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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IDChronic

HIV -Inpatient Essentials

What the IM resident needs to know: opportunistic infections by CD4 count, when to start ART, immune reconstitution inflammatory syndrome (IRIS), and drug interactions. ART is now "treat all, treat early" -start regardless of CD4.

🔍 Opportunistic Infections by CD4 Count

CD4 Count	Opportunistic Infection	Prophylaxis	Treatment
< 500	Kaposi sarcoma (HHV-8), oral hairy leukoplakia (EBV), candidal vaginitis	ART	ART ± chemo for KS
< 200	PCP (Pneumocystis jirovecii pneumonia) -bilateral GGOs, exertional desaturation, elevated LDH	TMP-SMX DS daily (or dapsone, atovaquone)	TMP-SMX 15–20 mg/kg/day (TMP component) × 21 days. If PaO₂ < 70 or A-a gradient > 35 → add prednisone (taper over 21 days).
< 200	Toxoplasmosis -ring-enhancing brain lesions (multiple, basal ganglia)	TMP-SMX* (covers both PCP + toxo) *TMP-SMX = Trimethoprim-Sulfamethoxazole (Bactrim)	Pyrimethamine + sulfadiazine + leucovorin × 6 weeks
< 150	Histoplasmosis / Coccidioidomycosis (endemic fungi)	ART + itraconazole in endemic areas	Amphotericin B (severe) → itraconazole maintenance
< 100	Cryptococcal meningitis -headache, AMS, ↑ opening pressure on LP. India ink, CrAg+	Consider CrAg screening if CD4 < 100	Amphotericin B + flucytosine × 2 weeks → fluconazole maintenance. Serial LPs for pressure management.
< 50	CMV retinitis (flame hemorrhages on fundoscopy), CMV colitis/esophagitis	ART (no specific prophylaxis)	Ganciclovir or valganciclovir
< 50	MAC (Mycobacterium avium complex) -disseminated: fever, weight loss, diarrhea, pancytopenia, elevated alk phos	Azithromycin 1200 mg weekly (if ART not started yet)	Clarithromycin + ethambutol ± rifabutin

CD4 < 200 = AIDS-defining. PCP and toxo prophylaxis start here. TMP-SMX DS daily covers both. Discontinue prophylaxis when CD4 > 200 for ≥ 3 months on ART.

💊 ART Basics

When to Start ART

Start ART in ALL HIV-positive patients regardless of CD4 count. START, 2015: immediate ART (any CD4) reduced serious AIDS events and death vs deferred treatment (CD4 < 350). SMART, 2006: ART interruptions increase mortality -never stop ART. HPTN 052, 2011: early ART reduces transmission by 96% (U=U). ACTG 076, 1994: zidovudine reduced vertical transmission 67.5% - foundation for PMTCT. Treat early, treat all.

Exception -delay ART in: cryptococcal meningitis (start ART 4–6 weeks after antifungal induction -early ART causes fatal IRIS) and TB meningitis (delay 2–8 weeks)
Rapid ART initiation (same day or within 7 days of diagnosis) is now recommended -improves linkage to care and viral suppression

Preferred Initial Regimen

Regimen	Components	Notes
Biktarvy PREFERRED	Bictegravir + emtricitabine + TAF (single pill, once daily)	Preferred first-line. High barrier to resistance, minimal drug interactions, well-tolerated. Renal/bone-safe (TAF > TDF).
Dovato	Dolutegravir + lamivudine (2-drug regimen)	Acceptable first-line if HBV-negative and viral load < 500,000. Not if HBV co-infected (needs 2 active HBV drugs).
Triumeq	Dolutegravir + abacavir + lamivudine	Alternative. *Requires HLA-B5701 testing before starting abacavir** (risk of fatal hypersensitivity reaction if positive).

IRIS (Immune Reconstitution Inflammatory Syndrome)

Occurs 2–12 weeks after starting ART -immune system "wakes up" and mounts an exuberant inflammatory response against pre-existing (often subclinical) infections
Unmasking IRIS: new OI symptoms appear after ART initiation (was subclinical before)
Paradoxical IRIS: known OI worsens after ART initiation despite appropriate treatment
Common IRIS pathogens: TB (#1), MAC, cryptococcus, CMV, PCP, hepatitis B/C, HPV, JC virus (PML), KSHV (Kaposi sarcoma).

