The differential diagnosis of acute altered mental status in
children involves diverse disorders that differ slightly from those
in adult patients. The familiar mnemonic AEIOU TIPS (alcohol, encephalopathy, insulin, opiates, uremia, trauma, infection, poisoning,
and seizure) remains a useful tool for organizing
the diagnostic possibilities (Table 131-1).
Procedures for diagnosis of causes of altered mental status include
analysis of blood, urine, and cerebrospinal fluid (CSF); electrocardiography; and
diagnostic imaging, including plain radiography, US, and CT.9 Diagnostic
tests should be guided by the clinical situation.10 Obtain
point-of-care blood glucose level with a glucose oxidase strip in
all cases and confirm results with laboratory analysis of venous
blood. Order serum electrolyte levels, liver function studies, and
renal function studies. If the history is consistent with a toxic
ingestion or a toxidrome is identified, serum or urine toxicology
screening is in order and consider consultation with a poison center.
The white blood cell count and differential blood cell count as
independent evaluations are rarely helpful, except perhaps in assisting
management decisions regarding highly febrile children <2 years
of age. Obtain a blood culture if serious bacterial infection is
An arterial blood gas or capillary blood gas analysis with pulse
oximetry may provide useful information in cases of trauma, respiratory
distress, or suspected acid-base imbalance.
Capnometry may be useful for rapid assessment of acid-base status.
Correct shock, hypotension, and hypoxia before attempting lumbar
puncture. Administer empiric antibiotics before lumbar puncture
if bacterial meningitis is suspected. Lumbar puncture with CSF examination
is necessary as soon as the patient is in stable condition (see Chapter 113, Fever and Serious Bacterial Illness).
Obtain a 12-lead ECG if there are pathologic auscultatory findings
or a rhythm disturbance is observed while monitoring the patient.
An ECG may further guide therapy in cases of tricyclic antidepressant
Imaging is directed by the clinical scenario. Cervical spine
immobilization is the first step in management of the patient with
head or multiple system trauma, followed by cervical spine radiography
and/or CT of the cervical spine and head. A chest radiograph
confirms or clarifies examination findings and documents endotracheal
tube placement. Abdominal radiographs are indicated if the acute
ingestion of radiopaque material is suspected or if the patient
exhibits signs and symptoms of an acute abdomen, including possible intussusception. Abdominal
US studies may be useful to screen for cases of intussusception
with an atypical presentation. A CT scan of the head may be obtained
for suspected increased intracranial pressure, vascular disorder,
or mass lesion. Magnetic resonance neuroimaging may be arranged
for children at high risk who have had a first seizure.11
Other studies that may be useful in specific cases are blood
ammonia level, serum osmolality, blood alcohol level, thyroid function tests, blood lead
level, and skeletal survey for suspected abuse. A portable electroencephalograph
may diagnose nonmotor status epilepticus.
Causing Altered Mental Status
Pediatric acute alcohol intoxication can occur from methanol,
ethanol, and isopropanol.12 In younger children,
alcohol ingestion is typically accidental; intentional ingestion
is more likely in adolescents. Hypoglycemia may coexist.
The classic presentation of pediatric diabetic ketoacidosis includes
weight loss, polyuria, polydipsia, polyphagia, weakness, vomiting,
abdominal discomfort, Kussmaul respirations, a fruity acetone breath,
and altered mental status. Children with diabetic ketoacidosis or
many other pediatric conditions associated with a loss of circulating
volume may develop hypotonic or hypertonic dehydration leading to
altered mental status, with or without seizures (see Chapter 139, The Child with Diabetes). Patients with poor perfusion or
inadequate air exchange have insufficient oxygen delivery to the
brain and exhibit insomnia, somnolence, and confusion. Children
who develop hypercapnia as a result of primary lung disease or neurologic
dysfunction also may present with altered mental status. Those with
hepatic failure present with nausea, fatigue, and behavioral alterations
and may rapidly become obtunded. Patients with inborn errors of
metabolism typically present early in life with poor feeding, recurrent
vomiting, seizures, metabolic acidosis, lethargy, stupor, and altered
mental status (see Chapter 137, Hypoglycemia and Metabolic Emergencies in Infants and Children).
Other Cardiogenic Disorders
In an Adams-Stokes attack, heart block results in loss of consciousness.
Critical aortic stenosis leads to unconsciousness through decreased
cardiac output. Altered mental status may be accompanied by tachypnea,
tachycardia, and hypotension unresponsive to IV volume expansion
with pericardial tamponade.9
Hypertensive encephalopathy may occur in children
at diastolic pressures of 100 to 110 mm Hg. Reye syndrome follows
a viral illness such as influenza or varicella, historically in
association with aspirin use. Patients are afebrile and anicteric
and develop pernicious vomiting. Confusion and delirium may lead
to increasing obtundation. Hemorrhagic shock and encephalopathy
syndrome is a symptom complex of unknown cause that affects
previously healthy infants. The common features include a mild prodromal,
nonspecific illness of several days’ duration followed
by the onset of profuse, watery diarrhea that becomes bloody and
seizures. Patients present poorly perfused, with profound metabolic
acidosis and evidence of disseminated intravascular coagulation.
