A 50 year old retired nursing officer, Mrs. Anabelle, a known hypertensive patient with poor compliance, presents to you with sudden onset right sided weakness. The patient is alert, and well oriented in time, place and person, but appears worried and anxious.
First differential : Left sided acute stroke. The hypertensive history can point to a hemorrhagic stroke, however there are no pressure symptoms, sudden onset headache, seizures nor a reduced GCS. A NCCT is necessary to rule it out. The clinical picture is more suggestive of an ischemic stroke.
What should you do next? ……….
Suspecting an acute stroke, you plan for Immediate intervention:
- Transferred to the stroke unit of the hospital
- Initial ABC + GCS à All assessments normal
- Patient was connected to the cardiac monitor and pulse oximeter
A quick History taking : About the event - The patient reveals the following:
- Weakness noticed first upon waking up from sleeping
- Right sided arm and leg weakness – with the left side normal
- Right arm and leg are equally weak
- No slurring of speech, dysphagia, or vomiting
- No headaches, or seizures
- No LOC, loss of sensation
- No bladder or bowel dysfunction
The patient was initially taken to a primary care
unit (PCU) before arrival at your hospital. At the PCU, her blood pressure was
found to be 176/130 mmHg. She had then been given a STAT dose of Nifedipine
30mg oral prior to being referred to our clinic for further management.
Further questioning regarding past medical history
yields no significant information except for poorly controlled Hypertension and dyslipidemia for
the past 6 years.
What are you thinking of? ……….
You perform a quick physical examination:
1. - The patient is lying comfortably in
bed, though notably anxious
2. - She is afebrile + anicteric + no pallor
- Temp : 36.6°C
- BP : 164/120
- HR : 95 BPM
3. - No signs of respiratory distress
4. - No neck stiffness | Kernig’s sign
(-)ve
You perform a quick neurological evaluation:
1. Muscle power : R/ Upper Limb – 3/5 and R/ Lower Limb – 2/5
2.
Muscle tone : R/ side – mildly reduced
3.
Deep tendon reflexes on the R/ side reduced
4.
Plantar response – flexor
What are you thinking of? ……….
What do you do next? ……….
You decide to order an urgent NCCT + basic blood investigations:
- CBS : 5.1mmol/l (normal)
- FBC :
- Lymphocyte tot 0.9 x109/L 1.0-4.0 x109/L
- WCC 3.8 x109/L 4.0-11.0 x109/L
- Neutrophils 1.7 x109/L 2.0-8.0 x109/L
- Hb 130 g/L 125-175 g/L
- RCC 4.0 x1012/L 3.5-5.5 x1012/L (female)
- HCT 0.39 0.36-0.46 (female)
- Lipid profile : Normal
- AST/ ALT : Normal
The NCCT of the brain is normal.
A subsequent CECT
scan of the brain also does not reveal any space-occupying lesion. MRI of the
brain was not done due to facility unavailability.
What should you do next? …….
As the Neutropenia catches your eye, you ask
further questions from the patient regarding any past medical history that could
be significant. On questioning the husband of the patient, he reveals that Mrs.
Anabelle has been suffering from “some mental health issues” recently, and is
on treatment by a psychiatrist at a different hospital. On further examining the medical records, you
find that the current medical regime includes Lithium and Quetiapine.
What are you thinking of? ……..
A full serum electrolyte panel is ordered, along with TSH and Aldosterone and renin markers. You see the results below:
- Serum potassium 2.75 mmol/L 3.5–5.5
- Serum sodium 140 mmol/L 135–145
- Serum magnesium 2.0 mg/dL 1.7–2.2
- Serum chloride 105 mmol/L 98–107
- Serum bicarbonate 26.5 mmol/L 22–29
- Thyroid stimulating hormone 0.75 mU/L 0.51–4.30
- Plasma aldosterone conc 15 ng/dL 5–30
- Plasma renin activity 2.0 ng/mL/hr 0.7–3.3
- Aldosterone-to-renin ratio 9.0 <20
What do you see? ……..
- ST depression and T wave inversions best noted in inferior leads
- Prominent U waves
- A prolonged QT interval
What are you thinking of? ……..
An initial diagnosis of Hypokalemia is made. Most likely
iatrogenic onset due to administration of second-generation antipsychotics like
Quetiapine.
Management - Following intravenous administration
of 60 mEq
of potassium chloride, the right-sided weakness completely resolved after 48 hours,
with serum potassium level rising to 3.5 mmol/L.
Oral supplementation with potassium chloride 600 mg
TD was given afterwards.
A diagnosis of Hypokalemic Paralysis is confirmed.
1. Clinical Presentation: Hypokalemic paralysis
typically presents as an acute onset of symmetrical, flaccid muscle weakness
that predominantly affects the proximal muscles, particularly in the lower
limbs, while sparing the upper limbs to a lesser extent. However these features
can vary, as there are reports of patients who present with even more confusing
features like slurred speech, dysarthria and facial drooping!
2. Muscle and Sensory Involvement: Patients
usually retain consciousness, maintain normal bladder and bowel function, and
have preserved sensory functions. Bulbar, ocular, and respiratory muscles are
often spared, though rare cases of their involvement have been reported.
3. Neurological Examination Findings: During
paralytic episodes, classic neurological signs include reduced muscle strength,
hypotonia, and decreased or absent reflexes (hyporeflexia or areflexia).
4. Diagnostic Challenges: Due to its presentation,
hypokalemic paralysis can be misdiagnosed as an acute stroke, particularly in
patients with cardiovascular comorbidities, as the presentation overlaps with
common stroke symptoms.
5. Atypical Presentations: While hypokalemic
paralysis generally involves bilateral limb weakness, some cases have presented
with atypical features, such as monoparesis, adding to diagnostic complexity in
certain clinical scenarios.
Anything else? ……..
After initial stabilization and management, a full psychiatric reevaluation is necessary for this patient, with an in-depth review into medication dosing and compliance.
It was later also found that the patient had stolen supplies of Antipsychotics from the hospital (including Quetiapine) where she previously worked at as a Nursing officer.
Conclusion : Asymmetric or unilateral muscle weakness is an uncommon manifestation of hypokalemic paralysis. This atypical form can easily be mistaken for an acute stroke, especially in patients with existing cardiovascular risk factors. Therefore, clinicians should consider this possibility when assessing patients presenting with stroke-like symptoms to prevent delays in diagnosis and timely initiation of the correct treatment.
Happy Halloween!
- Prashan Perera -
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