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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EmergentRheumatology

Antiphospholipid Syndrome

Autoimmune prothrombotic disorder. Triple-positive APS has highest risk. Warfarin is the standard, DOACs contraindicated (TRAPS trial). Catastrophic APS = multi-organ thrombosis requiring triple therapy.

🔍 Overview

Diagnostic Criteria (Revised Sapporo)

Requires ≥ 1 clinical criterion + ≥ 1 lab criterion, with lab confirmed on 2 occasions ≥ 12 weeks apart.

Clinical Criteria (≥ 1)	Lab Criteria (≥ 1, confirmed × 2)
Vascular thrombosis: arterial, venous, or small vessel thrombosis in any organ (DVT, PE, stroke, MI, renal/hepatic thrombosis)	Lupus anticoagulant (LA) -most strongly associated with thrombosis
Pregnancy morbidity: ≥ 1 unexplained fetal death ≥ 10 weeks, ≥ 3 unexplained consecutive losses < 10 weeks, premature birth < 34 weeks due to eclampsia/placental insufficiency	Anticardiolipin (aCL) IgG or IgM -medium-high titer
	Anti-β2 glycoprotein I IgG or IgM

Triple-positive APS (all 3 antibodies positive) has the highest thrombotic risk. DOACs are CONTRAINDICATED in APS -TRAPS, 2018 showed rivaroxaban was inferior to warfarin with more thrombotic events. Warfarin is the standard.

Treatment

Scenario	Treatment
Venous thrombosis (DVT/PE)	Warfarin INR 2–3, indefinite. No DOACs.
Arterial thrombosis (stroke, MI)	Warfarin INR 2–3 (some advocate INR 3–4 for arterial events, controversial). ± aspirin.
Obstetric APS (no thrombosis)	LMWH (enoxaparin prophylactic dose) + low-dose aspirin throughout pregnancy.
Catastrophic APS (CAPS)	Triple therapy: anticoagulation + high-dose steroids + plasma exchange or IVIG. Mortality ~50%. Multiorgan thrombotic microangiopathy.

📋 On Rounds

Why is the aPTT prolonged in APS if the patient is actually prothrombotic?

The lupus anticoagulant binds to phospholipids that are used as reagents in the aPTT assay. In the test tube, this binding interferes with the phospholipid-dependent coagulation cascade → prolonged aPTT in vitro. But in vivo, these same antibodies bind endothelial cell phospholipids, activate complement, inhibit natural anticoagulants (protein C, annexin V), and activate platelets and monocytes → prothrombotic state.

Why are DOACs contraindicated in antiphospholipid syndrome?

The TRAPS trial (2018) was stopped early for safety -triple-positive APS patients randomized to rivaroxaban had significantly more thrombotic events (including stroke and MI) than those on warfarin.

What is catastrophic APS (CAPS) and how do you treat it?

CAPS = rapid-onset multi-organ thrombotic microangiopathy in APS -affects ≥ 3 organs within 1 week. Mortality ~30-50%. Organs affected: renal (TMA/RPGN), CNS (stroke, seizures), cardiac (valve thrombosis, MI), pulmonary (PE, ARDS), skin (livedo, digital gangrene). Triggered by: infection (#1), surgery, anticoag withdrawal, SLE flare. Treatment = triple therapy: (1) Anticoagulation (heparin drip)

What lab tests confirm APS and why do you need them positive twice?

3 antibodies: (1) Lupus anticoagulant (LA) -functional assay (prolonged aPTT that doesn't correct with mixing study). (2) Anticardiolipin antibodies (aCL) -IgG and IgM, medium-to-high titer. (3) Anti-β2-glycoprotein I (anti-β2GP1) -IgG and IgM. Must be positive on ≥ 2 occasions, at least 12 weeks apart -because transient positivity occurs with infections (HIV, hepatitis, syphilis), medications, and acute thrombotic events.

Why must antiphospholipid antibodies be confirmed at 12 weeks?

