Pregnancy And Puerperium: Acute Neurological Disorders
Introduction
A variety of acute neurological disorders may be encountered during pregnancy and puerperium. Some are specific to the physiological process of reproduction (eclampsia, post-partum cerebral angiopathy, Sheehan’s and lymphocytic adenohypophysitis. ) and others are non specific but occur more often in pregnant women (infarction, CVT, pituitary apoplexy).
Pregnant women experience symptomatic improvement of migraine headache during pregnancy. However headache remains the most common symptoms experienced during pregnancy and puerperium. Thus the development of acute headache should be viewed seriously . There is a considerable overlap between clinical features of various neurological disorders affecting CNS during pregnancy. There is a general tendency for delayed diagnosis of uncommon but serious condition during pregnancy because of reluctance of performing appropriate timely imaging .
This article surveys the spectrum of neurological disorders with their typical and atypical imaging features during the course of pregnancy and puerperium, thereby familiarising the imagiologist and treating physicians to necessitate timely imaging and treatment for optimized better maternal and fetal outcome.
Materials and methods
A hospital based cross-sectional study of MRI Brain was conducted in the Department of Radiodiagnosis, SSIMS &RC, Davangere for a period of 1 year from January 2017-2018 on 105 women during their pregnancy and puerperium presenting with neurological complaints. Inclusion criteria: MRI of Brain was performed in 105 women, suspected of acute neurological disorders during pregnancy and puerperium.
Exclusion criteria: The patients who were unwilling for study and those with contra-indications for MRI imaging were excluded from the study.
MR Imaging Protocol: MR imaging was performed on a 1. 5 Tesla 16 channel MR system with dedicated head coil. MRI of brain was performed with standard brain protocol which included: Axial T2, Coronal and axial FLAIR, DWI, Sag T1, GRE/ SWAN, Inhance MR Venography, TOF MR angiography for Circle of Willis sequences were performed. Post gadolinium contrast imaging was done in unequivocal cases.
Results
Women in the age group of 24-26 years constituted the most common group among the total 105 patients. i. e. 24. 7%. Out of 105 patients 82 patients (79%) presented in puerperal period (Figure:2). In puerperal period 46 out of 82 patients presented at day 5-day 10 of puerperium(accounting to 56% of patients during the peurperium) .
Most common clinical symptom in our study population was headache, accounting for 50. 4% of our study population followed by seizure 29(27. 6%), neurological deficit, (9. 5%), decreased responsiveness(6. 6%) and altered sensorium (5. 8%). PRES was the most common neurological disorder in our study (accounting for 36% ) of acute neurological disorder followed by CVT (accounting for 22. 8% of acute neurological disorder ), CVA (8. 2%), SAH (6. 6%), meningitis (4. 7%), Wernicke’s encephalopathy and pituitary disorders( accounting for 1. 9%).
We also characterised 3 imaging patterns of posterior reversible encephalopathy syndrome, which was the most common neurological disorder, accounting for 36. 1% of cases.
- Typical feature-bilateral symmetrical T2 and FLAIR hyperintensities with no diffusion restriction on MRI.
- Bilateral symmetrical T2 and FLAIR hyperintensity with subtle diffusion restriction on MRI.
- Bilateral symmetrical T2 and FLAIR hyperintensity with foci of hemorrhage.
Typical imaging features were seen in 27 out of 38 patients (accounting for 71%) and 11 out of 38 patients showed atypical imaging features (accounting for 29%).
When PRES was analysed based on the region involved, more than one region was involved in majority of the cases. Occipital region was the most commonly involved, (30 out of 38 patients) followed by parietal lobe (24 out of 38 patients). Only 1 patient had brainstem involvement.
Among 24 patients with CVT, 11 of them (44%) presented with only venous thrombosis with no significant brain parenchymal changes. Eight of them (32%) presented with hemorrhagic infarct and rest 5 of them (24%) presented with non-hemorrhagic infarct. 8 patient in our study presented with cerebro-vascular accident (CVA). 5 of them were with ischemic infarct, accounting for 62. 5% of CVA and rest 3 were with hypertensive stroke, accounting for 37. 5% of CVA. The atypical venous haemorrhagic infarct secondary to CVT were not included in CVA and only the typical hypertensive hemorrhage was included.
Discussion
A wide range of neurologic conditions can affect women during pregnancy and puerperium. The acute neurological disorders encountered in our study were grouped under cerebrovascular disorders and others (pituitary and metabolic disorders). The patients in our study were between the age group of 18-39. Maximum of them presented between 24-26 age (24. 5%).
