[Catastrophes caused by neurologic diagnostic procedures]

Serious complications (catastrophes) resulting from diverse neurological diagnostic procedures can be caused by erroneous indication and omission, as well as by delay and erroneous execution or interpretation. Headache, caused by cerebrospinal fluid (CSF) hypotension, is a frequent complication of lumbar puncture; hematic patch is a therapeutic option for severe cases. The most serious complication is cerebral herniation and, for its prevention, computed tomography (CT) or cerebral magnetic resonance imaging (MRI) must always be performed before lumbar puncture: a lesion with evident mass effect is a contraindication. Some cases of minor subarachnoid hemorrhages can produce sentinel headache: when the findings of CT scans are normal, lumbar puncture must be performed for diagnosis and prevention of a catastrophic recurrence. Edrophonium testing can be complicated with bradycardia and/or asystole. The lack of indication of this procedure is a cause of under-diagnosis of myasthenia gravis, especially in older people. Electromyography produces few complications (rare cases of paraspinal hematomas and pneumothorax). Ultrasound, CT angiography and MR angiography examinations have decreased the indications for cerebral angiography, whose main complications -in addition to contrast reactions, hemorrhage and infection at the injection site- are neurological deficits caused by vascular dissection or atheromatous embolus. Video-electroencephalogram (EEG) recording with medication suppression can be used in the presurgical evaluation of epilepsy, which can precipitate repeated seizures with the risk of injuries and status epilepticus. The possible complications of studies performed with invasive electrodes are infections and intracranial hemorrhages. Cerebral biopsy is indicated when treatable disease is suspected but the therapeutic options (radiotherapy, chemotherapy) have potential serious adverse effects. Furthermore, cerebral biopsy can aggravate previous neurological deficits or produce new deficits. Genetic testing is not indicated in healthy children when an untreatable disease is suspected. In adults, genetic testing is appropriate in selected cases, but detailed previous information should be gathered and the possibility of triggering serious emotional reactions should always be considered.