Abbreviations: (CI) confidence interval, (DM) diabetes mellitus, (DN) diabetic neuropathy, (DSPN) distal symmetrical polyneuropathy, (EMG) electromyography, (NC) nervous conduction, (SD) standard deviation, (SFN) subclinical small fiber neuropathy, (T2DM) type 2 diabetes mellitus, (TT) thermal threshold Keywords: diabetic neuropathy, thermal threshold, nervous conduction The most commonly used technique for diagnosis of diabetic neuropathy (DN) is nervous conduction (NC). Our hypothesis is that the use of the thermal threshold (TT) technique to evaluate small fiber damage, which precedes large fiber damage, could enable earlier diagnosis and diminish false negatives. Research Design and Methods:The study involved 70 asymptomatic patients with type 2 diabetes mellitus (T2DM) all being treated with oral hypoglycemic medication, and having negative metabolic control levels with glycosylated hemoglobin A1c greater than 7% and less than 8%. Diabetic neuropathy was their only evident complication. All other complications or other causes of neuropathy were discarded. Their time of evolution was 1 to 48 months since date of diagnosis of diabetes. Both thermal threshold and sensory and motor nervous conduction were determined in upper and lower limbs. Results:Nervous conduction was found normal in 81% and altered in 19% of patients (large fiber neuropathy). Thermal threshold was normal in 57% and altered in 43% of patients (small fiber neuropathy). In those with normal TTs, no case with an altered NC was found (p < 0.001). Patients with altered TTs could have normal (57%) or altered NC (43%). Thus, NC showed a high frequency of false negatives for DN (57% of 30 cases).The frequency of small fiber neuropathy found with the TT test was higher than that of large fiber neuropathy found with the NC test (p < 0.001) and was found at an earlier age. Conclusions:The TT test demonstrated a higher frequency of neuropathy than the NC test in clinically asymptomatic T2DM patients. We suggest that small fiber should be studied before large fiber function to diagnosis distal and symmetrical DN.

No abstract

It is frequent meeting people sent to perform a tilt test suffering from a single or such isolated syncope that occur very occasionally during the patient's life. We ask ourselves how these people differ from those who never have syncopes. Methods: We performed tilt test in 104 patients who suffer a single or maximum 5 syncopes from any cause during their lifetimes. We try to explain how different predisposing factors act to provoke syncope. Results: We found differences between cases and controls in inheritance of syncopes, joint hypermobility, venous pooling during tilt test, food intake, use of drugs, stress and emotion as a trigger for syncope. Conclusions: Patients with single or occasional syncope have an organic predisposition (inheritance-joint hypermobility-failure in the baroreflexes, some neurological diseases, etc.) to present syncopes, but syncopes do not occur unless it is added simultaneously an environmental factor, which acts as a trigger (prolonged standing up-stress, pain and emotion-dehydration-drugs-abundant food, etc.) that is why these episodes are so rare.

Comparison of the use of isoproterenol or nitroglycerine during the Tilt test (Rev Med Chile 2015; 143: 69-76)

It is not common to start suffering from syncopes after age 50. They are mainly male patients who present causes other than vasovagal syncope, which predominates at an early age. Orthostatic hypotension is the predominant causal factor, which is attributed in many cases to advanced age, metabolic, cardiovascular or neurological diseases, to failure of baroreflexes, all of the above may be associated with the use of hypotensive drugs alone or in combination with psychotropic drugs. Furthermore, causes such as carotid sinus syncope, postprandial syncope and situational syncope become more frequent. Therefore, as people age, they present a favorable pathological terrain for the production of syncope. The older you are, the more likely you are to start with syncope. Finding the definitive diagnosis for their syncopes can be difficult, given the multiplicity of interacting factors. Their study is more exhaustive and requires a good anamnesis, knowing the drugs used by the patient, concomitant diseases and careful surveillance to get closer to the diagnosis.