correct karo!
4. Albumin low = Fake hypocalcemia - ionized calcium check karo
5. Chvostek sign = facial nerve tap → facial twitch (low specificity)
6. Trousseau sign = BP cuff → carpal spasm (more specific)
7. ECG: LONG QT = hypocalcemia (SHORT QT = hypercalcemia)
8. Alkalosis hypocalcemia ko worse banata hai (bound calcium badh jaata hai)
9. DiGeorge: 22q11.2 deletion → No parathyroids + No thymus → Hypocalcemia + Immune deficiency
10. Pseudohypoparathyroidism: PTH HIGH hai but organs respond nahi karte (Gs-alpha defect)
11. Albright features: Short stature, round face, short 4th/5th metacarpals = PHP
12. Acute treatment: IV Calcium Gluconate SLOW (5 min se zyada) - tezi se dene se cardiac arrest!
13. Chronic treatment: Calcitriol (active Vit D) + Oral calcium
14. Vitamin D deficiency: Ca LOW, PO4 LOW, PTH HIGH, 25-OH-D LOW, ALP HIGH
15. Hypoparathyroidism: Ca LOW, PO4 HIGH, PTH LOW, Vit D normal
16. PHP: Same as hypoparathyroidism EXCEPT PTH is VERY HIGH

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🦴 Paget Disease of Bone - Mukammal Urdu Roman Wazahat

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📌 Definition (Tarif)

• Osteoclasts zyadati se haddi tod dete hain (bone resorption badh jaati hai)
• Iske jawab mein osteoblasts bhi zor se haddi banane lagte hain
• Lekin jo nai haddi banti hai woh disorganized, weak aur mosaic pattern mein hoti hai
• Natija: Affected haddian badi, deformed, kamzor aur fracture prone ho jaati hain

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🌍 Epidemiology (Kon se log zyada mutasir hote hain)

• Prevalence: UK aur USA mein ~0.5% adults mein
• Western Europe (Britain, France, Germany) aur unse migrate karne wale logon mein common
• Scandinavians, Africans, Asians mein rare
• Males > Females (mard zyada mutasir)
• Age: 40 saal ke baad shuru hoti hai, umar ke sath badhti hai
• Autopsy studies: 3% logon mein jo 40+ umr ke hain
• Positive family history: 15-25% patients mein milti hai

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🧬 Etiology (Cause) - Dono theories hain

1. Genetic Theory:

• SQSTM1 gene (sequestosome-1 / p62 protein) - sabse common mutation, familial aur sporadic dono mein
• TNFRSF11A - RANK gene encode karta hai
• TNFRSF11B - Osteoprotegerin encode karta hai (juvenile Paget's mein deletion)
• VCP, OPTN, TM7SF4 genes bhi implicated hain

2. Viral Theory:

• Pagetic osteoclasts mein paramyxovirus (measles, respiratory syncytial virus) jaisi inclusions milti hain
• Measles vaccination ke widespread hone ke baad Paget's ka prevalence kam hua hai - indirect support
• Lekin live virus kabhi culture nahi hua - theory controversial hai

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⚙️ Pathophysiology (Kaise hota hai)

• Mesenchymal cells RANKL banate hain → Osteoclast precursors par RANK receptor activate karta hai → Mature osteoclast banta hai (bone todta hai)
• OPG (Osteoprotegerin) RANKL ko block karta hai - brakes ka kaam karta hai
• Paget's mein: RANKL badh jaata hai, OPG kam ho jaata hai → Osteoclasts uncontrolled ho jaate hain

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3 Phases of Paget's Disease:

Phase 1: OSTEOLYTIC (lytic phase)
- Overactive osteoclasts bone tod dete hain
- Extreme hypervascularization
- X-ray mein: "Blade of grass" lesion (advancing lytic wedge)
         ↓
Phase 2: MIXED (osteolytic + osteoblastic)
- Osteoblasts compensate karne ki koshish karte hain
- Normal lamellar bone → haphazard "WOVEN BONE" se replace
- Fibrous connective tissue marrow mein aa jaata hai
- MOST SYMPTOMATIC phase
         ↓
Phase 3: SCLEROTIC (burned-out phase)
- Bone resorption kam ho jaati hai
- Dense, hard, less vascular "mosaic bone" banti hai
- X-ray mein: Dense sclerotic lesions

