Spinal cord compression from hypertrophic nerve roots in chronic inflammatory demyelinating polyradiculoneuropathy - A case report.

BACKGROUND: Spinal cord compression secondary to nerve root hypertrophy is often attributed to hereditary neuropathies. However, to avoid misdiagnosis, rare immune-mediated neuropathy such as chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) should not be overlooked. This report presents a case of multilevel nerve root hypertrophy leading to significant cord compression from CIDP. CASE DESCRIPTION: We report a 56-year-old gentleman with type two diabetes mellitus who presented with subacute cervical cord syndrome following a fall. Mixed upper and lower motor neuron features were noted on examination. Magnetic resonance imaging showed significant pan-spinal proximal nerve root hypertrophy, compressing the cervical spinal cord. Initial radiological opinion raised the possibility of neurofibromatosis type 1 (NF-1), but neurophysiology revealed both axonal and demyelinating changes that were etiologically non-specific. C6 root and sural nerve biopsies taken at cervical decompression displayed striking features suggestive for CIDP. Although NF-1 is the most observed condition associated with root hypertrophy, other important and potentially treatable differentials need to be entertained. CONCLUSION: While rare, CIDP can cause significant spinal cord compression. Furthermore, clinical manifestations of CIDP can mimic those of inherited peripheral neuropathies. Neurologists and neurosurgeons should be aware of this condition to optimize subsequent therapeutic decision-making.

Surgical Management of Rathke Cleft Cysts.

BACKGROUND: The diagnosis of Rathke cleft cysts (RCC) has increased in recent times as a result of improvements in imaging techniques; however, symptomatic patients are uncommon and accurate preoperative diagnosis may sometimes be difficult. The indications of surgical management protocol are evolving. We aim to provide a comprehensive review of clinical, imaging, and histopathologic features with operative management strategies along with outcome and prognosis in RCC. METHODS: A retrospective analysis (2003-2015) was performed of 58 consecutive cases of RCC seen in a surgical unit. Twenty-seven surgically treated symptomatic RCCs were further evaluated for their clinical presentation, imaging characteristics, surgical approaches, and intraoperative findings. RESULTS: Headache was the most common presenting complaint followed by visual deficit. Hormonal abnormality was observed in 13 patients. On magnetic resonance imaging, the characteristic intracystic nodule was identified in 6 patients. Transsphenoidal surgery for cyst excision was performed in all 27 patients with an endoscopic route in 25 patients and radical excision was performed in 17 patients. The pituitary stalk and the normal gland were preserved in all patients. Headache improved in 96% of patients and visual field defect resolved in all. Around 46% had improvement of the anterior pituitary axis. New permanent hormone deficiency was not observed. The recurrence rate was 3.7% after a minimum of 18 months follow-up. CONCLUSIONS: RCCs are an uncommon disease with a wide spectrum of clinical and radiologic features. Endonasal endoscopic transsphenoidal surgery provides excellent clinical and endocrinologic improvement. We believe that radical excision does not necessarily result in endocrinologic impairment and may have a better impact on recurrence and cyst resolution.

The effective Planck mass and the scale of inflation.

Observable quantities in cosmology are dimensionless, and therefore independent of the units in which they are measured. This is true of all physical quantities associated with the primordial perturbations that source cosmic microwave background anisotropies such as their amplitude and spectral properties. However, if one were to try and infer an absolute energy scale for inflation-a priori, one of the more immediate corollaries of detecting primordial tensor modes-one necessarily makes reference to a particular choice of units, the natural choice for which is Planck units. In this note, we discuss various aspects of how inferring the energy scale of inflation is complicated by the fact that the effective strength of gravity as seen by inflationary quanta necessarily differs from that seen by gravitational experiments at presently accessible scales. The uncertainty in the former relative to the latter has to do with the unknown spectrum of universally coupled particles between laboratory scales and the putative scale of inflation. These intermediate particles could be in hidden as well as visible sectors or could also be associated with Kaluza-Klein resonances associated with a compactification scale below the scale of inflation. We discuss various implications for cosmological observables.

Tensor modes from a primordial Hagedorn phase of string cosmology.

It has recently been shown that a Hagedorn phase of string gas cosmology can provide a causal mechanism for generating a nearly scale-invariant spectrum of scalar metric fluctuations, without the need for an intervening period of de Sitter expansion. In this Letter, we compute the spectrum of tensor metric fluctuations (gravitational waves) in this scenario and show that it is also nearly scale invariant. However, whereas the spectrum of scalar modes has a small red tilt, the spectrum of tensor modes has a small blue tilt, unlike what occurs in slow-roll inflation. This provides a possible observational way to distinguish between our cosmological scenario and conventional slow-roll inflation.