A 16-year-old boy with type 1 diabetes for 7 years presents for transition planning to adult services. His current HbA1c is 72 mmol/mol. He admits to frequently missing insulin doses and not checking blood glucose regularly. He expresses anxiety about managing his diabetes independently and feels overwhelmed by the responsibility. According to best practice guidelines for transition, which approach is most appropriate?
Q82
A 9-year-old boy with drug-resistant epilepsy is being commenced on the ketogenic diet as adjunctive therapy. His seizures are characterized by daily focal impaired awareness seizures despite trials of three appropriate anti-epileptic medications. Before initiating the diet, baseline investigations reveal: random glucose 5.2 mmol/L, bicarbonate 24 mmol/L, urine ketones negative. Which metabolic parameter requires closest monitoring during the first 2 weeks after starting the ketogenic diet?
Q83
A 15-year-old girl with type 1 diabetes for 9 years attends for routine screening. She is asymptomatic. Fundoscopy performed by the ophthalmologist reveals several microaneurysms and dot haemorrhages in both eyes, but no cotton wool spots, venous changes, or new vessel formation. Visual acuity is normal at 6/6 bilaterally. What is the most appropriate classification and management of her retinopathy?
Q84
A 8-year-old girl with epilepsy controlled on sodium valproate 400 mg twice daily for 2 years presents with a 3-month history of tremor affecting her hands. The tremor is present at rest and worsens with intentional movements. Her seizures remain well controlled with no episodes in the past 18 months. Examination confirms a coarse tremor of both hands but is otherwise normal. Valproate level is within therapeutic range. What is the most appropriate management?
Q85
A 12-year-old boy with type 1 diabetes for 4 years presents for routine review. His recent capillary blood glucose readings show: pre-breakfast 6.5-8.0 mmol/L, pre-lunch 4.5-6.0 mmol/L, pre-evening meal 8.5-11.0 mmol/L, bedtime 5.5-7.0 mmol/L. His HbA1c is 64 mmol/mol. He takes insulin aspart before meals and insulin detemir at bedtime. Which modification to his insulin regimen would best address the pre-evening meal hyperglycaemia?
Q86
A 10-year-old girl with refractory focal epilepsy is being evaluated for potential epilepsy surgery. Video-EEG telemetry has identified a clear seizure focus in the right anterior temporal region. MRI brain shows right mesial temporal sclerosis. Neuropsychological testing reveals normal cognitive function. Which additional investigation is most important before proceeding with surgical evaluation?
Q87
A 11-year-old boy with type 1 diabetes is brought to the emergency department with vomiting, abdominal pain, and lethargy. Capillary blood glucose is 28.5 mmol/L. Urinalysis shows 3+ ketones. Blood gas analysis reveals: pH 7.15, pCO2 2.8 kPa, bicarbonate 8 mmol/L, base excess -18. He weighs 35 kg. According to current DKA management guidelines, what is the most appropriate initial fluid bolus?
Q88
A 5-year-old boy with newly diagnosed childhood absence epilepsy is being considered for treatment. He experiences 15-20 absence seizures daily, each lasting 5-10 seconds, significantly impacting his schooling. His neurological examination is normal and EEG shows classical 3 Hz spike-and-wave discharges. His mother is concerned about medication side effects. Which aspect of his condition makes treatment most strongly indicated at this time?
Q89
A 13-year-old girl with type 1 diabetes for 5 years presents to clinic. She uses an insulin pump (continuous subcutaneous insulin infusion). Over the past 3 months, her HbA1c has risen from 58 mmol/mol to 75 mmol/mol. Her insulin pump download shows frequent meal boluses being administered but basal rates appear unchanged from 3 months ago. She has grown 4 cm and gained 3 kg during this period. Which factor is most likely contributing to her deteriorating glycaemic control?
Q90
A 7-year-old girl with focal epilepsy has been taking carbamazepine 200 mg twice daily for 18 months with good seizure control. She now presents with progressive unsteadiness, double vision, and drowsiness over the past week. Examination reveals horizontal nystagmus and ataxia. Her mother reports no recent illness or medication changes. Blood tests show: carbamazepine level 58 micromol/L (therapeutic range 20-50 micromol/L), sodium 128 mmol/L, normal renal and liver function. What is the most appropriate immediate management?