In a study by Sarella et al the range of age in their study was 17-31years. In our study majority of the patients presented during puerperium with 56% of them presenting at 5-10days postpartum. Most disorders in a study by Gupta S et al were encountered in the peripartum period and they attributed it to noncompliance, physical exhaustion or metabolic derangements during the puerperal period. In a study by Sarella et al majority of patients presented during pregnancy with a small percentage presenting at puerperal period. Headache was the main clinical symptom encountered in our study followed by seizure, neurologcal deficits, decreased responsiveness and altered sensorium.
In the study by Sarella et al 49% of their patients presented with seizure. The most common acute neurological disorder encountered in our study was Posterior reversible encephalopathy syndrome (36. 1%) followed by cerebral venous thrombosis (22. 8%), cerebrovascular accidents (8. 2% ), SAH (6. 6%), Meningitis (4. 7%), Wernicke’s encephalopathy (1. 9%) and Pituitary disorder (1. 9%). The findings were similar to the study conducted by Magudeeswaran et al.
In a study conducted by Hiremath et al, CVT was the most common neurological entity encountered. The incidence of eclampsia in the developing world is reported to be 1 in 100 to 1 in 1700 pregnancies. The mechanism of posterior reversible encephalopathy syndrome in eclampsia is still debatable with predilection for posterior circulation explained by sparse vasomotor sympathetic innervations.
The current study showed that PRES is the most common acute neurological disorder in women during pregnancy and puerperium accounting for 36%. These patients who underwent MR Brain with features of PRES showed 3 patterns of imaging characteristics
- Typical imaging features of PRES, ie: Bilateral symmetrical T2/FLAIR hyperintensity with no diffusion restriction.
- PRES with subtle diffusion restriction.
- PRES with few foci of hemorrhage.
Typical features were seen in 71% of cases. In eclamptic encephalopathy most commonly involved brain regions are parieto-occipital, frontal, temporal and sometimes even cerebellar hemispheres with atypical cases even basal ganglia, thalamus & brainstem were involved.
In our study predominantly parieto- occipital lobe involvement was seen. The regions involved were similar to the study by Hiremath et al. In study conducted by Richard B et al. , in 20 patients with eclamptic encephalopathy, most commonly involved region was occipital lobe followed by parietal lobe . Two patients in his study showed changes in the cerebellum . In another study conducted by Bartynki et al, parieto-occipital lobe was involved most commonly (98%) followed by frontal lobe (68%) and cerebellar hemisphere s(32%).
Cerebral venous thrombosis refers to thrombosis on intracranial venous channels including dural venous thrombosis, cortical venous thrombosis and deep vein thrombosis. CVT may occur anytime during the course of pregnancy and the puerperium, but the risk is highest during the first 2 weeks of the puerperium. CVT accounts for 6% of maternal deaths and highest being for young mothers and after caesarean section. The clinical presentation varies depending on the severity and extent of thrombosis as well as the mode of onset. It may vary from headache to coma. In sepsis cavernous and lateral sinus thrombosis are mostly involved whereas superior sagittal sinus is most commonly involved in non-septic CVT.
MRI is more sensitive in picking up lesions and their extent than CT. Diagnostic merit of MRI can be enhanced by performing MR venography (MRV) with contrast or without contrast using TOF time of flight sequences. In our study majority (44% of patients with CVT) of patients presented with only venous thrombosis without brain parenchymal changes. In study by Hiremath et al out of 17 patients with cerebral venous thrombosis only three patients showed no parenchymal changes. 32% of the patients with CVT in our study had haemorrhagic infarct and 24% with ischemic infarct.
Being hyper coagulable state, women in pregnancy and peurperium are population prone for both ischemic and hemorrhagic stroke. Strokes, both ischemic and hemorrhagic are major contributor to morbidity and mortality during pregnancy and the puerperium. The overall incidence of ischemic stroke during pregnancy and postpartum is low (3. 5-5 per 100 000 pregnancies in the developed world) . But it has to be considered that when compared to stroke in the young as a broader group those related to pregnancy accounted for 12% to 35% of events in this otherwise low-risk population.
In our study only 8. 8% of patients presented with CVA with Ischemic stroke (63. 5%)being predominant over hemorrhagic. Meningitis and menigoencephalitis are common in peripartum period due to obstetric spinal anaesthesia and secondary to retained products of conception leading to sepsis. Patients presents with complaints of fever, headache and seizures. Out of 105 patients, 5 patients had features of menigoencephalitis with enhancing meninges & parenchymal signal changes on contrast enhanced MRI.
Conclusion
The dynamic changes occurring during pregnancy and puerperium may induce a variety of non-obstetric complications in central nervous system. A deep understanding of the imaging findings associated with these various conditions and their patho physiological relevance to pregnancy is needed. It is important for radiologist to make the distinction between the benign and more serious neurologic signs, symptoms, and complications seen in pregnant and puerperial period and thus allowing clinicians for more precise and early diagnosis.
