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Emergency And Acute Medicine – HIV And AIDS
Basics
Foundational Overview
Acquired immunodeficiency syndrome (AIDS) is defined by laboratory evidence of HIV infection with a CD4 count below 200 cells/mm³ or the presence of an AIDS-defining condition. These conditions include opportunistic infections (such as cryptosporidiosis), malignancies (including Kaposi sarcoma or invasive cervical cancer), and other HIV-related illnesses such as wasting syndrome or HIV-associated encephalopathy.
Opportunistic conditions correlate strongly with immune suppression:
At CD4 counts below 500 cells/mm³, patients are at risk for oroesophageal candidiasis, pneumococcal infections, oral hairy leukoplakia, and immune thrombocytopenic purpura.
At CD4 counts below 200 cells/mm³, common conditions include Pneumocystis jirovecii pneumonia (PCP), cryptococcal infection, disseminated tuberculosis, cryptosporidiosis, isosporiasis, toxoplasmosis, and histoplasmosis.
At CD4 counts below 50 cells/mm³, patients are vulnerable to central nervous system lymphoma, Mycobacterium avium complex (MAC), tuberculosis pericarditis or meningitis, cytomegalovirus (CMV) infection, and HIV-associated cholangiopathy, most commonly caused by Cryptosporidium parvum.
Diagnosis
Clinical Manifestations
Primary HIV infection typically occurs 2–6 weeks after exposure and may present with fever, malaise, a rash involving the face and trunk, flu-like symptoms with lymphadenopathy and hepatosplenomegaly, pharyngitis, and diarrhea. Up to 90% of patients may be asymptomatic during this stage.
Advanced HIV disease, usually defined by CD4 counts below 200 cells/mm³, commonly presents with fatigue, fevers, night sweats, weight loss or wasting, alopecia, chronic diarrhea, cough, dyspnea, hemoptysis, chronic low-grade headaches, altered mental status, seizures, dementia, neuropathy, painless visual loss, and various skin lesions.
History
Important risk factors include multiple sexual partners, unprotected intercourse with high-risk partners, men who have sex with men, intravenous drug use, blood transfusions prior to 1985, and lack of circumcision. Key historical elements include most recent and lowest recorded CD4 count, viral load, history of antiretroviral therapy and adherence, duration of HIV diagnosis, previous opportunistic infections, and prior hospitalizations or ICU admissions.
Initial Evaluation
HIV serologic testing is essential, recognizing a window period of up to 24 weeks between infection and seroconversion during which tests may be negative. HIV DNA amplification testing can detect infection within 1–2 weeks but is rarely available in the ED and requires careful follow-up.
Patients with respiratory symptoms require chest radiography, arterial blood gas analysis, sputum evaluation for Gram stain, acid-fast bacilli, and cultures, serum LDH levels, and blood cultures.
Cardiac symptoms warrant cardiac biomarkers, electrolytes, ECG, chest radiography, and blood cultures if endocarditis is suspected.
Neurologic symptoms require head CT with and without contrast and lumbar puncture with opening pressure and comprehensive CSF studies.
Gastrointestinal symptoms necessitate stool studies, urinalysis, pregnancy testing in women, pelvic examination when appropriate, liver enzymes, pancreatic enzymes, hepatitis serologies, and a low threshold for abdominal imaging or surgical consultation.
Fever of unknown origin requires broad infectious evaluation including bacterial, fungal, AFB, and MAC cultures.
Ocular complaints require slit-lamp examination with fluorescein staining.
Diagnostic Studies And Interpretation
Laboratory Testing
ELISA testing detects IgG antibodies against HIV with approximately 99% sensitivity and specificity but may be negative during the window period. Western blot testing confirms positive ELISA results by detecting antibodies to HIV proteins. Rapid HIV testing provides results within 5–20 minutes using oral swabs or blood samples but requires confirmatory testing.
Absolute lymphocyte count can estimate immune status: values above 2,000 cells/mm³ often correlate with CD4 counts above 200, while counts below 1,000 suggest advanced immunosuppression.
