Clinical Reasoning: Oculobulbar dysfunction Central or peripheral?

A 45-year-old man presented a few days after an upper respiratory tract infection with complaints of diplopia, dizziness, and difficulty walking that progressed within a few hours to complete ophthalmoplegia and facial diplegia. Brain MRI showed nonspecific T2 hyperintensities prior to transfer to our facility. On arrival, he was alert and oriented to person, place, and time. Pupils were dilated nonreactive and corneal reflexes were absent bilaterally. He had complete ophthalmoplegia, facial diplegia, and areflexia. His strength in the extremities per Medical Research Council (MRC) scale on initial presentation was preserved at 5/5. His clinical status declined rapidly, necessitating intubation for respiratory failure. Routine blood laboratory workup for infections, metabolic derangements including vitamin B1, and thyroid function tests were within normal limits. On day 1, CSF testing showed mildly elevated protein of 47 mg/dL with a normal cell count. CSF cultures and herpes simplex virus (HSV) testing were negative. He also had an EMG/nerve conduction study (NCS), repetitive nerve stimulation (RNS), and single fiber EMG on day 1, all of which were within normal limits. Serum acetylcholine receptor antibody testing was obtained on admission, which was negative.

Questions for consideration:

1. What is the most likely explanation for clinical

symptoms and implication of tests obtained so far?

2. What is a reasonable approach to management?

Free Full Text Article at neurology.org

Clinical Reasoning: Labyrinthine hemorrhage. An unusual etiology for peripheral vertigo

A 65-year-old man presented with a 2-week history of worsening vertigo. The sensation of vertigo was constant and exacerbated by turning in bed, sitting, and standing. Exacerbations lasted 5–10 minutes and were intense enough to cause gait impairment. Two days prior to presentation, the vertigo had worsened in severity and was associated with one episode of nausea and vomiting. Review of systems was positive for a 3-month history of a whistling noise in the patient’s left ear, a 2-week history of acute-on-chronic left-sided hearing impairment, and a recent upper respiratory infection. The patient’s medical history was notable for a left radical mastoidectomy performed 14 years prior to presentation for treatment of complications of chronic otitis media, which resulted in chronic leftsided hearing impairment. Medical history also included hepatitis C and remote alcohol and heroin abuse.

Questions for consideration:

1. What is the differential diagnosis for vertigo?

2. How do we clinically differentiate the peripheral

causes of vertigo from central causes of vertigo?

Free Full Text Article at neurology.org

An unusual cause of unilateral sixth nerve palsy.

Sotoodehnia M, Safaei A, Rasooli F, Bahreini M
Am J Emerg Med. 2016 Dec 12;:

BACKGROUND: The diagnosis of cerebral venous sinus thrombosis still remains a real challenge. Seizure, unusual headache with sudden onset, unexplained persistently unilateral vascular headache and neurologic deficit-which is difficult to be attributed to a vascular territory are some of the suggestive symptoms.
CASE: An isolated sixth nerve palsy is discussed as a rare presentation for cerebral venous thrombosis. Following the extensive investigation to rule out other possible diagnoses, magnetic resonance venogram revealed the final etiology of sixth nerve palsy that was ipsilateral left transverse sinus thrombosis; therefore, anticoagulant treatment with low molecular weight heparin was administered.
CONCLUSION: Rapid and accurate diagnosis and treatment cause to achieve excellent outcomes for most patients. Considering different clinical features, risk factors and high index of suspicion are helpful to reach the diagnosis.

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Hemiconvulsion-Hemiplegia-Epilepsy Syndrome.

By Novaksean - Own work, CC BY-SA 4.0,
 https://commons.wikimedia.org/w/index.php?curid=44348140

Stephens JR, Sams C
J Pediatr. 2016 Dec 30;:

An interesting case of a 4-year-old boy with a history of epilepsy presented with multiple seizures and subsequent hemiparesis. He was found by his parents in the early morning having a tonic-clonic convulsion. He was febrile at that time, and the episode resolved within 10 minutes, with return to normal baseline.

Free Article...

Absent Septum Pellucidum

The septum pellucidum (translucent hedge) is a thin, triangular, vertical double membrane separating the anterior horns of the left and right lateral ventricles of the brain. The septum pellucidum extends from the anterior part of the body, the genu, and the rostrum of the corpus callosum to the superior surface of the fornix. Its anterior to posterior extent therefore is from the lamina terminalis to the splenium of the corpus callosum. It bridges the midline gap between the corpus callosum above and the fornix below. Its width varies from 1 .5 to 3.0 mm. It contains glial cells, some scattered neurons, fiber bundles, and veins that connect with the choroid plexus veins. It is lined with ependyma on the ventricular side. There is no midline septum pellucidum, as the bodies of the lateral ventricles diverge posterior to the interventricular foramina. The diverging medial wall of the body of each lateral ventricle is instead formed by the ependyma-lined alvei of hippocampi. These alvei form a linkage between the medial margins of the fornices and the inferior surface of the body of the corpus callosum.

The septum pellucidum serves as an important relay station; its most anatomically and functionally important fiber connections are with the hippocampus and the hypothalamus and not with the primary olfactory structures.