Chronic Paediatric Conditions UK Medical PG Practice Questions and MCQs
Question 81: A 16-year-old boy with type 1 diabetes for 7 years presents for transition planning to adult services. His current HbA1c is 72 mmol/mol. He admits to frequently missing insulin doses and not checking blood glucose regularly. He expresses anxiety about managing his diabetes independently and feels overwhelmed by the responsibility. According to best practice guidelines for transition, which approach is most appropriate?
A. Transfer to adult services immediately as he is now 16 years old
B. Continue in paediatric services until he demonstrates better diabetes control
C. Arrange joint paediatric-adult clinic appointments with a structured transition plan (Correct Answer)
D. Refer to psychology services and delay transition until mental health improves
E. Transfer to adult services but arrange frequent review appointments initially
Explanation: ***Arrange joint paediatric-adult clinic appointments with a structured transition plan***
- Transition is a **gradual process**, not a single event, and **joint clinics** facilitate continuity of care and relationship building with the new adult team.
- A **structured transition plan** addresses the patient's anxiety and poor self-management by providing a safety net and clear milestones during the shift to adult services.
*Transfer to adult services immediately as he is now 16 years old*
- **Immediate transfer** based solely on age is linked to poor clinical outcomes, including **deteriorating glycaemic control** and disengagement from care.
- Abruptly moving a patient who is already **anxious** and struggling with self-care increases the risk of **diabetic ketoacidosis (DKA)** and loss to follow-up.
*Continue in paediatric services until he demonstrates better diabetes control*
- **Delaying transition** solely based on glycaemic control is ineffective, as the move to adult services is often the catalyst needed for maturing **self-management skills**.
- Paediatric services are not designed for long-term care of older adolescents, and **prolonged stay** may foster unhealthy dependency rather than independence.
*Refer to psychology services and delay transition until mental health improves*
- While **psychological support** is crucial for managing diabetes-related anxiety, it should be integrated into the transition process rather than used as a reason to **postpone** it.
- Delaying the process can exacerbate the patient's feelings of being overwhelmed; transition teams should include **multidisciplinary support** including psychologists.
*Transfer to adult services but arrange frequent review appointments initially*
- Transferring without a **joint handover** period lacks the necessary bridge between paediatric and adult care models, which differ significantly in **autonomy expectations**.
- Frequent reviews in adult services alone do not address the **emotional transition** or the need for a familiar paediatric presence to boost the patient's confidence.
Question 82: A 9-year-old boy with drug-resistant epilepsy is being commenced on the ketogenic diet as adjunctive therapy. His seizures are characterized by daily focal impaired awareness seizures despite trials of three appropriate anti-epileptic medications. Before initiating the diet, baseline investigations reveal: random glucose 5.2 mmol/L, bicarbonate 24 mmol/L, urine ketones negative. Which metabolic parameter requires closest monitoring during the first 2 weeks after starting the ketogenic diet?
A. Serum lipid profile for hypercholesterolaemia
B. Blood glucose for hypoglycaemia
C. Serum bicarbonate for metabolic acidosis (Correct Answer)
D. Serum calcium for hypocalcaemia
E. Liver transaminases for hepatotoxicity
Explanation: ***Serum bicarbonate for metabolic acidosis***
- The ketogenic diet involves the production of **beta-hydroxybutyrate** and **acetoacetate**, which are organic acids that can lead to **metabolic acidosis** during the initiation phase.
- **Serum bicarbonate** must be monitored closely in the first 2 weeks to ensure the patient does not develop clinically significant **ketoacidosis**, especially as the body adapts to fat-based metabolism.
*Serum lipid profile for hypercholesterolaemia*
- While a high-fat diet can lead to **hyperlipidaemia**, these changes typically manifest as a **long-term complication** rather than an acute risk in the first 14 days.
- Routine monitoring of **cholesterol and triglycerides** is usually scheduled at 3-month intervals rather than the acute initiation window.
