Page 907 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

638 PART 5: Infectious Disorders

TABLE 69-6 Neurologic Complications in HIV-Infected Individuals (Continued)
Neurologic Syndrome Etiologic Agents Clinical Presentation Diagnostic Evaluation
Lymphoma Strong association with Epstein-Barr virus Confusion, lethargy, memory loss, progressive focal MRI or contrast-enhanced CT scan: usually 1-2 lesions in
(EBV) deficit(s), headache, seizure; more slowly progres- white matter (often periventricular), may mimic toxoplas-
sive than toxoplasmosis. CD4 count usually mosis but enhancement usually weaker and homogenous;
<50 cells/µL possible brain biopsy. Conflicting results for utility of spinal
fluid PCR for EBV DNA for diagnosis, but may have improved
sensitivity and specificity when combined with increased
uptake on thallium SPECT scan
Progressive multifocal JC virus (papovavirus) Slowly progressive focal deficits (over weeks), but MRI or contrast-enhanced CT scan: nonenhancing white
leukoencephalopathy no systemic toxicity or reduced level of conscious- matter lesions without mass effect. Definitive diagnosis
(PML) ness in the early stage requires brain biopsy (sensitivity 64%-96%). Spinal fluid PCR
for JCV 72%-92% sensitive and 92%-100% specific in pre-
ART era, (lower sensitivity for patients on ART). Compatible
clinical presentation plus positive PCR supports diagnosis
Neurosyphilis Treponema pallidum Focal neurologic deficits (meningovascular involve- Positive serum RPR and FTA-ABS; CSF examination: mono-
ment) with prodromal symptoms for weeks- nuclear pleocytosis (>20/µL), with/without positive VDRL
months such as headache and behavioral changes. (sensitivity ~50%); mild CSF leukocytosis of 6-20 cells/µL
Syphilitic meningitis may include cranial nerve (if CSF VDRL negative) may be indistinguishable from CSF
palsies. Ocular syphilis (eg, optic neuritis) often abnormalities caused by HIV and require CSF-FTA-ABS test-
associated with CNS involvement ing or treatment for possible neurosyphilis
Myelopathy
a) Subacute chronic HIV (vacuolar), HTLV-1 Slowly progressive, painless ataxia, and spasticity; MRI or CT scan best reserved for patients with atypical
(diffuse) bowel-bladder dysfunction occurs late; often coexistent findings where segmental lesions are to be excluded.
with dementia. Usually no distinct sensory/motor level Consider HTLV-1 serology
b) Acute, subacute Varicella zoster, lymphoma, cytomegalovirus More rapid onset of myelopathy than for HIV CT scan or MRI, myelography
(transverse myelitis)
Radiculopathies Varicella-zoster virus Herpes zoster dermatomal vesicular lesions Clinical diagnosis, with/without positive viral PCR from skin lesions
Cytomegalovirus Subacute and progressive ascending polyradicu- CSF: polymorphonuclear pleocytosis, elevated protein,
lopathy with sensory loss, urinary retention, and low glucose, with/without CSF PCR positive for CMV
flaccid paraparesis
Mononeuritis multiplex Autoimmune vascular lesion in early HIV Findings compatible with involvement of multiple Nerve conduction studies
(CD4 200-500/µL) distinct peripheral nerves. More severe in advanced
HIV disease
associated with headache. However, most of the causes of diffuse brain to note that the diagnosis of meningitis may be overlooked because head-
involvement are not associated with headache. A suggested sequence of ache and other neurologic symptoms may be mild or absent. Furthermore,
investigations in the HIV-infected patient with headache or CNS dys- meningeal signs are present in only a minority of cases. Other presenta-
function is outlined in Figure 69-9. tions of cryptococcosis include skin lesions and unexplained fever.
■ MENINGITIS tococcal meningitis. Abnormalities in CSF cell count and glucose and
An elevated opening pressure at lumbar puncture is common in cryp-

The clinical presentation of both acute and chronic meningitis is little protein concentrations may be minimal or absent despite positive results
different in the AIDS patient from that seen in the immunocompetent for cryptococcal antigen and positive fungal cultures. The CSF white blood
host: headache, fever, and nuchal rigidity of variable duration and sever- cell count usually is less than 20/µL and predominantly lymphocytic. The
ity. Common causes of bacterial meningitis are similar to the general CSF glucose concentration is usually normal but may be low. The serum
adult population (pneumococcus, meningococcus, and Listeria mono- cryptococcal antigen determination provides a rapid, noninvasive test that
cytogenes). The most important cause of meningitis in the HIV-infected is highly sensitive for diagnosing extrapulmonary disease. The organism
patient is Cryptococcus neoformans. Uncommon etiologies include may be cultured from spinal fluid, blood, urine, sputum, and skin lesions.
Mycobacterium tuberculosis, 140,141 Coccidioides immitis, Histoplasma Patients with C neoformans initially isolated from the lung, skin, or blood
127
capsulatum, and Treponema pallidum (syphilis). HIV-related aseptic should be investigated for the presence of disseminated disease, including a
meningitis may occur at the time of seroconversion but is more common lumbar puncture, even in the absence of headache or neurologic symptoms.
later in the course of HIV disease. ■ MANAGEMENT
A suggested sequence of investigations in the HIV-infected patient with
CRYPTOCOCCUS NEOFORMANS headache or CNS dysfunction is outlined in Figure 69-9. An HIV-infected
■ CLINICAL PRESENTATION patient presenting with an illness compatible with cryptococcosis whose
serum cryptococcal antigen titer is positive (unless the serum crypto-
Although less common since the introduction of ART, cryptococcosis coccal antigen titer is 1:8 or less, which may represent a false-positive
occurred in approximately 5% to 10% of individuals at some point dur- result) should be started on antifungal therapy before completion of the
ing the course of HIV infection in the pre-ART era. Cryptococcal disease investigations if there are delays involved in obtaining neurologic imag-
in AIDS usually presents as a subacute to chronic meningitis, and con- ing, or if contraindications to performing a lumbar puncture exist (eg,
comitant pulmonary infection may be present. The duration of symptoms mass lesion or shift on CT head scan or coagulopathy). Initial treatment
before presentation varies from a few days to several weeks. It is important of AIDS-related cryptococcal meningitis is amphotericin B at 0.7 mg/kg

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