Acute management of autonomic dysreflexia is important to prevent complications. If untreated autonomic dysreflexia can lead to convulsions, subarachnoid hemorrhage, intracerebral bleeding, hypertensive encepha-lopathy, cardiac arrhythmias, neurogenic pulmonary edema and death (Shergill et al. 2004).
The acute management aims to relieve the precipitant cause and management of symptoms to prevent potential complications. The long-term goal is to prevent recurrence of autonomic dysreflexia.
Immediately the precipitant should be identified and treated.
To prevent a further increase in blood pressure, the patient should be seated upright with the head raised to induce an orthostatic drop in blood pressure. Tight clothing should be removed and during treatment the blood pressure should be monitored carefully (every 2-5 min).
Then the trigger for autonomic dysreflexia should be identified and eliminated. In most cases, a genitourinary problem is the precipitant. Therefore, if the patient has an indwelling catheter the catheter should be checked for kinks and obstructions. In addition, a full urinary bag can cause bladder distension leading to au-tonomic dysreflexia. If necessary, the catheter should be carefully flushed with saline solution. Irrigation should be limited to 5-10 ml in children under 2 years and 10 -15 ml in children older than 2 years and adults.
If no indwelling catheter is placed but bladder distension is the suspected trigger, a catheter should be inserted. Before inserting the catheter, the urethra should be instilled with lidocaine jelly to avoid further triggers for autonomic dysreflexia. In many cases, draining the bladder alleviates the symptoms of autonomic dysreflexia.
If afferent stimulation of bladder wall receptors (infection, stones) is supporting the autonomic dysrefle-xia, local anesthetic (lidocaine) instillation of the bladder might be effective (Dietz 1996).
High-dose antibiotics are delivered if urinary tract infection is suspected to be the cause. If symptoms persist other triggers must be sought.
The next step is a rectal examination for fecal impaction and a gentle manual evacuation if necessary.
If the precipitant for autonomic dysreflexia is not found within the first few minutes medical treatment is necessary when the blood pressure remains high.
There are only a few published studies on medical treatment of autonomic dysreflexia, but nifedipine and nitrates are the most commonly used drugs. The immediate release form is the preferred method of administration.
Nifedipine is given in a dose of10 mg using the bite-and-swallow method. Adverse effects of nifedipine have been reported (reflex tachycardia and hypotension), but in these studies nifedipine was not used to treat autonomic dysreflexia (Consortium for Spinal Cord Medicine 2001).
Nitrates (glyceryl trinitrate, isosorbide dinitrate, sodium nitroprusside) are also used to treat autonomic dysreflexia. If the blood pressure remains high an intravenous drip of sodium nitroprusside could be necessary. Before using these drugs (nitrates), the patient should be questioned regarding sildenafil or other PDE-5 inhibitors. If a PDE-5 inhibitor was used in the last 24 h an alternative short-acting, rapid-onset anti-hypertensive drug should be used. Drugs with these characteristics are captopril and prazosin.
Other drugs that have been used to treat autonomic dysreflexia include hydralazine, phenoxybenzamine, clonidine, diazoxide, and mecamylamine (Consortium for Spinal Cord Medicine 2001; Blackmer 2003).
With recurrent episodes of autonomic dysreflexia, prevention is the best approach. Therefore patients with spinal cord injury and their families should be educated about proper bladder, bowel, and skin management. If a catheter is present it should be changed regularly with great care and attention to avoid autonomic dysreflexia, ideally using local anesthetic jelly. Urody-namic investigations should be done with blood pressure monitoring in SCI patients. Other colleagues should be made aware of the propensity for autonomic dysreflexia in affected patients.
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