Congenital Variation Of Left Transverse Sinus Anatomy -Source Of Diagnostic Error

Presentor : Dr. S. Tejaswi

Designation : Student

Hospital : Andhra Mahila Sabha Hospital, Hyderabad

Date of Presentation : 21.10.2015

A 26 year old postnatal woman

Referred from another hospital.

She is para1 live1 abortion 1, post LSCS in her 4th

post op day

She was discharged on 4th day and was advised to

get reviewed after 3 days for suture removal.

Congenital Variation Of Left Transverse Sinus Anatomy - Source Of Diagnostic Error

Case History

She got readmitted in the same hospital for

generalized tonic clonic seizures for 2 min duration.

No bowel or bladder incontinence

She was conscious in the postictal period for about 15

min, after which she had 4 similar episodes without

regaining consciousness in the inter ictal period.

Referred to our hospital for further management

She was brought to our hospital in an unconscious

state with continuing fits.

Found to have accelerated hypertension

1st pregnancy

– Conceived spontaneously.

– Found to have blighted ovum at 3rd month of

amenorrheoa for which pregnancy was terminated.

History of present pregnancy (2nd pregnancy)

– One and a half year after first pregnancy.

– Was being worked up for secondary sub fertility.

– She was diagnosed to be hypothyroid and was started on

tab.thyronorm 50mcg.

– She conceived with ovulation induction

Obstetric History

1st trimester :

– She was a booked case and had regular ante-natal checkups.

– Took folic acid supplementation and continued taking

tab.thyronorm 50mcg.

– Initial investigations done. antenatal profile normal.

– Early TIFA was normal.

– Uneventful first trimester

2nd trimester:

– Quickening felt at 20 weeks.

– Took iron and calcium supplementation.

– Two prophylactic doses of inj.TT taken.

– TIFA was normal

3rd trimester:

– Perceiving fetal movements well.

– Continued taking iron and calcium tablets

– GTT normal

– Growth scan was normal

– Found to have gestational hypertension and was started on tab

alpha methyldopa 250mg thrice daily.

– Uneventful

– She had elective cesarean section indication – breech

presentation

– Postnatally at the time of discharge,her BP was under control.

Menstrual History

– Regular cycles, adequate flow of 3-5 days duration

Past history:

– Diagnosed as hypothyroidism on tab thyronorm 50

mcg

– Not a known case of hypertension/diabetes/epilepsy

Past surgical history:

– No history of surgeries in the past

Personal history:

– Marital history: 3years of married life

– Diet : Mixed diet

– Normal appetite

– Adequate sleep

– Bowel and bladder habits regular

Family history:

– No significant family history

Patient drowsy but, arousable to deep pain stimulus, GCS-8,

E2V2M4

No pallor, icterus, cyanosis, clubbing, lymphadenopathy and

pedal edema

Afebrile

PR-84 per min BP-180/110 mmhg

RR-20 per min GRBS-104mg/dl

SpO2-96% in room air Breast and thyroid – Normal

General Examination

CVS- S1S2 – heard

RS- lungs clear

Per abdomen-soft, non tender, linea nigra present

uterus involuting well

Per vaginal – lochia healthy

Systemic Examination

CNS:

– Patient drowsy but arousable to painful stimulus

with GCS-8,E2V2M4

– Bilateral pupils normal size and reacting to light

– Deep tendon reflexes: 1+

– Plantars : bilateral mute

Systemic Examination

Hb-11.5gm%

TLC-8500/cmm

DC-N-80%,L-15%,M-

2%,E-3%

ESR-35mm per hr

Blood urea -24mg/dl

Investigations

Serum creatinine-1.0mg/dl

Serum sodium-144mmol/lt

Serum potassium-

3.ommol/lt

Serum chloride – 105

mmol/lt

CUE –pus cells – 6-8/HPF

Loading dose of magnesium sulphate followed by

maintenance dose given and monitored for 24 hrs

Antihypertensive –inj. labetalol 20mg iv stat given

Repeated every 15 min and a maximum of 220 mg was given

When BP decreased to about 150/100 mmHg, she was

shifted to oral tab. Labetalol 200mg tid

Treatment

Though her seizures got controlled, and she

regained consciousness

She was complaining of headache which was

holocranial so we planned for MRI with MRV brain

in order to rule out PRESS/CSVT

Diagnosis Using MRI of Brain

Diagnosis Using MRV of Brain

MRI Report

Observation By Interventional NeuroRadiologist

Normal Venous System Of Brain

Discussion

Hypoplasia of the left transverse sinus is the most common

anomaly

Two previous studies showed the incidence to be 24% and

31% of normal asymptomatic population respectively.

Mostly transverse sinuses are of unequal size, the sinus with

the more direct connection to the superior saggital sinus

being the larger.

The right transverse is more often a direct continuation of

superior saggital sinus.

MRI was the most reliable procedure to differentiate

lateral sinus hypoplasia from lateral sinus thrombosis.

Left transverse sinus hypoplasia can be demonstrated

by frank asymmetry in sizes of transverse portion of the

sinuses without any abnormal signal in the expected

course of the sinuses.

Lateral sinus thrombosis was indicated by increased

intraluminal signal on all planes and with all pulse

sequences

ReferencesCase Reports – 1

BMJ Case Reports 2014; doi:10.1136/bcr-2013-202937

Rare anatomical variation in transverse sinuses(duplication on right, hypoplasia of left) falselymimicking transverse sinus thrombosis probably due toresultant slow flow(http://casereports.bmj.com/content/2014/bcr-2013-202937.full)

Case Reports – 2

Cerebral MR Venography: Normal Anatomy and Potential Diagnostic Pitfalls (http://www.ajnr.org/content/21/1/74.abstract?ijkey=f40d26cf408a60000183ac0563db638a13707da4&keytype2=tf_ipsecsha)

Case Reports – 3

– Importance of Anatomical Asymmetries of

Transverse Sinuses: An MR Venographic

Study

(http://www.karger.com/Article/Abstract/79

960)

Points Which Can Help Us OutSide prevalence:

Hypoplasia and aplasiaare more common on left side compared to

right.

Calibre of sinus: viewing sinus on cross sections for example sagittal sections

for transverse sigmoid sinus, sinus with

hypoplasia / aplasia will be smaller in calibre.

Signals : No abnormal high signal in the region of sinus

on T2 and Flair. A thrombosed sinus will be bulky with

abnormal T2 high signal instead of normal T2 flow

void.

Territory of sinus: if its a venous infarct it should be on

the side, in the territory of concerned sinus and

adjacent to the sinus.

Post contrast study: In case of hypoplasia or aplasia of

sinus , there will be no enhancement in the region of

sinus or may see enhancement along the dural

converging of sinus which is normal. Where as in case

of thrombosed sinus the intra luminal thrombus will

show profuse enhancement.

Jugular foramen: side of hypoplastic sinus will be

smaller in diameter being poorly developed compared

to opposite side. MRI is sufficient, but CT bone window

images are the best for this.

Conclusion

Hypoplasia or aplasia of transverse sinus is a common

finding, whose incidence is around 30%.

Most commonly it is mistaken for CSVT and patients

were put on anticoagulants

The purpose of this case report is to emphasize the

importance of knowing normal venous drainage system

of brain and its asymmetries.

To avoid unnecessary medication it is important know

the normal variations in the venous system of brain.