Laboratory evidence of hepatic, renal, pancreatic, and myocardial
dysfunction is common. Wernicke encephalopathy, characterized by
altered mental status, ataxia, and ocular palsies, can occur in
rare cases in children with nutritional deficiencies, malignancies,
Altered mental status is a rare presentation of endocrine disorders.
Children with Addison disease present with nausea, vomiting, abdominal
pain, weakness, malaise, hypotension, and mental status changes,
including psychosis. Presumptive diagnosis is provided by findings
of hyperpigmentation, depressed sodium and glucose levels, an elevated
potassium level, and a variably increased calcium level. Infants
with congenital adrenal hyperplasia may present in an acute salt-losing,
volume-depleted hypotensive crisis or with virilization characterized
by ambiguous genitalia and cortisol insufficiency also manifested
as hypoglycemia. Infants with thyrotoxicosis may present with ventricular
dysrhythmia. Children with thyrotoxicosis also may exhibit symptoms
similar to those of adults, including goiter, irritability, exophthalmos,
hyperthermia, high-output congestive heart failure, mania, delirium,
psychosis, and, later, apathy and decreasing levels of consciousness.
Patients with pheochromocytoma may present with hypertensive encephalopathy.
Hyponatremic children become symptomatic at plasma levels
of approximately 120 mEq/L. Manifestations include
anorexia, headache, nausea, vomiting, irritability, weakness, cramps,
disorientation, seizures, and altered mental status. Hypernatremia results
in muscle weakness, irritability, seizures, and altered mental status.
Disorders of calcium, magnesium, and phosphorus present with neuromuscular signs,
including weakness, tetany, seizures, and apathy (see Chapter 142, Fluid and Electrolyte Therapy in Infants and Children).
Hypoglycemia may be an end product of an endocrinopathy
(e.g., adrenal insufficiency, hyperthyroidism, or hypopituitarism)
or the result of exposure to an exogenous substance, such as ethanol,
salicylate, oral hypoglycemics, or insulin. Hypoglycemia also may
result from a common stress pathway of decreased gluconeogenesis,
as seen in sepsis or Reye syndrome.6 Adrenergic
signs of palpitations, hunger, and sweating are seen at levels of
<60 milligrams/dL. Irritability, confusion, seizures,
and coma occur at levels of ≤40 milligrams/dL (see Chapter 137, Hypoglycemia and Metabolic Emergencies in Infants and Children). Infants and children are prone
to develop ketotic hypoglycemia with fasting, especially with infections
in early infancy. Altered mental status from hyperglycemia
had been rare during childhood. With the escalation in the incidence of
childhood diabetes, however, there has been a rise in the number
of cases of altered mental status due to a hyperglycemic-hyperosmolar
Intussusception is readily diagnosed in the small percentage
of younger children who present with the classic constellation of abdominal
pain, vomiting, abdominal mass, and rectal bleeding. Altered mental
status may be the initial and predominant symptom of intussusception.
Altered mental status remains until the bowel obstruction is reduced
(see Chapter 124, Acute Abdominal Pain in Children).15
Children who have ingested opiates may present with miosis, absent
bowel sounds, and lethargy. Common opiates that may be present in
the household include dextromethorphan, diphenoxylate plus atropine
(Lomotil), and loperamide (Imodium). Ingestion of clonidine may
cause signs and symptoms similar to those of opiate intoxication. Suspect
abuse and neglect in children with opiate intoxication.
In children with chronic renal failure, neurologic dysfunction may
develop secondary to stroke, hypertension, or metabolic derangements. Encephalopathy
occurs in more than one third of patients with chronic renal failure
and is manifested by headache, irritability, cognitive derangement,
and seizures. Hemolytic-uremic syndrome is the
most common cause of acute renal failure in childhood. It is characterized
by oliguria, microangiopathic hemolytic anemia, and thrombocytopenia
with purpura (see Chapter 128, Renal Emergencies in Infants and Children). Although there are many causes, the
most common are prodromal Escherichia coli enteritis
and an invasive Streptococcus pneumoniae infection.