*Blood glucose for hypoglycaemia*
- Although **hypoglycaemia** can occur during the transition to ketosis, it is usually a transient risk managed in the **first 48–72 hours**.
- Compared to the persistent risk of developing acidosis during the first few weeks, sustained glucose monitoring is less critical than **bicarbonate** surveillance after the initial few days.
*Serum calcium for hypocalcaemia*
- Long-term use of the ketogenic diet is associated with **osteopenia** and **kidney stones**, requiring **calcium and vitamin D** monitoring.
- These mineral disturbances are **chronic side effects** and do not represent a primary acute metabolic concern within the first 2 weeks of therapy.
*Liver transaminases for hepatotoxicity*
- **Hepatotoxicity** is a rare complication and is more commonly associated with concurrent use of **valproate** rather than the diet itself.
- While baseline and periodic **liver function tests** are performed, they are not the most critical metabolic parameter to track for acute diet-induced instability.
Question 83: A 15-year-old girl with type 1 diabetes for 9 years attends for routine screening. She is asymptomatic. Fundoscopy performed by the ophthalmologist reveals several microaneurysms and dot haemorrhages in both eyes, but no cotton wool spots, venous changes, or new vessel formation. Visual acuity is normal at 6/6 bilaterally. What is the most appropriate classification and management of her retinopathy?
A. No diabetic retinopathy; continue annual screening
B. Background diabetic retinopathy; continue annual screening (Correct Answer)
C. Pre-proliferative diabetic retinopathy; increase screening to 6-monthly
D. Proliferative diabetic retinopathy; refer for laser photocoagulation
E. Diabetic maculopathy; refer for optical coherence tomography
Explanation: ***Background diabetic retinopathy; continue annual screening***
- The presence of **microaneurysms** and **dot haemorrhages** in the absence of more severe signs (like cotton wool spots or new vessel formation) is characteristic of **background (non-proliferative) diabetic retinopathy**.
- At this stage, the standard management involves continued **annual screening** to monitor progression, alongside optimization of **glycaemic control** and blood pressure.
*No diabetic retinopathy; continue annual screening*
- This classification is incorrect because the presence of **microaneurysms** and **dot haemorrhages** indicates the earliest signs of diabetic retinal damage.
- A diagnosis of "No diabetic retinopathy" would mean a completely normal fundoscopic examination without any vascular changes.
*Pre-proliferative diabetic retinopathy; increase screening to 6-monthly*
- **Pre-proliferative retinopathy** is characterized by more severe signs such as **cotton wool spots**, venous beading, or intraretinal microvascular abnormalities (IRMA), which are explicitly absent in this patient.
- Without these features, increasing screening frequency to **6-monthly** is not yet indicated.
*Proliferative diabetic retinopathy; refer for laser photocoagulation*
- **Proliferative diabetic retinopathy** is defined by the presence of **neovascularization** (new blood vessel formation) or vitreous/preretinal haemorrhage.
- The patient has no new vessel formation, therefore, immediate referral for **laser photocoagulation** is not required.
*Diabetic maculopathy; refer for optical coherence tomography*
- **Diabetic maculopathy** involves oedema or exudates affecting the **macular area**, which typically leads to a reduction in **visual acuity**.
- This patient has normal **visual acuity (6/6)** and no reported macular oedema or exudates, making this diagnosis unlikely.
Question 84: A 8-year-old girl with epilepsy controlled on sodium valproate 400 mg twice daily for 2 years presents with a 3-month history of tremor affecting her hands. The tremor is present at rest and worsens with intentional movements. Her seizures remain well controlled with no episodes in the past 18 months. Examination confirms a coarse tremor of both hands but is otherwise normal. Valproate level is within therapeutic range. What is the most appropriate management?
A. Continue valproate and add propranolol for tremor
B. Reduce valproate dose and monitor seizure control
C. Switch to levetiracetam as monotherapy
D. Add lamotrigine and gradually withdraw valproate (Correct Answer)
E. Reassure that tremor will resolve and continue current treatment
Explanation: ***Add lamotrigine and gradually withdraw valproate***
- **Valproate-induced tremor** is a common dose-related side effect; given the patient's age and sex, switching to a safer alternative like **lamotrigine** is appropriate to avoid long-term side effects such as **teratogenicity** and **metabolic issues**.
