Cholestatic pattern for opportunistic cholangitis consideration
Venous blood gas
pH
pCO2 mmHg
Lactate mmol/L
Blood cultures
Two sets before antibiotics if feasible
HIV status clarification
HIV antigen antibody test
If suspected acute HIV and test negative, nucleic acid testing pathway
HIV RNA viral load
High level supports acute HIV if antibody negative
CD4 count and percent
Risk stratification for opportunistic infections
Targeted infectious labs by syndrome
Respiratory syndrome labs
LDH
Elevated LDH supportive but nonspecific for PJP
Beta D glucan
Elevated value supportive for PJP and invasive fungal infection
Sputum Gram stain and culture
If productive cough
CNS syndrome labs
Serum cryptococcal antigen
High sensitivity in cryptococcosis
Toxoplasma IgG
Positive supports prior exposure
Diarrhea syndrome labs
Stool PCR panel where available
Stool ova and parasites for persistent diarrhea
C difficile toxin or PCR
Medication safety labs
G6PD level if dapsone or primaquine considered
Pregnancy test in reproductive age
EKG for QT risk if macrolides or fluoroquinolones planned
Lumbar puncture studies when performed
CSF infection profile
Opening pressure
Elevated value suggests cryptococcal meningitis
Cell count and differential
Lymphocytic pleocytosis common in viral and fungal infection
Glucose mmol/L
Low value suggests bacterial or fungal infection
Protein
Elevated value supports infection or inflammation
CSF cryptococcal antigen
High diagnostic yield in suspected cryptococcosis
CSF bacterial culture and Gram stain
CSF HSV PCR
CSF TB testing where available
AFB smear low sensitivity
NAAT where available
Diagnostic Tests
Scoring Systems
Severity and risk tools
qSOFA elements
Respiratory rate ≥ 22 per minute
Altered mentation
SBP ≤ 100 mmHg
CURB-65 elements for pneumonia context
Confusion
Urea
Respiratory rate ≥ 30 per minute
Blood pressure low
Age ≥ 65 years
Pneumonia hypoxemia markers
A a gradient elevation as PJP supportive concept
SpO2 decline with exertion as PJP supportive concept
Limitations
Immunocompromised patients may decompensate despite low scores
Clinical judgment supersedes score outputs in advanced HIV
MRI
Brain MRI with contrast for focal deficits or seizures
Toxoplasma encephalitis pattern
Multiple ring enhancing lesions
Basal ganglia involvement common
Primary CNS lymphoma pattern
Solitary enhancing lesion common
Restricted diffusion possible
PML consideration
Nonenhancing white matter lesions
JC virus testing pathway
Spinal MRI for myelopathy
Epidural abscess consideration
CMV polyradiculopathy consideration
CT
Chest CT angiography only if PE concern
Dyspnea disproportionate to chest x ray findings
D dimer interpretation limited in inflammation
Chest CT for hypoxemic respiratory failure
PJP pattern
Ground glass opacities
Perihilar distribution common
TB pattern
Cavitation
Tree in bud
Head CT before LP when indicated
Indications for CT first
Focal neurologic deficit
New seizure
Papilledema
Severe immunosuppression with concern for mass lesion
ACEP Level C approach for CT before LP based on expert consensus for elevated ICP risk
Ultrasound
Point of care ultrasound in shock
Cardiac function
LV function estimate
Pericardial effusion
IVC assessment for volume status adjunct
Lung ultrasound
B lines for edema pattern
Consolidation for pneumonia pattern
Abdominal ultrasound in RUQ pain or abnormal LFTs
Biliary obstruction
Hepatomegaly and splenomegaly
Disposition
Level of care decisions
ICU criteria
Vasopressor requirement
Mechanical ventilation requirement
Severe hypoxemia
High flow oxygen requirement
Rapidly escalating oxygen needs
CNS infection concern
Altered mental status
Seizures
Elevated intracranial pressure features
Admission criteria
Suspected opportunistic infection
New HIV diagnosis with systemic illness
Failure of outpatient therapy
Significant dehydration
Electrolyte derangements
Discharge criteria
Mild illness with stable vitals
Reliable follow up within 24 to 72 hours
Clear return precautions provided
ART and prophylaxis plan reconciled
Transfer criteria
Need for bronchoscopy or ICU not available
Need for neurosurgical services for mass lesion
Follow up planning
HIV linkage to care
Rapid HIV clinic referral
Public health notification per local policy
Medication access planning
ART supply continuity
Prophylaxis initiation if indicated
Social supports
Housing instability screening
