When to intubate in GCS?

GCS ≤ 8 requires intubation for airway protection. The patient cannot protect their own airway at this level of consciousness. Motor score is the most prognostically important component.

What is the best initial fluid for sepsis resuscitation?

Lactated Ringer's (LR) is the preferred resuscitation fluid. The SMART trial (2018) showed balanced crystalloids reduced death, new renal failure, and persistent renal dysfunction compared to normal saline.

When to start vasopressors in septic shock?

Start norepinephrine (first-line vasopressor) if MAP remains < 65 mmHg after initial 30 mL/kg crystalloid resuscitation, or earlier if patient is profoundly hypotensive. Do not delay pressors to complete full fluid resuscitation.

Why can serum uric acid be normal during acute gout?

During acute inflammation, IL-6 increases renal urate excretion and redistributes urate from plasma to tissues. Up to 40% of acute gout flares have normal serum uric acid. Joint aspiration with polarized microscopy is needed for definitive diagnosis.

How do you distinguish lupus flare from infection in SLE?

Key clues: CRP is low/normal in flare but elevated in infection. Complement (C3/C4) drops in flare but is normal/elevated in infection. Procalcitonin is elevated in bacterial infection but normal in flare. Anti-dsDNA rises in flare, stable in infection.

What is the difference between DKA and HHS?

DKA features acidosis (pH 600), hyperosmolality (> 320), and minimal ketosis -typically in Type 2 DM. DKA requires insulin drip; HHS requires aggressive fluid resuscitation first.

When to give tPA in acute ischemic stroke?

IV alteplase (tPA) can be given within 4.5 hours of last known well time in eligible patients. CT head must rule out hemorrhage first. For large vessel occlusion, mechanical thrombectomy can be performed up to 24 hours with favorable imaging.

What antibiotics for community-acquired pneumonia?

Inpatient non-ICU: ceftriaxone + azithromycin. ICU: ceftriaxone + azithromycin (add vancomycin if MRSA risk). Outpatient healthy: amoxicillin. Outpatient with comorbidities: augmentin + azithromycin or respiratory fluoroquinolone. Duration: 5 days if clinically stable for 48 hours.

How to interpret iron studies?

Iron deficiency: low ferritin (< 30), high TIBC, low iron, low transferrin saturation (< 20%). Anemia of chronic disease: normal/high ferritin (acute phase reactant), low TIBC, low iron. A ferritin of 50-100 in an inflamed patient may still represent iron deficiency.

What is the correction rate for hyponatremia?

Correct sodium no more than 8 mEq/L in 24 hours to avoid osmotic demyelination syndrome (ODS). For symptomatic severe hyponatremia with seizures, give 3% hypertonic saline 100-150 mL bolus over 10-20 minutes. If overcorrected, use D5W + DDAVP rescue protocol.

When to start antibiotics in meningitis?

Within 30-60 minutes. Do NOT delay antibiotics for LP or CT. Draw blood cultures, start empiric antibiotics (vancomycin + ceftriaxone ± ampicillin if > 50 or immunocompromised), then perform LP when possible. Dexamethasone should be given before or with the first antibiotic dose.

DOACs vs warfarin in antiphospholipid syndrome?

DOACs are contraindicated in APS. The TRAPS trial (2018) showed rivaroxaban was inferior to warfarin with more thrombotic events in triple-positive APS patients. Warfarin with INR target 2-3 is the standard for APS, indefinitely.

How to manage scleroderma renal crisis?

ACE inhibitors (captopril) are life-saving -start immediately and titrate aggressively. Do NOT hold for rising creatinine. Steroids > 15 mg prednisone per day precipitate scleroderma renal crisis. ARBs are NOT a substitute -evidence is only for ACEi.

What are the 4 pillars of heart failure treatment?

Guideline-directed medical therapy (GDMT) for HFrEF: (1) ARNI or ACEi/ARB, (2) beta-blocker (carvedilol, metoprolol succinate, or bisoprolol), (3) MRA (spironolactone or eplerenone), (4) SGLT2 inhibitor (dapagliflozin or empagliflozin). All four should be initiated and titrated to target doses.

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URGENTHeme/Onc

Hypercalcemia of Malignancy

The most common cause of hypercalcemia in hospitalized patients. "Stones, bones, groans, psychiatric moans." PTH will be SUPPRESSED (unlike primary hyperparathyroidism). Treatment is stepwise: fluids → calcitonin (hours) → bisphosphonate (days). Furosemide for hypercalcemia is outdated.

