Pathophysiology
Pediatric Infectious Disease
Case Study
Patient Profile
Name: Emily Johnson
Age: 2 years old
Gender: female
History of Present Illness
E.J. is a 2-year-old girl whose parents brought her to the emergency department after she experienced a seizure at home. After being at daycare all day, she came home, ate normally, but seemed fatigued and a bit fussy after dinner. Her parents woke up to her crying at 1 a.m. and went into her room. She was warm and had a fever of 103.1°F. They gave her Tylenol to bring her fever down. About ten minutes after taking the Tylenol, Emily had a seizure that lasted for about 3 minutes. Emily was unresponsive during the seizure and exhibited generalized shaking of her arms and legs. Parents stated on the ride to the hospital that Emily was drowsy but arousable.
Past Medical History
No significant past medical history, up-to-date on vaccinations
Family History
Mother had febrile seizures as a child
Physical Assessment
Vitals
Upon admission at 2 a.m.
- Temperature: 101.1°F
- Heart Rate: 140 bpm
- Respiratory Rate: 30 bpm
- Blood Pressure: 90/60 mm Hg
Currently: Responsive to parents; appropriate interaction with environment; appears well hydrated with no dysmorphic features
General Survey
- Head: Pupils equal, round, and reactive to light, extraocular movements intact, facial movements symmetrical, responds appropriately to visual and auditory stimuli, fontanelle closed, no focal neurological deficits noted.
- Ears: Tympanic membranes mildly erythematous bilaterally, no bulging, no drainage.
- Throat: Mild pharyngeal erythema without exudates, mild post-nasal drip visible.
- Neck: Full range of motion, no nuchal rigidity, no signs of meningitis or encephalitis.
- Skin: Warm and flushed, no rash or lesions present, no petechiae, bruising, or signs of trauma, capillary refill < 2 seconds.
- Chest: Clear to auscultation bilaterally, no wheezing or crackles, tachycardic but normal rhythm without murmur.
- Abdomen: Soft, non-tender, no organomegaly, normal bowel sounds, no suprapublic tenderness.
- Motor Function: Normal tone in all extremities, moving all limbs equally, age-appropriate balance when standing.
- Reflexes: Deep tendon reflexes +2 and symmetric, no ankle clonus, normal plantar responses.
Diagnostic Assessment
- Complete Blood Count (CBC): Normal
- Electrolytes: Normal
- Blood Glucose: Normal
Diagnosis
- Viral upper respiratory infection
- Febrile seizure
Activity: Pathophysiology of Febrile Seizures: The Role of Fever
Fill in the blanks with the correct term: hypothalamus, pituitary gland, depolarization, blood-brain barrier, GABAergic, inhibitory, exciting, more, less, generalized tonic-clonic, simple, dehydration, physical activity, 5, 15.
Febrile seizures are convulsions triggered by fever in young children, typically between the ages of 6 months and ____________________ years. Febrile seizures occur when a child’s body temperature rises rapidly, often due to an infection (usually viral). The ____________________, which regulates body temperature, responds to pyrogens by raising the body’s set point temperature, leading to fever. High fever can increase neuronal excitability, making it more likely for neurons to fire action potentials, the electrical impulses of the nervous system. A high fever can also affect ion channels in neurons, particularly sodium and calcium channels, making them more likely to open and cause ____________________. The increased likelihood of depolarization can lead to the synchronous firing of neurons, which manifests as a seizure. Also, during a febrile episode, pro-inflammatory cytokines are released, disrupting the integrity of the ____________________, This disruption allows cytokines to cross the blood-brain barrier and enter the central nervous system, lowering the seizure threshold. These cytokines increase neuronal excitability by enhancing glutamate release and reducing its reuptake, while simultaneously decreasing GABA-mediated inhibition, thereby creating an imbalance between excitatory and inhibitory neurotransmission.
Activity: Pathophysiology of Febrile Seizures: Developmental Factors
Fill in the blanks with the correct term: GABAergic, pulmonary, inhibitory, exciting, more, less, physical activity, dehydration.
Children have an immature ____________________ system with decreased levels of the ____________________ neurotransmitter, which contributes to their increased risk of febrile seizures. The developing brain of young children is especially vulnerable to immune-mediated changes due to its immature state and ____________________ permeable blood-brain barrier. Risk factors also include a family history of febrile seizures, as there is a genetic component influencing both neuronal excitability and the body’s response to fevers. The rapid rise in temperature, rather than the absolute temperature, is often what triggers these seizures by lowering the seizure threshold; ____________________ and electrolyte imbalances can further destabilize neuronal membranes and increase seizure activity.
Activity: Clinical Manifestations of Febrile Seizures
Fill in the blanks with the correct term: tonic-clonic, simple, dehydration, physical activity, 30, X-ray, 15, EEG.
