Case of the Month
Section Editor: Nicholas Stence, MD
Children's Hospital Colorado, Aurora, CO
May 2021
Next Case of the Month Coming June 8...
Toxoplasmosis with Myelitis
- Background:
- Neurologic symptoms in patients with HIV/AIDS can be due to several causes and toxoplasmosis-associated myelitis remains uncommon, with only a handful of cases reported in the literature.
- Up to half of these cases are reported postmortem.
- In this case, a biopsy of the frontal lesion was done. Histopathology suggested a diagnosis of toxoplasmosis. The patient was then tested for HIV on chemiluminescence, which was positive and was later confirmed by PCR.
- The patient was referred to an infectious diseases specialist who started him on antiretrovirals and co-trimoxazole. As of last follow-up, he ambulates in a wheelchair, and his higher mental functions are intact.
- Clinical Presentation:
- Toxoplasmic myelitis presents with myelopathic symptoms which include a sensory level, paraparesis, incontinence, and changes in the deep tendon reflexes.
- These symptoms may also be found in other disorders of the spinal cord affecting a patient with HIV/AIDS, such as neoplasms, viral infections, tuberculosis, and vascular pathologies.
- Cerebral toxoplasmosis presents with a variety of symptoms including headache, fever, confusion, hemiparesis, speech disturbances, cerebellar dysfunction, cranial nerve palsies, and sensory loss.
- Key Diagnostic Features:
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CSF and serum Toxoplasma IgG and IgM levels, if elevated, can be helpful, but may not be positive. The most common findings are elevated protein levels with values up to 2.2 g/dL; the number of white blood cells can be normal or elevated up to 500 cells/mm3.
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Imaging of the entire neuroaxis is the key investigation in the demonstration of Toxoplasma lesions. Typical MRI findings of spinal toxoplasmosis comprise a ring-enhancing intramedullary lesion, mostly affecting the thoracic segment, with more than half of cases simultaneously having intracranial lesions.
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In the brain, they present as multiple parenchymal lesions with ring enhancement, which are generally localized at the corticomedullary junction or basal ganglia. On MRI, these lesions appear hypointense on T1-weighted images with up to 70% showing ring enhancement with contrast.
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- Differential Diagnoses
- Differentials in this case will usually include other infective pathologies, although a neoplastic lesion should also be considered.
- Treatment:
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A combination of pyrimethamine and sulfadiazine, along with folinic acid, is usually the first-line treatment.
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If associated with AIDS, as usually is the case, HAART is also indicated.
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