Transient aPL positivity occurs commonly during infections, medications, and other acute illnesses. Persistent positivity (≥ 12 weeks apart on 2 occasions) is required for diagnosis to avoid overdiagnosis and unnecessary lifelong anticoagulation.

What is catastrophic APS (CAPS)?

Multi-organ failure developing over < 1 week due to widespread small-vessel thrombosis. ~50% mortality. Affects ≥ 3 organ systems simultaneously. Treat with triple therapy: anticoagulation + high-dose steroids + PLEX or IVIG.

What is the standard regimen for obstetric APS?

Low-dose ASA (81 mg) started preconception + prophylactic LMWH (enoxaparin 40 mg daily) added once pregnancy confirmed. This reduces pregnancy loss from ~70% to ~20-30%.

Which APS patients are highest risk for recurrent thrombosis?

Triple-positive patients (lupus anticoagulant + anticardiolipin + anti-β2GP1 all positive). These patients need lifelong anticoagulation -never stop. Single positivity has lower (but not zero) recurrence risk.

Clinical Examples

📋 Case 1, Triple-Positive APS with Recurrent DVT

Patient: 34-year-old man with known triple-positive APS on warfarin, presenting with new left leg swelling. INR 1.4 (subtherapeutic, missed doses). Compression US confirms acute proximal DVT.

Key findings: Triple-positive: LA+, aCL IgG 82 GPL, anti-β2GP1 IgG+. Prior DVT 2 years ago. No SLE features.

Management:

Start heparin drip immediately (bridge to therapeutic warfarin)
Target INR 2-3 (some experts target 3-4 for recurrent events on therapeutic INR) TRAPS, 2018
No DOACs, contraindicated in APS (TRAPS showed excess thrombosis with rivaroxaban)
Add hydroxychloroquine 200 mg daily (antithrombotic properties in APS)
Lifelong warfarin, never stop in triple-positive APS

Teaching point: Triple-positive APS has the highest thrombotic risk. DOACs are absolutely contraindicated. Warfarin adherence is critical, even brief subtherapeutic periods can lead to recurrent events.

📋 Case 2, Catastrophic APS (CAPS)

Patient: 28-year-old woman with known APS (single-positive aCL), hospitalized for pneumonia. Over 3 days develops acute renal failure (Cr 1.0 → 4.2), altered mental status, thrombocytopenia (platelets 38K), and livedo reticularis with digital ischemia.

Key findings: Schistocytes on smear. LDH 1,200. Multi-organ thrombosis on imaging: renal infarcts, cerebral microthrombi on MRI. Infection triggered CAPS.

Management:

Triple therapy for CAPS: (1) Heparin drip, (2) Methylprednisolone 1g IV × 3 days, (3) Plasma exchange (PLEX) daily × 5-7 days
Continue treating the trigger (antibiotics for pneumonia)
If refractory → add rituximab or eculizumab (complement inhibitor)
ICU admission, mortality 30-50% even with treatment

Teaching point: CAPS = multi-organ thrombosis developing in less than 1 week. Most often triggered by infection, surgery, or anticoagulation withdrawal. Recognize by the pattern: ≥ 3 organ systems + microvascular thrombosis + known aPL.

📋 Case 3, Obstetric APS

Patient: 31-year-old woman with 3 consecutive first-trimester miscarriages. No prior thrombosis. Workup reveals persistent anticardiolipin IgG (52 GPL) and anti-β2GP1 IgG positive on two occasions 14 weeks apart. LA negative.

Key findings: Meets criteria for obstetric APS: ≥ 3 consecutive pregnancy losses before 10 weeks + persistent aPL positivity (confirmed at ≥ 12 weeks).

