Reye's Syndrome Nursing Care Planning and Management

Reye syndrome is rare now but still deadly: acute noninflammatory encephalopathy plus fatty degenerative liver failure in a child or young adult recovering from a viral infection, classically influenza or chickenpox. Neurologic deterioration can be rapid, so recognition, close monitoring, and supportive care drive the outcome. The diagnosis is exceedingly rare today because aspirin use in children dropped sharply and because medication reactions, toxins, and inborn errors of metabolism (IEMs) that mimic Reye's are now identified.

It was first described in 1963 in Australia by RDK Reye and a few months later in the United States by GM Johnson.

Pathophysiology

The mechanism is not fully worked out, but it centers on mitochondrial injury. Dysfunction inhibits oxidative phosphorylation and fatty-acid beta-oxidation in a virus-infected, sensitized host who has usually been exposed to mitochondrial toxins, most commonly salicylates. Histology shows cytoplasmic fatty vacuolization in hepatocytes, astrocyte edema and neuron loss in the brain, and edema with fatty degeneration of the proximal lobules in the kidneys. Cells carry pleomorphic, swollen mitochondria reduced in number, with glycogen depletion and minimal inflammation. Hepatic mitochondrial dysfunction drives hyperammonemia, which is thought to trigger astrocyte edema, cerebral edema, and increased intracranial pressure (ICP).

Statistics and Incidences

National surveillance in the United States began in 1973. The peak annual incidence of 555 cases reported to the CDC was in 1979-1980. Cases fell after 1980, when the government began warning about the aspirin association. An average of 100 cases per year were reported in 1985 and 1986, but the maximum reported annually between 1987 and 1993 was 36, with a range of 0.03-0.06 cases per 100,000 per year. Since 1994, two or fewer cases have been reported each year. Seasonal occurrence initially peaked from December to April, tracking viral respiratory infections, especially influenza.

In the United Kingdom, 597 cases were reported between 1981 and 1996. After 1986 warnings, incidence fell from a high of 0.63 per 100,000 children younger than 12 years in 1983-1984 to 0.11 cases per 100,000 in 1990-1991. Of the 597 cases, 155 were later reclassified, 76 of them as involving an IEM. US CDC surveillance for 1980-1997 in patients younger than 18 years counted 1207 cases. Incidence peaks between age 5 and 14 years (median, 6 years; mean, 7 years); 13.5% were younger than 1 year. Racial distribution is 93% white and 5% African American, the remainder Asian, American Indian, and Native Alaskan.

Causes

Influenza virus types A and B and varicella-zoster virus are the pathogens most commonly associated. Salicylates are the key exposure: less than 0.1% of children who took aspirin developed Reye's, but more than 80% of patients diagnosed with Reye's had taken aspirin in the prior 3 weeks. IEMs that produce Reye-like syndromes include fatty-acid oxidation defects (particularly medium-chain acyl dehydrogenase [MCAD] and long-chain acyl dehydrogenase [LCAD] deficiency, inherited and acquired), urea-cycle defects, amino and organic acidopathies, primary carnitine deficiency, and disorders of carbohydrate metabolism.

Clinical Manifestations

Protracted vomiting (with or without clinically significant dehydration), hepatomegaly (liver enlargement with fatty change in 50% of patients), and lethargy progressing to encephalopathy.

The CDC uses the Hurwitz classification but adds stage 6:

• Stage 0. Alert; abnormal history and labs consistent with Reye's; no clinical manifestations.
• Stage 1. Vomiting, sleepiness, lethargy.
• Stage 2. Restlessness, irritability, combativeness, disorientation, delirium, tachycardia, hyperventilation, dilated pupils with sluggish response, hyperreflexia, positive Babinski sign, appropriate response to noxious stimuli.
• Stage 3. Obtunded, comatose, decorticate rigidity, inappropriate response to noxious stimuli.
• Stage 4. Deep coma, decerebrate rigidity, fixed and dilated pupils, loss of oculovestibular reflexes, dysconjugate gaze with caloric stimulation.
• Stage 5. Seizures, flaccid paralysis, absent deep tendon reflexes (DTRs), no pupillary response, respiratory arrest.
• Stage 6. Cannot be classified because the patient was treated with curare or another medication that alters consciousness.

