(BMJ)—A 59-year-old woman with HTN complained of R eyelid drooping with left gaze diplopia, dull R eye pain, and throbbing headache. Exam: R eye ptosis, mydriasis with sluggish reaction to light, lateral deviation, motor/reflexes WNL. A non-contrast head CT was negative. What’s the dx?
Preseptal cellulitis
Oculomotor nerve palsy
Myasthenia gravis
Horner syndrome
Miller-Fisher syndrome
You are correct. Oculomotor nerve palsy (ONP) is characterized by ipsilateral ptosis, ophthalmoplegia, diplopia, mydriasis and impaired pupillary light reflex. Shortly after exam in the ED, the patient had a tonic-clonic seizure and emergent CT showed diffuse subarachnoid hemorrhage and ruptured posterior communicating artery. Intracranial aneurysm is a leading cause of isolated ONP. Diabetic peripheral neuropathy is the second most common cause of ONP. Ptosis may be due to periorbital infection or inflammation but typically has other associated s/sx. Myasthenia gravis is usually bilateral, and Miller-Fisher syndrome is associated with progressive, ascending sx. Horner syndrome is associated with miosis (vs. mydriasis).

The patient underwent emergent external ventricular drainage and clipping of aneurysm. She was discharged stable 10 weeks later.

Emergency Medicine Journal 2023;40:19-55
A 25-yo woman w/ type 1 DM calls your office to report higher-than-usual glucose readings on her FreeStyle Libre continuous glucose monitor (CGM) over the past day. She uses a multi-dose insulin regimen, and her A1c 3 weeks ago was 6.7%. She was in her usual state of health until developing a mild URI 2 days ago, at which point she implemented her sick day plan and started taking vitamin C 1000 mg daily, plus an OTC sugar-free guaifenesin/dextromethorphan/phenylephrine syrup. You ask her to check a fingerstick glucose, and she notes that it's significantly lower than the current reading on her CGM. What's the most likely cause of this discrepancy?
failure of her CGM sensor
phenylephrine
dextromethorphan
guaifenesin
vitamin C
You are correct. Several agents are known to interfere with the sensors of continuous glucose monitors (CGM), causing spurious readings. Checking a fingerstick blood glucose, as in this case, can rule out true hyperglycemia. Those interfering substances are listed in Chapter 7 of the American Diabetes Association’s 2023 Standards of Care in Diabetes and vary according to the specific CGM. They include:

Dexcom G6: acetaminophen >4 g/day, hydroxyurea

Medtronic Guardian: acetaminphen (any dose), alcohol, hydroxyurea

FreeStyle Libre: ascorbic acid (vitamin C) >500 mg/day

Senseonics Eversense: mannitol, tetracycline


SOURCE: ADA 2023 Standards of Care in Diabetes
A 48-yo woman w/ T2DM and hypertension presents after suffering a symptomatic hypoglycemic episode earlier in the day. Her A1c last month was 7.6%. She takes metformin, glipizide, valsartan, and rosuvastatin. She called the office two days ago with typical UTI symptoms and was prescribed ciprofloxacin. Which of the following interactions with ciprofloxacin is likely responsible for her hypoglycemic episode?
rosuvastatin
metformin
valsartan
glipizide
You are correct. Sulfonylureas interact with a number of common antimicrobials, including: ciprofloxacin, levofloxacin, clarithromycin, fluconazole, metronidazole, and trimethoprim/sulfamethoxazole. The interaction can increase the effective dose of sulfonylurea by 3-fold or greater, causing hypoglycemia. Holding or reducing the sulfonylurea during antimicrobial treatment is reasonable.

Free full-text JAMA Internal Medicine article at PubMed Central