🔍 Overview

Mechanisms of Malignancy-Related Hypercalcemia

Mechanism	Frequency	Associated Cancers	Key Lab Finding
PTHrP (Humoral)	~80%	Squamous cell carcinomas (lung, H&N), renal cell, breast, bladder	PTHrP elevated, PTH suppressed, PO₄ low
Osteolytic metastases	~20%	Breast cancer, multiple myeloma	PTHrP normal, local cytokine release (RANKL, IL-6)
1,25-dihydroxyvitamin D	< 1%	Lymphoma (Hodgkin and non-Hodgkin)	1,25-vit D elevated (tumor-produced 1-alpha hydroxylase)
Ectopic PTH	Very rare	Ovarian, lung small cell (rare)	PTH elevated (from tumor)

Symptoms -"Stones, Bones, Groans, Psychiatric Moans"

Stones: Nephrolithiasis, nephrocalcinosis, polyuria (nephrogenic DI from Ca²⁺ → impaired ADH response)
Bones: Bone pain, pathologic fractures, osteoporosis
Groans: Abdominal pain, constipation, nausea, vomiting, pancreatitis (rare)
Psychiatric moans: Confusion, lethargy, depression, psychosis, coma
Cardiac: Shortened QT interval, bradycardia, AV block (severe)
Renal: Polyuria → dehydration → worsening hypercalcemia (vicious cycle)

Severity Classification

Severity	Corrected Ca²⁺	Approach
Mild	10.5–12.0 mg/dL	Oral hydration, monitor, treat underlying malignancy
Moderate	12.0–14.0 mg/dL	IV fluids ± calcitonin + bisphosphonate
Severe / Symptomatic	> 14.0 mg/dL or symptomatic	Aggressive IV fluids + calcitonin + bisphosphonate. May need ICU.

🚨 Management

Stepwise Treatment Protocol

Step	Intervention	Onset	Details
Step 1: IV NS	Normal Saline 200–300 mL/hr	Immediate	Most patients are severely volume-depleted from hypercalcemia-induced nephrogenic DI (polyuria + poor PO intake). This alone drops Ca by 1–2 mg/dL. Goal: restore euvolemia and enhance renal calcium excretion.
Step 2: Calcitonin	Calcitonin (Miacalcin) 4 IU/kg SQ/IM q12h	4–6 hours	Bridge therapy -works FAST but tachyphylaxis by 48h (receptors downregulate). Drops Ca by ~1–2 mg/dL. Mild side effect: flushing, nausea. Used while waiting for bisphosphonate to kick in.
Step 3: Bisphosphonate	Zoledronic acid (Zometa) 4 mg IV over 15 min	2–4 DAYS	Definitive treatment. Inhibits osteoclast-mediated bone resorption. Effect lasts weeks. Check Cr first -reduce dose if CrCl < 60. Alternative: pamidronate 60–90 mg IV over 2–4h (slower infusion, may be better in renal impairment).
Step 4 (Refractory)	Denosumab (Xgeva) 120 mg SQ	Days	For bisphosphonate-refractory hypercalcemia. RANKL inhibitor. Works even in renal failure (not renally cleared, unlike bisphosphonates). Dose on days 1, 8, 15, 29, then monthly.

Furosemide (Lasix) for hypercalcemia is OUTDATED. Old teaching was "saline + Lasix." Current evidence: Lasix only if volume overloaded. It does not meaningfully lower calcium and risks further dehydration and electrolyte derangements.

Special Situations

Lymphoma (1,25-vit D mediated): Glucocorticoids (dexamethasone 4 mg IV q6h or equivalent) are effective -they inhibit 1-alpha hydroxylase in tumor cells and decrease 1,25-vit D production.
Multiple myeloma: Bisphosphonates are standard (both for hypercalcemia and skeletal events). Zoledronic acid or pamidronate.
Dialysis: If refractory or anuric, hemodialysis with low-calcium dialysate can rapidly lower calcium.

🧪 Workup

Laboratory Workup

Corrected calcium = measured Ca + 0.8 × (4.0 − albumin). Or check ionized calcium (more accurate, not affected by albumin).
PTH -should be SUPPRESSED (< 20 pg/mL) in malignancy. If PTH is elevated → think primary hyperparathyroidism (even in cancer patients -can coexist).
PTHrP -elevated in humoral hypercalcemia of malignancy (80% of cases). Order if PTH suppressed.
1,25-dihydroxyvitamin D -elevated in lymphoma. Order if PTHrP is normal and PTH is suppressed.
25-hydroxyvitamin D -to rule out exogenous vitamin D toxicity.
Phosphate -low in PTHrP-mediated (PTHrP causes renal phosphate wasting, same as PTH).
BMP -Cr (renal function), K⁺, Mg²⁺.
ECG -shortened QT interval is the classic finding. Also watch for bradycardia, AV block.
SPEP/UPEP -if myeloma suspected.