Harm reduction supports where relevant
Treatment
Empiric syndrome based therapy
Sepsis in advanced HIV
Broad spectrum antibiotics per source suspicion
If pneumonia source, ceftriaxone plus azithromycin pathway
If healthcare exposure, antipseudomonal beta lactam pathway
Early antifungal consideration when high risk
If severe immunosuppression plus shock plus travel or exposure risk, amphotericin pathway after ID input
Class I recommendation alignment for early sepsis management based on major sepsis guidelines
Suspected Pneumocystis jirovecii pneumonia
TMP SMX therapy
TMP component 15 to 20 mg/kg/day divided q6 to q8 hours
Renal adjustment per creatinine clearance
Monitor potassium mmol/L
Monitor creatinine
Adjunct corticosteroids
If PaO2 < 70 mmHg on room air, prednisone 40 mg twice daily days 1 to 5
Prednisone 40 mg daily days 6 to 10
Prednisone 20 mg daily days 11 to 21
If IV needed, methylprednisolone 75% of prednisone dose
Alternatives if TMP SMX intolerance
Clindamycin plus primaquine
G6PD deficiency exclusion before primaquine
IV pentamidine
Monitor glucose
Monitor QT interval
Atovaquone for mild disease
Class I recommendation alignment for steroids in moderate to severe PJP based on major HIV OI guidelines
Suspected cryptococcal meningitis
Induction antifungal therapy
Amphotericin B formulation per local protocol
Flucytosine dosing per weight and renal function
Monitor CBC for cytopenias
Monitor creatinine and electrolytes
Intracranial pressure management
If opening pressure ≥ 25 cmH2O, therapeutic CSF drainage
Repeat drainage daily if symptoms persist
ART timing
Delay ART initiation to reduce mortality risk from IRIS in cryptococcal meningitis per guideline consensus
Class I recommendation alignment for amphotericin plus flucytosine induction in cryptococcal meningitis based on major HIV OI guidelines
Suspected toxoplasma encephalitis
Initial therapy options
Pyrimethamine plus sulfadiazine plus leucovorin regimen pathway
TMP SMX high dose alternative pathway
Seizure management
If active seizures, antiseizure medication initiation
Steroids
If significant mass effect with herniation risk, dexamethasone limited course
Response assessment
If no improvement by day 10 to 14, alternate diagnosis evaluation
Suspected tuberculosis
Isolation
Airborne precautions
Diagnostic confirmation before RIPE when feasible
Sputum AFB and NAAT pathway
If severe disease and high suspicion, RIPE initiation after ID and public health alignment
Drug interaction management
Rifampin interaction with many ART regimens
Esophageal candidiasis
Fluconazole therapy
Oral dosing per local protocol
IV option if unable to swallow
If refractory, echinocandin pathway after ID input
Antiretroviral therapy and IRIS
ART status decisions in acute illness
If already on ART, continuation favored unless severe toxicity or critical interaction
If newly diagnosed HIV with most OIs, early ART initiation favored after stabilization
ART deferral scenarios
Cryptococcal meningitis
TB meningitis
IRIS management
Clinical suspicion features
Worsening inflammation after ART initiation
Improving HIV viral load with paradoxical clinical decline
Management principles
Treat underlying infection adequately
If severe IRIS, corticosteroids after excluding uncontrolled infection
Class I recommendation alignment for early ART in most settings based on major HIV treatment guidelines
Medication interaction and safety
Interaction screening
Boosted protease inhibitors and cobicistat
CYP3A4 inhibition increases levels of many sedatives and antiarrhythmics
Integrase inhibitors
Polyvalent cation interaction with antacids and supplements
Renal and electrolyte monitoring during therapy
Amphotericin nephrotoxicity
TMP SMX hyperkalemia
Tenofovir renal effects
Anaphylaxis and severe rash
If severe cutaneous adverse reaction suspected, immediate culprit discontinuation
If mucosal involvement, burn unit or dermatology pathway
Special Populations
Pregnancy
Pregnancy specific priorities
Maternal stabilization as primary
Fetal monitoring when viable gestation and maternal stable
HIV transmission prevention
Viral load suppression as key determinant of transmission risk
Intrapartum management coordination with obstetrics for late presentation
Medication safety considerations
TMP SMX use in pregnancy
Folate supplementation consideration
Near term hyperbilirubinemia theoretical risk counseling
