ABSTRACT

Acute neuromuscular paralysis is one of the common neurological emergencies, of which Guillain Barre Syndrome (GBS) remains the most common cause. This syndrome presents with acute ascending muscle weakness and loss of deep tendon reflexes (DTR), often preceded by distal paresthesia and back pain. However, a severe hypokalemia may have a similar presentation and put the treating physician in dilemma.

We report a 42-year-old previously healthy man, who presented with acute areflexic ascending quadriparesis associated with impending respiratory failure. This followed a one day history of frequent diarrhea, vomiting and low grade fever. A provisional diagnosis of GBS was given by the treating physician and the patient was intubated for ventilatory support. A few hours later the serum potassium and magnesium were reported to be very low, so the patient was given parenteral potassium chloride (KCl), later supplemented with magnesium. Following KCl infusion, the patient’s neurologic and respiratory conditions improved dramatically and he was extubated .Despite continued KCL infusion; however, the patient suddenly sustained cardiac arrest and expired, which is attributable to multiple electrolyte disturbance especially low potassium and low magnesium, it’s important to bear in mind that in 5% of the cases GBS is associated with autonomic dysfunction.

Even though severe hypokalemia related muscle weakness reported rarely, it is a potentially treatable and correctable cause of neuromuscular weakness. Therefore treating physician should have this in mind whenever faced with such acute areflexic ascending weakness associated with hypokalemia, especially in resource limited setup like Ethiopia, where it’s difficult to have comprehensive emergency work up for such patients to differentiate possible causes of acute generalized weakness.

Keywords: Cardiac arrest, Guillain-Barre syndrome, Hypokalemia, Hypomagnesemia.

INTRODUCTION

Guillain-Barre syndrome includes a spectrum of autoimmune polyradiculoneuropathy in which peripheral nerve myelin is the major target. The prototype variant is acute inflammatory demylinating polyneuropathy (AIDP).The onset can be sudden, unexpected and may progress very rapidly to cause respiratory failure, especially in some variants like Acute Motor Axonal Neuropathy (AMAN), so prompt and early recognition as well as ventilator support have significant advantage in reducing both mortality and morbidity which are much higher than the typically reported 5% (10) in resource limited countries like Ethiopia (4).

Guillain-Barre syndrome commonly follows minor infectious illness like acute gastroenteritis, upper respiratory infection, some vaccinations. Recent outbreaks of Zika infection in South America and in the United States suggests an association of GBS with the Zika virus as well (3). Although GBS is the most common cause of acute flaccid quadriparesis in the United States, a retrospective study done by Zenebe et al highlights the importance of GBS as a cause of peripheral nerve disease in Ethiopia as well (4). The typical presentation of GBS is acute progression of ascending limb weakness and areflexia with minimal sensory deficit and intact bladder function, unless there is associated severe autonomic dysfunction at presentation (2,7).However, patients presenting to emergency department with acute flaccid weakness may have a wide differential diagnosis including neurological disorders such as GBS and myasthenia gravis, metabolic diatheses including hypokalemia, and infectious causes. Since any of the above may have symptoms similar to those found in GBS, a rapid certain diagnosis may be difficult. Even though acute hypokalemia induced areflexic weakness is a rare disorder, it is a potentially treatable and reversible cause of acute ascending areflexic muscle weakness (9)

CASE REPORT

A 42 year-old healthy male was brought to emergency room of Tikur Anbessa Specialized Tertiary Hospital (TASH) by his family with rapidly progressing, ascending weakness of all four extremities of 10 hours duration. During that time he was also having increasing difficulty breathing. He gave a history of frequent watery diarrhea, vomiting, and low grade fever a day prior to onset of the weakness. This followed attendance at a wedding ceremony in Addis Ababa, and at the onset of diarrhea with subsequent weakness he visited a local health center that referred him to TASH after they gave him unspecified oral medications for diarrhea. The patient denies any history of recent vaccination, flu symptoms or exposure to barium or any other drugs. He denied history of similar weakness in the past and had no history of chronic illness. His social history is pertinent for occasional khat chewing but he denies drinking any alcohol. There was no history of loss of consciousness, abnormal body movement, urinary retention or incontinence.