💊 Medications

Hypercalcemia Medications

Drug	Dose	Onset	Duration	Key Notes
Normal Saline	200–300 mL/hr	Immediate	During infusion	First-line. Volume expansion + calciuresis. Drops Ca ~1–2 mg/dL. Watch for volume overload.
Calcitonin (Miacalcin)	4 IU/kg SQ/IM q12h	4–6 hours	48h (tachyphylaxis)	Bridge only. Drops Ca ~1–2 mg/dL. Safe but temporary. Tachyphylaxis limits use beyond 48h.
Zoledronic acid (Zometa)	4 mg IV over 15 min	2–4 days	Weeks	Definitive treatment. Check CrCl -reduce dose if < 60. Risk: osteonecrosis of jaw (rare), renal toxicity.
Pamidronate	60–90 mg IV over 2–4h	2–4 days	Weeks	Alternative to zoledronic acid. Longer infusion but may be better tolerated in renal impairment.
Denosumab (Xgeva)	120 mg SQ	Days	Weeks	Bisphosphonate-refractory cases. RANKL inhibitor. Works in renal failure. Risk: hypocalcemia, ONJ.
Glucocorticoids	Dexa 4 mg IV q6h	Days	During treatment	Effective for lymphoma and granulomatous disease (1,25-vit D mediated). Not effective for PTHrP-mediated.

📋 On Rounds

Why is PTH suppressed in hypercalcemia of malignancy?

In malignancy-related hypercalcemia, the elevated calcium provides negative feedback to the parathyroid glands via the calcium-sensing receptor (CaSR). Since the hypercalcemia is driven by PTHrP, osteolytic metastases, or tumor-produced 1,25-vit D -NOT by the parathyroid glands -the glands appropriately suppress PTH secretion. This is the key lab distinction: Malignancy → PTH LOW, PTHrP HIGH.

What is tachyphylaxis with calcitonin, and how does it affect your treatment plan?

Tachyphylaxis = diminishing response to a drug after repeated doses. Calcitonin works by inhibiting osteoclast activity and promoting renal calcium excretion. However, calcitonin receptors downregulate within 48 hours of continuous exposure, and the calcium-lowering effect is lost. This is why calcitonin is a bridge therapy only -it buys you 24–48h of calcium lowering while you wait for the bisphosphonate (zoledronic acid)

When would you use denosumab instead of zoledronic acid?

Denosumab (Xgeva) is a RANKL inhibitor (monoclonal antibody) used for hypercalcemia refractory to bisphosphonates. Key advantages: (1) Not renally cleared -safe in renal failure (CrCl < 30), whereas bisphosphonates require dose adjustment or are contraindicated. (2) Bisphosphonate-refractory -if Ca remains elevated after adequate bisphosphonate trial. Disadvantages: (1) Risk of rebound hypercalcemia if discontinued abruptly.

Clinical Examples

📋 Case 1, Hypercalcemia of Malignancy (PTHrP-Mediated)

Patient: 62M with 30-pack-year smoking history. Confusion, polyuria, constipation. Ca 15.2, PTH < 5, PTHrP 14.8 pmol/L (elevated). CT chest: 5 cm RUL mass with hilar LAD. Cr 2.1.

Key findings: Severe hypercalcemia of malignancy via PTHrP from probable squamous cell lung cancer. Suppressed PTH confirms non-parathyroid etiology. Dehydration worsening renal function.

Management:

NS 200-300 mL/hr (aggressive rehydration, these patients are profoundly volume-depleted)
Calcitonin 4 IU/kg SQ q12h (bridge, works within hours but tachyphylaxis by 48h)
Zoledronic acid 4 mg IV over 15 min (definitive, onset 2-4 days, lasts 2-4 weeks)
No furosemide unless volume overloaded (old teaching of "lasix for hypercalcemia" is outdated and harmful in dehydrated patients)
Oncology consult for biopsy and staging of lung mass

Teaching point: Calcitonin is a bridge, not a treatment. Its effect wears off in 48h due to receptor tachyphylaxis. Zoledronic acid is the definitive agent but takes 2-4 days, hence the bridge strategy.

📋 Case 2, Severe Hypercalcemia with Renal Failure

Patient: 71F with metastatic breast cancer. Ca 17.8, Cr 4.2 (baseline 1.0), AMS. PTH < 3. No urine output × 6h despite 2L NS bolus. ECG: short QT.