Trauma may occur at the cellular or global level. Hypovolemia
or hemorrhage from multisystem trauma may lead to insufficient cerebral perfusion
and result in altered mental status. Hypovolemic states from other
conditions, such as primary peritonitis or ruptured appendix, can also
result in altered mental status. Children may experience transient
loss of consciousness after closed head injury. Occasionally, a
seizure may occur immediately after closed head injury, which results
in altered mental status due to the postictal state. The signs and
symptoms of acute epidural hematoma are typically post-traumatic
loss of consciousness followed by a lucid interval and then rapid
progression of decreasing consciousness. Acute epidural hematoma
also can present with a gradual loss of consciousness associated
with ipsilateral pupillary dilatation. As in adults, subdural hematomas
may be acute, subacute, or chronic. Most children with subdural
hematomas have external signs of trauma. The exceptions are abused
infants, typically <6 months old, who may have no external signs
of injury. Abused children who are shaken typically present with
a history of vomiting, seizures, changes in respiratory pattern,
and altered mental status. Retinal hemorrhages or a tense fontanelle
may suggest the diagnosis. (see Chapter 290, Child Abuse and Neglect). Children with blunt head trauma are
more likely than adults to develop diffuse cerebral swelling, increased
intracranial pressure, and altered mental status without extracerebral
or intracerebral collections of blood (see Chapter 254, Head Trauma in Adults and Children).16
Primary brain tumor, or metastatic or meningeal leukemic infiltration,
may alter the metabolism of the brain. Intracerebral tumors commonly
produce focal neurologic dysfunction, whereas posterior fossa tumors
typically block the ventricular system and create signs and symptoms
suggestive of hydrocephalus. Supratentorial and infratentorial tumors
may present abruptly with altered mental status, fever, or meningismus
after an intratumor hemorrhage (see Chapter 136, Oncology and Hematology Emergencies in Children).17
Extremes of body temperature also may lead to central nervous
system dysfunction. Progressive hypothermia leads to insidious altered
mental status. Children who develop body core temperatures of >41°C
(105.8°F) develop headache, weakness, and dizziness followed by confusion,
euphoria, combativeness, and altered mental status. Posturing, seizures,
hemiparesis, and pupillary changes may be present.
Infection is more common as a cause of altered mental status in
children than in adults. The incidence of bacterial meningitis and
septicemia is highest in early infancy and is considerably higher
throughout childhood than in adulthood. Bacterial meningitis should
be high on the differential diagnostic list for a febrile child
with altered mental status. Unless there are contraindications
to lumbar puncture, examination of CSF should be considered in lethargic,
febrile children. Patients with encephalitis have fever and headache
and may have signs of meningeal irritation or neurologic deficits.
Herpesviruses, arbovirus, rotavirus, and Epstein-Barr virus are
among the most common viral agents associated with encephalitis.
Encephalitis may occur in the course of mycoplasmal illness, shigellosis,
Lyme disease, or cat-scratch disease.18 Visceral
larva migrans may produce encephalopathy in the young.
A brain abscess may create signs and symptoms suggestive of encephalitis.
Children with a brain abscess have fever and headache that precede changes
in presentation and consciousness. Presenting symptoms also include
generalized or focal seizures. Risk factors for brain abscess include
sinusitis, otitis media, mastoiditis, soft tissue infections of
the face, cyanotic congenital heart disease, immunodeficiency, comminuted
skull fracture, ventriculoperitoneal shunt, and IV drug abuse.19
Any systemic infection associated with vasculitis or the production
of vasodepressant toxins and accompanied by shock may lead to altered
mental status secondary to cerebral hypoperfusion.
Cerebrovascular events are uncommon in children, but subarachnoid
hemorrhage from arteriovenous malformations or a ruptured berry
aneurysm may cause focal neurologic deficits followed by status
epilepticus and coma. Nuchal rigidity is an inconstant finding.
Telangiectasias or hemangiomas of the skin may be present in some
hereditary disorders associated with vascular malformations. Venous
thrombosis may follow severe dehydration or a pyogenic infection
of the paranasal sinuses, mastoid, or middle ear. Periorbital edema
with cranial nerve abnormalities is a clue. Arterial thrombosis
is uncommon in children, except in those with homocystinuria. Children with
homocystinuria have a marfanoid appearance, dislocated lenses, and mental
retardation. Intracerebral and intraventricular hemorrhages may follow
birth asphyxia or trauma in neonates, but in older children they may
signify a congenital or acquired coagulopathy. Signs of subacute
bacterial endocarditis include splinter hemorrhages, splenomegaly,
microscopic hematuria, and altered mental status caused by cerebral
emboli. Acute infantile hemiplegia presents with an acute seizure
followed by hemiparesis and coma. Acute confusional migraine may
be associated with profound alterations in consciousness. Children
with sickle cell anemia can develop cerebral thrombosis, status
epilepticus, and coma.
Drugs may be transferred to a fetus transplacentally. Infants and
children may ingest drugs due to neglect, abuse, or accident. Drugs may
be taken as a suicide gesture in adolescents. Altered mental status
may be caused by exogenous intoxicants such as ethanol, ethylene
glycol, methyl alcohol, paraldehyde, salicylates, anticholinergics,
antihistamines, cholinergics, opiates, carbamazepine, clonidine,
sedative-hypnotics, amphetamines, cocaine, cannabis, nicotine, carbon
monoxide, hydrocarbons, and multiple psychotropic drugs within the
categories of selective serotonin reuptake inhibitors, mood stabilizers,
and antipsychotics. Ingestion of household and beauty products also
may cause altered mental status.
Psychogenic unresponsiveness is rare in children. It is characterized
by decreased responsiveness but otherwise normal findings on neurologic
examination, including normal oculovestibular reflexes. Psychogenic
unresponsiveness may occur as a conversion reaction, an adjustment
reaction, a panic state, or a manifestation of malingering.
Generalized tonic-clonic major motor seizures and absence status
epilepticus are associated with prolonged unresponsiveness in children.20 A
prolonged postictal phase in a febrile child with seizure suggests
intracranial infection (see Chapter 129, Seizures and Status Epilepticus in Children).