SCE QUESTION FELLOWSHIP EXAMINATION 2007



1. Lead examiner ………….…………………….….

2. Co-examiner …………..……………………….

SCENARIO

A 3 year-old boy is brought to your department by his mother with abdominal pain and vomiting. The mother is concerned that the child may have ingested some of her Iron (Ferrogradumet) tablets.

She is sure that there are more than 10 tablets missing from the bottle.

Each Ferrogradumet tablet contains 105mg of elemental Iron. Q1 included in stem.

Question 1: How would you clinically assess the risk of toxicity for this child?

|Expected Response |Details and Comments | |

|History |Number of tablets possibly taken and approximate time of ingestion |Weight and |

| |Inspect bottle if available |recognition of |

|Estimated body weight: |Calculate the amount of elemental Fe ingested per kg/body weight. |severity |

|14 - 15kg. |Toxic effects with 10 to 20mg/kg (unlikely) |essential |

| |Moderate toxicity with 20 to 60mg/kg | |

| |Severe toxicity with >60mg/kg | |

|Examination |Has symptoms of stage 1 toxicity |Focused exam |

| |Careful attention to vital signs: BP, HR, RR, capillary refill, Temperature, O2 sats |needed |

|Prompt: “What are the features of the |Signs of volume depletion, hypoperfusion, | |

|stages of Fe toxicity?” |Lethargy and hypotonia | |

Question 2: List and justify your investigations in this child.

|Expected Response |Details and Comments | |

|Determine severity of toxicity; complications; prognosis. Guide to Mx. |

| |Indicators of toxicity: | |

|Full blood evaluation |Leucocytosis |Essential |

| |Thrombocytosis | |

|Urea / Electrolytes |Renal impairment | |

| |K derangements from acidosis | |

| |High anion gap | |

|Blood glucose |Hyperglycaemia |Essential |

|Clotting profile |Bleeding diathesis | |

|Blood gas analysis |Metabolic / lactic acidosis |Essential |

|Serum Fe levels |- 300 to 500mcg/dl (50-90umol/l) = significant GI toxicity and mild systemic toxicity |Essential |

| |- 500mcg/dl (90umol/l) and above = significant systemic toxicity | |

| | | |

| |Serum Fe levels depend on time of ingestion and preparation; low levels. does not rule out toxicity. | |

| | | |

| |Correlation between leukocytosis, hyperglycaemia and elevated serum Fe levels are not yet established | |

| |TIBC = relatively meaningless in the setting of iron toxicity | |

|Plain Abdo XR |May confirm pills in the GI tract, and their location. | |

| |But only 50% sensitivity for Fe pills. | |

Question 3: Discuss the options for decontamination in this child.

|Expected Response |Details and Comments | |

|Depends on number of tabs ingested, and the period between ingestion and presentation. |

|Urgent consultation with Paed toxicology service. |

|Upper GI endoscopy |May remove large iron load, but will need multiple insertions |Essential |

|Whole bowel irrigation |Polyethylene glycol solution – 250 to 500mls/hr |Essential |

| |Cardiorespiratory support is critical should WBI be performed | |

|GI lavage |Requires ETT | |

| |Useful only within 60 minutes of ingestion | |

|Induced emesis contraindicated |Prompt: “What is the role of charcoal in this child?” |Essential |

|Activated charcoal not effective | | |

Question 4: Describe your specific Rx for Fe toxicity in this case.

|Expected Response |Details and Comments | |

|Desferioxamine |Chelating agent which binds primarily to free iron. Also to other Fe forms. |Essential |

| |Forms complex ferioxamine which is renally excreted. | |

|Dose |90mg/kg IV up to 1g | |

|Rate |5 to 15 mg/kg/hr. | |

|Complications |Neurotoxicity, renal impairment, pulmonary toxicity, ocular toxicity, ARDS | |

|Monitoring |Urine colour changes to rusty/brown: vin rose | |

|Duration |Controversial |Essential |

| |Recommended end points: | |

| |Clinical recovery, normal Fe levels, Fe to creatinine ratio, normalisation of the urine colour | |

| |Infusions exceeding 24 hours need careful monitoring owing to SEs | |

Question 5: These are the patient’s arterial blood gases. Describe and interpret them.

pH 7.30

pCO2 28 mmHg

pO2 120 mmHg

Bicarbonate 16 mmol/l

|Expected Response |Details and Comments | |

|Mild acidaemia | | |

|Moderate to severe metabolic acidosis |Anticipate high anion gap | |

|Partial resp compensation |Hyperventilation, respiratory alkalosis | |

|Oxygen tension > 100 mmHg |Probably on supplemental O2 | |

| |Unable to determine A-a gradient | |

| |Anticipate O2 dissociation curve shifted to right | |

|Signs of significant Fe toxicity |

Comments: (if you fail the candidate, please state why)

If the candidate fails the exam overall, what feedback would you suggest CIC provide for this SCE?

SCENARIO

A 3 year-old boy is brought to your department by his mother with abdominal pain and vomiting. The mother is concerned that the child may have ingested some of her Iron (Ferrogradumet) tablets.

She is sure that there are more than 10 tablets missing from the bottle. Each Ferrogradumet tablet contains 105mg of elemental Iron.

Question 1: How would you clinically assess the risk of toxicity for this child?

Question 5: These are the patient’s arterial blood gases. Describe and interpret them.

pH 7.30

pCO2 28 mmHg

pO2 120 mmHg

Bicarbonate 16 mmol/l

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Candidate Number

Final Mark:

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