Key findings: Life-threatening hypercalcemia with oliguric AKI. Bisphosphonates relatively contraindicated at CrCl < 30. Need alternative approach.

Management:

Continue aggressive IVF, target UOP > 200 mL/hr if achievable
Calcitonin 4 IU/kg SQ q12h (immediate bridge)
Denosumab 120 mg SQ (not renally cleared, safe in renal failure, preferred over zoledronic acid here)
If refractory: emergent hemodialysis with low-calcium dialysate (can drop Ca 3-4 mg/dL per session)
Telemetry monitoring, QT shortening, arrhythmia risk at Ca > 14

Teaching point: Denosumab is the rescue agent when bisphosphonates are contraindicated (renal failure) or have failed. Key risk: rebound hypercalcemia if stopped abruptly, always plan for ongoing dosing or transition.

📋 Case 3, Granulomatous Disease Hypercalcemia

Patient: 38F with known sarcoidosis. Ca 12.6, PTH 6 (suppressed), PTHrP normal, 1,25-dihydroxy vitamin D 88 pg/mL (elevated), 25-OH vitamin D 22 (normal). Bilateral hilar LAD on CXR.

Key findings: Granulomatous hypercalcemia, activated macrophages in granulomas express 1-alpha-hydroxylase, converting 25-OH vitamin D → 1,25-dihydroxy vitamin D (calcitriol) autonomously. Not PTH-driven.

Management:

IV hydration (NS 150-200 mL/hr)
Prednisone 20-40 mg daily (first-line, glucocorticoids inhibit 1-alpha-hydroxylase in macrophages)
Expect calcium normalization within 3-5 days of steroids
Avoid vitamin D supplementation and excessive sun exposure (fuel the pathway)
Treat underlying sarcoidosis per pulmonology

Teaching point: Granulomatous hypercalcemia (sarcoidosis, TB, fungal) responds to glucocorticoids because steroids suppress macrophage 1-alpha-hydroxylase. This is the one form of hypercalcemia where steroids are first-line, not bisphosphonates.

Monitoring Parameters

Parameter	Frequency	Target / Action
Ionized calcium or corrected Ca	q6–8h until stable	Trend toward normalization. Recheck 2–4 days after bisphosphonate.
BMP (Cr, K⁺, Mg²⁺, PO₄)	q12h initially	Cr for AKI/renal recovery. Watch for hypokalemia, hypomagnesemia, hypophosphatemia with fluids.
Fluid balance / I&Os	Strict	Maintain euvolemia. Aggressive IVF but watch for volume overload (especially if cardiac history).
ECG	Admission + PRN	Shortened QT, bradycardia, AV block.
Mental status	q shift	Improvement in confusion/lethargy as calcium normalizes.

Monitoring Parameters -Hypertrophic Cardiomyopathy

Parameter	Frequency	Target / Action
Vitals	q4h floor, q1–2h ICU	HR, BP, RR, SpO₂, Temp -notify for significant deviations
Labs (BMP, CBC)	Daily AM or as indicated	Trend Cr, K⁺, WBC, Hgb -adjust treatment based on trajectory
Disease-specific markers	Per clinical context	See Overview and Management tabs for condition-specific targets
I&Os	Strict if volume-sensitive	UOP ≥ 0.5 mL/kg/hr. Net fluid balance guides diuresis or resuscitation.
Telemetry	Continuous if indicated	Arrhythmia detection. Discontinue when no longer indicated (reduces alarm fatigue).
Clinical response	Each assessment	Symptom improvement, functional status, appetite, mental status -the exam matters more than labs

Don't just order labs -act on them. Every lab should have a clear clinical question. If you wouldn't change management based on the result, don't order it.

⚡ Summary

Hypercalcemia of Malignancy -Key Points

Mechanisms

PTHrP (80% -squamous, renal, breast), osteolytic mets (20% -breast, myeloma), 1,25-vit D (<1% -lymphoma).

Key Lab

PTH SUPPRESSED (unlike primary hyperparathyroidism). PTHrP elevated. Corrected Ca or ionized Ca. Shortened QT on ECG.

Step 1

Aggressive IV NS 200–300 mL/hr. Most patients are severely volume-depleted. Drops Ca 1–2 mg/dL alone.

Step 2

Calcitonin 4 IU/kg SQ q12h -works in HOURS but tachyphylaxis by 48h. Bridge therapy only.

Step 3

Zoledronic acid 4 mg IV -definitive treatment. Takes 2–4 DAYS. Lasts weeks. Check Cr first.

Outdated

Furosemide for hypercalcemia is OUTDATED. Only use if volume overloaded. Does not meaningfully lower calcium.