6.2 Seizures, Encephalopathy & Altered Mental Status

Seizures, Encephalopathy & Altered Mental Status

Altered brain function in the progressive care unit ranges from momentary electrical storms to global metabolic derangement. Differentiating seizure activity, encephalopathy, delirium, and dementia determines whether the correct intervention is an anticonvulsant, a metabolic correction, an environmental change, or simply time.

Seizure Disorders and Status Epilepticus

Seizures are classified as focal (originating in one hemisphere, may or may not impair awareness) or generalized (involving both hemispheres from onset, such as tonic-clonic seizures). Status epilepticus is defined as a single seizure lasting longer than 5 minutes, or recurrent seizures without return to baseline consciousness between them — it is a true emergency because ongoing seizure activity causes progressive neuronal injury and can precipitate rhabdomyolysis, hyperthermia, and respiratory compromise.

Most generalized tonic-clonic seizures follow a recognizable pattern: an aura (a subjective warning some patients experience), the ictal phase (the seizure itself — tonic rigidity followed by clonic jerking, often with loss of consciousness, incontinence, or tongue biting), and the postictal phase (a period of confusion, drowsiness, or transient focal weakness as the brain recovers), which can last minutes to hours and should not be mistaken for a new neurologic event.

First-line treatment is an IV benzodiazepine (lorazepam is preferred for its longer anticonvulsant duration; midazolam is a reasonable alternative when IV access is delayed). If seizures continue, a second-line agent such as IV levetiracetam, fosphenytoin, or valproate is loaded. Refractory status epilepticus may require continuous infusion of propofol or midazolam with continuous EEG monitoring to confirm electrographic seizure termination, since paralysis or heavy sedation can mask ongoing seizure activity on the surface exam. Nursing priorities during an active seizure include protecting the airway, positioning the patient side-lying to reduce aspiration risk, padding to prevent injury, and never restraining the convulsing limbs.

Encephalopathy: A Symptom, Not a Diagnosis

Encephalopathy describes globally altered brain function and always has an underlying cause that must be identified:

• Hypoxic-ischemic encephalopathy follows cardiac arrest or prolonged hypotension/hypoxemia; targeted temperature management is used to limit secondary injury.
• Metabolic encephalopathy results from uremia, severe electrolyte derangement, hypoglycemia or hyperglycemia, or hypercapnia.
• Infectious encephalopathy accompanies sepsis or a CNS infection such as meningitis or encephalitis.
• Hepatic encephalopathy results from the liver's failure to clear ammonia and other gut-derived neurotoxins, producing confusion that can progress to coma. Lactulose is the mainstay treatment: it acidifies the colon, traps ammonia as ammonium, and promotes its excretion in stool — the therapeutic endpoint is typically two to three soft bowel movements per day, not simply "more."

Altered Mental Status and Delirium

When a patient's mentation changes, the nurse's job is to distinguish an acute, reversible process from a chronic one. Delirium is an acute, fluctuating disturbance of attention and awareness that is common, under-recognized, and associated with worse outcomes including longer ventilation, longer stay, and higher mortality. The validated bedside tool is the Confusion Assessment Method for the ICU (CAM-ICU), which is positive when the patient shows:

1. Acute onset or fluctuating course, and
2. Inattention, and
3. Either disorganized thinking or an altered level of consciousness

Delirium has three subtypes: hyperactive (agitated, easily recognized), hypoactive (withdrawn, lethargic — the most common and most frequently missed), and mixed. Risk factors include mechanical ventilation, sedative or opioid use, sleep disruption, immobility, and pre-existing cognitive impairment; prevention bundles (the "ABCDEF bundle") emphasize spontaneous awakening and breathing trials, delirium monitoring, early mobility, and family engagement.

Dementia, by contrast, is a chronic, gradually progressive decline in cognition with a generally clear sensorium, which helps distinguish it from delirium — though patients with dementia are also at higher baseline risk for superimposed delirium during acute illness. Because impaired cognition and neurologic weakness both threaten airway protection, every patient with a new neurologic deficit, decreased level of consciousness, or post-extubation status should receive a bedside dysphagia (swallow) screen before resuming oral intake; failing the screen means keeping the patient NPO and escalating to a formal swallow evaluation to prevent aspiration pneumonia.

Grading and Managing the Confused Patient

Hepatic encephalopathy severity is commonly staged with the West Haven criteria, ranging from minimal changes detectable only on testing, through mild confusion and lethargy, to stupor and coma; asterixis (a flapping tremor elicited by asking the patient to extend the arms and dorsiflex the wrists) is a classic bedside finding in moderate hepatic encephalopathy and should prompt an ammonia check and lactulose titration. When agitation accompanies delirium, non-pharmacologic strategies come first: reorientation, day-night lighting cues, minimizing unnecessary lines and restraints, involving family, and correcting the underlying trigger (pain, hypoxia, urinary retention, constipation, withdrawal). If medication is required, current guidelines favor avoiding benzodiazepines in ICU delirium — except when the cause is alcohol or benzodiazepine withdrawal — because they can worsen confusion; short-acting antipsychotics or dexmedetomidine are generally preferred instead. Recognizing that a benzodiazepine given for "sundowning" may deepen rather than resolve delirium is a common exam distinction between appropriate and inappropriate sedation choices in the confused progressive care patient.