Imaging
Chest radiographs may show bilateral interstitial infiltrates in PCP, reticulonodular patterns in TB or fungal infections, hilar lymphadenopathy in TB or malignancy, lobar consolidation in bacterial pneumonia, or cavitary lesions in TB and necrotizing infections. A normal chest x-ray does not exclude PCP or TB.
Head CT may demonstrate multiple ring-enhancing lesions consistent with toxoplasmosis or CNS lymphoma, or nonenhancing subcortical lesions suggestive of progressive multifocal leukoencephalopathy.
Abdominal and pelvic CT imaging may reveal splenomegaly, intestinal perforation or obstruction, biliary disease, or pancreatitis related to infection, malignancy, or medications.
Differential Diagnosis
Pulmonary complaints may represent pulmonary embolism, pulmonary hypertension, TB, bacterial, viral, or fungal pneumonia, malignancy, or lymphocytic interstitial pneumonitis.
Neurologic symptoms raise concern for neurosyphilis, viral encephalitis, toxoplasmosis, CNS lymphoma, meningitis, stroke, metabolic encephalopathy, or progressive multifocal leukoencephalopathy.
Cardiac presentations include cardiomyopathy, myocarditis, pericarditis, endocarditis, acute coronary syndrome, or pericardial effusion.
Oral and esophageal symptoms may result from candidiasis, viral infections, bacterial disease, autoimmune conditions, or malignancy.
Chronic diarrhea, hepatomegaly, and renal dysfunction have broad infectious, metabolic, medication-related, and neoplastic etiologies in HIV-infected patients.
Treatment
Emergency Department Management
Patients appearing toxic or with rapidly progressive illness should receive empiric antibiotics in the ED. Initiation of antiretroviral therapy is recommended for patients with low CD4 counts, high viral loads, pregnancy, AIDS-defining illnesses, or HIV-associated nephropathy.
Highly active antiretroviral therapy (HAART) typically consists of triple therapy using combinations of non-nucleoside reverse transcriptase inhibitors, protease inhibitors, and nucleoside reverse transcriptase inhibitors.
Post-exposure prophylaxis should begin within 2 hours of exposure when possible and continue for 4 weeks, with two-drug regimens for most exposures and expanded three-drug regimens for high-risk cases.
Specific opportunistic infections require targeted therapy, including pyrimethamine-based regimens for toxoplasmosis, amphotericin B with flucytosine for cryptococcal meningitis, ganciclovir for CMV retinitis, fluconazole for esophageal candidiasis, clarithromycin-based therapy for MAC, trimethoprim-sulfamethoxazole for PCP with adjunctive steroids when hypoxemia is present, and plasmapheresis for acute HIV-related demyelinating neuropathy.
Medication-Related Considerations
Antiretroviral therapy is associated with numerous potential adverse effects including hypersensitivity reactions, pancreatitis, peripheral neuropathy, nephrolithiasis, hepatotoxicity, lactic acidosis, Stevens–Johnson syndrome, hemolytic anemia, neuropsychiatric effects, metabolic derangements, cardiomyopathy, and hematologic abnormalities.
Follow-Up And Disposition
Admission Criteria
Indications for hospitalization include unexplained fever with neurologic involvement, hypoxemia, suspected acute coronary syndrome, pericardial effusion, suspected bacterial pneumonia or TB, new neurologic deficits or seizures, hemodynamic instability, inability to ambulate or tolerate oral intake, and severe diarrhea with dehydration.
Discharge Criteria
Patients may be discharged if they can maintain oral intake, ambulate, perform self-care, and have reliable follow-up.
Referral Considerations
All patients should be referred to an HIV specialist for initiation and management of antiretroviral therapy. Screening for depression and psychiatric referral are essential to ensure treatment adherence. Patients with concerning symptoms should be referred for malignancy evaluation.
Key Clinical Insights And Common Pitfalls
Immune reconstitution inflammatory syndrome typically occurs within 8 weeks of initiating HAART. Occupational exposure carries a low but real risk of seroconversion. Patients on HAART have increased risk for metabolic disease and acute coronary syndromes. Exercise-induced desaturation may aid in diagnosing PCP when imaging is normal. HIV is an independent risk factor for COPDukar
COPD, pulmonary hypertension, stroke, venous thromboembolism, thrombotic thrombocytopenic purpura, osteoporosis, and osteonecrosis of the hip.