• Normal osteoclast: 3-5 nuclei
• Pagetic osteoclast: up to 100 nuclei!
• 10-100 guna zyada in number
• Resorption rate: 9 mcg/day (normal: 1 mcg/day)

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📍 Common Sites (Kahan kahan hoti hai)

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😣 Clinical Manifestations (Symptoms)

Aksar ASYMPTOMATIC hota hai!

• Zyada tar diagnosis routine blood test mein elevated ALP ya incidental X-ray se hoti hai

Jab symptoms hon:

🦴 Bone Pain (Sabse common symptom):

• Localized dard - affected bone mein
• Raat ko bhi rehta hai (rest pain)
• Causes: Increased vascularity, lytic lesions, microfractures, bowing

📐 Deformity:

• Tibia bowing (curved tibia) - "Sabre tibia" - most classic
• Femur bowing → chalne mein takleef, secondary osteoarthritis of hip/knee
• Skull enlargement - hat size badh jaata hai, frontal bossing
• Short stature with kyphosis aur "simian posture" (age ke sath)
• Platybasia - skull ka base soft ho jaata hai

👂 Deafness (Hearing Loss):

• Temporal bone mein Paget's → cochlear nerve compression → sensorineural deafness (rare mein conductive bhi)
• Kaan ki problems skull involvement mein common

🦷 Jaw/Dental Problems:

• Facial bones mein Paget's → teeth loose ho jaate hain, facial deformity

🔴 Neurological Complications:

• Spinal stenosis → nerve compression → radiculopathy, myelopathy
• Cranial nerve palsies - facial, oculomotor
• Brainstem compression (platybasia se)
• Rarely: Spinal cord compression

❤️ Cardiac Complications:

• Agar 15-35% skeleton involved ho aur ALP 4x normal se zyada:
• Pagetic bone mein arteriovenous shunting → excessive blood flow
• High-output cardiac failure (rare, usually sath mein cardiac disease ho toh)
• Calcific aortic stenosis

🦠 Malignant Transformation (Sabse feared complication):

• Incidence: <0.5% (rare lekin serious)
• Mostly Osteosarcoma (long bones mein, especially femur)
• Presentation: Purani Paget's lesion mein naya pain → RED FLAG
• Prognosis: Very poor
• Giant cell tumors bhi ho sakte hain - glucocorticoids se respond karte hain

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🔍 Diagnosis

Lab Tests:

Key point: Immobilization ke sath Paget's → rare mein hypercalcemia ho sakti hai

X-Ray Findings (Bohot important for USMLE!):

Imaging Modalities:

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💊 Treatment (Ilaj)

Treatment kab karein?

1. Bone pain jo pagetic site se related ho
2. Fracture ya fracture ka high risk
3. Surgery planned pagetic bone par (blood loss kam karna)
4. Neurological complications (nerve compression)
5. High disease activity (ALP bahut high) + involvement of skull, vertebra, ya weight-bearing bones
6. Hearing loss se bachao ke liye

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🥇 Drug of Choice: BISPHOSPHONATES

• Single injection - prolonged effect, effects saalon tak reh sakte hain
• Best pain response
• Treatment of choice

2. Calcitonin

• 100 U subcutaneous daily × 6-18 months
• ALP sirf 50% tak kam karta hai
• Second line - jab bisphosphonates available na hon ya contraindicated hon

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⚠️ Important: Bisphosphonate se pehle zaroor do:

• Calcium + Vitamin D supplements - kyunki bone resorption suddenly block hone se "hungry bone syndrome" ho sakta hai → hypocalcemia

