• Figure 37-2. Chest radiograph showing classic appearance of PCP

pneumonia (bilateral interstitial infiltrates).

HUMAN IMMUNODEFICI ENCY VIRUS

£. Figure 37-3. Head CT scan showing ringenhancing lesions of CNS toxoplasmosis in a patient

with AI DS.

PROCEDURES

Lumbar puncture. In patients with new headache or fever,

especially in patients with CD4 count <200/mL. CT before

lwnbar puncture (LP) is recommended in all patients with

HIV to rule out mass lesion and increased intracranial

pressure. Check opening pressure (particularly important

for cryptococcal meningitis). Routine studies (cell count

with differential, total protein, glucose) should be sent.

Additional cerebrospinal fluid studies performed in HIV

patients include India ink (Cryptococcus), viral and fungal

culture, toxoplasmosis, cryptococcal titers or antigens, and

VDRL for neurosyphilis.

MEDICAL DECISION MAKING

The medical decision-making process is especially depen ­

dent on the presenting symptoms in a patient with HIV.

Fever. Although fever in the HIV-positive patient with

preserved CD4 count (>500) may be benign, the likelihood that fever represents opportunistic infection goes up

markedly with lower CD4 count and should be treated as

such. Fever alone in the immunocompromised patient is

sufficient grounds for admission/observation. Differential

diagnosis includes pneumonia (PCP, bacterial), histoplasmosis (especially for those living in, or recently traveling

to, the Ohio/Mississippi river valley areas), toxoplasmosis

(disseminated or encephalitis), cryptococcal meningitis,

bacterial meningitis and sepsis, TB (anywhere),

salmonellosis, sinusitis, lymphoma, CMV, dMAC, or drug

reaction.

Respiratory symptoms. Most standard prognosis/decision algorithms do not apply to the immunocompromised.

Therefore, admission and empiric treatment are appropriate for the HIV-positive patient with low CD4 count and

possible pnewnonia. Differential diagnosis includes PCP,

community-acquired pneumonia, TB, fungal pnewnonia

(histoplasmosis, coccidioidomycosis), Kaposi sarcoma, or

lymphoma. As a special note, patients with HIV, cough,

and fevers are at risk for pulmonary TB. They should be

masked and placed in a respiratory isolation room directly

from triage. Up to 12% of HIV-infected patients with TB

may have a normal chest x-ray.

Neurologic symptoms. Neurologic symptoms in the

HIV-positive patient, particularly with low CD4 count,

should be treated as a medical emergency. The evaluation is as above, and empiric treatment, when warranted, should not be delayed. Differential diagnosis

includes toxoplasmosis, cryptococcal meningitis, bacterial or viral meningitis, encephalitis (JC virus-PML,

primary HIV encephalitis, herpes simplex virus, CMV,

varicella zoster virus), primary CNS lymphoma, or drug

reactions.

Gastrointestinal symptoms. Diarrhea is the most common gastrointestinal (GI) complaint in the HIV-positive

population, and this may be due to many factors, including

acute retroviral therapy (ART) or opportunistic infection

(OI), in addition to usual causes of diarrhea in the nonHIV-infected population. Many GI complaints can be

managed successfully without requiring admission,

although certain diagnoses ( eg, pancreatitis, lactic acidosis)

merit close monitoring, usually in an inpatient setting.

Differential diagnosis is dependent on the particular GI

symptom(s) and includes esophagitis (candida, CMV, herpes), pancreatitis (ART, viral), cholangiopathy (microsporidia), nephrolithiasis (ART), enteritis (CMV, bacterial,

parasitic), lactic acidosis (ART).

See Figure 37-4 for a diagnostic algorithm for a patient

with HIV presenting with fever, respiratory, or neurologic

complaints.

TREATMENT

The treatment and management of HIV itself is rarely an

emergency. Data have shown that initiation of ART earlier

in the course of HIV infection benefits both those with OI

(eg, TB), and those without OI. Current Department of

Health and Hwnan Services guidelines recommend treatment for all persons diagnosed with HIV. However, given

the complexities associated with initiation of an antiretroviral regimen, the decision about what to start should be

made in conjunction with an expert in the management

of HIV.

� Fever (Undifferentiated)

Well-appearing patients with CD4 counts >500/J.LL without

an obvious source of infection do not need specific antimicrobial therapy and are treated as an immunocompetent

CHAPTER 37

Admission

Consider

discharge

depending on

clinical picture

LP (cryptococcus,

meningitis), consider

MRI

Antimicrobial

therapy if CT/MRI

scan or LP positive

Likely admission

Figure 37-4. Human immunodeficiency virus diagnostic algorithm. ABG, arterial

blood gas; CT, computed tomography; CXR, chest x-ray; ED, emergency department;

HIV, human immunodeficiency syndrome; LB, lumbar puncture; MRI, magnetic resonance imaging; PCP, Pneumocystis carinii pneumonia; TB, tuberculosis; UA, urinalysis.

host. Patients who appear ill and have CD4 counts <200/jlL

should be treated with broad-spectrum antibiotic coverage

(piperacillin-tazobactam plus arninoglycoside, consider

addition of vancomycin when concerned for methicillinresistant Staphylococcus aureus as etiologic agent).

� Pulmonary Complaints

Patients with suspected PCP should be treated with

trimethoprim-sulfamethoxazole. If Pa02 is <70 mmHg or

A-a gradient is >35 mmHg, adjunctive steroids should be

given (usually a prednisone taper). Because PCP is often indistinguishable from community-acquired pneumonia, a thirdgeneration cephalosporin (eg, ceftriaxone) with macrolide

( eg, azithromycin), or monotherapywith a respiratory fluoroquinolone (eg, levofloxacin, moxifloxacin) should be added.

All patients should be isolated until TB has been ruled out.

� CNS Complaints

Patients with CT /MRI findings consistent with toxoplasmosis and mass effect from the CNS lesion require neurosurgical consultation and steroids (dexamethasone 10 mg

intravenously [IV] ). Cryptococcal meningitis is treated with

IV amphotericin B (often with 5-fluorocytosine) after consultation with an infectious disease specialist. Suspected

bacterial meningitis should be treated immediately (see

Chapter 35) and not delayed for imaging or LP. Retinal

lesions consistent with possible CMV retinitis should be

treated with ganciclovir (IV) in conjunction with consultation with an ophthalmologist and infectious disease specialist. There is currently no effective treatment for PML,

although immune reconstitution can help slow or halt progression of the disease.

HUMAN IMMUNODEFICIENCY VIRUS

..... Gl Complaints

Suspected candida} esophagitis should be treated with oral

fluconazole. Failure to improve suggests drug-resistant

Candida, CMY, or herpes as the cause. Acute diarrhea that is

negative for ova and parasites is treated symptomatically ( eg,

loperamide) in the ED, with outpatient referral.

DISPOSITION

..... Admission

• Fever without a source if the patient is ill-appearing

or the CD4 count is <500/j.tL.

• Any ill-appearing or dehydrated patient.

• All patients with pulmonary infections should be

admitted to an isolation bed until the possibility of

TB is excluded.