Thursday 14 May 2015

Haemorrhagic encephalitis - CNS Leptospirosis MRI

41 y o male patient admitted with c/o bilateral Lower limb Pain, Fever and Rapidly falling platelets.
Lab Investigations on admission Hb- 11.0, Platelets - 20,000 , Creatinine - 2.5, Bil(T)- 3.7, SGOT - 185, LDH- 1570

MRI Brain

Axial T1 and T2w images:
Axial GRE images:
DW images:
Sagittal T2wi for pituitary:

MRI shows multiple, patchy T2 hyperintense lesions of varying sizes on Flair and T2 W images in bilateral cerebral parenchyma involving the cortex and sub cortical white matter.
Some of the lesions show hyperintense foci on T1 weighted images, which appear hypointense on T2 weighted images and bloom on gradient echo images representing hemorrhage.
Restricted diffusion along the pyramidal tracts from the corona radiata upto the pons. These lesions are symmetric. Similar changes are seen in the corpus callosum, especially in the genu and splenium.
The pituitary gland appears hyperintense on T1 weighted images and hypointense on T2 weighted images and is probably also involved.

Findings are suggestive of haemorrhagic encephalitis. It involves cerebral hemispheres, corpus callosum and brain stem, as described.
The middle cerebellar peduncles and pituitary gland are also involved.

Follow up lab investigations shows raising Creatinine to 6.9,  Platelets on lower side.
Dengue NS1Ag -negative, Chikungunya IgM- Negetive, Leptospira IgM positive, Malaria -ve.

Final diagnosis : 

Haemorrhagic encephalitis - CNS Leptospirosis

Discussion: 

Hemorrhagic fevers are febrile illnesses with abnormal vascular regulation and vascular damage. Although the combination of fever and hemorrhage can be caused by a number of human pathogens: viruses, rickettsiae, bacteria, protozoa, and fungi, the term hemorrhagic fever usually refers
to a group of illnesses that are caused by 4 different families of
viruses: Arenaviridae, Filoviridae, Bunyaviridae, and Flaviviridae

Classic hemorrhagic fever with renal syndrome is a syndrome characterized by sequential periods of fever, hypotension, oliguria, and diuresis.

Headache may be associated with aseptic cerebral edema, or CNS hemorrhage .
Brainstem or posterior fossa subarachnoid hemorrhages are found.
May be associated with Pituitary dysfunction with pituitary apoplexy or panhypopituitarism

Leptospirosis

Infection caused by bacteria of the Leptospira type.
Symptoms - none to mild such as headaches, muscle pains, and fevers.
The disease presents with variable combinations of clinical syndromes, which cause diagnostic confusion.
In most cases hemorrhage in Leptospirosis occurs in the pulmonary and GI system and not in the Central Nervous system.
A small proportion of patients develop severe icteric illness with renal failure- Weils Disease.
Marked elevations of bilirubin with mildly elevated transaminases are some
characteristic features of leptospirosis.

Spectrum of CNS Leptospirosis

Aseptic Meningitis - most common
Rarely encephalitis , cerebellitis , myelitis.
Intracranial hemorrhage is a rare and serious presentation of leptospirosis.
Peripheral Nervous System - Polyneuritis.
Other associations- GBS , Stroke.

Contributed by Dr Mitusha Verma SR DNB Radiology Nanavati. 

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