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📊 Paget's Disease - Lab Summary

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🎯 USMLE Step 2 High-Yield Points:

1. Definition: Focal bone remodeling disorder - osteoclast overactivity → disorganized bone
2. Most common sites: Pelvis > Vertebra > Skull > Femur > Tibia
3. Calcium: NORMAL - yeh bohot important hai (hypercalcemia nahi hoti normally)
4. ALP: VERY HIGH - best marker for diagnosis and monitoring
5. Deafness - temporal bone involvement se cochlear nerve compression
6. "Cotton wool" skull - X-ray mein classic pagetic finding
7. "Picture frame vertebra" - vertebra mein cortical thickening at end plates
8. "Blade of grass" - long bone mein early lytic advancing front
9. "Ivory vertebra" - dense sclerotic vertebra
10. Osteosarcoma - Paget's ka feared complication (<0.5%) - naya pain = RED FLAG
11. Treatment: Zoledronic acid - single IV dose, 90% mein ALP normalize karta hai
12. High-output cardiac failure - extensive pagetic skeleton, AV shunting
13. Before bisphosphonates: Calcium aur Vitamin D zaroor do
14. Immobilization + Paget's = Hypercalcemia risk
15. Bone scan (Tc-99m) = most sensitive test for disease extent
16. Paramyxovirus (measles) - viral theory (controversial)
17. SQSTM1/p62 gene - most common mutation in familial + sporadic cases
18. Males > Females, Age > 40, Western European ancestry

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🩺 Hypercortisolism (Cushing Syndrome) - Mukammal Urdu Roman Wazahat

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📌 Definition

• Cushing SYNDROME: Sare causes ki wajah se hypercortisolism (broad term)
• Cushing DISEASE: Specifically pituitary adenoma se ACTH excess → cortisol high (narrow term)

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🔬 Normal HPA Axis (Samajhne ke liye zaroori)

Hypothalamus → CRH (Corticotropin Releasing Hormone)
         ↓
Anterior Pituitary → ACTH (Adrenocorticotropic Hormone)
         ↓
Adrenal Cortex (Zona Fasciculata) → CORTISOL
         ↓
Cortisol HIGH → Feedback inhibition → CRH aur ACTH dono suppress hote hain

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⚡ Causes of Hypercortisolism - Classification

🔴 EXOGENOUS (Most Common Overall!)

• Iatrogenic Cushing's - steroids bahar se de rhe hain (doctor ne diya)
• Asthma, RA, SLE, transplant patients mein steroid therapy
• ACTH LOW, Cortisol HIGH
• Adrenal glands ATROPHY ho jaati hain (exogenous ACTH suppress karta hai)
• Yeh overall sabse common cause hai - USMLE mein pehla dhundho!

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🟡 ENDOGENOUS CAUSES:

1. PITUITARY CUSHING'S DISEASE - 60-70% of endogenous

• Pituitary mein ACTH-secreting adenoma (corticotroph adenoma) hota hai
• Adenoma bahut chota hota hai - mass effect nahi hota aksar
• ACTH HIGH → Bilateral adrenal hyperplasia → Cortisol HIGH
• Females 4x zyada affected, age 20-40
• ACTH-dependent Cushing's
• Adrenal glands: bilateral diffuse hyperplasia

2. ECTOPIC ACTH SYNDROME - 10-15% of endogenous

• Non-pituitary tumor ACTH banata hai
• Sabse common: Small cell carcinoma of lung
• Iske alawa: Carcinoid tumor, Medullary thyroid carcinoma, Pancreatic NETs
• ACTH bahut HIGH (pituitary se bhi zyada)
• Hypokalemia - zyada ACTH → aldosterone-like effect → K+ loss
• Hyperpigmentation - ACTH ke sath MSH (melanocyte stimulating hormone) bhi release hota hai
• Classic Cushing features kam prominent hote hain (disease tezi se chalti hai)
• ACTH-dependent Cushing's