Basics
Foundational Overview
Acquired immunodeficiency syndrome (AIDS) is defined by laboratory evidence of HIV infection with a CD4 count below 200 cells/mm³ or the presence of an AIDS-defining condition. These conditions include opportunistic infections (such as cryptosporidiosis), malignancies (including Kaposi sarcoma or invasive cervical cancer), and other HIV-related illnesses such as wasting syndrome or HIV-associated encephalopathy.
Opportunistic conditions correlate strongly with immune suppression:
At CD4 counts below 500 cells/mm³, patients are at risk for oroesophageal candidiasis, pneumococcal infections, oral hairy leukoplakia, and immune thrombocytopenic purpura.
At CD4 counts below 200 cells/mm³, common conditions include Pneumocystis jirovecii pneumonia (PCP), cryptococcal infection, disseminated tuberculosis, cryptosporidiosis, isosporiasis, toxoplasmosis, and histoplasmosis.
At CD4 counts below 50 cells/mm³, patients are vulnerable to central nervous system lymphoma, Mycobacterium avium complex (MAC), tuberculosis pericarditis or meningitis, cytomegalovirus (CMV) infection, and HIV-associated cholangiopathy, most commonly caused by Cryptosporidium parvum.
Diagnosis
Clinical Manifestations
Primary HIV infection typically occurs 2–6 weeks after exposure and may present with fever, malaise, a rash involving the face and trunk, flu-like symptoms with lymphadenopathy and hepatosplenomegaly, pharyngitis, and diarrhea. Up to 90% of patients may be asymptomatic during this stage.
Advanced HIV disease, usually defined by CD4 counts below 200 cells/mm³, commonly presents with fatigue, fevers, night sweats, weight loss or wasting, alopecia, chronic diarrhea, cough, dyspnea, hemoptysis, chronic low-grade headaches, altered mental status, seizures, dementia, neuropathy, painless visual loss, and various skin lesions.
History
Important risk factors include multiple sexual partners, unprotected intercourse with high-risk partners, men who have sex with men, intravenous drug use, blood transfusions prior to 1985, and lack of circumcision. Key historical elements include most recent and lowest recorded CD4 count, viral load, history of antiretroviral therapy and adherence, duration of HIV diagnosis, previous opportunistic infections, and prior hospitalizations or ICU admissions.
Initial Evaluation
HIV serologic testing is essential, recognizing a window period of up to 24 weeks between infection and seroconversion during which tests may be negative. HIV DNA amplification testing can detect infection within 1–2 weeks but is rarely available in the ED and requires careful follow-up.
Patients with respiratory symptoms require chest radiography, arterial blood gas analysis, sputum evaluation for Gram stain, acid-fast bacilli, and cultures, serum LDH levels, and blood cultures.
Cardiac symptoms warrant cardiac biomarkers, electrolytes, ECG, chest radiography, and blood cultures if endocarditis is suspected.
Neurologic symptoms require head CT with and without contrast and lumbar puncture with opening pressure and comprehensive CSF studies.
Gastrointestinal symptoms necessitate stool studies, urinalysis, pregnancy testing in women, pelvic examination when appropriate, liver enzymes, pancreatic enzymes, hepatitis serologies, and a low threshold for abdominal imaging or surgical consultation.
Fever of unknown origin requires broad infectious evaluation including bacterial, fungal, AFB, and MAC cultures.
Ocular complaints require slit-lamp examination with fluorescein staining.
Diagnostic Studies And Interpretation
Laboratory Testing
ELISA testing detects IgG antibodies against HIV with approximately 99% sensitivity and specificity but may be negative during the window period. Western blot testing confirms positive ELISA results by detecting antibodies to HIV proteins. Rapid HIV testing provides results within 5–20 minutes using oral swabs or blood samples but requires confirmatory testing.
Absolute lymphocyte count can estimate immune status: values above 2,000 cells/mm³ often correlate with CD4 counts above 200, while counts below 1,000 suggest advanced immunosuppression.
Imaging
Chest radiographs may show bilateral interstitial infiltrates in PCP, reticulonodular patterns in TB or fungal infections, hilar lymphadenopathy in TB or malignancy, lobar consolidation in bacterial pneumonia, or cavitary lesions in TB and necrotizing infections. A normal chest x-ray does not exclude PCP or TB.
