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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Cardio

Mitral Regurgitation

Acute MR (papillary rupture, endocarditis) = surgical emergency with flash pulmonary edema. Chronic MR is insidious, EF is misleadingly preserved. EF 60% in severe MR = significant dysfunction.

Overview

Acute vs Chronic

Feature	Acute MR	Chronic MR
Causes	Papillary rupture (post-MI), endocarditis, chordae rupture	Myxomatous (MVP), rheumatic, functional (LV dilation)
Presentation	Flash pulmonary edema, cardiogenic shock	Asymptomatic years → dyspnea
Treatment	EMERGENCY SURGERY	Surgery when criteria met

EF in MR is misleading. LV ejects into low-pressure LA → EF artificially preserved. EF 60% in severe MR = significant dysfunction. Don’t wait for 40%.

Acute vs Chronic MR, Detailed Comparison

Feature	Acute MR	Chronic MR
LA size	Normal (no time to dilate)	Enlarged (compensatory dilation)
LA pressure	Markedly elevated → pulmonary edema	Only mildly elevated (compliant LA absorbs volume)
LV size	Normal	Dilated (eccentric hypertrophy from volume overload)
Murmur	May be soft/absent (equalization of pressures) or decrescendo	Holosystolic, blowing, radiates to axilla
Hemodynamics	Cardiogenic shock, pulmonary edema	Gradual decompensation over years
CXR	Flash pulmonary edema, normal heart size	Cardiomegaly, chronic congestion
Urgency	Surgical emergency. Stabilize with nitroprusside/IABP	Elective surgery when criteria met

Acute MR pearl: A patient with sudden flash pulmonary edema + normal-sized heart on CXR + new murmur = acute MR until proven otherwise. Most commonly post-MI (papillary muscle rupture, typically 3–7 days after inferior MI affecting posteromedial papillary muscle).

MR Severity Grading

Parameter	Mild	Moderate	Severe
Regurgitant volume (mL/beat)	<30	30–59	≥60
Regurgitant fraction (%)	<30	30–49	≥50
EROA (cm²)	<0.20	0.20–0.39	≥0.40
Vena contracta (cm)	<0.3	0.3–0.69	≥0.7
Color jet area	Small, central	Moderate	Large (>40% LA area) or wall-hugging eccentric jet

Eccentric jets are deceptive. Wall-hugging (Coanda effect) jets appear smaller on color Doppler than their true severity. Always use quantitative measures (EROA, regurgitant volume) rather than relying on color jet area alone.

Primary vs Secondary MR

Feature	Primary (Degenerative) MR	Secondary (Functional) MR
Pathology	Intrinsic valve disease (leaflets, chordae, papillary muscles)	Normal valve; MR from LV dilation/dysfunction
Common causes	Myxomatous/MVP, rheumatic, endocarditis, radiation	Ischemic cardiomyopathy, dilated cardiomyopathy
Treatment	Mitral valve repair (preferred) or replacement	Optimize GDMT first; MitraClip if persistent COAPT, 2018

Workup

TTE (severity, LV size/function), TEE for surgical planning
ECG: Afib common
CXR, BNP
Cardiac cath pre-op

Management

Surgery Indications (Chronic Primary MR)

Indication	Action
Symptomatic severe MR	Surgery (repair > replacement)
Asymptomatic + EF ≤60%	Surgery
Asymptomatic + LVESD ≥40mm	Surgery
Secondary MR + HFrEF	MitraClip if on optimal GDMT COAPT 2018
Asymptomatic + new AF	Consider surgery (Class IIa)
Asymptomatic + pulm HTN	PASP >50 mmHg at rest, consider surgery (Class IIa)

Repair > Replacement. Mitral valve repair has lower operative mortality, better LV function preservation, and avoids lifelong anticoagulation. Repair success rates >95% at experienced centers for degenerative MR (posterior leaflet prolapse). Always refer to a surgeon with high repair volume.