- The standard management for changing anti-epileptic drugs in a stable patient is **cross-titration**, which involves adding the new drug and reaching a therapeutic dose before gradually tapering the offending agent to prevent **seizure recurrence**.
*Continue valproate and add propranolol for tremor*
- Adding a second medication to treat a side effect increases the **pill burden** and the risk of further side effects from the **beta-blocker**.
- This approach does not address the underlying **valproate toxicity** or other long-term risks associated with valproate use in a young female.
*Reduce valproate dose and monitor seizure control*
- While reducing the dose may diminish the **tremor**, it often fails to eliminate it completely and places the patient at a higher risk of **breakthrough seizures**.
- Since the patient has been seizure-free for 18 months, maintaining optimal control while transitioning to an agent without a **tremor-related profile** is preferred.
*Switch to levetiracetam as monotherapy*
- An abrupt switch or rapid substitution to **levetiracetam** carries a significant risk of **status epilepticus** or pharmacological instability.
- While levetiracetam is a valid alternative, the **cross-tapering** method with a drug like lamotrigine is typically safer for ensuring continuous seizure suppression.
*Reassure that tremor will resolve and continue current treatment*
- **Valproate-induced tremors** are generally not self-limiting and persist as long as the medication remains at the current therapeutic dosage.
- Ignoring the tremor can significantly impair functionality, such as **fine motor tasks** or school performance, and is not an appropriate clinical response.
Question 85: A 12-year-old boy with type 1 diabetes for 4 years presents for routine review. His recent capillary blood glucose readings show: pre-breakfast 6.5-8.0 mmol/L, pre-lunch 4.5-6.0 mmol/L, pre-evening meal 8.5-11.0 mmol/L, bedtime 5.5-7.0 mmol/L. His HbA1c is 64 mmol/mol. He takes insulin aspart before meals and insulin detemir at bedtime. Which modification to his insulin regimen would best address the pre-evening meal hyperglycaemia?
A. Increase the breakfast insulin aspart dose
B. Increase the lunchtime insulin aspart dose (Correct Answer)
C. Increase the evening insulin detemir dose
D. Add a second dose of insulin detemir in the morning
E. Change from insulin detemir to insulin glargine
Explanation: ***Increase the lunchtime insulin aspart dose***- The **pre-evening meal hyperglycemia** (8.5–11.0 mmol/L) indicates that the rapid-acting insulin given at lunch was insufficient to cover the carbohydrates consumed, leading to elevated glucose levels later in the afternoon.- Since **insulin aspart** is a rapid-acting analogue, increasing its **lunchtime dose** will provide better coverage for the lunch meal and the subsequent post-prandial period, effectively lowering blood glucose before the evening meal.*Increase the breakfast insulin aspart dose*- Increasing this dose would primarily affect **post-breakfast** and **pre-lunch** blood glucose levels.- The **pre-lunch** readings are already within the target range (4.5–6.0 mmol/L), so increasing this dose risks **hypoglycemia** during the late morning.*Increase the evening insulin detemir dose*- **Insulin detemir** is a long-acting basal insulin given at bedtime, primarily controlling **fasting (pre-breakfast)** glucose levels.- The **pre-breakfast** readings (6.5–8.0 mmol/L) and bedtime readings are not the primary issue, so increasing this dose would risk **nocturnal hypoglycemia** without directly addressing the pre-evening meal hyperglycemia.*Add a second dose of insulin detemir in the morning*- Adding a morning basal dose would provide additional long-acting insulin, but the specific pattern points to a **prandial insulin deficit** at lunch.- Adjusting the rapid-acting insulin dose for a specific meal-related hyperglycemia is generally the most direct and appropriate first-line strategy.*Change from insulin detemir to insulin glargine*- Both **insulin detemir** and **insulin glargine** are long-acting basal insulins, with similar profiles.- Switching basal insulin types is typically considered for issues like frequent **nocturnal hypoglycemia**, significant **glucose variability**, or insufficient duration of action, not for targeted pre-meal hyperglycemia from a specific bolus deficiency.
