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Biomedical subjects

A S Mark

Publications and source records attributed to A S Mark.

At least 19 recordsLinked to original sources
PubMed1999

MRI in vitamin B12 deficiency myelopathy.

BACKGROUND: Little is known about vitamin B12 deficiency myelopathy's magnetic resonance imaging (MRI) manifestations and their relationship to the onset, evolution, and resolution of neurologic signs and symptoms. METHODS: We present a case and review eleven additional reported cases of subacute combined degeneration of the spinal cord detected by MRI. RESULTS: Our patient had increased T2-weighted signal and gadolinium contrast enhancement of the posterior columns in the cervical and thoracic regions and enhancement of the lateral columns in the high cervical region. This is a case with imaging evidence for lateral column lesions. Two prior reports have shown posterior column enhancement. T1-weighted images may show decreased signal in the posterior columns and sometimes demonstrate reversible spinal cord swelling. MRI abnormalities typically improve after vitamin replacement therapy. However, clinical signs may persist despite resolution of imaging abnormalities, and these abnormalities do not always resolve completely. In addition, symptoms may precede the imaging abnormality. CONCLUSIONS: Vitamin B12 deficiency may produce an increased T2-weighted signal, decreased T1-weighted signal, and contrast enhancement of the posterior and lateral columns of the spinal cord, mainly of the cervical and upper thoracic segments. Because the symptoms may precede any imaging abnormality, it is clear that spinal cord MRI may not be a highly sensitive, early test for subacute combined degeneration.

Adult↗
PubMed1999

Intralabyrinthine schwannomas.

OBJECTIVE: To describe characteristic features of intralabyrinthine schwannomas (ISs) that may be used to distinguish them from other otologic disorders with similar symptoms so that appropriate evaluation and management can be instituted. STUDY DESIGN: This study was a retrospective case review. SETTING: This study was conducted at a university-affiliated urban tertiary care medical center and a university medical center in the same city. PATIENTS: Seven patients with ISs were included in this study. INTERVENTIONS: Tumor removal versus observation and monitoring with periodic magnetic resonance imaging (MRI) scans was investigated. MAIN OUTCOME MEASURES: Hearing, vertigo, and tumor growth were measured. RESULTS: Four of seven patients with ISs underwent surgical excision with no evidence of tumor recurrence. The remaining three patients are being followed-up with repeat MRI that has demonstrated minimal or no tumor growth. CONCLUSIONS: ISs can be detected in early stages if MRI is performed in patients with unilateral sensorineural hearing loss without vertiginous symptoms typical of Meniere's disease. Although complete surgical excision can be achieved readily with labyrinthectomy, observation and monitoring with rep--MRI is an option for some patients.

Adult↗
PubMed1998

Cervical spinal cord injury during cerebral angiography with MRI confirmation: case report.

We report the first case of MRI-documented cervical spinal cord injury during cerebral angiography. A 54-year-old woman underwent an angiogram for subarachnoid hemorrhage. Her head was secured in a plastic head-holder. At the end of the procedure, she was found to have a left hemiparesis. MRI revealed high signal in the cervical spinal cord. The etiology may have been mechanical due to patient positioning, or toxic, from contrast medium injection in the vessels feeding the spinal cord, or a combination of both.

Cerebral Angiography↗
PubMed1998

Sclerotic lesions of the cervical spine in sarcoidosis.

Sarcoidosis is a common multisystem disorder characterized by noncaseating epithelial granulomata, with osseous involvement typically seen in 5% of patients. While the lace-like or cystic pattern frequently seen in radiographs of the phalanges is well appreciated, sclerotic lesions of the spine are uncommon. We review a case of sarcoidosis of the cervical spine with sclerotic changes that mimicked blastic metastatic disease.

Adult↗
PubMed1998

Oculomotor motion disorders: current imaging of cranial nerves 3, 4, and 6.

The eye movements are controlled by the cranial nerves 3, 4, and 6 working in close cooperation under the supervision of the voluntary cortex. Clinically, the most common presentation of abnormal ocular motor motion is double vision. A thorough clinical examination can usually separate a local orbital cause which can produce a restriction of the muscles moving the eye from a neurogenic cause due to an abnormality of one of the three nerves or their association pathways. Recent articles in the scientific literature have described major advances in our understanding of the anatomy and vascular relationships of the three ocular motor nerves (cranial nerves 3, 4, and 6) and of the diagnosis and treatment of a variety of pathological processes that damage these nerves, including ischemia, inflammation, and compression.

Abducens Nerve↗
PubMed1998

Solitary cerebellar metastasis from papillary thyroid carcinoma: a case report.

Papillary thyroid carcinoma is a common thyroid malignancy that generally has a good prognosis. However, this type of cancer may give rise to distant metastasis and may behave more aggressively in older patients. Here we report clinical, radiological, and pathological findings of a patient with papillary thyroid carcinoma who had a solitary cerebellar metastasis. The patient was known to have metastatic thyroid cancer to the lungs, but this had been stable and the cerebellar metastasis presented an unanticipated significant problem. The rapid detection of cerebellar metastatic disease is critical because neurosurgical removal of the solitary lesion should be considered as the treatment of choice. This case also serves to remind us of the importance of considering possible metastatic brain lesions and their acute life-threatening complications in contrast to the relatively prolonged course associated with metastases of thyroid carcinoma to other organs.