🧪 Workup

Workup

HIV RNA viral load
CD4 count + %
Resistance genotype before ART
HLA-B*5701 if considering abacavir
BMP, LFTs, CBC
HBV/HCV serologies
RPR, QuantiFERON, toxo IgG
CXR

🚨 Management

Management

ART: start ALL patients, within 2wk. Exception: crypto meningitis.
Preferred: bictegravir/FTC/TAF (1 pill daily)
OI prophylaxis: CD4<200→TMP-SMX. CD4<50→azithromycin.
IRIS: continue ART + treat OI + steroids if severe.

💊 Medications

ART Regimens

Regimen	Dose	Route	Notes
Bictegravir/emtricitabine/TAF (Biktarvy) PREFERRED 1ST LINE	1 tab daily	PO	INSTI-based single-tablet regimen. High barrier to resistance. Few drug interactions. Well-tolerated. CrCl ≥30.
Dolutegravir (Tivicay) + emtricitabine/TAF (Descovy)	50 mg + 1 tab daily	PO	INSTI-based alternative. Dolutegravir has high barrier to resistance. Avoid with dofetilide, carbamazepine.
Dolutegravir/lamivudine (Dovato)	1 tab daily	PO	Two-drug regimen. Only if VL <500K, no HBV coinfection, and resistance testing available before starting.

OI Prophylaxis

Infection	Drug	Indication	Notes
PCP	TMP-SMX DS (Bactrim) 1 tab daily	CD4 <200 or oropharyngeal candidiasis	Also covers toxoplasma prophylaxis. Alternatives: dapsone (check G6PD), atovaquone, aerosolized pentamidine.
MAC	Azithromycin (Zithromax) 1200 mg weekly	CD4 <50	Discontinue when CD4 >100 for ≥3 months on ART. Alternative: clarithromycin 500 mg BID.
Crypto maintenance	Fluconazole (Diflucan) 200 mg daily	After induction/consolidation for cryptococcal meningitis	Secondary prophylaxis. Discontinue when CD4 >200 for ≥6 months + undetectable VL.

📋 On Rounds

Why do you delay ART in cryptococcal meningitis?

COAT Trial, 2014: starting ART within 1–2 weeks of cryptococcal meningitis diagnosis increased mortality vs waiting 5–6 weeks. The mechanism: early immune reconstitution causes a massive inflammatory response in the CNS against cryptococci → cerebral edema → herniation → death.

When should you NOT start ART immediately after HIV diagnosis?

Cryptococcal meningitis is the main exception. Starting ART during active crypto meningitis causes immune reconstitution inflammatory syndrome (IRIS) → cerebral edema → herniation → death. The COAT trial showed early ART (within 1–2 weeks) had higher mortality than deferred ART (5 weeks after antifungal induction). Treat crypto first (amphotericin B + flucytosine × 2 weeks), then start ART at 4–6 weeks.

What are the 3 most important opportunistic infections to know by CD4 count?

CD4 < 200: PCP (Pneumocystis jirovecii pneumonia) -bilateral GGO, elevated LDH, hypoxia with exertion. Prophylaxis: TMP-SMX DS daily. Treatment: TMP-SMX high-dose + prednisone if PaO₂ < 70. CD4 < 100: Toxoplasmosis -ring-enhancing brain lesions (multiple, basal ganglia). Prophylaxis: TMP-SMX (same pill covers both PCP and toxo). Treatment: pyrimethamine + sulfadiazine + leucovorin. CD4 < 50: MAC (Mycobacterium avium complex)

What is IRIS and how do you manage it?

Immune Reconstitution Inflammatory Syndrome (IRIS) = paradoxical clinical worsening after starting ART, caused by the recovering immune system mounting an inflammatory response against pre-existing (often subclinical) infections. Onset: usually 1-12 weeks after ART initiation. Common in: TB-IRIS (lymph node enlargement, worsening CXR), crypto-IRIS (increased intracranial pressure), MAC-IRIS (lymphadenitis), CMV-IRIS (vitritis). Management: Continue ART, do NOT stop unless life-threatening (CNS IRIS with herniation risk). Treat the underlying OI aggressively. Add corticosteroids (prednisone 1 mg/kg or dexamethasone) for moderate-severe IRIS, especially TB-IRIS with CNS involvement or crypto-IRIS with elevated ICP. Serial LPs for crypto-IRIS to control pressure. NSAIDs for mild symptoms. Treat TB and start ART early (within 2 weeks if CD4 < 50; 8 weeks if CD4 ≥ 50) to reduce IRIS risk per AHA/IDSA guidelines.