Question 86: A 10-year-old girl with refractory focal epilepsy is being evaluated for potential epilepsy surgery. Video-EEG telemetry has identified a clear seizure focus in the right anterior temporal region. MRI brain shows right mesial temporal sclerosis. Neuropsychological testing reveals normal cognitive function. Which additional investigation is most important before proceeding with surgical evaluation?
A. Functional MRI to assess language lateralization (Correct Answer)
B. Repeat EEG after sleep deprivation
C. PET scan to identify areas of hypometabolism
D. Single-photon emission computed tomography (SPECT)
E. Genetic testing for epilepsy gene mutations
Explanation: ***Functional MRI to assess language lateralization***
- Before **temporal lobe surgery**, it is critical to determine **language dominance** to minimize the risk of post-operative deficits, especially if surgical margins are close to eloquent areas.
- **fMRI** provides a non-invasive alternative to the **Wada test** for assessing both language and memory lateralization in pediatric surgical candidates.
*Repeat EEG after sleep deprivation*
- The seizure focus has already been clearly identified in the **right anterior temporal region** through **video-EEG telemetry**, making repeat baseline studies redundant.
- **Sleep deprivation** is typically used to increase the yield of interictal discharges in patients with non-diagnostic initial studies, which is not the case here.
*PET scan to identify areas of hypometabolism*
- **FDG-PET** is most useful when the **MRI is normal** or when there is discordance between EEG and imaging findings.
- Since the MRI clearly shows **mesial temporal sclerosis** and matches the EEG focus, PET scan wouldn't change the management plan.
*Single-photon emission computed tomography (SPECT)*
- **Ictal SPECT** is used to localize the seizure onset zone by detecting focal hyperperfusion but is reserved for **MRI-negative cases** or discordant data.
- In this patient, the **MRI and EEG are concordant**, so additional localization studies are not the priority over functional mapping.
*Genetic testing for epilepsy gene mutations*
- **Genetic testing** is indicated for specific syndromes or when there is no structural cause found; however, this patient has a clear **structural lesion** (**mesial temporal sclerosis**).
- Identification of a mutation would not alter the surgical necessity or the pre-surgical mapping requirements for a **symptomatic focal epilepsy**.
Question 87: A 11-year-old boy with type 1 diabetes is brought to the emergency department with vomiting, abdominal pain, and lethargy. Capillary blood glucose is 28.5 mmol/L. Urinalysis shows 3+ ketones. Blood gas analysis reveals: pH 7.15, pCO2 2.8 kPa, bicarbonate 8 mmol/L, base excess -18. He weighs 35 kg. According to current DKA management guidelines, what is the most appropriate initial fluid bolus?
A. 0.9% sodium chloride 350 mL over 60 minutes (Correct Answer)
B. 0.9% sodium chloride 700 mL over 15 minutes
C. 0.45% sodium chloride with 5% dextrose 350 mL over 60 minutes
D. 0.9% sodium chloride 175 mL over 30 minutes
E. Hartmann's solution 350 mL over 30 minutes
Explanation: ***0.9% sodium chloride 350 mL over 60 minutes***- According to **BSPED guidelines**, children in **Diabetic Ketoacidosis (DKA)** should receive an initial fluid bolus of **10 mL/kg** (350 mL for a 35 kg child) of **0.9% sodium chloride**.- The bolus must be administered slowly over **60 minutes** to reduce the risk of **cerebral oedema**, unless the patient is in clinical **shock**.*0.9% sodium chloride 700 mL over 15 minutes*- This dose corresponds to **20 mL/kg** and is given too rapidly; high volumes and rapid infusion are major risk factors for **cerebral oedema** in children.- Rapid boluses over 15 minutes are reserved only for patients in **hypovolaemic shock** with signs of circulatory collapse.*0.45% sodium chloride with 5% dextrose 350 mL over 60 minutes*- **Hypotonic solutions** and **dextrose** should not be used for the initial fluid resuscitation bolus in DKA.- Dextrose is only added to the maintenance fluids once the blood glucose levels fall below **14 mmol/L**.*0.9% sodium chloride 175 mL over 30 minutes*- This represents a weight-based dose of **5 mL/kg**, which is lower than the recommended initial bolus of **10 mL/kg** for DKA management.- While caution is needed, **10 mL/kg** is the standard protocol to begin correcting dehydration before starting fixed-rate **insulin infusion**.*Hartmann's solution 350 mL over 30 minutes*- Although Hartmann's is a balanced crystalloid, **0.9% sodium chloride** is the preferred and standard recommended fluid for the initial bolus in paediatric **DKA protocols**.- The infusion rate of **30 minutes** is twice as fast as the recommended **60-minute duration** intended to prevent rapid osmotic shifts.
