Foot Drop

FOOT DROPFOOT DROP

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The Case of Mr. A.The Case of Mr. A.

• 40 year old man40 year old man

• Self-employed systems administratorSelf-employed systems administrator

• Divorced Divorced

• Lives with girlfriendLives with girlfriend

• R handedR handed

• Presented with a 2 week history of Presented with a 2 week history of back pain and difficulty walkingback pain and difficulty walking


HPCHPC

• 2 weeks prior to admission2 weeks prior to admission– Lower back pain ( more on R)Lower back pain ( more on R)– Started tripping and falling ( no injury)Started tripping and falling ( no injury)– Urinary incontinence “ dripping”Urinary incontinence “ dripping”– Presented to ER , on examination weakness of Presented to ER , on examination weakness of

R ankle dorsiflexion foundR ankle dorsiflexion found– CT: mild discopathy L3 - S1 without suspicion CT: mild discopathy L3 - S1 without suspicion

of root compressionof root compression– Discharged with recommendation to continue Discharged with recommendation to continue

investigation as out-patientinvestigation as out-patient


HPC IIHPC II

• Following dischargeFollowing discharge– Continued to fall ( x4) with no injuryContinued to fall ( x4) with no injury– Urinary problems resolved spontaneouslyUrinary problems resolved spontaneously

• 10 days later10 days later– Loss of anal sphincter controlLoss of anal sphincter control– Unaware of passing stool except for smellUnaware of passing stool except for smell– No change in state of legNo change in state of leg– Presented to ER 3 days later with no changePresented to ER 3 days later with no change


HPCIIIHPCIII

• Patient deniesPatient denies– Urinary problemsUrinary problems– Erectile dysfunctionErectile dysfunction– Sensory disturbancesSensory disturbances– Arm or left leg weaknessArm or left leg weakness– Definable psychological trauma in Definable psychological trauma in

previous yearprevious year


PMH IPMH I

• Age 9Age 9– Hospitalised for 1 yearHospitalised for 1 year– According to patient unable to move legs According to patient unable to move legs

with total anaesthesia below waistwith total anaesthesia below waist– Possibly associated with sphincter Possibly associated with sphincter

disturbancedisturbance– “ “ no diagnosis found”no diagnosis found”– Spontaneously recovered under Spontaneously recovered under

interesting circumstances !interesting circumstances !


PMH IIPMH II

• Similar episodes recurred at least 3 Similar episodes recurred at least 3 times:times:– Aged 11 yearsAged 11 years– Aged 14 yearsAged 14 years– Aged 17 yearsAged 17 years

• Each episode would last a few hours Each episode would last a few hours and was usually hospitalised and and was usually hospitalised and discharged without a diagnosisdischarged without a diagnosis


PMH IIIPMH III

• Aged 32Aged 32– Following mother’s death had episode of Following mother’s death had episode of

feeling legs “ frozen” below kneesfeeling legs “ frozen” below knees– Resolved spontaneously after arriving in ERResolved spontaneously after arriving in ER


PMH IVPMH IV

• Aged 35Aged 35– Hospitalised with DVT + SVT left legHospitalised with DVT + SVT left leg– Treated with heparin and then warfarinTreated with heparin and then warfarin– ““Borderline” homocysteine ( according Borderline” homocysteine ( according

to pt)to pt)•14 nmol / ml ( 0-15)14 nmol / ml ( 0-15)


PMH IVPMH IV

• 4 months prior to admission4 months prior to admission– Admitted to Neurology wardAdmitted to Neurology ward– Left leg superficial thrombophlebitisLeft leg superficial thrombophlebitis– Global weakness right arm ( 4/5)Global weakness right arm ( 4/5)– Distal > Proximal weakness Left legDistal > Proximal weakness Left leg– Reflexes ++ symmetricalReflexes ++ symmetrical– No pyramidal singsNo pyramidal sings– Sensory loss “ stocking” on leftSensory loss “ stocking” on left– NCV + LP normalNCV + LP normal– Weakness improved spontaneously Weakness improved spontaneously


Social HistorySocial History

• Smokes 1 pack / daySmokes 1 pack / day

• Divorced 2 years ago following Divorced 2 years ago following marriage of 8 months ( infidelity of marriage of 8 months ( infidelity of partner)partner)

• Currently lives with girlfriend of 3 Currently lives with girlfriend of 3 monthsmonths

• No childrenNo children

• Self- employed, business going wellSelf- employed, business going well


Examination in ERExamination in ER

• CN’s intactCN’s intact

• Tone intactTone intact• Power Power

– Preserved in arms and L LegPreserved in arms and L Leg– Weakness R leg Weakness R leg

• DFDF• INVINV• EVEV• PF preservedPF preserved

• ? Decreased right achilles reflex? Decreased right achilles reflex• No pyramidal signsNo pyramidal signs


