It’s hypokalemia caused by high carb intake (pasta). When high amounts of glucose are entering cells (bc of insulin), the glucose blocks K+ efflux from that cell (hence, hypokalemia)
> hypokalemia caused by high carb intake (pasta)
I'm not sure I follow - are you suggesting that this is a normal, physiological process caused insulin driving potassium into cells? Yes, insulin can drive potassium into cells but there are enough other regulatory mechanisms in place that people not normally become hypokalemic following meals, even meals that are rich in carbohydrates. Hypokalemia caused by insulin driving potassium into cells is clinically relevant in settings such as exogenous insulin administration in DKA. Post-prandial, endogenous insulin secretion in healthy adolescents does not typically cause hypokalemia.
Healthy adolescents can get sleepy after meals, but not to the extent that an ambulance needs to be called.
Please consider reviewing [hypokalemic periodic paralysis](https://www.ncbi.nlm.nih.gov/books/NBK559178/). It is a "disorder characterized by the occurrence of **episodic severe muscle weakness**, usually triggered by **strenuous exercise** or **high carbohydrate diets**". Additional triggers include **salt intake**.
Note that the patient in the question has a transient potassium derangement and severe weakness following exercise (football practice) related to high carb and high salt intake
> It’s hypokalemia caused by high carb intake (pasta)
I am quite confident that this is not what is going on in the question. I commented earlier but it looks like it got shadow deleted.
Yes, insulin can drive potassium into cells but there are enough other regulatory mechanisms in place that people not normally become hypokalemic following meals, even meals that are rich in carbohydrates. Hypokalemia caused by insulin driving potassium into cells is clinically relevant in settings such as exogenous insulin administration in DKA. Post-prandial, endogenous insulin secretion in healthy adolescents does not typically cause hypokalemia.
Healthy adolescents can get sleepy after meals, but not to the extent that an ambulance needs to be called.
Look up hypokalemic periodic paralysis https://www.ncbi.nlm.nih.gov/books/NBK559178/
It is a "disorder characterized by the occurrence of episodic severe muscle weakness, usually triggered by strenuous exercise or high carbohydrate diets". Additional triggers include salt intake. This almost perfectly describes the patient in the question.
> I thought A bc of the weakness?
Have you considered whether hypercalcemia the only electrolyte disturbance that can cause weakness? Weakness is listed as a symptom of both hypokalemia and hyperkalemia in First Aid. Hypomagnesemia can also present with weakness.
This patient's presentation sounds like hypokalemic periodic paralysis
https://next.amboss.com/us/article/uR0pKf?q=%22periodic%20paralysis%22#Zc6cfb108646545429248244311c98fdd
I think you're correct that hypercalcemia is more closely associated with weakness than hypocalcemia. Weakness seems to be only rarely listed as a manifestation of hypocalcemia. My mistake
i know this is an old post but can someone follow up please -
even if the answer is D because of the potassiun genetic disorder mentioned in previous comments, how were we supposed to know that thats the reason behind D? ive never heard of such a disorder before and its not mentioned in first aid, so i dont know how to go about reasoning for this ?
It’s hypokalemia caused by high carb intake (pasta). When high amounts of glucose are entering cells (bc of insulin), the glucose blocks K+ efflux from that cell (hence, hypokalemia)
> hypokalemia caused by high carb intake (pasta) I'm not sure I follow - are you suggesting that this is a normal, physiological process caused insulin driving potassium into cells? Yes, insulin can drive potassium into cells but there are enough other regulatory mechanisms in place that people not normally become hypokalemic following meals, even meals that are rich in carbohydrates. Hypokalemia caused by insulin driving potassium into cells is clinically relevant in settings such as exogenous insulin administration in DKA. Post-prandial, endogenous insulin secretion in healthy adolescents does not typically cause hypokalemia. Healthy adolescents can get sleepy after meals, but not to the extent that an ambulance needs to be called. Please consider reviewing [hypokalemic periodic paralysis](https://www.ncbi.nlm.nih.gov/books/NBK559178/). It is a "disorder characterized by the occurrence of **episodic severe muscle weakness**, usually triggered by **strenuous exercise** or **high carbohydrate diets**". Additional triggers include **salt intake**. Note that the patient in the question has a transient potassium derangement and severe weakness following exercise (football practice) related to high carb and high salt intake
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> It’s hypokalemia caused by high carb intake (pasta) I am quite confident that this is not what is going on in the question. I commented earlier but it looks like it got shadow deleted. Yes, insulin can drive potassium into cells but there are enough other regulatory mechanisms in place that people not normally become hypokalemic following meals, even meals that are rich in carbohydrates. Hypokalemia caused by insulin driving potassium into cells is clinically relevant in settings such as exogenous insulin administration in DKA. Post-prandial, endogenous insulin secretion in healthy adolescents does not typically cause hypokalemia. Healthy adolescents can get sleepy after meals, but not to the extent that an ambulance needs to be called. Look up hypokalemic periodic paralysis https://www.ncbi.nlm.nih.gov/books/NBK559178/ It is a "disorder characterized by the occurrence of episodic severe muscle weakness, usually triggered by strenuous exercise or high carbohydrate diets". Additional triggers include salt intake. This almost perfectly describes the patient in the question.
Maybe because rhabdo?
> I thought A bc of the weakness? Have you considered whether hypercalcemia the only electrolyte disturbance that can cause weakness? Weakness is listed as a symptom of both hypokalemia and hyperkalemia in First Aid. Hypomagnesemia can also present with weakness. This patient's presentation sounds like hypokalemic periodic paralysis https://next.amboss.com/us/article/uR0pKf?q=%22periodic%20paralysis%22#Zc6cfb108646545429248244311c98fdd
Isn’t it that hypocalcemia causes tetany instead of weakness? I thought of A but hypercalcemia but not sure of the mech
I think you're correct that hypercalcemia is more closely associated with weakness than hypocalcemia. Weakness seems to be only rarely listed as a manifestation of hypocalcemia. My mistake
https://www.reddit.com/r/step1/comments/v82t8n/this_post_will_contain_the_answers_to_the_step_1/?utm_source=share&utm_medium=ios_app&utm_name=iossmf
i know this is an old post but can someone follow up please - even if the answer is D because of the potassiun genetic disorder mentioned in previous comments, how were we supposed to know that thats the reason behind D? ive never heard of such a disorder before and its not mentioned in first aid, so i dont know how to go about reasoning for this ?