1. “Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.”

2.  A 25 year old woman is brought to the emergency department after tripping during a volleyball match. Her teammate notes that she had been stumbling.  On arrival in ED, she can no longer raise her legs and labours to adjust herself in bed. She has also begun to complain of shortness of breath. She denies fever but states that three weeks ago the entire team suffered from abdominal cramps and diarrhoea after a championship BBQ  Hx  PMH: G1P1 with no complications  PSHx, All, FHx, CIGS, ALC – all nil  Examination:  T = 36.6oC; HR 50/min; RR 26/min; BP 90/60mm Hg  CVS, ABDO, Skin: NAD  RESP: poor inspiratory effort, lungs, airways clear  CN’s intact  Neuro upper limb (P: 3,3 10 sec, R:0+)  Neuro lower limb (P:1,1, R: 0+, S: pain and light touch diminished to her knees) “It is a capital mistake to theorise before one has data”

3.  Describe the accident (how did you land?)  First signs?  Duration?  Sexual Hx (?pregnancy, unsafe sex?)  Fever, sweats, night sweats, weight loss?  Urine output, fluid intake (dehydration?)  Headache, dizziness, nausea, photophobia?  Possible precipitating factors for the gastroenteritis (type of food?, recent travel?)

4.  Kernig’s, Brudzinski's  Fundoscopy looking for pappiloedema

5.  Spirometry  Pulse O2%  LP for protein in CSF  Clostridium jejuni serum Ig and stool culture  CT/ MRI brain and spine  ECG  FBC  Urea and electrolytes  Qual. B-HCG test  Nerve conduction testing

6. FBC NAD, ELFTs NAD urine HCG neg, MRI brain & spine NAD CSF: Appearanceclear WBC1 cells/mm 3 (<5) 65%lymphs, 25% PMNs, 10% monos RBC3 cells/mm 3 (none - few) Protein150mg/dL (15-40) Glucose65mg/dL (50 - 70 ½ to 2/3 blood glucose level) Gram stainnegative

7.  Firstly, is this a LMN lesion of UMN lesion?  The woman has decreased muscle tone (including muscles of respiration), absent muscle stretch reflexes and sensory disturbances. She is fully conscious although she looks quite weak – it’s probably not a problem with her brain; this suggests Lower Motor Neuron disease (if UMN would probably be unilateral with increased reflexes and tone).  Her lower limbs seem more affected than her upper limbs – ascending paralysis. She is not shown to be favouring one side – we can assume I think that she has bilateral weakness.  Interestingly her cranial nerves are all intact but her autonomic nervous system seems disrupted  Disorders of the brain that cause acute weakness include acute stroke, space occupying lesion, or an inflammatory or infectious processes. Stroke seems unlikely for so many reasons, and clinically, symptoms are not unilateral and not including speech changes, and altered mental status. A space occupying lesion would present with symptoms of decreased level of consciousness, headache, ophthalmoparesis/ blown pupil etc.

8.  Respiratory distress with poor inspiratory effort, tachypnoea BUT bradycardia and low BP!!!  Ascending flaccid paralysis within a short period (days or weeks, not months)  Reflexes absent  Cytoalbumin dissociation (increased protein with low cell count in CSF)

9.  Considering the woman’s history of abdominal infection/ food poisoning, the acutely ascending bilateral flaccid paralysis and areflexia, a diagnosis of Guillain-Barré Syndrome should be considered. GBS affects the population in a bimodal fashion (15- 35yrs and 50-75yrs).  Autonomic involvement in GBS is variable, and this may account for her bradycardia and hypotension. This diagnosis is supported by the elevated protein and the low number of cells in CSF.  The absence of fever is important, steering the diagnosis away from an infective one.  Pregnant ladies are at a higher risk of getting GBS, and the risk increases after delivery for about 2 weeks.  About 40% of GBS cases are found to have positive C. jejuni serum antibodies and/or stool cultures. There are 4 types of GBS - Acute Inflammatory Demyelinating Polyneuropathy (AIDP), Miller- Fisher variant, Acute Motor Axonal Neuropathy (AMAN) and Acute Motor-Sensory Axonal Neuropathy (AMSAN). AIDP is the most common subtype.

10.  What features indicate severity of this condition:  Rapid progression of paralysis  Poor inspiratory effort  The condition is a medical emergency because patient is at risk of respiratory failure as well as cardiac arrest due to autonomic failure (can you propose a mechanism for this?)

11.  Respiratory support (intubation, mechanical ventilation)  Cardiovascular support if needed  Plasmapheresis (plasma transfusion)  Intravenous immunoglobulin (IVIG)  Prednisone is ineffective  Expect partial recovery in 2-3 weeks with possibility of months of rehab followup  Mortality rate 2-5% (poor prognostic factors are older age, rate of progress of disease, level of autonomic dysfunction)

12. “There is nothing more deceptive than an obvious fact”