Examination in ER IIExamination in ER II

• Sensory examinationSensory examination– Inconsistent sensory level T8Inconsistent sensory level T8– Decreased vibration sense R leg onlyDecreased vibration sense R leg only

• No cerebellar signsNo cerebellar signs• GaitGait

– Antalgic / paretic ( R Leg)Antalgic / paretic ( R Leg)

• Anal sphincter tone intact with Anal sphincter tone intact with normal perianal sensationnormal perianal sensation


During hospitalisationDuring hospitalisation

• No nursing observations regarding No nursing observations regarding sphincter disturbancessphincter disturbances

• One episode of fever > 38.0One episode of fever > 38.0• Request to receive heparin injections for a Request to receive heparin injections for a

DVT he suspects he has developedDVT he suspects he has developed• Episodes of sudden loss of power in both Episodes of sudden loss of power in both

legs associated with “ knees giving way”legs associated with “ knees giving way”• Inconsistencies between examinersInconsistencies between examiners• No real change in right leg functionNo real change in right leg function


Examination follow-upExamination follow-up

• CN’s intactCN’s intact

• Tone intactTone intact• Power Power

– Preserved in arms and L LegPreserved in arms and L Leg– Weakness R leg Weakness R leg

• TA, EHL, EDBTA, EHL, EDB• Proximal strength preserved includingProximal strength preserved including

– GluteiGlutei– HamstringsHamstrings

• INV, EV, PF preservedINV, EV, PF preserved• Reflexes symmetricalReflexes symmetrical• No pyramidal signsNo pyramidal signs


Examination follow-up IIExamination follow-up II

• Sensory examination normalSensory examination normal

• No cerebellar signsNo cerebellar signs

• Gait variable “ foot drop” on RGait variable “ foot drop” on R

• Preserved perianal sensation and Preserved perianal sensation and anal reflexesanal reflexes


Investigations 1Investigations 1

• CBCCBC• ESRESR All normalAll normal• BiochemistryBiochemistry• LPLP

– Pressure 8Pressure 8– TP 192 mg / lTP 192 mg / l– Glu 3.5Glu 3.5– 2 lymphocytes2 lymphocytes

}


Investigations 2Investigations 2

• Electrophysiology 3 weeks following Electrophysiology 3 weeks following onsetonset– Normal peroneal CV ( 56 m/s)Normal peroneal CV ( 56 m/s)– Normal EDB and TA CMAPs below and Normal EDB and TA CMAPs below and

above fibular head ( EDB CMAP = 9.0 mv)above fibular head ( EDB CMAP = 9.0 mv)– No spontaneous activityNo spontaneous activity– Normal unitsNormal units– Little / no voluntary recruitmentLittle / no voluntary recruitment


Electrophysiology Electrophysiology timescalestimescales• Conduction blockConduction block

– Occurs within daysOccurs within days– Demyelinative / early axonal lesionDemyelinative / early axonal lesion

• CMAP’sCMAP’s– Should decrease by 1 week in axonal lesions Should decrease by 1 week in axonal lesions

( Wallerian degeneration)( Wallerian degeneration)

• Fibrillations / PSW’sFibrillations / PSW’s– Occur at 7 –21 days ( “ active denervation”)Occur at 7 –21 days ( “ active denervation”)

• Large polyphasic MUP’sLarge polyphasic MUP’s– Occurs after 2-3 months ( “ chronic denervation”)Occurs after 2-3 months ( “ chronic denervation”)


Investigations 3 Investigations 3

• Brain CT : normal Brain CT : normal – ( 2 ½ weeks following onset)( 2 ½ weeks following onset)

• MRI lumbosacral regionMRI lumbosacral region


DD of Foot-dropDD of Foot-drop• MuscleMuscle• NMJNMJ• NerveNerve

– Deep peronealDeep peroneal– Common peroneal Common peroneal – SciaticSciatic– Lumbosacral plexusLumbosacral plexus

• L5 radicualopathy ( rarely L4)L5 radicualopathy ( rarely L4)• Motor neuronMotor neuron• Cerebral lesion ( cortical / subcortical)Cerebral lesion ( cortical / subcortical)• Non-organicNon-organic


Two types of disc herniation.

Dorsolateral –a, lateral -b


Dorsal view of the lumbar spine and sacrum showing different types of disc herniation


LUMBOSACRAL PLEXUS


COMMON PERONEAL NERVE


Sural nerve


Sensory loss in common Sensory loss in common peroneal nerve lesionsperoneal nerve lesions


Sensory loss in deep Sensory loss in deep peroneal nerve lesionsperoneal nerve lesions


Weight loss predisposes}


DD of Foot-dropDD of Foot-drop• MuscleMuscle• NMJNMJ• NerveNerve

– Deep peronealDeep peroneal– Common peroneal Common peroneal – SciaticSciatic– Lumbosacral plexusLumbosacral plexus