Assessment and Diagnostic Findings

Work up to exclude IEMs: evaluate for fatty-acid oxidation defects, amino and organic acidurias, urea-cycle defects, and disorders of carbohydrate metabolism. An ammonia level as high as 1.5 times normal 24-48 hours after onset of mental status changes is the most frequent lab abnormality. ALT and AST rise to 3 times normal but may return to normal by stages 4 or 5. Bilirubin is higher than 2 mg/dL (usually lower than 3 mg/dL) in 10-15% of patients; if direct bilirubin is more than 15% of total or total exceeds 3 mg/dL, consider other diagnoses. PT and aPTT are prolonged more than 1.5-fold in more than 50% of patients. Glucose is usually normal but may be low, particularly during stage 5 and in children younger than 1 year. On lumbar puncture (only if hemodynamically stable with no signs of increased ICP), opening pressure may or may not be increased and the CSF WBC count is 8/µL or fewer.

Medical Management

No specific treatment exists; supportive care is staged.

• Stage 0-1. Keep the patient quiet; frequently monitor vital signs and labs; correct fluid and electrolyte abnormalities, hypoglycemia, and acidosis; keep electrolytes, serum pH, albumin, serum osmolality, glucose, and urine output in normal ranges; consider restricting fluids to two-thirds of maintenance, since overhydration may precipitate cerebral edema; use colloids (eg, albumin) as needed to maintain intravascular volume.
• Stage 2. Continuous cardiorespiratory monitoring, central or arterial lines for hemodynamics, urine catheter for output, ECG for cardiac function, EEG for seizure activity; prevent increased ICP, elevate the head to 30°, keep the head midline, use isotonic rather than hypotonic fluids, and avoid overhydration.
• Stage 3-5. Continuously monitor ICP, central venous pressure, arterial pressure, or end-tidal carbon dioxide; intubate if not already done.

Pharmacologic Management

No specific treatment is available. Ammonia detoxicants treat hyperammonemia by enhancing nitrogen elimination; sodium phenylacetate-sodium benzoate is FDA-approved for hyperammonemia from urea-cycle defects and is available only from a specialty wholesaler, Ucyclyd Pharma, Inc. Antiemetics such as ondansetron reduce vomiting and cover the initiation of sodium phenylacetate-sodium benzoate therapy.

Nursing Management

Nursing Assessment

Findings track the stage: stage 1, lethargy, vomiting, hepatic dysfunction; stage 2, hyperventilation, hyperactive reflexes, delirium, hepatic dysfunction; stage 3, coma, decorticate rigidity, hyperventilation, hepatic dysfunction; stage 4, deepening coma, large fixed pupils, decerebrate rigidity, minimal hepatic dysfunction; stage 5, seizures, flaccidity, loss of deep tendon reflexes, respiratory arrest (death usually from cerebral edema or cardiac arrest).

Nursing Diagnosis

Based on the assessment data, the major nursing diagnoses are: deficient fluid volume related to failure of regulatory mechanism; ineffective cerebral tissue perfusion related to diminished arterial or venous blood flow and hypovolemia; risk for trauma related to generalized weakness, reduced coordination, and cognitive deficits; reduced breathing pattern related to decreased energy and fatigue, cognitive impairment, tracheobronchial obstruction, and inflammatory process.

Nursing Care Planning and Goals

The patient will maintain adequate ventilation and a normal respiratory rate, stay oriented to environment without deficit, and keep skin integrity, joint mobility, and range of motion.

Nursing Interventions

Monitor vital signs and pulse oximetry for oxygenation. Monitor ICP with a subarachnoid screw or other invasive device. Track blood glucose to catch hyper- or hypoglycemia. Monitor I&O to prevent fluid overload. Assess cardiac, respiratory, and neurologic status to gauge interventions and catch complications such as seizures. Read pulmonary artery catheter pressures for cardiopulmonary status. Keep the head of the bed at a 30-degree angle to lower ICP and promote venous return. Maintain seizure precautions. Maintain oxygen therapy, including intubation and mechanical ventilation as needed, and support thermoregulation. Give medications as ordered and watch for adverse effects. Transfuse blood products as ordered to raise oxygen-carrying capacity and prevent hypovolemia. Check for loss of reflexes and flaccidity to gauge neurologic involvement. Use a hypothermia blanket as needed and check temperature every 15 to 30 minutes while it is in use. Provide postoperative craniotomy care if needed. Give good skin and mouth care and perform ROM exercises. Keep the family informed and supported to reduce anxiety.

Evaluation

Goals are met when the patient maintains adequate ventilation and a normal respiratory rate, stays oriented without deficit, and keeps skin integrity, joint mobility, and range of motion.

Documentation Guidelines

Document assessment findings including degree of deficit and current sources of fluid intake; I&O, fluid balance, weight changes, edema, urine specific gravity, and vital signs; diagnostic results; past and recent injury history and awareness of safety needs; use of safety equipment or procedures; the plan of care; the teaching plan; responses to interventions and teaching; progress toward outcomes; and any modifications to the plan.