Urgent considerations
See Differentials for more details
Guillain-Barré syndrome, acute inflammatory demyelinating polyradiculoneuropathic (AIDP) form
This condition has an abrupt onset, typically with paraesthesias starting in the toes and progressing proximally over hours or days. The ascending paralysis can affect respiratory muscle function and lead to respiratory failure or arrest if the condition is not recognised and treated. Patients may also develop acute dysautonomia with potentially life-threatening fluctuations in blood pressure and heart rate. The diagnosis depends on recognition of the clinical features, including the rapid onset and progression of the symptoms, and is confirmed by the finding of albuminocytological dissociation on cerebrospinal fluid (CSF) examination and characteristic findings on electromyogram (EMG). Suspected AIDP requires close monitoring of neurological and respiratory function and early institution of treatment with emergent plasma exchange or intravenous immunoglobulin.
How to perform a diagnostic lumbar puncture in adults. Includes a discussion of patient positioning, choice of needle, and measurement of opening and closing pressure.
Stroke
Ischaemic or haemorrhagic strokes present with acute onset of neurological symptoms, which may include paraesthesias. The location and extent of the stroke determines the severity of the neurological deficit, associated neurological symptoms and findings, and the risk of damage to adjacent brain tissue from swelling of the infarcted brain tissue. Large strokes in the cerebral hemispheres or haemorrhagic strokes in the brainstem pose an immediate risk of brainstem compression or herniation. The diagnosis is based on clinical history and neurological examination, with supporting evidence from neuro-imaging such as head computed tomography (CT) or brain magnetic resonance imaging (MRI).
Spinal cord compression
Spinal cord compression, either acutely from traumatic injury or a spinal cord infarct, or subacutely from a metastatic or primary mass lesion compressing the spinal cord, requires urgent diagnosis and treatment. Patients may develop irreversible loss of neurological function and, in some cases, respiratory function. A spinal cord compression syndrome is suspected based on the history and examination findings, and confirmed using neuro-imaging (MRI) of the suspected segments of the spinal cord. Surgical decompression or treatment with high-dose steroids is required to reduce oedema of the spinal cord tissue and prevent further loss of neurological function.
Transverse myelitis
Transverse myelitis is an acute inflammatory lesion in the spinal cord that usually involves one or two spinal segments. Patients may present with a spinal cord syndrome of weakness and numbness and bowel/bladder incontinence. Depending on the location of the lesion, respiratory muscle control may be affected and become life-threatening. The diagnosis depends on clinical history and examination, followed by neuro-imaging (MRI) of the spinal cord and lumbar puncture with CSF exam. If recognised early, treatment with high-dose intravenous corticosteroids may reduce oedema and prevent further loss of function.
Acute disseminated encephalomyelitis
Acute disseminated encephalomyelitis is a central demyelinating disease that appears following infection (usually viral) or vaccination, or sometimes spontaneously. Patients present with an acute encephalitis, and may develop rapid neurological decline with coma and seizures. Brain and spinal cord MRI reveal characteristic lesions. Patients require intravenous corticosteroid therapy such as methylprednisolone. If the response to steroids is inadequate, plasma exchange or intravenous immunoglobulin may be used.[62][63]
Vasculitic neuropathy
Patients who present with a clinical syndrome of mononeuritis multiplex (pain, followed by paraesthesias and weakness in multiple single peripheral nerve distributions) should be suspected to have vasculitis and need urgent evaluation to confirm the diagnosis. Initial tests for specific disease markers should be sent. Immunosuppressive therapy should be initiated as soon as possible. If left untreated, patients are likely to experience further loss of neurological function and devastating multi-organ damage. Definitive diagnosis requires a tissue biopsy.
Focal seizures
Focal seizures (formerly known as partial seizures) involving the somatosensory cortex may cause stereotyped episodes of hemifacial and/or hemibody sensory symptoms such as transient paraesthesias. These may be isolated events or part of the aura initiating a complex focal seizure. An electroencephalogram (EEG) may identify epileptiform activity or a focal, localising abnormality. Neuro-imaging may reveal evidence of a structural lesion or other process that has caused the seizure. It is important to identify this subset of patients as they can be effectively treated with anticonvulsant medications.
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