[Diagnosis of peripheral neuropathies: a clinical and neurophysiological study]

The diagnosis of peripheral neuropathy is based on clinical and neurophysiological features. This study aims to establish the diagnostic validity of different symptoms and clinical signs, as well as its correlation with electroneurography (ENG), to determine its sensitivity (SE), specificity (SP), positive (PLR) and negative likelihood ratio (NLR) for every peripheral neuropathies type.

A sample of 108 patients with clinical suspicion of peripheral neuropathy (pain, paresthesias, loss of strength, areflexia) was studied. ENG (nerve conduction velocity and response amplitude values in 208 nerves [Median and Posterior Tibial]) was used to confirm the diagnosis, classifying the sample in axonal group (A), demyelinating (D) and normal (N). It was made descriptive statistics of this sample, studies of SE, SP, PLR and NLR of symptoms, and association (contingency tables [Chi square] and Odds Ratio) between symptoms and clinical features.

The patients with paresthesias, loss of strength or pathologic reflexes have larger motor latency (p< 0.01). Those with paresthesias, areflexia or pain have fewer sensitive conduction velocity (p< 0.05). Symptoms's value for sensory damage's diagnosis is (SE= 0.92, SP= 0.48, PLR= 1.78, NLR= 0.14). For motor damage (SE= 0.72, SP= 0.68, PLR= 2.25, NLR= 0.41). For axonal damage (SE= 0.83, SP= 0.44, PLR= 1.49, NLR= 0.37). And for demyelinating damage (SE= 0.92, SP= 0.44, PLR= 1.66, NLR= 0.16).

The symptoms's combination is much more sensitive and has fewer NLR than each isolated symptom in all neuropathic damage's types. Paresthesias's presence is more indicative of sensory damage and loss of strength of motor damage. Pain is the only symptom that can aim for axonal damage than demyelinating.