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Amer Al-Shekhlee

Publications and source records attributed to Amer Al-Shekhlee.

11 recordsLinked to original sources
PubMed2007

Sensory sparing patterns and the sensory ratio in acute inflammatory demyelinating polyneuropathy.

The relative preservation (sparing) of sural sensory nerve action potentials (SNAPs) is a useful diagnostic finding in patients with acute inflammatory demyelinating polyneuropathy (AIDP). However, recording of sural SNAPs is not always technically feasible, especially in obese, edematous, or elderly individuals. Hence, we systematically evaluated the predictive values of the commonly employed SNAPs in the diagnosis of AIDP within 2 weeks from onset of symptoms. Sensory sparing patterns and sensory ratios of the sural, radial, median, and ulnar SNAPs of AIDP patients were included in a retrospective and blinded analysis, and compared to patients with diabetic polyneuropathy (DPN) and controls. Logistic regression models for the sural plus radial SNAPs/median plus ulnar SNAPs (sensory ratio) were constructed. A sural sparing pattern was present only in the AIDP group (34.4%, P < 0.001). A radial sparing pattern did not discriminate the AIDP from the DPN groups. The sural/radial sensory ratio was useful to ascertain DPN, but did not discriminate AIDP from controls. The sensory ratio was higher in AIDP compared to DPN and controls and was an independent predictor for AIDP. This study implies that the sensory ratio is a useful predictor for the diagnosis of AIDP and may substitute for sural sparing in technically difficult situations.

Action Potentials↗
PubMed2006

Optimal recording electrode placement in the lumbrical-interossei comparison study.

The lumbrical-interossei comparison study is commonly employed in the electrodiagnosis of carpal tunnel syndrome. Placement of the recording electrodes relies on anatomic landmarks as the muscles being recorded cannot be seen or palpated. To determine the optimal active electrode location, 15 controls and 5 patients were studied using a grid of 12 electrodes placed over the lateral palm. Amplitudes, rise-times, and latencies of the responses at each location were measured. The lowest control latency difference was located in the lateral mid-proximal palm (mean 0 ms, upper range of 0.5 ms). This location also had the highest lumbrical amplitude and rise-time. More distal in the palm, the mean latency difference increased to 0.5 ms with an upper range of 0.9 ms. When performing the lumbrical-interossei comparison study, it is essential to place the active recording electrode in the optimal location. Failure to do so will result in an increased number of false-positive studies.

Adult↗
PubMed2006

Classification of sporadic Creutzfeldt-Jakob disease revisited.

The sporadic form of Creutzfeldt-Jakob disease (sCJD) has been classified on the basis of the molecular mass of the protease-resistant scrapie prion protein (PrP(Sc)), which can be type 1 or type 2, and the genotype at the methionine (M)/valine (V) polymorphic codon 129, which can be MM, MV or VV. In one classification proposed by Parchi et al., [Parchi P, Giese A, Capellari S, Brown P, Schulz-Schaeffer W, Windl O, Zerr I , Budka H , Kopp N , Piccardo P , Poser S , Rojiani A , Streichemberger N , Julien J , Vital C , Ghetti B , Gambetti P , Kretzschmar H . Classification of sporadic Creutzfeldt-Jakob disease based on molecular and phenotypic analysis of 300 subjects. Ann Neurol 1999; 46: 224-33.] the most common subtype of sCJD, designated sCJDMM1, is viewed as a single entity. Two other classifications proposed by Collinge et al. [Collinge J, Sidle KC, Meads J, Ironside J, Hill AF. Molecular analysis of prion strain variation and the aetiology of 'new variant' CJD. Nature 1996; 383: 685-90.] and Zanusso et al., [Zanusso G, Farinazzo A, Fiorini M, Gelati M, Castagna A, Righetti PG, Rizzuto N, Monaco S . pH-dependent prion protein conformation in classical Creutzfeldt-Jakob disease. J Biol Chem 2001; 276: 40377-80.] respectively, subdivide sCJDMM1 into two subtypes on the basis of the different molecular mass and phenotypic characteristics, primarily disease duration. To resolve this discrepancy, we divided a group of 22 subjects with confirmed sCJDMM1 according to Parchi et al. into two sub-populations according to whether the disease duration was <5 months (short-duration subjects) or >7 months (long-duration subjects). We then examined the PrP(Sc) molecular mass under the conditions that allowed wide variability of the pH of the PrP(Sc) preparations as well as under stringent pH conditions, using high-resolution gel electrophoresis. We also compared the characteristics of the PrP(Sc) associated with the short- and long-duration subjects using two-dimensional immunoblot, conformational stability immunoassay and sucrose gradient fractionation. Finally, the two sub-populations were also compared with regard to their clinical and pathological features including the lesion profiles. When sample homogenization and protease digestion were performed under stringent pH conditions, the PrP(Sc) molecular mass did not differ between short- and long-duration sCJDMM1 subjects. The conformational characteristics of the protease-resistant PrP(Sc) as well as the clinical and pathological phenotypes were also homogeneous except for the more severe lesions of the long-duration cases. We therefore conclude that the variability of the PrP(Sc) molecular mass underlying the division of sCJDMM1 into two subtypes is largely due to pH variations during tissue preparation, and sCJDMM1 with short and long disease duration have similar phenotypes and PrP(Sc) characteristics. These data indicate that the differentiation of sCJDMM1 into two subgroups is not currently justified.