3. ADRENAL CUSHING'S - 20-30% of endogenous

• Adrenal gland khud autonomously cortisol banati hai
• Causes: Adrenal adenoma ya adrenal carcinoma ya primary hyperplasia
• ACTH SUPPRESSED (cortisol feedback se) → dono adrenals compress
• Ek adrenal tumor → doosri adrenal atrophy
• ACTH-independent Cushing's

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Causes ka Quick Summary:

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😣 Clinical Features (Symptoms & Signs)

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🔴 1. FAT REDISTRIBUTION (Central Obesity - Sabse Characteristic)

• Truncal obesity - pet bara, haath pair patlay
• Moon face (Moon facies) - gol sootha hua chehra
• Buffalo hump - gardan ke peeche fat ka deposit (posterior neck)
• Supraclavicular fat pads - collar bone ke upar fat
• Extremities: Thin (muscle atrophy se)

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🔴 2. SKIN CHANGES

• Purple/violaceous striae - pet, janghon, kaankhon par (>1 cm wide, purple rang) - CLASSIC!
• Thin, fragile skin - skin atrophy
• Easy bruising - minor trauma se nishan pad jaate hain
• Poor wound healing - cortisol fibroblast activity suppress karta hai
• Hyperpigmentation - SIRF ectopic ACTH mein (MSH ka co-secretion)
• Acne, hirsutism (androgen excess se)

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🔴 3. MUSCLE WEAKNESS (Myopathy)

• Proximal muscle weakness - upar uthhna, seedhiyan chadhna mushkil
• Type II (fast-twitch) myofibers atrophy specifically
• Thin extremities despite truncal obesity - classic finding

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🔴 4. HYPERTENSION

• Diastolic hypertension - most common cardiovascular feature
• Cortisol mineralocorticoid receptors par act karta hai → sodium aur pani retain
• Renin-angiotensin system bhi stimulate hota hai

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🔴 5. METABOLIC EFFECTS

• Hyperglycemia / Diabetes mellitus - cortisol gluconeogenesis badhata hai, insulin resistance
• Hypokalemia - especially ectopic ACTH mein (mineralocorticoid excess)
• Dyslipidemia - cholesterol, triglycerides badhte hain
• Metabolic alkalosis (ectopic ACTH mein)

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🔴 6. BONES - Osteoporosis

• Osteoporosis - vertebral compression fractures
• Cortisol osteoblast activity suppress karta hai + calcium absorption kam karta hai
• Back pain, height loss

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🔴 7. REPRODUCTIVE / GONADAL

• Females: Menstrual irregularities (oligomenorrhea/amenorrhea), infertility, hirsutism, acne
• Males: Decreased libido, erectile dysfunction, testicular atrophy
• Cortisol gonadotropins suppress karta hai

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🔴 8. PSYCHIATRIC / NEUROLOGICAL

• Depression - most common psychiatric manifestation
• Anxiety, irritability, emotional lability
• Cognitive dysfunction, memory impairment
• Psychosis (severe mein)
• Fatigue (chronic)

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🔴 9. IMMUNE SUPPRESSION

• Recurrent infections (bacterial, fungal)
• Lymphopenia, eosinopenia
• Cortisol T-cell proliferation block karta hai

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🔴 10. EXTRA FEATURES (Ectopic ACTH mein khas)

• Hyperpigmentation - skin aur mucous membranes par (ACTH ke sath MSH release)
• Severe hypokalemia
• Metabolic alkalosis
• Rapid onset - moon face etc. kam prominent kyunki disease tez hoti hai

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🔍 Diagnosis Algorithm

1. Pehle CONFIRM karo ke Cushing's hai
2. Phir pata karo CAUSE kya hai

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STEP 1: Screening Tests (Cushing's confirm karna)

• Normal mein: Cortisol subah HIGH, raat ko LOW
• Cushing's mein: Yeh rhythm KHATAM ho jaati hai - raat ko bhi cortisol high

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STEP 2: Differential Diagnosis (Cause pata karna)

