CPC:38 yearold AIDS patient with brain and pulmonary lesions

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CPC38 year-old AIDS patient with brain and
pulmonary lesions

• Gregory M. Lucas, MD PhD
• Division of Infectious Diseases

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Pre-Hopkins course

• CD4 cell count 3/mm3, HIV RNAgt750,000 c/mL, OI
  candidal esophagitis
• Crack cocaine and alcohol use, no ART, no OI
  prophylactic medications
• Admitted to outside hospital with subacute
  deterioration in mental status and seizure
• CNS and pulmonary lesions noted induced sputum
  negative for PCP, AFB
• Rx with phenytoin, corticosteroids and
  fluconazole
• Discharged to hospice

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Hopkins course

• P.E. low-grade fever, hypoxia, encephalopathic,
  LUE flaccid
• Labs Toxoplasma IgG, serum CRAG negative.
• CSF mildly elevated protein, CRAG negative
• Brain imaging innumerable enhancing masses with
  edema and mass effect
• Chest imaging Nodular infiltrates
  (wedge-shaped), pulmonary embolism RLL

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Could a viral CNS infection present this way?

• Herpes viruses CMV, VZV, HSV can affect the CNS
• Typical picture is encephalitis often with
  ventriculitis
• CSF usually abnormal
• CNS mass lesions not seen
• Couldnt explain pulmonary findings

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Initial approach to an AIDS patient with brain
lesions

• No mass effect, no enhancement with IV contrast
• HIV encephalopathy
• Progressive multifocal leukoencephalopathy (PML)

• Mass effect, enhancement with IV contrast
• Abscess
• Malignancy

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Differential diagnosis of contrast-enhancing CNS
lesions in an AIDS patient

• Abscess
• Toxoplasmosis
• Cryptococcosis, dimorphic fungi (histoplasmosis,
  coccidioidomycosis)
• Pyogenic abscess (Staph, Strep, polymicrobial)
• Tuberculosis
• Nocardiosis
• Filamentous fungi
• Neurocysticercosis

• Malignancy
• Primary CNS lymphoma
• Non-CNS cancer metastatic to brain

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Toxoplasma gondii

• Cats are definitive host, many other animals
  incidental host
• Seroprevalence in Baltimore 10
• Disease in AIDS is reactivation of latent
  infection

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CNS toxoplasmosis
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Yeast H. capsulatum (C. neoformans)

• Found worldwide, but geographical variation in
  intensity of exposure
• Lung fungemia CNS involvement in 10-20
  (usually meningitis)
• Histoplasma antigen testing from serum or urine
  highly accurate in disseminated disease

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Pyogenic brain abscess

• Classification
• Extension from sinuses or ear,
• Metastatic typically multiple
• trauma or post-operative
• S. aureus, Streptococci, anaerobic organisms

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Mycobacterium tuberculosis

• Infects 1/3 of global population
• Transition from latent to active disease occurs
  in 10 of HIV co-infected patients per
  year
• CNS involvement
• Meningitis prominent basilar meningeal
  enhancement
• Tuberculomas often multiple, solid-appearing
  grossly, often accompanied by meningitis
• Tuberculous abscess quite rare, large,
  solitary, multiloculated

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Tuberculomas
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Nocardiosis

• Higher-order bacteria, gram-positive branching
  filaments, usually acid-fast
• Ubiquitous environmental saprophytes
• Defects in cell-mediated immunity important risk
  factor
• Manifestations
• Cutaneous infections (nodular lymphangitis,
  mycetoma)
• Pulmonary disseminated (usually N. asteroides)

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Acid fast stain of N. asteroides
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Nocardia pulmonary infection in transplant patient
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Nocardia brain abscess
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Rhodococcus equi

• Gram-positive, weakly acid-fast rod
• May be mistaken for a diptheroid contaminant
• Causes pneumonia in foals
• Present in soil, 1/3 infected have exposure to
  horses
• In immunocompromised humans it presents as a TB
  mimic indolent, upper-lobe, cavitary
• Difficult to treat

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Filamentous fungi Aspergillus, Pseudallescheria,
zygomycosis

• Neutrophil defects strongest risk factor for
  invasive aspergillosisbone marrow transplant,
  chronic granulomatous disease (CGD)
• Other risk factors steroids, alcoholism
• Lung or sinuses typical portal of entry
• Dissemination to brain common, never meningitis
• Unusual in AIDS patients very advanced disease,
  relative neutropenia, steroid use
• Notable aspect of pathogenesis is angioinvasion

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Aspergillus invading blood vessel
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Neurocysticercosis

• Taenia solium (pork tapeworm)
• Eat pigs (undercooked) tapeworm infection
  secrete eggs
• Eat poop (containing eggs) cysticercosis
  (tissue infection with parasites)
• Infection common south of the Mexican border
• Accounts for 50 of adult onset seizures

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Neurocysticercosis
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Malignancies
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Primary CNS lymphoma

• 2nd Most common cause of ring-enhancing brain
  lesions in AIDS patients in US
• Unlike peripheral lymphomas PCNSL seen
  exclusively in advanced disease
• Solitary lesion in 50, multicentric in 50
• Non-Bx methods to distinguish from toxo Toxo
  IgG, EBV PCR from CSF, metabolic function scans
  (SPECT, PET)

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Malignancy metastatic to brain

• Most common tumors metastasizing to brain lung,
  kidney, colon, breast, melanoma
• Kaposis sarcoma metastasis to brain extremely
  rare
• Peripheral lymphomas may metastasize to brain

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Differential diagnosis of contrast-enhancing CNS
lesions in an AIDS patient

• Abscess
• Toxoplasmosis
• Cryptococcosis
• Histoplasmosis
• Pyogenic abscess (Staph, Strep, polymicrobial)
• Tuberculosis
• Nocardiosis
• Aspergillosis
• Neurocysticercosis

• Malignancy
• Primary CNS lymphoma
• Non-CNS cancer metastatic to brain

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Clinical diagnosis

• Pulmonary aspergillosis disseminated to brain
• Nocardiosis
• Histoplasmosis
• Tuberculosis