Question 88: A 5-year-old boy with newly diagnosed childhood absence epilepsy is being considered for treatment. He experiences 15-20 absence seizures daily, each lasting 5-10 seconds, significantly impacting his schooling. His neurological examination is normal and EEG shows classical 3 Hz spike-and-wave discharges. His mother is concerned about medication side effects. Which aspect of his condition makes treatment most strongly indicated at this time?
A. The high frequency of seizures affecting educational development (Correct Answer)
B. The risk of progression to generalized tonic-clonic seizures
C. The need to prevent cognitive decline from repeated seizures
D. The requirement for treatment before starting school activities
E. The potential for spontaneous remission being low without treatment
Explanation: ***The high frequency of seizures affecting educational development***- In **childhood absence epilepsy (CAE)**, treatment is primarily indicated when the frequent seizures result in **functional impairment**, significantly disrupting **learning and educational progress**.- Experiencing 15-20 daily seizures, each causing a brief **loss of awareness**, means the child is missing critical instructional periods, directly impeding his **academic performance**.*The risk of progression to generalized tonic-clonic seizures*- While a minority of children with CAE may eventually develop **generalized tonic-clonic seizures (GTCS)**, this potential future risk is not the most immediate or primary indication for starting treatment.- The decision to initiate medication is more strongly driven by the **current impact** of the absence seizures on the child's daily life and schooling.*The need to prevent cognitive decline from repeated seizures*- Absence seizures, even if frequent, are generally not associated with **progressive cognitive decline** or permanent brain damage over time.- Treatment aims to improve **attention and focus** by reducing seizure frequency, thereby enhancing learning and participation, rather than preventing a decline in innate **cognitive abilities**.*The requirement for treatment before starting school activities*- Treatment for CAE is indicated when seizures are **symptomatic** and interfere with a child's **development and daily functioning**, not merely as a prerequisite for school activities.- Children with very infrequent or mild absence seizures might not require immediate **pharmacological intervention** to participate in school.*The potential for spontaneous remission being low without treatment*- This statement is **incorrect**; a substantial proportion (approximately **70-80%**) of children with CAE achieve **spontaneous remission** by adolescence, often irrespective of early treatment.- Medication is used to manage acute symptoms and improve **quality of life** during the active phase of the disorder, not to fundamentally alter the long-term **natural history** or likelihood of remission.
Question 89: A 13-year-old girl with type 1 diabetes for 5 years presents to clinic. She uses an insulin pump (continuous subcutaneous insulin infusion). Over the past 3 months, her HbA1c has risen from 58 mmol/mol to 75 mmol/mol. Her insulin pump download shows frequent meal boluses being administered but basal rates appear unchanged from 3 months ago. She has grown 4 cm and gained 3 kg during this period. Which factor is most likely contributing to her deteriorating glycaemic control?