Management:

Low-dose aspirin 81 mg daily, start preconception
Prophylactic LMWH (enoxaparin 40 mg SQ daily), add once pregnancy confirmed
This regimen reduces pregnancy loss from ~70% to ~20-30%
Monitor for preeclampsia, IUGR, and placental insufficiency
Postpartum: continue anticoagulation × 6 weeks (high thrombosis risk peripartum)

Teaching point: Obstetric APS requires persistent aPL positivity on 2 tests ≥ 12 weeks apart to avoid overdiagnosis from transient infection-related positivity. ASA + LMWH is the standard regimen. Warfarin is teratogenic, must switch to LMWH.

📣 Sample Presentation

One-Liner

"Mr. Garcia is a 38-year-old with triple-positive APS (LA+, aCL+, anti-β2GP1+) on warfarin who presents with INR 1.3 and new left leg DVT on compression ultrasound."

Key Points to Cover on Rounds

Recurrent thrombosis in known triple-positive APS -INR subtherapeutic at 1.3 (goal 2-3). Acute DVT management: heparin drip started (bridge to therapeutic warfarin). INR target remains 2-3 -some experts recommend 3-4 for recurrent events on therapeutic warfarin. No DOACs (contraindicated in APS TRAPS, 2018). Adding hydroxychloroquine (reduces thrombosis risk in APS, especially SLE-associated). Warfarin adherence and diet counseled. Plan: lifelong warfarin, rheumatology follow-up, consider adding low-dose ASA if arterial events occur.

Monitoring Parameters -Discharge Planning Checklist

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.

🧪 Workup

Workup

Lupus anticoagulant (LA) -functional assay (dRVVT or PTT-LA). Paradoxically prolongs aPTT but is PROthrombotic. Most specific of the 3 tests.
Anticardiolipin antibodies (IgG and IgM) -ELISA. Titers > 40 GPL/MPL are clinically significant.
Anti-β2-glycoprotein I (IgG and IgM) -ELISA. Associated with thrombosis + obstetric complications.
Repeat positive at 12 weeks -diagnosis requires positive on 2 occasions ≥ 12 weeks apart (transient positivity in infections is common).
Triple positivity (all 3 positive) = highest thrombotic risk -lifelong anticoagulation, never stop.
CBC -thrombocytopenia (20-40% of APS), hemolytic anemia (Coombs+)
Peripheral smear -schistocytes if TMA component (catastrophic APS)
Cr, LFTs -APS nephropathy, hepatic involvement
Echocardiogram -Libman-Sacks endocarditis (non-bacterial vegetations, usually mitral valve)
MRI brain -if neurological symptoms (stroke, TIA, cognitive dysfunction, seizures)

💊 Medications

Medications

Drug	Dose	Route	Notes
Warfarin	Target INR 2-3 (arterial: 2.5-3.5)	PO	First-line for thrombotic APS. Lifelong after first event. DOACs are INFERIOR to warfarin in APS -TRAPS trial stopped early for excess arterial events with rivaroxaban TRAPS, 2018. ASTRO-APS confirmed: use warfarin, not DOACs.
Heparin (LMWH)	Enoxaparin 1 mg/kg BID	SQ	Acute thrombosis treatment, bridge to warfarin. Also used in obstetric APS.
ASA	81 mg daily	PO	Primary prevention in asymptomatic aPL-positive patients (especially with SLE). Added to warfarin for arterial events.
Hydroxychloroquine	200-400 mg daily	PO	Reduces thrombotic risk in SLE-associated APS. Antithrombotic + immunomodulatory properties. Consider in all APS patients.
Obstetric APS
ASA + LMWH	ASA 81 mg + enoxaparin 40 mg daily	PO/SQ	Standard regimen for obstetric APS (recurrent pregnancy loss, preeclampsia). Start ASA preconception, add LMWH at positive pregnancy test.
Catastrophic APS (CAPS)
Triple therapy	Anticoag + steroids + PLEX or IVIG	IV	CAPS = multi-organ failure in < 1 week. ~50% mortality. Anticoagulation + methylprednisolone 1g × 3d + plasma exchange. Add rituximab or eculizumab if refractory.

