Hot Seat Case 128: 11yo with seizures
Posted on: March 25, 2019, by : Mary Beth Howard
Nicole Barbera, MD, INOVA Fairfax Children’s Hospital with Sarah Combs, Children’s National Medical Center
HPI: 11 yo previously healthy, fully vaccinated, premenarchal female presents with “shaking” episode in the context of 2 days of fever, sore throat and headache. Patient reported to be flu and rapid strep negative the day prior in PCP office. She vomited 5 times on the day of presentation without diarrhea. Upon arrival of EMS, the patient was noted to be “staring off” and then full body shaking including all extremities for 15-20 seconds. No significant post-ictal period and the patient was back to baseline immediately. Her mother stated “everyone at school is sick.”
ROS: No abdominal pain, diarrhea, neck pain. Denies any apnea or cyanosis or injuries during the episode.
PMHx: Immunization up to date, denies any previous similar episodes, no history of migraines
PSHx: None
Allergies/Meds: NKDA. Took Motrin earlier that day for fever and headache. No daily medications.
Family Hx: no family history of seizures or neurologic disorders
Social Hx: lives with parents and brother, attends regular school.
Physical Exam
Vitals: BP 93/50, HR 85, Temp 98.8, RR 18, SaO2 98% on room air, Wt 28 kg
General: Alert. Appears well-developed and well-nourished. Active and appropriately answering questions and following commands for age. No distress.
Head: Normocephalic. Atraumatic.
Ears: Tympanic membranes without swelling or erythema bilaterally.
Nose: No nasal discharge.
Mouth/Throat: Mucous membranes are moist. Pharynx is normal without erythema or exudate. No oral lesions or lacerations.
Eyes: Pupils are equal, round, and reactive to light. Conjunctivae and EOM are normal.
Neck: Normal range of motion. Neck supple. No neck rigidity or neck adenopathy.
Cardiovascular: Normal rate, regular rhythm, S1 normal and S2 normal. Pulses 2+. No murmur. Capillary refill < 2 seconds.
Pulmonary/Chest: CTABL. No wheezes, rhonchi or rales. No retractions.
Abdominal: Soft. Bowel sounds are normal. No distention, mass, hepatosplenomegaly or tenderness.
GU: Normal external female genitalia.
Musculoskeletal: No edema or deformity.
Neurological: Awake and alert. No cranial nerve deficit. Normal muscle tone. 5/5 bilateral UE and LE strength. Sensation grossly intact. Normal gait.
Skin: Skin is warm and dry. No rash noted.
A workup is initiated with BMP. Patient administered Zofran and NS 20mL/kg bolus.
Labs result with Na+ 122, K+ 3.4, Cl- 90, bicarb 22, BUN 7.0, Cr 0.5, glucose 127, calcium 8.4
UA and urine sodium were sent at this point.
At 2 am the mother calls you into the room stating “she’s asking to leave the room to get things that don’t make sense”. When asked, patient oriented to person but disoriented to place. without other changes to her vital signs or neuro exam.
The information in these cases has been changed to protect patient identity and confidentiality. The images are only provided for educational purposes and members agree not to download them, share them, or otherwise use them for any other purpose
FYI, a serum K of 90 is not compatible with human life :-). I realize that this was a typo (= the Cl value). But, seriously, the K would be essential to know as this could be an Addisonian (salt-wasting) crisis (which presents with low serum Na and high K; also Type IV RTA). However, most likely, this is simply an adolescent with intravascular volume loss who is drinking free water to rehydrate — a case of the Syndrome of Appropriate (not Inappropriate) ADH (SAADH). The urine Na concentration and urine OSM will easily distinguish between an Addisonian crisis (high urine Na) and ADH excess (low urine Na; higher urine OSM than serum OSM). The only other thing to consider (with the history of headache), is that could the low serum Na be secondary to cerebral salt wasting. Hence, I might push to get a Head CT.
Ah, the dreaded hyponatremia and appropriate fluid correction problem. In terms of what started it all, now that we know K=3.4, I’d agree with Dewesh that we’re likely looking at an excess of free water intake relative to solute loss. Unless of course we’re both missing the point here and the fever/sore throat/headache prodrome is simply a red herring leading us down an acute infection pathway while what we’re actually dealing with is the unmasking of a more subacute/ insidious process (central, malignant, etc).
The case progression suggests the development of hyponatremic encephalopathy. Being prepubertal places this patient at higher risk of cerebral injury in the setting of brain edema (reduced Na-K-ATPase activity compared with the mature brain). Presuming this is an acute hyponatremia, correcting the sodium is key given that severe sequelae (seizure, AMS) have already set in. I’d vote for judicious use of hypertonic, aiming to increase the Na by 1-2 per hour for the initial 6 hours or so.