Febrile seizures are typically generalized ____________________, meaning they involve the whole body. They begin with muscle stiffening (tonic phase) and are followed by rhythmic jerking (clonic phase). After a febrile seizure, children often enter a postictal state where they may be drowsy or confused but gradually return to their normal state as the fever is managed.
In cases of complex febrile seizures (defined as seizures lasting longer than ____________________ minutes, occurring more than once in 24 hours, or having focal features) further diagnostic tests may be warranted. These can include an ____________________ to measure brain activity and an MRI to visualize the brain’s structure. Additionally, if there is a suspicion of meningitis or another serious infection, a lumbar puncture may be performed to analyze cerebrospinal fluid. This thorough approach rules out other potential causes of seizures and confirms the diagnosis of febrile seizures.
Review Questions
Click the arrow to expand the section and view the correct answers.
- Emily’s seizure occurred during a high fever. What is the most likely underlying cause of her febrile seizure?
- Bacterial meningitis
- Epilepsy
- Viral infection
- Brain tumor
Answer:
C) Viral infection
Feedback: Febrile seizures are often triggered by high fevers associated with viral infections. Bacterial meningitis and brain tumors are less common causes and would present with additional symptoms.
- Which of the following is a characteristic feature of a simple febrile seizure?
- Focal onset.
- Duration longer than 15 minutes.
- Occurs more than once in 24 hours.
- Generalized tonic-clonic activity.
Answer:
D) Generalized tonic-clonic activity.
Feedback: Simple febrile seizures are characterized by generalized tonic-clonic activity, lasting less than 15 minutes, and occurring only once in 24 hours.
- Emily’s seizure occurred during a high fever. What is the primary physiological factor that increases the risk of febrile seizures in young children?
- Fully developed GABAergic system.
- Decreased neuronal excitability.
- Immature brain development.
- Stable ion channels.
Answer:
C) Immature brain development
Feedback: The immature brain development in young children makes their neuronal networks more excitable and less stable, increasing the risk of febrile seizures.
- Which neurotransmitter system is not fully mature in young children, contributing to the increased risk of febrile seizures?
- Dopaminergic system
- GABAergic system
- Serotonergic system
- Glutamatergic system
Answer:
B) GABAergic system
Feedback: The GABAergic system, which plays a crucial role in stabilizing neuronal activity, is not fully mature in young children, contributing to the increased risk of seizures during fever.
- What role do cytokines play in the development of febrile seizures?
- They stabilize neuronal membranes.
- They decrease neuronal excitability.
- They cross the blood-brain barrier and affect neuronal activity.
- They reduce the risk of seizures.
Answer:
C) They cross the blood-brain barrier and affect neuronal activity.
Feedback: Cytokines, which are inflammatory mediators released during fever, can cross the blood-brain barrier and affect neuronal activity, potentially lowering the seizure threshold.
- Emily’s mother had febrile seizures as a child. How does family history influence the risk of febrile seizures?
- It has no influence.
- It decreases the risk.
- It increases the risk.
- It only affects males.
Answer:
C) It increases the risk.
Feedback: A family history of febrile seizures suggests a genetic predisposition that may increase the risk of a child experiencing these seizures.
- What is the primary treatment goal for a child experiencing a febrile seizure?
- Immediate initiation of antiepileptic drugs.
- Reducing the fever and providing reassurance.
- Performing a lumbar puncture.
- Administering antibiotics.
Answer:
B) Reducing the fever and providing reassurance.
Feedback: The primary treatment goal for febrile seizures is to reduce the fever with antipyretics and reassure the parents. Antiepileptic drugs and antibiotics are not typically indicated unless there is an underlying infection or other specific cause.
- An hour after her seizure, Emily’s temperature is down to 101 °F, but she still appears somewhat drowsy. Her father is concerned that this means she has brain damage from her seizure. An appropriate response would be:
- “Though this is not Emily’s usual condition, it will resolve on its own. This is a transitory state that children are often in after a seizure, and it does not indicate neurologic damage.”
- “We won’t be able to tell if Emily has any long-term neurological damage until she starts speaking.”
- “If she has another febrile seizure in the next 24 hours, she is at risk for neurological damage, but we caught this one in time today, and she is just tired.”
- “I submitted a neurology consult, and they will be in to talk to you soon about your concerns.”
Answer:
A) “Though this is not Emily’s usual condition, it will resolve on its own. This is a transitory state that children are often in after a seizure, and it does not indicate neurologic damage.”
Feedback: This is a typical postictal state that will resolve further as her temperature resolves.
References
Heavey, E. (2024). Lecture on the Nervous System. [Transcript].
Microsoft. (2024). Copilot [AI assistant]. Microsoft Corporation.
Tkacs, N. (Ed.). (2020). Advanced physiology and pathophysiology: Essentials for clinical practice. Springer Publishing Company.
You.com. (n.d.). Homepage. You.com. Retrieved February 22, 2025, from https://www.you.com