⚡ Summary

Summary

Criteria

Thrombosis (arterial or venous) OR pregnancy morbidity + persistent antiphospholipid antibodies (positive × 2, ≥ 12 weeks apart).

3 Antibodies

Lupus anticoagulant (functional), anticardiolipin (IgG/IgM), anti-β2-glycoprotein I (IgG/IgM). Triple-positive = highest risk.

Treatment

Warfarin (INR 2-3) lifelong. DOACs contraindicated TRAPS, 2018. Add hydroxychloroquine (reduces thrombosis). Low-dose ASA for arterial events.

Pregnancy

Low-dose aspirin + LMWH throughout pregnancy. Warfarin is teratogenic -must switch to LMWH pre-conception.

CAPS

Catastrophic APS: multi-organ thrombosis in ≤ 1 week. Mortality 30-50%. Triple therapy: anticoag + steroids + PLEX/IVIG. Add rituximab if refractory.

Don't Forget

APS can be primary or secondary (SLE). Screen all SLE patients for aPL antibodies. Screen young strokes and unprovoked VTE.

⚡ Management

Management

Thrombotic APS -first event: Lifelong anticoagulation with warfarin (target INR 2-3). DOACs are inferior in triple-positive APS TRAPS, 2018 -higher thrombotic events vs warfarin. DOACs may be acceptable for single/double-positive with venous events only.
Thrombotic APS -recurrent event on warfarin INR 2-3: Increase target to INR 3-4, or add low-dose ASA, or switch to LMWH.
Obstetric APS (recurrent pregnancy loss): Low-dose ASA 81 mg + prophylactic LMWH (enoxaparin 40 mg SQ daily) starting at positive pregnancy test through 6 weeks postpartum. [PROMISSE]
Catastrophic APS (CAPS): Triple therapy -anticoagulation + high-dose steroids + PLEX or IVIG. Mortality 30-50% even with treatment. Rituximab or eculizumab for refractory cases.
Asymptomatic aPL carriers: Low-dose ASA 81 mg for primary prevention (especially if lupus anticoagulant positive + additional CV risk factors). No anticoagulation.

Perioperative bridging: APS patients on warfarin require therapeutic bridging with LMWH -do NOT leave them unprotected. High thrombotic risk during interruptions.

📄 One Pager

Rheumatology / Hematology · One Pager

Antiphospholipid Syndrome

Thrombosis + persistent aPL antibodies (× 2, ≥ 12 weeks apart). Warfarin lifelong (no DOACs [TRAPS]). Triple-positive = highest risk. CAPS = ICU emergency.

🧪 Diagnosis

Thrombosis (arterial or venous) OR pregnancy morbidity + persistent aPL antibodies (positive ×2, ≥ 12 weeks apart). 3 antibodies: LA, aCL (IgG/IgM), anti-β2GP1 (IgG/IgM).

🚨 Treatment

Warfarin INR 2-3 (lifelong). DOACs are CONTRAINDICATED TRAPS, 2018. Add hydroxychloroquine (reduces thrombosis). ASA for arterial events. Pregnancy: LMWH + low-dose ASA.

⚠️ CAPS -Catastrophic APS

Multi-organ thrombosis in ≤ 1 week (≥ 3 organs). Mortality 30-50%. Triple therapy: anticoag + high-dose steroids + PLEX/IVIG. Add rituximab or eculizumab if refractory.

💊 Key Drugs

WarfarinINR 2-3 (lifelong)

Hydroxychloroquine200-400 mg daily

ASA81 mg daily (arterial events)

LMWH1 mg/kg BID (pregnancy)

⚠️ Pitfalls

DOACs in APS (contraindicated -increased thrombosis [TRAPS])
Single antibody test (need positive × 2, ≥ 12 weeks apart)
Not screening SLE patients for aPL antibodies
Missing CAPS (think of it in multi-organ thrombosis)