Good morning and welcome to your Tuesday dose of Your Daily Meds.
Bonus Review: What are platelets? Where do they come from? Where do they go?
Answer: Well, platelets are small cellular fragments (2-4 micrometer diameter) that ‘bud off’ from megakaryocytes in the bone marrow. They have a life span of 8-12 days circulating in the blood. Mostly, old and abnormal platelets are removed by macrophages in the spleen.
Kids Case:
A 16-year-old female is brought to the Emergency Department with persistent vomiting for the last 2-days.
She reports a history of malaise and fatigue for some months.
On examination, she is haemodynamically unstable with a blood pressure of 90/60 mmHg and pulse rate of 130/min.
Her serum sodium is 117 mmol/L (135-145), her serum chloride is 75 mmol/L (95-110) and urinalysis is normal.
Which of the following is the most likely diagnosis?
* 21-hydroxylase enzyme deficiency
* Addison’s disease
* Chronic fatigue syndrome
* Phaeochromocytoma
* Chronic reflux nephropathy
Sheesh. Have a think.
Remember some physiology.
Scroll for the chat.
Query:
A 52-year-old female presents to the Emergency Department with fever, right upper quadrant pain and jaundice. After a surgical consult, empiric antibiotics are administered while further investigations are organised. Which of the following is the most suitable empiric antibiotic regimen in this case?
* Intravenous gentamicin and intravenous amoxycillin
* Intravenous metronidazole
* Oral amoxycillin and clavulanate
* Oral trimethoprim and sulfamethoxazole
* Intravenous amoxycillin
Have a think.
More scroll for more chat.
The Crisis
This girl has features of an Addisonian crisis (Addison’s Disease gone bad in a time of physiological stress), including vomiting, circulatory decompensation with hypotension, hyponatraemia and hypochloraemia. The hypotension is likely due to the lack of adrenal steroid production in a time of stress.
21-hydroxylase enzyme deficiency is a cause of salt-losing congenital adrenal hyperplasia. It causes a defect in the glucocorticoid pathway and so results in a deficiency of cortisol and aldosterone. It normally manifests at an early age, often in the neonatal period.
Chronic fatigue syndrome does not present with haemodynamic instability and investigation results are often normal.
Phaeochromocytoma classically presents with episodes of palpitations, hypertension and anxiety and is unlikely to give the clinical history in this case.
Chronic reflux nephropathy may account for the serum abnormalities but is more likely to present as normotensive or hypertensive.
Right Upper:
Key to answering this question is recognising the likelihood diagnosis of cholangitis. Fever, right upper quadrant pain and jaundice is consistent with Charcot’s triad in the description of cholangitis.
The recommended empiric therapy for suspected cases of cholangitis is intravenous gentamicin and intravenous amoxycillin (or ampicillin).
Plus having a chat with some surgeons…
It is recommended that, if the results of susceptibility testing are not available within 72 hours and empiric therapy is still required, the gentamicin-containing regimen should be ceased and replaced with ceftriaxone, cefotaxime, piperacillin and tazobactam or ticarcillin and clavulanate.
In patients with signs and symptoms of cholangitis with a history of chronic biliary obstruction, metronidazole should be added to regimes containing gentamicin and ceftriaxone or cefotaxime.
Therapy should be changed to oral administration after clinical improvement and sensitivity testing.
Thus, of the options listed, intravenous gentamicin and intravenous amoxycillin is the most suitable empiric antibiotic regimen in this case.
Bonus: What do platelets do?
Answer in tomorrow’s dose.
Closing:
Thank you for taking your Meds and we will see you tomorrow for your MANE dose. As always, please contact us with any questions, concerns, tips or suggestions. Have a great day!
Luke.
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Just credit us where credit is due.