Case 1: New HIV Diagnosis, Rapid ART Start

Presentation: 28M presents to clinic after positive HIV screening. Asymptomatic. CD4 180, viral load 250,000 copies/mL. No prior ART. No active opportunistic infections on workup.

Assessment: New HIV diagnosis with CD4 < 200 (AIDS-defining) but no active OI. Candidate for rapid ART initiation (same-day start).

Plan:
• Start bictegravir/emtricitabine/TAF (Biktarvy), single pill, once daily, high barrier to resistance
• OI prophylaxis: TMP-SMX DS daily for PCP (CD4 < 200), also covers toxoplasmosis
• MAC prophylaxis not needed (CD4 > 50), would add azithromycin 1200 mg weekly if CD4 < 50
• Send baseline resistance genotype, HLA-B*5701, QuantiFERON, RPR, hepatitis B/C serologies, BMP, LFTs, fasting lipids
• Viral load at 4 weeks (expect > 1-log drop), then q3–6 months. Goal: undetectable (< 50 copies/mL) by 24 weeks

Key point: Rapid ART initiation (same day) improves linkage to care and viral suppression. Do not wait for genotype results, switch later if resistance detected.

Case 2: Immune Reconstitution Inflammatory Syndrome (IRIS)

Presentation: 35F started ART 3 weeks ago with baseline CD4 45, viral load 520,000. Now presents with worsening cervical lymphadenopathy, fevers to 39.2°C, and night sweats despite improving viral load (now 8,000 copies/mL).

Assessment: Paradoxical IRIS, clinical worsening despite virologic response to ART. Low baseline CD4 (< 50) is a major risk factor. Differential: TB-IRIS (most common cause of lymphadenopathy-predominant IRIS) vs unmasking of new opportunistic infection.

Plan:
• Continue ART, do NOT stop. Stopping ART worsens outcomes
• Workup: lymph node biopsy for AFB/culture/pathology, blood cultures for MAC, CXR, QuantiFERON, CrAg
• If TB-IRIS confirmed and severe (airway compromise, systemic toxicity): prednisone 1.5 mg/kg/day × 2 weeks then taper over 4 weeks
• NSAIDs for mild-moderate IRIS symptoms
• Monitor closely, IRIS is self-limited once immune reconstitution stabilizes

Key point: IRIS typically occurs 1–12 weeks after ART initiation, especially when baseline CD4 < 50. Continue ART. Steroids reserved for severe or life-threatening IRIS.

Case 3: ART Failure with Drug Resistance

Presentation: 42M on efavirenz/emtricitabine/TDF for 18 months. Reports good adherence but viral load persistently detectable at 4,200 copies/mL (was previously undetectable). CD4 stable at 310.

Assessment: Virologic failure, detectable VL despite reported adherence. Must assess true adherence (pharmacy refills, pill counts) and obtain resistance genotype. Genotype reveals K103N mutation, confers high-level NNRTI resistance (efavirenz, nevirapine).

Plan:
• Switch to INSTI-based regimen: dolutegravir/emtricitabine/TAF, high barrier to resistance, once daily
• Adherence counseling, identify barriers (side effects, pill burden, social factors, substance use)
• Check full resistance panel including integrase resistance (especially if prior INSTI exposure)
• Repeat viral load at 4 weeks after switch, expect > 1-log drop
• If multi-class resistance: consult HIV specialist for salvage regimen construction

Key point: K103N is the most common NNRTI resistance mutation. Always obtain genotype before switching. Never add a single drug to a failing regimen, switch at least 2 active agents to avoid accumulating resistance.

📣 Sample Presentation

One-Liner

"Mr. Roberts is a 34-year-old newly diagnosed with HIV after presenting with PCP pneumonia. CD4 42, viral load 380,000. LDH 520, bilateral GGO on CT chest. Started on TMP-SMX for PCP."