• L5 radicualopathy ( rarely L4)L5 radicualopathy ( rarely L4)• Motor neuronMotor neuron• Cerebral lesion ( cortical / subcortical)Cerebral lesion ( cortical / subcortical)• Non-organicNon-organic


DD of Foot-dropDD of Foot-drop• MuscleMuscle Sudden onset, unilateral, restricted, Sudden onset, unilateral, restricted,

rarely rarely causes foot-drop as major causes foot-drop as major featurefeature

• NMJNMJ Focal, no fluctuations, rarely causes foot-Focal, no fluctuations, rarely causes foot-drop drop as major featureas major feature

• NerveNerve– Deep peronealDeep peroneal– Common peroneal Common peroneal – SciaticSciatic– Lumbosacral plexusLumbosacral plexus

• L5 radiculopathy ( rarely L4)L5 radiculopathy ( rarely L4)• Motor neuronMotor neuron normal EMGnormal EMG• Cerebral lesion Cerebral lesion Rare cause of foot-drop, no other Rare cause of foot-drop, no other

UMN UMN signs, normal Head CTsigns, normal Head CT• Non-organicNon-organic Explanation of documented DVT?Explanation of documented DVT?

Absence of motor and sensory involvement expected to be associated with various syndromes

Normal NCV / EMG with profound weakness ( at 3 weeks)


Deep Venous Thrombosis: Risk Factor Deep Venous Thrombosis: Risk Factor Assessment and DiagnosisAssessment and Diagnosis

Emergency Medicine Review 1996Emergency Medicine Review 1996

“Be alert for psychiatric patients or prisoners who may tie a tourniquet around their thigh to produce factitious DVT.”


Non-Organic disordersNon-Organic disorders• Somatoform disorders Somatoform disorders

– Patient believes they have a real disorderPatient believes they have a real disorder• Somatisation disorder ( IBS, palpitations etc)Somatisation disorder ( IBS, palpitations etc)

– Over-interpretation of real physiological Over-interpretation of real physiological phenomenaphenomena

– Often reflect an affective disorderOften reflect an affective disorder• Conversion disorder ( hysterical blindness etc)Conversion disorder ( hysterical blindness etc)

– Loss of physical functioningLoss of physical functioning– Usually follows acute stressUsually follows acute stress

• HypochondriasisHypochondriasis– More disease-centered than somatisation disorderMore disease-centered than somatisation disorder

• Factitious disorder ( Munchausen)Factitious disorder ( Munchausen)– Intentional production / reporting of clinical features in Intentional production / reporting of clinical features in

order to enter sick-role…Motives unknown to patientorder to enter sick-role…Motives unknown to patient• MalingeringMalingering

– Intentional production / reporting of clinical features for a Intentional production / reporting of clinical features for a conscious concrete gainconscious concrete gain


Munchausen SyndromeMunchausen Syndrome

• Baron MunchausenBaron Munchausen– Served in German Army against Turkey Served in German Army against Turkey

(1700’s)(1700’s)– Told “ wild and wonderful stories” of life Told “ wild and wonderful stories” of life

as an adventurer and soldieras an adventurer and soldier– Most stories untrueMost stories untrue– Stories were not medically directedStories were not medically directed


Munchausen syndrome IIMunchausen syndrome II

• 3 Major presentations3 Major presentations– HaemorrhagicHaemorrhagic– AbdominalAbdominal– NeurologicalNeurological

• TriadTriad– Dramatic presentationDramatic presentation– Falsely elaborating symptomsFalsely elaborating symptoms– Travel to a number of medical institutionsTravel to a number of medical institutions


Munchausen Syndrome IIIMunchausen Syndrome III

• Often acquire medical knowledgeOften acquire medical knowledge– Health care professionalsHealth care professionals– Independent researchIndependent research– Previous hospitalisationsPrevious hospitalisations

• Usually like to remain on familiar medical ground

• Explanation of clinical pattern?


Possible evolutionPossible evolution• Initial 1 year hospitalisation as a child with Initial 1 year hospitalisation as a child with

paraplegia with subsequent frequent relapsesparaplegia with subsequent frequent relapses• Became aware of concept of stasis as a cause for Became aware of concept of stasis as a cause for

DVTDVT• Factitious DVTFactitious DVT• Attempt to reproduce factitious DVT results in Attempt to reproduce factitious DVT results in

SVT only…patient exaggerates weakness in SVT only…patient exaggerates weakness in region of painful area….sent to neurologistregion of painful area….sent to neurologist

• Hospitalisation in neurology dept, becomes Hospitalisation in neurology dept, becomes aware of concept of foot-dropaware of concept of foot-drop

• ? asked about back-pain, sphincter disturbances ? asked about back-pain, sphincter disturbances – May have gained knowledge from earlier May have gained knowledge from earlier

hospitalisations hospitalisations • Presents with a triad of foot-drop, back pain, Presents with a triad of foot-drop, back pain,

sphincter disturbances sphincter disturbances


Thank you!Thank you!

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Foot Drop

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