Post-partum complications

Clinical History

A 22-year-old woman, who gave birth 5 days before, was admitted at the Emergency ward of our hospital suffering from headache, seizures, vision and motor deficits. She had hypertension and diabetes during pregnancy.

Imaging Findings

A CT examination revealed some subtle bilateral scattered hypodense foci in cerebellar and parieto-occipital lobes and nucleo-capsular regions. Venous CT angiography (not shown) demonstrated a patent venous system.
A MR confirmed the CT findings, showing a T2 hyperintensity of the described foci. There was no restricted diffusion.
Venous MR angiography was negative.
A 22-day follow-up MR examination showed a complete regression of the described findings.

Discussion

Posterior reversible encephalopathy syndrome (PRES) is characterised by an acute onset of several neurological symptoms (headache, seizures, altered mental status, visual disturbances). [1]
It can be determined by several causes, such as toxic agents (anti-tumoural drugs, immunosuppressive agents, cocaine abuse), sepsis, pre-eclampsia/eclampsia, autoimmune diseases, transplantation. [2, 3]
All these causes determine cerebral oedema, as the final result of the activation of pro-inflammatory cytokines with disruption of the blood-brain barrier, whether by an activation of the immune system (non hypertensive causes) or by an alteration of the autoregulation of the brain perfusion pressure with vasoconstriction, followed by a reactive release of vasodilator agents and an activation of the renin-aldosterone system (hypertensive causes). [2, 4]
Although the anamnesis and the clinical symptoms may suggest the syndrome, imaging is needed to make differential diagnosis in the first instance with cerebral venous sinus thrombosis and then with other causes (such as ischaemic or tumoural diseases) and to evaluate the extent of the oedema and the potential complications (infarction or haemorrhage [5]).
CT usually shows very subtle hypodense areas, which can be missed.
MRI is the gold standard as it allows evaluating the disease. A protocol should include T2 TSE, FLAIR, DWI, T1 with cm and a venous angiography.
T2-FLAIR: bilateral hyperintense lesions in the white matter;
DWI: usually no restricted diffusion (d.d. with infarction);
T1: usually no enhancement;
venous angiography: patent sinuses (d.d. with thrombosis).
Althogh classically described as "posterior", actually the oedema can show 3 different patterns plus an incomplete expression of the primary patterns, all almost equally recurrent: [2, 6, 7]
1. holohemispheric: involvement of frontal, temporal, parietal and occipital lobes as well as cerebellum and brainstem;
2. Superior frontal sulcus: main involvement of the superior frontal sulcus;
3. Dominant parietal-occipital: posterior aspect of supratentorial brain;
4. Partial expression of the three primary patterns: frontal and parietal oedema with sparing of the occipital lobes.
The treatment consists of removing toxic agents and treating hypertension and seizures. [2]
Usually the oedema and the symptoms regress in a few weeks.
Take-home messages:
- Always consider the syndrome when risk factors are present;
- An MRI is necessary to assess the diagnosis and to exclude other causes;
- Always include in the MRI protocol DWI (d.d. with infarction) and venous angiography (d.d. with venous thrombosis);
- A follow-up MRI is necessary to evaluate the evolution of the disease (potential complications).

Differential Diagnosis List

Final Diagnosis

Posterior reversible encephalopathy syndrome

URL:	https://eurorad.org/case/10878
DOI:	10.1594/EURORAD/CASE.10878
ISSN:	1563-4086