On physical examination the patient was fully conscious, but in acute respiratory distress wearing a face mask with high oxygen flow supplementation. His blood pressure was 100/70mmg, pulse 94 and regular, temperature 37.5 centigrade, and respiratory rate 40, labored but with a peripheral capillary oxygen saturation of 94%. On respiratory system examination there was visible use of use of accessory muscles and single breath count of 8.Neurologic examination revealed flaccid quadriparesis (lower extremity > upper extremity) with absent deep tendon reflexes and bilateral equivocal plantar responses. Examination of sensory and cranial nerves as well as spinal vertebrae revealed no abnormality. No evidence of Tick bites on body examination.

After considering this examination with his history of ascending weakness and preceding acute gastroenteritis, a provisional diagnosis of ascending GBS with impending type 2 respiratory failures was made, and the patient was intubated for ventilatory support. He was kept in the emergency department since there was no bed available in the intensive care unit (ICU). Analyses of blood samples sent for electrolyte and complete blood count testing returned after 2 hours revealed low potassium (K+ = 2.5mEq/L, normal 3.7 – 5.2) and magnesium (Mg++ = 1.2 mg/dL, normal 1.7 – 2.2), and mild hyponatremia (Na+ = 132mEq/L, normal 136 – 144), this mild hyponatremia could be explained by hypovolemic hyponatremia, due to diarrhea and vomiting, subsequent repeat of serum electrolyte was not done. His complete blood count was normal. Arterial blood gas testing was not available.

Following this patient was given parenteral potassium chloride (40milliequivalents in 1000 milliliters normal saline over 4 hours) supplemented with magnesium sulfate. After 4 hours potassium was infused at typical maintenance levels. Following the first dose of potassium supplementation, the patient’s muscle power and respiratory condition markedly improved, so that he was successfully extubated. He was then able to support himself and chat with his family. Plans for further testing including nerve conduction studies, spinal MRI, and CSF analysis were deferred, and he was kept in the emergency department overnight, with complete metabolic evaluation planned for the next morning. However, the patient suddenly sustained cardiac arrest and passed away, due to cardiac arrest secondary to fatal cardiac arrhythmia, despite 20-30 minute Cardio respiratory resuscitation (CPR), as patient was given standard replacement dose of KCL the risk of hyperkalemia induced cardiac arrhythmia is low.

DISCUSSION

Acute neuromuscular weakness with associated respiratory failure is not an uncommon problem to emergency departments all over the world, including Ethiopia. The differential diagnosis includes neurological problems, metabolic disorders and infectious disease (8).Guillain-Barre syndrome is the most common cause, classically presenting with initial symptoms of distal paresthesia and back pain followed by ascending, areflexic extremity weakness, occasionally progressing to involve cranial nerves (CN VII,IX,X). It also commonly affects respiratory muscles, making it one of the neurologic emergency disorders (2,7). The diagnosis of GBS is mainly clinical, utilizing criteria of the National Institute of Neurologic Diseases and Stroke (NINDS) criteria (6) supporting evidence including albuminocytologic dissociation in cerebrospinal fluid (high protein with low cell count) and absent or prolonged F-waves with electrophysiological testing are very useful, although they are typically positive after 1-2 weeks respectively(7).

In our patient, the clinical presentation and physical findings had similarity with Guillain Barre Syndrome, although more typically weakness progresses over several days in GBS, rather than the rapid involvement of upper extremity muscles and respiratory muscles, within few hours of symptom onset in this patient. Moreover, the presence of low grade fever on admission speaks against GBS, as usually patients with GBS had fever days or weeks prior to onset of the symptoms (2,7). A preceding history of respiratory tract infection or diarrhea and vomiting occurs in more than 50% of GBS patients, but these commonly occur 3 days to 6 weeks before of GBS symptoms, rather than within 1 day as with our patient(7). Above all, the dramatic improvement of both neurologic and reparatory symptoms following potassium infusion favors the rarely occurring manifestation of hypokalemia. The fact that our patient suddenly sustained cardiac arrest and passed away could be attributed to high frequency of cardiac arrhythmia accompanying hypokalemia and hypomagnesemia. This is supported by Vandana et al (9) in which they report a case with hypokalemia induced muscle weakness, in which the patient had an episode of ventricular tachycardia had resuscitated with an injection of lignocaine and direct current shock (9).

This is the first case report of hypokalemic induced quadriparesis mimicking GBS in Ethiopia to the authors’ knowledge. Our emergency department has limited ability to detect fatal cardiac arrhythmia, and limited capacity to reverse such an arrhythmia. However, this case demonstrates the importance of having this alternative diagnosis to GBS when facing a rapidly ascending quadriparesis; and to do the best they can do to diagnose it, and thus reverse both the weakness and an otherwise fatal condition.