• → ACTH-independent = Adrenal tumor
• → Unenhanced CT adrenals karo
• Unilateral mass → Adrenal tumor
• Bilateral → Primary adrenal hyperplasia

• → ACTH-dependent = Pituitary ya Ectopic
• → MRI pituitary karo

• Sabse accurate test pituitary vs ectopic differentiate karne ke liye
• Pituitary se drain hone wali veins mein ACTH measure karte hain
• Central/peripheral ratio > 2 baseline = pituitary source confirm

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Lab Summary Table:

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💊 Treatment (Ilaj)

🥇 Cause ke hisaab se ilaj:

1. Exogenous/Iatrogenic:

• Steroid dose gradually taper karo (abrupt bandh karna dangerous - adrenal crisis!)
• Steroid-sparing agents use karo

2. Pituitary Cushing's Disease - DEFINITIVE TREATMENT:

• Transsphenoidal pituitary surgery (endoscopic) - 1st line
• Cure rate: 60-80% (experienced surgeon ke haath se)
• Agar surgery fail ho: Repeat surgery, Radiotherapy (fractionated ya stereotactic), Medical therapy, Bilateral adrenalectomy

3. Adrenal Tumor:

• Laparoscopic adrenalectomy - benign adenoma mein
• Open adrenalectomy - malignancy suspected ho toh
• Bilateral hyperplasia → Bilateral adrenalectomy

4. Ectopic ACTH:

• Primary tumor treat karo (lung cancer, carcinoid)
• Agar tumor na mile: Medical therapy ya bilateral adrenalectomy

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💊 Medical / Drug Therapy (Cortisol kam karne ke liye):

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⚠️ Post-Surgery Consideration:

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Nelson Syndrome (Rare):

• Bilateral adrenalectomy ke baad agar pituitary adenoma baaki ho
• ACTH feedback remove hone se pituitary tumor grow karta hai
• Mass effects: headache, visual field defects
• Hyperpigmentation (ACTH bahut high)

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🎯 USMLE Step 2 High-Yield Points:

1. Most common cause overall = Exogenous steroids (Iatrogenic) - pehle poochho!
2. Cushing DISEASE = specifically pituitary ACTH adenoma (60-70% endogenous)
3. Ectopic ACTH = small cell lung cancer - hyperpigmentation + hypokalemia + rapid onset
4. Moon face + Buffalo hump + Purple striae + Truncal obesity = classic Cushing's picture
5. Purple/violaceous striae > 1 cm = Cushing's (normal striae pale/white hoti hain)
6. First test: 24h urine free cortisol / Overnight 1 mg Dex suppression test
7. ACTH measure karo - pituitary/ectopic (HIGH) vs adrenal/exogenous (LOW)
8. High-dose Dex test: Pituitary adenoma suppress KARTA hai, ectopic nahi karta
9. IPSS = most accurate for pituitary vs ectopic differentiation
10. Hypokalemia + alkalosis especially in ectopic ACTH (excessive mineralocorticoid effect)
11. Hyperpigmentation = ONLY ectopic ACTH ya untreated Addison's (ACTH + MSH)
12. Definitive treatment: Transsphenoidal surgery (pituitary), laparoscopic adrenalectomy (adrenal)
13. Post-surgery: Steroid cover zaroori - HPA axis suppressed hota hai
14. Metyrapone aur Osilodrostat - 11β-hydroxylase inhibitors (cortisol kam karte hain)
15. Nelson Syndrome - bilateral adrenalectomy ke baad pituitary tumor grow karna
16. Osteoporosis Cushing's mein - vertebral fractures common
17. Diurnal rhythm loss - midnight cortisol HIGH = sensitive marker
18. Proximal muscle weakness - characteristic (type II fiber atrophy)
19. Pseudo-Cushing's = alcohol excess, obesity, depression mein bhi cortisol high - dex test se distinguish
20. Crooke hyaline change - histology mein pituitary ACTH cells ka characteristic finding

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