MitraClip (Transcatheter Edge-to-Edge Repair) Criteria

Criterion	COAPT Eligibility
MR severity	Moderate-severe to severe (EROA ≥0.3 cm², regurgitant volume ≥45 mL)
Symptoms	NYHA II–IVa despite optimal GDMT
LVEF	20–50%
LVESD	≤70 mm
GDMT	Must be on maximally tolerated guideline-directed medical therapy
Anatomy	Suitable valve morphology for clip placement (assessed by TEE)
Heart Team	Deemed prohibitive or high surgical risk

COAPT vs MITRA-FR: COAPT, 2018 showed benefit; MITRA-FR, 2018 did not. Key difference: COAPT enrolled patients with disproportionate MR (severe MR relative to LV size), while MITRA-FR included proportionate MR (LV too dilated for clip to help). Ensure MR severity is disproportionate to LV dilation before referring for MitraClip.

Medications

Medical Therapy

Drug	Role
ACEi/ARB	Afterload reduction. Reduces regurgitant fraction
Diuretics	Volume management
GDMT (HF pillars)	For secondary MR with HF
Nitroprusside	Acute severe MR bridge to surgery (ICU only)

On Rounds

Why is EF misleading in MR?

LV ejects into both aorta AND low-pressure LA → inflated EF. EF 60% with severe MR = significant dysfunction (normal heart would be >70%). Surgery threshold is EF ≤60%, not 40%.

What is the COAPT trial?

MitraClip (transcatheter repair) reduced HF hospitalization and mortality in secondary MR with persistent symptoms despite optimal GDMT. Must optimize HF meds first.

Why is repair preferred over replacement for primary MR?

Mitral valve repair preserves the subvalvular apparatus (chordae + papillary muscles), which is critical for LV function. Repair has lower operative mortality (~1% vs 5–10%), better long-term LV function, no need for lifelong anticoagulation (unlike mechanical replacement), and lower risk of prosthetic valve endocarditis. Posterior leaflet prolapse has >95% repair success rate at experienced centers.

What papillary muscle is more commonly involved in ischemic MR, and why?

The posteromedial papillary muscle is far more commonly affected because it has a single blood supply (from the PDA, a branch of the RCA or LCx). The anterolateral papillary muscle has dual blood supply (LAD + LCx) and is therefore protected from single-vessel ischemia. This is why acute MR from papillary rupture most often occurs after inferior MI.

How do you differentiate primary from secondary MR on echo?

Primary MR: structural valve abnormality visible, flail leaflet, prolapse, perforation, vegetation. Jet direction often eccentric. Secondary (functional) MR: valve leaflets appear structurally normal but with restricted closure due to LV dilation/dysfunction, look for tethering, incomplete coaptation, and central regurgitant jet. LV is dilated with wall motion abnormalities.

What is the Coanda effect and why does it matter in MR assessment?

The Coanda effect describes how an eccentric MR jet adheres to the LA wall and appears smaller on color Doppler than its true severity. Wall-hugging jets are common in flail leaflets and prolapse. This leads to underestimation of MR severity by color jet area. Always use quantitative measures (EROA, regurgitant volume, vena contracta) when you see an eccentric jet, rather than relying on visual jet area.

What are the key differences between COAPT and MITRA-FR trials?

Both studied MitraClip in secondary MR, but reached opposite conclusions. COAPT (positive): enrolled patients with disproportionate MR, severe MR (EROA ≥0.3) with only moderate LV dilation (LVESD ≤70mm). MITRA-FR (negative): enrolled patients with proportionate MR, MR severity matched the degree of LV dilation.

When should you use nitroprusside or IABP in acute MR?

Acute severe MR with hemodynamic instability requires urgent afterload reduction as a bridge to emergency surgery. Nitroprusside (ICU, arterial line monitoring): reduces SVR → more blood goes forward through aorta, less regurgitates into LA. IABP: augments diastolic coronary perfusion + reduces afterload during systole, ideal bridge in post-MI papillary rupture. Neither is definitive treatment, surgery is the only cure.

Clinical Examples

📋 Case 1, Acute MR Post-MI (Papillary Rupture)

Patient: 66M, day 5 post-inferior STEMI (delayed presentation, no reperfusion). Sudden onset severe dyspnea with pink frothy sputum.

Vitals: HR 125, BP 78/52, RR 32, SpO2 82% on NRB.

