Transcript Acute hemorrhagic leukoencephalitis

AMERICAN ASSOCIATION OF NEUROPATHOLOGISTS
51ST ANNUAL DIAGNOSTIC SLIDE SESSION
Case 2010-10
Douglas C Miller MD,PhD
University of Missouri School of Medicine
Department of Pathology & Anatomical
Sciences
Case History
This 65 year old man developed a cough and sore throat, which worsened
over several days, bringing him initially to his primary care physician. He had a
negative test for influenza and was told he had a viral illness, was given cough
syrup, and was sent home. He developed fever to 104˚F, weakness, and anorexia
and came to the hospital. He was admitted, started on oxygen, antibiotics, and
bronchodilators, and was noted to have febrile neutropenia. He was neurologically
normal. However he further deteriorated and required sedation, intubation, ICU
admission, and pressors for septic shock. He developed ventricular tachycardia and
then had an arrest after being given amiodarone; he was resuscitated. He
developed acute renal failure. Six days after admission a head CT was said to show
subarachnoid hemorrhage. He was weaned from sedation but remained comatose,
thought secondary to hypoxic brain damage after his cardiac arrest. Given the poor
prognosis the family agreed to comfort care only, and shortly thereafter he died.
Permission for a full autopsy was obtained.
CT scan without contrast
Autopsy
The general autopsy documented septicemia and a bilateral
lower lobe pneumonia with Candida glabrata and coagulasenegative Staphylococcus; the bone marrow was hypercellular,
thought consistent with sepsis. There was cardiomegaly with
moderate coronary artery disease.
The brain was 1600 grams (fixed weight) and was swollen with
central herniation and had small foci of fresh subarachnoid
hemorrhage. Coronal sections showed no abnormalities of the
cortex, but the white matter had numerous scattered round
petechiae, the largest of which was 0.6 x 0.5 cm in one section.
There were also petechiae in the brainstem and in the cerebellar
white matter.
Material submitted:
One Luxol Fast Blue/H&E combination stained section of
cerebrum (from one of three areas)
Small lesion from slide in
DSS set.
Note absence of LFB myelin
staining in the lesion, which
contains microglia and
histiocytes.
Diagnosis?
Pathogenesis?
From the gross the differential diagnosis included fat emboli. Oil Red O stains on frozen
tissue showed no fat, and no bone marrow elements were seen in any vessels in any
brain sections.
Bielschowsky silver stains suggested relative preservation of axons in the
perivascular areas with and without hemorrhage but lacking LFB +
myelin.
Immunostains for intermediate molecular weight neurofilament
protein (NF-M; antibody RMDO20) confirmed the presence of axons
but suggested acute axonal swelling and damage in the perivascular
lesions.
The cellular infiltrates were mostly histiocytes (CD68 +), and there was
extensive diffuse activation of and infiltration by microglia.
CD68, 20x
CD45/LCA, 20x
Azocarmine stains did not show fibrinoid necrosis of vessel walls
although there is obviously fibrin in the hemorrhages.
GFAP immunostains demonstrated an early gliosis in and around the
lesions
20x
40x
Diagnosis
ACUTE HEMORRHAGIC
LEUKOENCEPHALITIS
(SYNONYMS: WESTON HURST DISEASE; ACUTE
NECROTIZING ENCEPHALITIS; ACUTE NECROTIZING
HEMORRHAGIC ENCEPHALITIS)
Diagnosis, Pathogenesis
AHEM is an post-infectious demyelinating disease often thought of as a
fulminant and hemorrhagic variant of Acute Disseminated
Encephalomyelitis
In contrast to ADEM, AHEM is more often fatal, and (as here) is often
discovered only at autopsy, although with MRI the diagnosis is made more
frequently in life than formerly
Survival has been reported with aggressive immunosuppressive therapy
including high dose steroids, and survivors often have minimal sequelae
This is believed to be a florid auto-immune disorder or immune-related
hypersensitivity reaction causing vascular damage and demyelination,
essentially a brain-limited Arthus reaction. It has been associated with a
broad spectrum of triggering illnesses, with increasing attention paid to
Mycoplasma pneumoniae upper respiratory infections
References
Hurst EW. Acute hemorrhagic leucoencephalitis: a previously undefined entity. Med J Aust
2, 1-6, 1941.
General Neuropathological Descriptions
Greenfield JG. Infectious Diseases of the Central Nervous System. Ch 3 in Neuropathology,
1st ed (JG Greenfield, W Blackwood, WH McMenemy, Meyer A, Norman KM, eds). London:
Edward Arnold, 1958; pp. 205-207.
Sobel RA, Moore GRW. Demyelinating Diseases. Ch 20 in Greenfield’s Neuropathology, 8th
ed (S Love, DN Louis, DW Ellison, eds). London:Hodder-Arnold, 2008; pp. 1586-1588.
Kleinschmidt-DeMasters BK, Simon JH. Dysmyelinating and Demyelinating Disorders. Ch 5
in Neuropathology. (R Prayson, ed). Philadelphia: Elsevier/Churchill Livingstone, 2007; pp.
217-219.
Hart MN, Earle KM. Haemorrhagic and perivenous encephalitis: a clinical-pathological
review of 38 cases. J Neurol Neurosurg Psychiatr 38, 585-591, 1975.
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References
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