Aged↗
PubMed2006

Re-evaluating the diagnostic methods in herpes simplex encephalitis.

Several methods are used in clinical practice to investigate herpes simplex encephalitis (HSE), including electroencephalography (EEG) and polymerase chain reaction (PCR) of the viral genome in cerebrospinal fluid. PCR is the most sensitive and specific of the diagnostic methods currently employed. We retrospectively examined the diagnostic utility of EEG and cranial imaging within the first 24-48 h of symptom onset in patients with suspected HSE. Patients with herpes simplex-positive PCR results were compared with those with herpes simplex-negative PCR results. Periodic lateralized epileptiform discharges and/or focal temporal slowing were present in 90% of the PCR-positive patients at symptom onset compared with only 30% of the PCR-negative group. The sensitivity of EEG recordings decreased after 48 h. Although no patients had computed tomography findings suggestive of HSE, magnetic resonance imaging results were consistent with HSE in 86% of those with herpes simplex-positive PCR results obtained after 48 h from symptom onset.

Diagnosis, Differential↗
PubMed2005

New criteria for early electrodiagnosis of acute inflammatory demyelinating polyneuropathy.

A variety of electrodiagnostic methods are used to confirm the diagnosis of acute inflammatory demyelinating polyneuropathy (AIDP), but difficulties are frequent during the first few weeks of weakness. We compared the nerve conduction studies (NCS) of patients with AIDP to those with critical illness polyneuropathy (CIP), a subacute axonal polyneuropathy. New electrodiagnostic criteria with graded certainty (normal, nondiagnostic, suggestive, highly suggestive, and definite) were designed and applied in a blinded manner to both groups. Among the AIDP patients, 64% met the highly suggestive and definite criteria (specificity 95-100%, P < 0.01), whereas 80% of the CIP group fell in the nondiagnostic criteria (P < 0.001). The relative preservation of the sural sensory response in spite of at least two abnormal sensory NCS in the upper limb suggested acute demyelination (sensitivity 48%, specificity 96%, P < 0.001) and was even more conclusive when associated with absent or prolonged F waves. Motor and sensory response amplitudes were lower in the CIP group, with comparable mean motor and sensory distal latencies and motor conduction velocities. Motor conduction blocks were present in 10% of nerves in AIDP and were not encountered in CIP. The frequency of absent or delayed F waves and absent H reflex was similar in both groups. The correlation coefficient of the cerebrospinal fluid protein concentration with the designed criteria was higher in the AIDP group (r = 0.9). We conclude that a new criterion with graded certainty is of higher specificity in the majority of patients with early AIDP.

Acute Disease↗
PubMed2005

The value of autonomic testing in postural tachycardia syndrome.

Postural tachycardia syndrome (POTS) is a fairly common condition that may or may not be associated with autonomic neuropathy. In a retrospective analysis, we compared two groups of patients based on clinical and autonomic criteria, those with POTS in isolation (POTS-Alone), and POTS with evidence of autonomic neuropathy (POTS-AN). Of 260 records reviewed, 57 patients met the criteria for POTS; 38 (67%) patients assigned to the POTS-Alone group and 19 (33%) patients assigned to the POTS-AN group. A decreased sweat output on the quantitative sudomotor axon reflex test is the most frequent abnormal finding in the POST-AN group suggesting sympathetic cholinergic neuropathy. Clinically, headache and gastrointestinal symptoms were more frequent among the POTS-AN group. Therefore, POTS may exist in isolation and may differ from those associated with AN.

Adult↗
PubMed2004

Electrodiagnostic features of acute paralytic poliomyelitis associated with West Nile virus infection.