It is linked with the hippocampus by precommissural fornix fibers, with preoptic and hypothalamic nuclei by the phylogenetically regressive median forebrain bundle of Broca that also relates the limbic with the olfactory system, with the amygdaloid nuclei by way of the striae terminalis, with the habenula and colliculi by way of the striae medullaris, and with the midbrain by its connection with the anterior fornix. It has a connection with the infracallosal precommissural primordium hippocampi through the paraterminal body.



Neurons from the Septum Pellucidum. Nissl staining. Mag 10X.

Absence of the septum pellucidum occurs in septo-optic dysplasia, a rare developmental disorder also characterized by abnormal development of the optic disk and pituitary deficiencies. Symptoms of septo-optic dysplasia are highly variable and may include vision difficulties, low muscle tone, hormonal problems, seizures, intellectual problems, and jaundice at birth. Children born without any other cognitive issues, other than an absent septum pellucidum, usually progress through life normally, and usually have no learning or cognitive disabilities.

Case courtesy of Dr Bruno Di Muzio, Radiopaedia.org. From the case rID: 41832.

1.      Lennart Heimer; Gary W. Van Hoesen (16 November 2007). Anatomy of neuropsychiatry: the new anatomy of the basal forebrain and its implications for neuropsychiatric illness. Academic Press. p. 28. ISBN 978-0-12-374239-1. Retrieved 24 December 2010. 

2.      David L. Clark; Nash N. Boutros; Mario F. Mendez (2010). The Brain and Behavior: An Introduction to Behavioral Neuroanatomy. Cambridge University Press. pp. 217–8. ISBN 978-0-521-14229-8. Retrieved 24 December 2010. 

3.      Love J; Hollenhorst R (1956). "Bilateral palsy of the sixth cranial nerve caused by a cyst of the septum pellucidum (fifth ventricle) and cured by pneumoencephalography". Mayo Clin Proc. 31 (2): 43–6. PMID 13289891. 

4.      Alonso J; Coveñas R; Lara J; Piñuela C; Aijón J (1989). "The cavum septi pellucidi: a fifth ventricle?". Acta Anat (Basel). 134 (4): 286–90. doi:10.1159/000146704. PMID 2741657. 

5.      Liccardo G; Ruggeri F; De Cerchio L; Floris R; Lunardi P (2005). "Fifth ventricle: an unusual cystic lesion of the conus medullaris". Spinal Cord. 43 (6): 381–4. doi:10.1038/sj.sc.3101712. PMID 15655569. 

6.      "NINDS Septo-Optic Dysplasia Information Page". National Institute of Neurological Disorders and Stroke. 1 August 2008. Retrieved 18 October 2013.



18q syndrome

Case courtesy of A.Prof Frank Gaillard, Radiopaedia.org. From the case rID: 8350

Cause

18q syndrome is caused by a deletion of part of chromosome 18 with varying numbers of genes being lost.

Symptoms

The symptoms of 18q syndrome may vary dramatically between cases, and can include:

1. Mental retardation (IQ<70)
2. Developmental delay
3. Growth deficiency: short stature
4. Craniofacial dysmorphism: refers to an abnormality of the face and/or the head. Craniofacial dysmorphism can include abnormal growth patterns of the face or skull, and may involve the soft tissue as well as the bones. In the case of 18q-syndrome, craniofacial abnormalities will most likely include deep-set eyes, a “carp-shaped” mouth, microcephaly (small head), prominent ears, and midfacial hypoplasia (underdeveloped midfacial regions).
5. Limb anomalies (including clubfoot, short thumbs)
6. Eye movement disorders
7. Genital hypoplasia: incomplete development of the genitals
8. Hypotonia: poor muscle tone
9. Hearing impairment
10. Heart disease
11. Skin manifestations
12. Autism
13. Behavioral Problems: might include hyperactivity, aggressive behavior, tantrums
14. Seizures: sudden episodes of electrical activity in the brain
15. Microcephaly: small head

Diagnosis

The syndrome can be diagnosed by genetic analysis using Fluorescent In Situ Hybridization (FISH). Furthermore brain MRI can show abnormal white matter, particularly posteriorly and in the periventricular region. It is characterised by bilateral symmetric deep white matter hyperintensity on T2 weighted images, with associated involvement of the subcortical white matter, while the brainstem and cerebellum are usually spared.

Treatment

Surgery can correct some of the craniofacial abnormalities often present in 18q-syndrome. Beyond this, treatment of 18q-syndrome is supportive, and can alleviate some of the symptoms of the disease. Prognosis is highly varied.

Neurology Case of the month from bcm.edu

59-year old right-handed white male, self-referred, with a history of progressive numbness in his lower extremities beginning in the early 1980's, as well as increasing horizontal diplopia beginning in 1991. The patient himself was a vague historian. He claims to have noticed joint discomfort in early 1980 which was diagnosed as "arthritis" and prompted therapy with low dose prednisone. Beginning in 1981 he complained of numbness in and around his upper and lower lip, as well as in his lower extremities. The numbness in the legs gradually increased up to his mid-thighs and to a lesser extent involved his hands. In the mid-1980's the patient had complaints of inability to maintain an erection. He was thought by his physician to have possible autonomic dysfunction. Beginning in 1990 the patient developed mild leg weakness and had balance problems, "walking like a drunk person". He denied any pain.

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