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Bilateral medial medullary stroke: A rare stroke syndrome masquerading as myasthenia crisis in a young diabetic lady

Benjamin NHS, Gin TH, Ling Elora OY, Yung Kelly WK

J R Coll Physicians Edinb, 2022 Mar;52(1):30-33.
PMID: 36146975 DOI: 10.1177/14782715221088914

Bilateral medial medullary stroke is a rare stroke syndrome. The clinical presentation of bilateral medial medullary stroke is heterogenous and often overlaps with other non-stroke neurology emergencies such as Guillain-Barrésyndrome, myasthenic crisis and acute vestibular syndrome, leading to misdiagnosis. We wish to present a case of a young lady with type 1 diabetes mellitus, who had presented with subacute neuromuscular weakness which was erroneously treated as myasthenic crisis. Her case was subsequently diagnosed as bilateral medial medullary stroke, following evolving clinical signs and magnetic resonance imaging (MRI) findings of a heart-shaped abnormality at the rostral medulla. This rare stroke syndrome represented a diagnostic challenge which necessitated a strong clinical suspicion and an urgent MRI scan of the brain for prompt diagnosis to enable appropriate treatment initiation.

Matched MeSH terms: Medulla Oblongata/pathology
Fatal enterovirus 71 encephalomyelitis

Lum LC, Wong KT, Lam SK, Chua KB, Goh AY, Lim WL, et al.

J Pediatr, 1998 Dec;133(6):795-8.
PMID: 9842048

During an outbreak of hand-foot-mouth disease caused by enterovirus 71 (EV-71) in 1997, 4 children presented with sudden cardiopulmonary collapse and minimal neurologic features. All children received cardiopulmonary resuscitation but died within a few hours of admission. Postmortem studies showed infection by EV-71 with extensive damage to the medulla and pons. We postulate an etiologic link between EV-71 and brainstem encephalomyelitis as the cause of pulmonary edema and death.

Matched MeSH terms: Medulla Oblongata/pathology
Fulltext Induction of apoptosis in neurogenic pulmonary edema

Abu Bakar S, Shafee N, Chee HY

Med J Malaysia, 1999 Sep;54(3):402-3.
PMID: 11045072
Matched MeSH terms: Medulla Oblongata/virology*
Localization of the spinal nucleus of accessory nerve in rat: a horseradish peroxidase study

Ullah M, Mansor O, Ismail ZI, Kapitonova MY, Sirajudeen KN

J Anat, 2007 Apr;210(4):428-38.
PMID: 17428204

The spinal nucleus of the accessory nerve (SNA) comprises the group of somata (perikarya) of motor neurons that supply the sternocleidomastoid and trapezius muscles. There are many conflicting views regarding the longitudinal extent and topography of the SNA, even in the same species, and these disagreements prompted the present investigation. Thirty Sprague-Dawley rats (15 males, 15 females) were used. The SNA was localized by retrograde axonal transport of horseradish peroxidase. Longitudinally, the SNA was found to be located in the caudal part (caudal 0.9-1.2 mm) of the medulla oblongata, the whole lengths of cervical spinal cord segments C1, C2, C3, C4, C5 and rostral fourth of C6. In the caudal part of the medulla oblongata, the SNA was represented by a group of perikarya of motor neurons lying immediately ventrolateral to the pyramidal fibres that were passing dorsolaterally after their decussation. In the spinal cord, the motor neuronal somata of the SNA were located in the dorsomedial and central columns at C1, in the dorsomedial, central and ventrolateral columns at C2 and in the ventrolateral column only at C3, C4, C5 and rostral quarter of C6. The perikarya of motor neurons supplying the sternocleidomastoid were located in the caudal part (caudal 0.9-1.2 mm) of the medulla oblongata ventrolateral to the pyramidal fibres that were passing dorsolaterally after their decussation. They were also located in the dorsomedial and central columns at C1, in the dorsomedial, central and ventrolateral columns at C2 and only in the ventrolateral column at the rostral three-quarters of C3. The perikarya of motor neurons supplying the trapezius muscle were located in the ventrolateral column only in the caudal three-quarters of C2, the whole lengths of C3, C4 and C5, and in the rostral quarter of C6.

Matched MeSH terms: Medulla Oblongata/cytology
Localization of the motor neuron somata of geniohyoid muscle in rat: A horseradish peroxidase study

Razlan ANB, Ullah M, Kapitonova MY, Liaqat Ali Khan NB, Fuad SBSA

Anat Histol Embryol, 2018 Oct;47(5):410-416.
PMID: 29888399 DOI: 10.1111/ahe.12372

The aim of the study was to investigate the location of motor neuron somata of geniohyoid muscle in rat. Nine Sprague-Dawley rats were used in this study. Operations were performed under general anaesthesia. Nembutal sodium, 40 mg per kg intraperitoneally was used for anaesthesia. 0.02 to 0.05 ml of 30% horseradish peroxidase (Sigma Type VI) solution in normal saline was injected into the exposed right geniohyoid muscle. After 48 hr, the animals were fixed by perfusion through left ventricle of heart, first by 100 ml normal saline and then with 500 ml of 1.25% glutaraldehyde and 1% paraformaldehyde in 0.1 M phosphate buffer, pH 7.4, at room temperature, and finally with 500 ml of 10% sucrose in the same buffer at 4°C. The medulla oblongata and first cervical segment of spinal cord were removed, kept in 10% sucrose in above phosphate buffer at 4°C for 24 hr. Thereafter, their serial transverse sections were cut in a cryostat at a thickness of 60 μm. The sections were treated according to tetramethyl benzidine (TMB)-horseradish peroxidase (HRP) method. HRP-labelled neuron somata were observed at the following sites: (a) In ventral part of right main hypoglossal nucleus in upper two-thirds of the closed part of medulla oblongata. (b) In ventrolateral subnucleus of hypoglossal nucleus in lower third of closed part of medulla oblongata. (c) At spinomedullary junction, they were located in dorsomedial part of right ventral grey column; a few were also seen here scattered on right side of central canal and among corticospinal fibres.