A. Development of insulin pump malfunction
B. Inadequate basal insulin rates for increased body mass (Correct Answer)
C. Coeliac disease affecting insulin absorption
D. Deliberate insulin omission (diabulimia)
E. Development of insulin antibodies
Explanation: ***Inadequate basal insulin rates for increased body mass***- During **puberty** and periods of rapid **growth** (4 cm and 3 kg in 3 months), total daily insulin requirements significantly increase due to the effects of **growth hormone** and sex hormones on insulin sensitivity.- The pump download confirms **unchanged basal rates** despite increasing body mass, indicating that the baseline insulin supply is no longer sufficient to maintain **glycemic control**.*Development of insulin pump malfunction*- **Pump malfunction** or infusion site failure typically leads to **acute hyperglycemia** and a high risk of **diabetic ketoacidosis (DKA)** rather than a gradual 3-month rise in HbA1c.- Frequent meal boluses being recorded in the download suggests the device is operational and being utilized by the patient.*Coeliac disease affecting insulin absorption*- **Coeliac disease** reduces the absorption of **carbohydrates** from the gut, which typically results in unexplained **hypoglycemia** and a decrease in insulin requirements.- It does not affect the absorption of **subcutaneous insulin**, but rather the metabolic demand for it based on nutrient intake.*Deliberate insulin omission (diabulimia)*- The pump download shows that **frequent meal boluses** are still being administered, which argues against systemic, deliberate **insulin omission** for weight control.- Patients with **diabulimia** often show a pattern of missed boluses and weight loss, whereas this patient has **gained weight** and is actively using the pump.*Development of insulin antibodies*- The development of clinically significant **insulin antibodies** is extremely rare with the use of modern **recombinant insulin analogues**.- This would not be the primary suspicion in a growing adolescent compared to the physiological demand for **dose titration** during puberty.
Question 90: A 7-year-old girl with focal epilepsy has been taking carbamazepine 200 mg twice daily for 18 months with good seizure control. She now presents with progressive unsteadiness, double vision, and drowsiness over the past week. Examination reveals horizontal nystagmus and ataxia. Her mother reports no recent illness or medication changes. Blood tests show: carbamazepine level 58 micromol/L (therapeutic range 20-50 micromol/L), sodium 128 mmol/L, normal renal and liver function. What is the most appropriate immediate management?
A. Reduce carbamazepine dose and monitor symptoms (Correct Answer)
B. Stop carbamazepine immediately and start levetiracetam
C. Continue current dose and treat with fluid restriction
D. Add sodium valproate to improve seizure control
E. Perform urgent brain MRI to exclude posterior fossa pathology
Explanation: ***Reduce carbamazepine dose and monitor symptoms***
- The patient presents with classic signs of **carbamazepine toxicity**, including **ataxia**, **nystagmus**, **diplopia**, and drowsiness, supported by a serum level of 58 micromol/L (above the therapeutic range).
- A dose reduction is the most appropriate immediate step to alleviate these symptoms and manage the associated **SIADH-induced hyponatremia** (128 mmol/L) without risking the withdrawal seizures associated with abrupt discontinuation.
*Stop carbamazepine immediately and start levetiracetam*
- Abruptly stopping an anticonvulsant after long-term use, especially in a patient with previously well-controlled epilepsy, carries a significant risk of precipitating **status epilepticus** or breakthrough seizures.
- While toxicity is evident, the drug should be **tapered** or its dose reduced rather than stopped suddenly, unless there is a life-threatening allergic reaction like Stevens-Johnson syndrome.
*Continue current dose and treat with fluid restriction*
- Continuing the current dose directly ignores the primary cause of the patient's symptoms, which is **dose-dependent toxicity** confirmed by the elevated serum drug levels.
- While fluid restriction is a treatment for **hyponatremia**, it does not address the neurological symptoms caused by the **toxic concentration** of carbamazepine itself.
*Add sodium valproate to improve seizure control*
- The patient previously had **good seizure control**, indicating that adding another antiepileptic drug is unnecessary and could increase the risk of **drug-drug interactions** and further side effects.
- Sodium valproate can inhibit the metabolism of certain drugs, which could potentially worsen the existing **carbamazepine toxicity**.
*Perform urgent brain MRI to exclude posterior fossa pathology*
- Although neurological symptoms like ataxia and nystagmus can be indicative of posterior fossa pathology, the presence of an **elevated carbamazepine level** and characteristic signs of drug toxicity provide a clear medical explanation for the symptoms.
- An **urgent brain MRI** is not the initial most appropriate step when a clear pharmacological cause for the symptoms has been identified.