Acute hypokalaemic paralysis is a clinical syndrome characterized by acute ascending, areflexic extremity weakness associated with low serum potassium. It is a rare but treatable cause of acute weakness (8) Extensive review of literature revealed only three case reports in which the patients had presented like GBS, but later the cause was found out to be hypokalemia and respond well to potassium supplementation (5). The most prominent clinical features of hypokalaemia are neuromuscular, although other systems, such as cardiovascular and gastrointestinal, may also be affected. Some patients complain of muscular weakness, especially of the lower extremities, while marked and generalized weakness of skeletal muscles is common with more severe potassium depletion. If potassium depletion is very severe it may lead to total muscular paralysis including respiratory, bulbar and cranial musculature, and deaths from respiratory failure and arrhythmia have been reported (8). A wide variety of conditions may result in hypokalemia, due either to alteration in transcellular distribution of potassium or actual potassium depletion from renal or extrarenal – mainly gastrointestinal – losses. Our patient demonstrates this, with frequent watery diarrhea and vomiting a day prior to onset of his symptoms.

Most reported cases are due to a transcellular shift of potassium and possibly associated with familial periodic paralysis. This is an autosomal dominant condition in 70% of patients, sporadic in the rest, and manifests as sudden recurrent episodes of painless weakness (5). Our patient’s presentation did not seem to fit this condition because familiar periodic paralysis typically has an early onset, rarely after age 25, and our patient never had similar illness in the past. Another consideration is thyrotoxic periodic paralysis, although our patient had no history of thyrotoxicosis. The patient also denied exposure to barium, barium containing rat poisons, or renal disease.(8).Thus hypokalemia is a well known cause of muscle weakness if rarely reported. It shares similar clinical features with GBS, and is otherwise commonly overlooked in differential diagnosis of a patient who presents to the emergency department with acute neuromuscular weakness (7).In our particular case it was detected not by thinking of hypokalemia as a possible etiology of acute systemic weakness, but just to complete the available work up for the patient as routine activity.

CONCLUSION

The take home message from this case report is, every physician and intensivist working in emergency room, especially in resource limited setup like Ethiopia, where it’s difficult to have comprehensive emergency work up to differentiate possible causes of acute generalized weakness, consider hypokalemia and other severe electrolyte disturbance as possible treatable differential diagnosis, whenever they are faced with a patient presenting to ER with acute ascending, flaccid quadriparesis without sensory deficit, and should determine serum electrolyte for every such patient. If a potentially reversible or correctable metabolic abnormality such as hypokalemia can be quickly identified such patients may not need ventilation, unnecessary investigations, and costly interventions like intravenous immunoglobulin, usually given to patients with GBS. In addition, even though the differential for pure motor weakness is vast one has to think of multifocal motor neuropathy with conduction block, especially if the presentation is insidious and asymmetrical. A diagnosis of hypokalemic paralysis should always be considered if a patient having hypokalemia presents with sudden onset, areflexic, pure lower motor patter weakness in one or more limbs, with no change in mentation or sphincter function.

Abbreviations
– GBS – Guillain-Barre syndrome
– AIDP – Acute inflammatory demylinating polyradiculoneuropathy
– TASH – Tikur Anbessa Specialized Hospital
– AMAN – Acute Motor Axonal Neuropathy
– ER – Emergency Room

Declarations:

1- Ethics approval and consent to participate

– Ethical approval of obtained from department of neurology, Addis Ababa University, the approval letter is available, to relevant authority request.
– Since this is a case report , consent to participate was not obtained, but consent to publish was obtained from the brother of the patient was obtained, since the patient passed away, the bother of the deceased was communicated via a phone call made by principal author.

2- Consent to publish

– Consent to publish was obtained from the brother of the patient and was filed in the patient medical record and copy was attached with this cover letter.

3- Availability of data and materials

– The data used to prepare this manuscript is available from the corresponding author on reasonable request.

4- Competing interest

– The author declares that they have no competing interests.

5- Funding

– No funding was received from any organization or individuals.

6- Authors contributions

a. All authors are involved in:-

• Evaluation, diagnosing and management of this patient.
• Drafting the manuscript & revising it critically for important intellectual content.
• All authors given final approval of the version to be published.
• All authors agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

7- Acknowledgement

– The authors, would like to acknowledge Head of department of Department of Neurology, Addis Ababa University Dr. Seid Ali, for his continuous support and facilitation of approval of this manuscript by department ethical committee.
– We are also grateful to family of the patient for their willingness and cooperation on giving consent for publication.