Key Points to Cover on Rounds

New HIV diagnosis with AIDS-defining illness (PCP, CD4 42). Treatment: TMP-SMX 15-20 mg/kg/day (trimethoprim component) × 21 days + prednisone taper (PaO₂ <70). ART start timing: within 2 weeks of OI treatment (not day 1 -IRIS risk). Planned ART: bictegravir/emtricitabine/TAF. OI prophylaxis needed: PCP (already treating), MAC (azithro 1200 weekly if CD4 <50), toxo (TMP-SMX covers). Screening: QuantiFERON, RPR, hepatitis panel, Pap smear. Resistance genotype sent before starting ART.

Monitoring

Parameter	Frequency	Target / Notes
HIV viral load	At 4 weeks, then q3-6 months	Goal: undetectable (<50 copies/mL). Should suppress within 12-24 weeks of ART. Detectable VL → assess adherence, resistance testing.
CD4 count	q3-6 months until immune reconstitution	Guides OI prophylaxis. Discontinue monitoring once CD4 >300 ×2 and VL suppressed (CD4 no longer clinically actionable).
BMP, LFTs	Baseline, then q6-12 months	ART hepatotoxicity and nephrotoxicity. Tenofovir (TDF/TAF): monitor Cr, phosphate. TAF has less renal toxicity than TDF.
Fasting lipids, HbA1c	Baseline, then annually	Metabolic monitoring -HIV and ART increase cardiovascular risk. Protease inhibitors most lipid-unfriendly. Screen and treat per guidelines.
STI screening	At diagnosis, then annually (or more frequently if high-risk)	Syphilis (RPR), gonorrhea/chlamydia (NAAT, 3-site), hepatitis B/C serology.
Cervical/anal cancer screening	Per guidelines	HPV-related malignancy risk increased. Cervical Pap for women. Anal Pap for MSM and history of anal dysplasia.
Resistance testing	At diagnosis + treatment failure	Genotype before starting ART. Repeat if VL rebounds on treatment (adherence must be assessed first).

⚡ Summary

Summary

Start ART

In ALL patients regardless of CD4. Start within 2 weeks of diagnosis. Exception: crypto meningitis (wait until CSF sterilized -IRIS risk).

Preferred ART

Bictegravir/emtricitabine/TAF (single pill, once daily). Alternative: dolutegravir-based regimen.

OI Prophylaxis

CD4 < 200: TMP-SMX (PCP + toxo). CD4 < 100: add toxo coverage (same TMP-SMX). CD4 < 50: azithromycin weekly (MAC).

Monitoring

Viral load at 4 weeks (should drop > 1 log), then q3-6 months. Goal: undetectable (< 50 copies/mL). CD4 q3-6 months.

IRIS

Paradoxical worsening 1-12 weeks after starting ART. Continue ART + treat OI + steroids if severe. Don't stop ART.

Resistance

Genotype before starting ART. If virologic failure (detectable VL on ART) → resistance testing → switch regimen.

📄 One Pager

ID · One Pager

HIV

Start ART in ALL patients regardless of CD4. OI prophylaxis by CD4 count. TMP-SMX covers PCP + toxo. Monitor VL + CD4. Watch for IRIS.

🧪 Key CD4 Thresholds

< 200: PCP risk → TMP-SMX. < 100: toxoplasma risk → TMP-SMX covers both. < 50: MAC risk → azithromycin weekly. < 50: CMV risk → monitor.

🚨 ART

Start in ALL patients. Preferred: bictegravir/emtricitabine/TAF (single pill, once daily). Get resistance genotype before starting. Goal: undetectable VL (< 50) by 6 months.

⚠️ IRIS

Paradoxical worsening 1-12 weeks after starting ART (immune reconstitution). Continue ART + treat OI aggressively. Steroids for severe IRIS. Don't stop ART.

💊 Key Drugs

Bictegravir/FTC/TAF1 tab daily

TMP-SMX DS1 tab daily (PCP/toxo)

Azithromycin1200 mg weekly (MAC)

Fluconazole200 mg daily (crypto maintenance)

⚠️ Pitfalls

Delaying ART initiation
Starting ART during active crypto meningitis (high IRIS risk -wait until CSF sterile)
Forgetting pre-ART screening (QuantiFERON, RPR, HBV, genotype)
Not recognizing IRIS (can mimic OI relapse)