Matched MeSH terms: Medulla Oblongata/anatomy & histology*
Basilar invagination: A mimicker of bulbar-onset amyotrophic lateral sclerosis

Tan JSH, Lee S, Hiew FL

eNeurologicalSci, 2021 Mar;22:100321.
PMID: 33553704 DOI: 10.1016/j.ensci.2021.100321

Amyotrophic lateral sclerosis (ALS) is characterized by progressive onset motor deficits with heterogenous presentations ranging from dysarthria to foot drop. Approximately 20% of the patients present with focal bulbar symptoms, in which some may remain restricted to bulbar region (isolated bulbar palsy), and the remaining eventually spreads to involve other body regions (classical ALS). Without accompanying upper and lower motor neurons signs elsewhere, differential diagnoses for isolated bulbar symptoms are extensive, include ALS variants as well as potentially treatable mimics. Therefore, it is important to take heed on every possible aetiology that may disrupt the hypoglossal nucleus, nerve, or lingual muscle itself. Herein, we illustrated a rare presentation of Group A basilar invagination, which mimicked bulbar-onset ALS.

Matched MeSH terms: Medulla Oblongata
A Rare but Disabling Stroke

Lau KF, Tan KS, Goh KJ, Ramli N, Tai SM

Ann Acad Med Singap, 2019 Mar;48(3):109-111.
PMID: 30997481
Matched MeSH terms: Medulla Oblongata/blood supply*
Effects of age on feeding response: Focus on the rostral C1 neuron and its glucoregulatory proteins

Ramlan H, Damanhuri HA

Exp Gerontol, 2020 01;129:110779.
PMID: 31705967 DOI: 10.1016/j.exger.2019.110779

BACKGROUND: Older people are likely to develop anorexia of aging. Rostral C1 (rC1) catecholaminergic neurons in rostral ventrolateral medulla (RVLM) are recently discovered its role in food intake control. It is well established that these neurons regulate cardiovascular function.
OBJECTIVE: This study aims to determine the effect of age on the function of rostral C1 (rC1) neurons in mediating feeding response.
METHOD: Male Sprague Dawley rats at 3-months (n = 22) and 24-months (n = 22) old were used and further divided into two subgroups; 1) treatment group with 2-deoxy-d-glucose (2DG) and 2) vehicle group. Feeding hormones such as cholecystokinin (CCK), ghrelin and leptin were analysed using enzyme-linked immunosorbent assay (ELISA). Rat brain was carefully dissected to obtain the brainstem RVLM region. Further analysis was carried out to determine the level of proteins and genes in RVLM that were associated with feeding pathway. Protein expression of tyrosine hydroxylase (TH), phosphorylated TH at Serine40 (pSer40TH), AMP-activated protein kinase (AMPK), phosphorylated AMPK (phospho AMPK) and neuropeptide Y Y5 receptor (NPY5R) were determined by western blot. Expression of TH, AMPK and NPY genes were determined by real-time PCR.
RESULTS: This study showed that blood glucose level was elevated in young and old rats following 2DG administration. Plasma CCK-8 concentration was higher in the aged rats at basal and increased with 2DG administration in young rats, but the leptin and ghrelin showed no changes. Old rats showed higher TH and lower AMPK mRNA levels. Glucoprivation decreased AMPK mRNA level in young rats and decreased TH mRNA in old rats. Aged rC1 neurons showed higher NPY5R protein level. Following glucoprivation, rC1 neurons produced distinct molecular changes across age in which, in young rats, AMPK phosphorylation level was increased and in old rats, TH phosphorylation level was increased.
CONCLUSION: These findings suggest that glucose-counterregulatory responses by rC1 neurons at least, contribute to the ability of young and old rats in coping glucoprivation. Age-induced molecular changes within rC1 neurons may attenuate the glucoprivic responses. This situation may explain the impairment of feeding response in the elderly.

Matched MeSH terms: Medulla Oblongata/metabolism
Fulltext Role of excitatory amino acid input in rostral ventrolateral medulla neurons in rats with obesity-induced hypertension

Suhaimi FW, Yusoff NH, Dewa A, Yusof AP

Acta Neurol Belg, 2010 Mar;110(1):57-64.
PMID: 20514927

Obesity is intimately associated with hypertension; increases in blood pressure are closely related to the magnitude of weight gain. The present study aims to determine whether the excitatory amino acid input to rostral ventrolateral medulla (RVLM) contributes to elevated blood pressure in rats with diet-induced obesity. Male Sprague-Dawley rats weighing 280 to 300 grams were fed with a low-fat diet (10% kcal from fat) or moderately high-fat diet (32% kcal from fat) for 16 weeks. At week 16, rats on the moderate high-fat diet were segregated into obesity-prone and obesity-resistant rats based on body weight distribution. Baseline mean arterial pressure (MAP) was significantly higher in obesity-prone rats as compared to obesity-resistant and rats on a low-fat diet. Bilateral injection of kynurenic acid (KYN) (40 nM) into the RVLM of the obesity-prone rats reduced MAP to levels significantly different from those observed in rats on a low-fat diet and obesity-resistant rats (no change in MAP). At a lower concentration (4 nM), KYN injection did not produce any change in MAP in any group. The results obtained suggest that excitatory amino acid input to the RVLM does contribute to the development of hypertension in rats with diet-induced obesity.

Matched MeSH terms: Medulla Oblongata/injuries; Medulla Oblongata/pathology*