Hyperreflexia (Overactive Autonomic Reflex)


Autonomic Hyperreflexia is a condition in which your involuntary nervous system overreacts to external or bodily stimuli and is a sign of upper motor neuron damage. When affecting the autonomic system, hyperreflexia has the dangerous ability to make your blood pressure spike while causing your heart to beat very slowly. This will put you at serious risk of stroke.

When associated with spasticity and limb reflexes, the most common signs are finger flexion reflexes, jaw jerks, involuntary rhythmic muscular contraction and relaxation, and reflexes where an impulse enters one segment and activate motor neurons located in many other segments (Irradiation of Reflexes).

Hyperreflexia stems from the spinal cord and nerve dysfunction associated with myelopathy.

Possible Body Responses to Autonomic Hyperreflexia

  • a dangerous spike in blood pressure -high blood pressure with systolic readings often over 200 mm Hg
  • a pounding headache
  • slow heartbeat
  • constriction of your peripheral blood vessels
  • other changes in your body’s autonomic functions
  • bladder incontinence
  • bladder failure to empty


Your neurologist will identify which of your body’s systems are being affected and refer you to the appropriate specialty for care. This may include gastroenterology, physical therapy, or urology. Blood pressure and heart rate issues need to be addressed immediately by cardiology.

Arq. Neuro-Psiquiatr. vol.75 no.2 São Paulo Feb. 2017
Siderose superficial (SS) do sistema nervoso central (SNC) é uma doença rara e provavelmente subdiagnosticada, resultante de sangramento crônico no espaço subaracnóide, levando ao depósito de produtos sanguíneos nas camadas meníngeas subpiais. Ressonância magnética (RM) mostra um padrão curvilíneo característico com hipointensidade nas suas sequências sensíveis a sangue.
Série de casos coletados de centros brasileiros.
Apresentamos 13 casos de pacientes com história progressiva de disfunção neurológica causada por SS-SNC. Os achados clínicos mais frequentes destes pacientes foram ataxia progressiva da marcha, perda auditiva, hiperreflexia e disfunção cognitiva. O diagnóstico de SS-SNC foi firmado de sete meses a 30 anos após o início da doença.
SS-SNC é uma condição rara que pode permanecer sem diagnóstico por longos períodos. O conhecimento desta entidade é essencial ao clínico.

Updated: April 18, 2018

Sources: Superficial siderosis is a rare neurologic disease characterized by progressive sensorineural hearing loss, cerebellar ataxia, pyramidal signs, and neuroimaging findings revealing hemosiderin deposits in the spinal and cranial leptomeninges and subpial layer. The disease progresses slowly, and patients may present with mild cognitive impairment, nystagmus, dysmetria, spasticity, dysdiadochokinesia, dysarthria, hyperreflexia, and Babinski signs. Additional features reported include dementia, urinary incontinence, anosmia, ageusia, and anisocoria. Superficial siderosis MedGen UID: 831707 •Concept ID: CN226971 •Finding Orphanet: ORPHA247245
Living With SuperficialSiderosis Website PubMed Reference Library 
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