What are the signs and symptoms of toxic neuropathy?

Updated: Dec 06, 2017
  • Author: Jonathan S Rutchik, MD, MPH, FACOEM; Chief Editor: Tarakad S Ramachandran, MBBS, MBA, MPH, FAAN, FACP, FAHA, FRCP, FRCPC, FRS, LRCP, MRCP, MRCS  more...
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Patients with neuropathy typically present with symptoms of pain, tingling, or numbness in their feet, consistent with dysfunction affecting the longest and largest fibers of the peripheral nervous system (PNS). Other manifestations of neurologic dysfunction that may be present include the following:

  • Hypohidrosis or hyperhidrosis

  • Diarrhea or constipation

  • Urinary incontinence or retention

  • Gastroparesis

  • Sicca syndrome

  • Blurry vision

  • Facial flushes

  • Orthostatic intolerance

  • Sexual dysfunction

  • Cramping

  • Tachycardia

  • Rapid alterations in blood pressure

During physical examination, the following symptoms of polyneuropathy may be found:

  • Sensory loss in a stocking-glove distribution

  • Distal to proximal progression: Consistent with the commencement of axonal degeneration

  • Early loss of symmetrical ankle jerk

  • Motor dysfunction (eg, abnormal gait and foot drop): In severe cases

Central nervous system (CNS) disease can manifest as follows:

  • Corticospinal tract disease: Hyperreflexia, Babinski responses, and stiff-leg ataxic gait

  • Dorsal column degeneration: Diffusely decreased proprioceptive and vibratory sensations and gait ataxia

The following examples list the neuropathic signs and symptoms associated with specific toxins:

  • Thallium: Acute intoxication leads to pain and paresthesias in the distal extremities followed by weakness and eventual atrophy; autonomic dysfunction also may be part of the clinical syndrome; peripheral reflexes are preserved

  • Dimethylaminopropionitrile (DMAP): Industrial exposure has led to prominent urinary and sexual dysfunction, as well as to distal sensory neuropathy

  • Alcohol: Ataxia and other systemic symptoms may accompany dysesthesia and weakness of the lower extremities

  • Carbon disulfide: Reduced or absent sensory nerve action potentials (SNAPs) are common; conduction velocities are usually normal, but they may be borderline low owing to selective involvement of large fibers

  • Ethylene oxide (EtO): Symptoms suggestive of neuropathy, such as numbness and weakness of extremities, leg cramps, and gait difficulties, are reported mostly after long-term EtO exposures

  • Mercury: Reportedly causes reduced strength and coordination, tremor, impaired sensation, and higher prevalence of Babinski and snout reflexes

  • Lead: Acute, high-level exposure can reportedly cause motor neuropathy with minimal sensory involvement and, in rare cases, wrist drop; chronic, lower-level exposures cause axonal dying back neuropathies that appear similar to neuropathies from diabetes or alcohol

See Clinical Presentation for more detail.

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