Avoid teratogenic agents when alternatives exist
Opportunistic infection management
PJP treatment and steroids guided by maternal severity
Cryptococcal therapy coordinated with ID and obstetrics
Geriatric
Age related considerations
Higher baseline cardiovascular and renal comorbidity
Polypharmacy interaction risk increased
Presentation differences
Blunted fever response
Delirium as primary manifestation
Dosing adjustments
Renal dosing for TMP SMX and flucytosine
QT risk monitoring with macrolides and fluoroquinolones
Pediatrics
Pediatric HIV contexts
Perinatal acquisition history
Adolescent acquisition risk assessment
Weight based dosing
TMP SMX mg/kg dosing verification
Amphotericin and flucytosine dosing verification
Opportunistic infection patterns
Severe bacterial infections common in advanced disease
PJP risk high in infants without prophylaxis
Safeguarding and consent considerations
Confidential sexual health care per jurisdiction policy
Mandatory reporting pathways per local law when applicable
Background
Epidemiology
Burden and risk distribution
Opportunistic infections primarily occur with advanced immunosuppression
Acute HIV syndrome occurs weeks after exposure and is commonly misdiagnosed
Transmission considerations
Sexual transmission most common in many regions
Blood exposure and perinatal transmission remain important contexts
Coinfections
Hepatitis B and C coinfection prevalence elevated in shared risk populations
Tuberculosis coinfection remains major driver of morbidity globally
Pathophysiology
Immune system impact
CD4 T cell depletion drives opportunistic infection susceptibility
High viral replication in untreated infection
CD4 threshold concept
CD4 < 200 cells/μL associated with PJP risk
CD4 < 100 cells/μL associated with toxoplasma and cryptococcus risk
CD4 < 50 cells/μL associated with CMV and MAC risk
Inflammatory reconstitution
ART initiation increases immune response
IRIS represents exaggerated inflammatory response to latent or treated pathogens
Therapeutic Considerations
Timing principles
Empiric therapy prioritized when diagnostic delay increases mortality
ART initiation timing depends on OI type and CNS involvement
Steroid use principles
PJP steroids reduce respiratory failure and mortality in moderate to severe disease
Steroids can worsen uncontrolled fungal CNS infection without antifungal coverage
Drug interaction principles
Boosted ART regimens cause clinically significant CYP interactions
Rifamycins reduce levels of many ART agents
Patient Discharge Instructions
copy discharge instructions
Discharge guidance
Medication instructions
Complete all prescribed antimicrobials as directed
Do not stop ART unless instructed by HIV clinician or ED
Follow up timing
HIV clinic or primary care within 1 to 3 days if new diagnosis or regimen issues
Return visit for test results plan if pending cultures or PCR
Return to ED now
Trouble breathing
Chest pain
Confusion
Fainting
Severe headache
New weakness
Seizure
Persistent vomiting
Inability to keep fluids down
Worsening rash with mouth sores
Infection control at home
Mask use and isolation guidance if TB evaluation ongoing
Avoid contact with pregnant or immunocompromised people if chickenpox like rash present
Harm reduction and prevention
Condom use guidance
Partner notification support options
Needle safety guidance where relevant
References
Clinical guidelines and evidence sources
HIV treatment guidelines
U.S. DHHS Guidelines for the Use of Antiretroviral Agents in Adults and Adolescents with HIV
WHO consolidated guidelines on HIV prevention, testing, treatment, service delivery, and monitoring
Opportunistic infection guidelines
NIH CDC IDSA guidelines for prevention and treatment of opportunistic infections in adults and adolescents with HIV
IDSA guidelines for cryptococcosis management
Tuberculosis guidance
WHO tuberculosis guidelines and TB preventive treatment guidance
CDC TB diagnosis and infection control guidance
Sepsis and critical care guidance
Surviving Sepsis Campaign international guidelines for management of sepsis and septic shock
Evidence grading note
ACEP Level C references indicate expert consensus where ACEP specific evidence levels are not available for HIV syndromes
Class I IIa IIb labels used to communicate strength of consensus when specialty guideline classes are not directly defined for HIV topics
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.