Head CT may demonstrate multiple ring-enhancing lesions consistent with toxoplasmosis or CNS lymphoma, or nonenhancing subcortical lesions suggestive of progressive multifocal leukoencephalopathy.
Abdominal and pelvic CT imaging may reveal splenomegaly, intestinal perforation or obstruction, biliary disease, or pancreatitis related to infection, malignancy, or medications.
Differential Diagnosis
Pulmonary complaints may represent pulmonary embolism, pulmonary hypertension, TB, bacterial, viral, or fungal pneumonia, malignancy, or lymphocytic interstitial pneumonitis.
Neurologic symptoms raise concern for neurosyphilis, viral encephalitis, toxoplasmosis, CNS lymphoma, meningitis, stroke, metabolic encephalopathy, or progressive multifocal leukoencephalopathy.
Cardiac presentations include cardiomyopathy, myocarditis, pericarditis, endocarditis, acute coronary syndrome, or pericardial effusion.
Oral and esophageal symptoms may result from candidiasis, viral infections, bacterial disease, autoimmune conditions, or malignancy.
Chronic diarrhea, hepatomegaly, and renal dysfunction have broad infectious, metabolic, medication-related, and neoplastic etiologies in HIV-infected patients.
Treatment
Emergency Department Management
Patients appearing toxic or with rapidly progressive illness should receive empiric antibiotics in the ED. Initiation of antiretroviral therapy is recommended for patients with low CD4 counts, high viral loads, pregnancy, AIDS-defining illnesses, or HIV-associated nephropathy.
Highly active antiretroviral therapy (HAART) typically consists of triple therapy using combinations of non-nucleoside reverse transcriptase inhibitors, protease inhibitors, and nucleoside reverse transcriptase inhibitors.
Post-exposure prophylaxis should begin within 2 hours of exposure when possible and continue for 4 weeks, with two-drug regimens for most exposures and expanded three-drug regimens for high-risk cases.
Specific opportunistic infections require targeted therapy, including pyrimethamine-based regimens for toxoplasmosis, amphotericin B with flucytosine for cryptococcal meningitis, ganciclovir for CMV retinitis, fluconazole for esophageal candidiasis, clarithromycin-based therapy for MAC, trimethoprim-sulfamethoxazole for PCP with adjunctive steroids when hypoxemia is present, and plasmapheresis for acute HIV-related demyelinating neuropathy.
Medication-Related Considerations
Antiretroviral therapy is associated with numerous potential adverse effects including hypersensitivity reactions, pancreatitis, peripheral neuropathy, nephrolithiasis, hepatotoxicity, lactic acidosis, Stevens–Johnson syndrome, hemolytic anemia, neuropsychiatric effects, metabolic derangements, cardiomyopathy, and hematologic abnormalities.
Follow-Up And Disposition
Admission Criteria
Indications for hospitalization include unexplained fever with neurologic involvement, hypoxemia, suspected acute coronary syndrome, pericardial effusion, suspected bacterial pneumonia or TB, new neurologic deficits or seizures, hemodynamic instability, inability to ambulate or tolerate oral intake, and severe diarrhea with dehydration.
Discharge Criteria
Patients may be discharged if they can maintain oral intake, ambulate, perform self-care, and have reliable follow-up.
Referral Considerations
All patients should be referred to an HIV specialist for initiation and management of antiretroviral therapy. Screening for depression and psychiatric referral are essential to ensure treatment adherence. Patients with concerning symptoms should be referred for malignancy evaluation.
Key Clinical Insights And Common Pitfalls
Immune reconstitution inflammatory syndrome typically occurs within 8 weeks of initiating HAART. Occupational exposure carries a low but real risk of seroconversion. Patients on HAART have increased risk for metabolic disease and acute coronary syndromes. Exercise-induced desaturation may aid in diagnosing PCP when imaging is normal. HIV is an independent risk factor for COPDukar
COPD, pulmonary hypertension, stroke, venous thromboembolism, thrombotic thrombocytopenic purpura, osteoporosis, and osteonecrosis of the hip.
1 Comments
thanks for info.