Exam: New harsh holosystolic murmur at apex radiating to axilla. Bilateral crackles to apices. JVD. Cold, clammy extremities.

CXR: Flash pulmonary edema with normal heart size (classic for acute MR).

Bedside echo: Flail posterior mitral leaflet with severe eccentric MR jet, ruptured posteromedial papillary muscle head. LVEF 40%.

Management:

Intubation for respiratory failure
IABP placed for hemodynamic support (afterload reduction + coronary perfusion augmentation)
Nitroprusside drip initiated with arterial line monitoring
Emergent CT surgery consultation, mitral valve replacement (repair often not feasible with ruptured papillary muscle)
Intraoperative finding: necrotic posteromedial papillary muscle with complete rupture

Teaching point: Papillary rupture is a mechanical complication of MI occurring 3–7 days post-infarct. The posteromedial papillary muscle (single blood supply from PDA) is affected far more often than anterolateral. Normal heart size on CXR + flash pulmonary edema = acute MR. This is a surgical emergency with ~75% mortality without surgery.

📋 Case 2, Chronic Severe MR with Declining EF

Patient: 54F with known myxomatous mitral valve prolapse and severe MR, followed with serial echos. Previously LVEF 68%, LVESD 36mm. Latest echo: LVEF 58%, LVESD 42mm. Patient reports mild exertional dyspnea (NYHA II).

Echo details: Posterior leaflet prolapse (P2 segment), EROA 0.52 cm², regurgitant volume 72 mL, vena contracta 0.8 cm. Moderate LA dilation. New onset AF on ECG.

Decision analysis:

Three independent triggers for surgery: (1) Symptoms (NYHA II dyspnea), (2) EF ≤60% (now 58%), (3) LVESD ≥40mm (now 42mm)
Additionally: new AF is a Class IIa indication
P2 prolapse is the most favorable anatomy for repair (>98% success rate)

Management: Referred for mitral valve repair (not replacement) at a high-volume center. Successful posterior leaflet repair with annuloplasty ring. Post-op echo: trivial residual MR, EF 52% (expected transient drop after eliminating low-resistance LA pathway).

Teaching point: Do not wait for EF to drop to 40%, EF ≤60% in severe MR already represents significant dysfunction. Multiple triggers were present here. P2 prolapse is the ideal repair scenario. Repair at high-volume centers (>25 repairs/year) has superior outcomes.

📋 Case 3, Functional MR in Heart Failure

Patient: 71M with ischemic cardiomyopathy (prior LAD stent), LVEF 28%, on maximally tolerated GDMT (sacubitril/valsartan, carvedilol, spironolactone, dapagliflozin, hydralazine/ISDN). Persistent NYHA III symptoms despite 6 months of optimized therapy.

Echo: Dilated LV (LVESD 58mm), severe functional MR with central jet. Leaflets structurally normal but tethered with incomplete coaptation. EROA 0.35 cm², regurgitant volume 50 mL.

Assessment:

Secondary MR from LV dilation, valve is structurally normal
Already on maximal GDMT with CRT-D in place
COAPT criteria met: EROA ≥0.3, LVEF 20–50%, LVESD ≤70mm, persistent symptoms on optimal therapy
STS score high risk for open surgery
MR appears disproportionate to LV dilation (COAPT phenotype, not MITRA-FR)

Management: Proceeded with MitraClip (transcatheter edge-to-edge repair). Post-procedure: MR reduced to mild, NYHA improved to II, no HF hospitalization at 1-year follow-up. COAPT, 2018

Teaching point: In secondary MR, always optimize GDMT first (including CRT if indicated). MitraClip is reserved for patients with persistent symptoms despite maximal therapy who meet COAPT criteria. The key is ensuring MR is disproportionate to LV size.

Monitoring

Parameter	Frequency
Echo	q6–12mo severe; q1–2y moderate
AF surveillance	ECG at visits

Summary

Acute MR

Flash pulm edema, papillary rupture. EMERGENCY surgery.

Surgery Triggers

Symptomatic, EF ≤60%, LVESD ≥40mm.

EF Trap

EF falsely preserved. 60% = significant dysfunction.

Secondary MR

Optimize GDMT first. MitraClip (COAPT) if persistent.