West Nile virus (WNV) infection is a potentially fatal disease, with meningoencephalitis being its most common neurological manifestation. Guillain-Barré syndrome (GBS) has also been described, but acute paralytic poliomyelitis has only recently been recognized. We report the clinical and electrodiagnostic findings of five patients with WNV infection, who presented with acute paralytic poliomyelitis. Three patients manifested focal asymmetrical weakness, and two had rapid ascending quadriplegia mimicking GBS. Electrodiagnostic studies during the acute illness showed normal sensory nerve action potentials, compound motor action potentials of normal or reduced amplitude, and no slowing of nerve conduction velocities. Depending on the timing of the examination, fibrillation potentials were widespread, including in those with focal weakness. Cervical magnetic resonance imaging in one patient showed abnormal T2-weighted signals in the spinal cord gray matter. On follow-up, signs of clinical improvement were seen in one patient, whereas two remained quadriplegic and ventilator-dependent 5 months after the onset. This report highlights the value of the electrodiagnostic studies in the diagnosis and prognosis of focal or generalized weakness due to acute paralytic poliomyelitis associated with WNV infection.

Action Potentials↗
PubMed2003

Iatrogenic complications and risks of nerve conduction studies and needle electromyography.

Electrodiagnostic procedures are routinely performed in patients with a variety of neuromuscular disorders. These studies are generally well tolerated and rarely thought to be associated with any significant side effects. However, needle electromyography is an invasive procedure and under certain situations has the potential to be associated with iatrogenic complications, including bleeding, infection, nerve injury, pneumothorax, and other local trauma. Similar complications are possible if needles are used for either stimulating or recording. In addition, like all other electrical devices and monitoring equipment connected to patients, electrodiagnostic testing carries the risk of stray leakage currents that under certain circumstances can result in electrical injury, especially in patients in the intensive care setting. Similarly, certain precautions are required during nerve conduction studies (NCS) in patients with pacemakers and other similar cardiac devices. In this review, we address the known and theoretical complications of NCS and needle electrode examination, and the possible methods to avoid such hazards.

Electromyography↗
PubMed2003

Spinal accessory neuropathy, droopy shoulder, and thoracic outlet syndrome.

Droopy shoulder has been proposed as a cause of thoracic outlet syndrome. Two patients developed manifestations of neurovascular compression upon arm abduction, associated with unilateral droopy shoulder and trapezius muscle weakness caused by iatrogenic spinal accessory neuropathies following cervical lymph node biopsies. The first patient developed a cold, numb hand with complete axillary artery occlusion when his arm was abducted to 90 degrees. The second patient complained of paresthesias in digits 4 and 5 of the right hand, worsened by elevation of the arm, with nerve conduction findings of right lower trunk plexopathy (low ulnar and medial antebrachial cutaneous sensory nerve action potentials). Spinal accessory nerve grafting (in the first patient) coupled with shoulder strengthening physical exercises in both patients resulted in gradual improvement of symptoms in 2 years. These two cases demonstrate that unilateral droopy shoulder secondary to trapezius muscle weakness may cause compression of the thoracic outlet structures.

Accessory Nerve↗
PubMed2002

Review: small-fiber neuropathy.

BACKGROUND: Most peripheral neuropathies involve large as well as small-fiber dysfunction. A small subset of neuropathies present with restricted or predominant small-fiber involvement. REVIEW SUMMARY: In this review, we discuss the differential diagnosis, clinical presentation, evaluation, and treatment of small-fiber neuropathies. Although these neuropathies are rare, their differential diagnosis is broad, and includes many disorders, including metabolic, toxic, inflammatory, infectious, and genetic etiologies. As small fibers subserve pain and autonomic functions, these neuropathies usually present with pain and temperature loss, painful dysesthesias, autonomic dysfunction, or a combination. These neuropathies are especially challenging as nerve conductions and EMG, which help guide the evaluation of most peripheral neuropathies, may have normal findings in patients with small-fiber neuropathies. Other specialized studies, including tests of autonomic function, intraepidermal nerve fiber analysis, and quantitative sensory testing, are often required to confirm the presence of a small-fiber neuropathy. In some cases, the underlying etiology can be directly treated. In most, management is limited to symptomatic treatment of sensory and autonomic dysfunction. CONCLUSION: Small-fiber neuropathies are a heterogeneous group of disorders. They vary in etiologies and require special attention, as many disorders are rare and the differential diagnosis is broad. Evaluation is often extensive and may need pathologic specimen. Many patients respond to symptomatic therapy, but some are difficult to treat.

Journal Article↗