Aged↗
PubMed1998

Sudden hearing loss: frequency of abnormal findings on contrast-enhanced MR studies.

BACKGROUND AND PURPOSE: Our purpose was to determine the frequency of abnormal findings on contrast-enhanced high-resolution MR imaging studies in patients with sudden hearing loss. METHODS: Seventy-eight consecutive patients with sudden hearing loss underwent contrast-enhanced MR imaging of the temporal bone, cerebellopontine angle, and brain. Additional tests included audiologic examination, electrocochleography, fistula tests, and serologic tests for viral agents and autoimmune disorders. RESULTS: Probable causes of the sudden hearing loss in these patients included viral or immune-mediated disease, Meniere disease, vascular disorder, syphilis, neoplasm, multiple sclerosis, and perilymphatic fistula. Twenty-four (31%) of the 78 patients were found to have abnormal imaging results early in the course of their work up and treatment. CONCLUSION: The prevalence of abnormal findings on contrast-enhanced MR studies is higher than previously reported in patients with sudden hearing loss.

Adult↗
PubMed1997

Ménière disease.

Explore the source record for details and available documents.

Endolymphatic Hydrops↗
PubMed1996

Vestibular dysfunction in chronic inflammatory demyelinating polyneuropathy.

Chronic inflammatory demyelinating polyneuropathy (CIDP) has occasionally been associated with clinical or laboratory evidence (magnetic resonance imaging,[MRI], visual evoked response, and brainstem auditory evoked response [BAER] of cranial neuropathy. In most cases, the relationship of cranial nerve involvement to CIDP remains unclear. A 45-year-old woman noted foot numbness, limb weakness, gait and postural instability, and oscillopsia. An IgG kappa monoclonal gammopathy of undetermined significance was found. Bilateral vestibulopathy was documented by clinical examination, bithermal calorics, rotary chair testing, BAERs, and dynamic posturography. MRI with gadolinium demonstrated enhancement of cranial nerve VIII bilaterally. Over the next 6 years, the patients's relapsing and remitting course of CIDP and vestibulopathy was assessed by quantitative muscle and vestibular function testing (clinically and neurophysiologically), and dynamic visual acuity. There was a striking synchronization between her CIDP and vestibulopathy with respect to clinical course including relapses and responses to immune therapy. The response to therapy, and evidence derived from clinical and laboratory investigations, suggest that the vestibular dysfunction was immune mediated.

Chronic Disease↗
PubMed1996

Unilateral optic neuritis caused by Histoplasma capsulatum in a patient with the acquired immunodeficiency syndrome.

PURPOSE: To evaluate the potential of Histoplasma capsulatum to cause optic neuritis in the setting of the acquired immunodeficiency syndrome (AIDS). METHODS: We examined a 35-year-old man with a history of AIDS and disseminated histoplasmosis who developed a unilateral progressive optic neuritis of enigmatic origin. An optic nerve sheath biopsy was performed to provide a tissue diagnosis. RESULTS: Histoplasma capsulatum was identified in both the optic nerve sheath and fungal culture. CONCLUSION: Histoplasma capsulatum should be considered in the differential diagnosis of optic neuritis in patients with AIDS, even in the absence of chorioretinal findings.

AIDS-Related Opportunistic Infections↗
PubMed1996

Zoster myelitis: improvement with antiviral therapy in two cases.

This report describes two patients with acquired immunodeficiency syndrome (AIDS) and herpes zoster myelopathy. Patient one had a T-8 myelitis that preceded the onset of T-8-distribution zoster and was followed by cervical myelopathy. Antibody to varicella zoster virus (VZV) was present in the CSF. He never received steroids or other immunosuppressive drugs, and his condition improved dramatically after treatment with intravenous acyclovir. The second patient had a rapidly progressive myelitis with paralysis of both legs. Detection of VZV DNA and antibody to VZV in his CSF led to successful treatment with famciclovir despite discontinuation of dexamethasone and earlier treatment failure with acyclovir. These cases support the idea that VZV myelopathy in the immunosuppressed host is caused by virus invasion. CSF analysis for antiviral antibody and for VZV DNA by polymerase chain reaction are helpful in establishing the diagnosis. Aggressive antiviral therapy is advised.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Endolymphatic duct/sac enhancement on gadolinium magnetic resonance imaging of the inner ear: preliminary observations and case reports.

Twelve patients with auditory and/or vestibular symptoms were examined with a gadolinium magnetic resonance imaging (Gd-MRI) study. They all were found to have enhancement of only the endolymphatic duct/sac structures of the inner ear. Most of these findings were unilateral, but a few were bilateral. The patients underwent auditory, vestibular, and blood tests in an attempt to clarify the reason for this abnormal enhancement. Several specific etiologies were identified, but several cases had unknown causes. In this article we review the concept of inflammation of the inner ear structures with particular attention to the role of the endolymphatic duct/sac in the immune response of the inner ear. The idea of an inflammatory response of the inner ear leading to endolymphatic hydrops (Meniere's disease) is discussed, but these patients did not follow a clear path from inflammation of the endolymphatic duct/sac to endolymphatic hydrops. However, the longest follow-up was only 4 years, and our observations remain preliminary. Finally, the authors have found that Gd-MRI study of the inner ear provides valuable information in the investigation of patients with new auditory and/or vestibular symptoms.

Adult↗