Blog with interesting cases and/or problems related to anesthesia with discussion based on best evidence in the literature.

October 1, 2012

post partum headache after history of CSE

This case presentation is not a case I did, but one posted on Sermo, an online community of physicians with a variety of experiences.  The case is one in which a 28 y/o F presents to the ED 5 days  post partum with a significant headache.  She has had one episode of emesis but is otherwise asymptomatic with normal physical exam. She states that her headache is worse when she stands, but is not significantly improved in the supine position.  The ED doc ordered a CBC which shows a very slight WBC increase with mild neutrophil shift.  Importantly, her BP on being admitted was 200/100 mmHg. This imroved to 170's/89 mmHg with hydralazine. 

It is very common for anesthesiologists to be consulted by the ED for headaches, but in most case the ED doc is requesting technical help with placement of an epidural blood patch.  As physician consultant, it is important to consider all of the important possible causes of headache given the patient and their circumstances.  To arrive and without further consideration perform a bloodpatch could result in harm to the patient if not indicated and does a diservice to our specialty.

In this case, the patient is post partum.  It is important to understand that pre eclampsia can present several days after delivery and can lead to full blown eclamptic seizures if not managed agressively in a patient with severe pre eclampsia.  So, while PDPH is unlikely to result in acute harm to the patient, pre eclampsia with a neurological component can be harmful to the patient.  Other serious illnesses to include on a differential or at least be aware of include: SAH, posterior reversible encephalopathy syndrome, venous sinous thrombosis, and hypertensive encephalopathy. 

Briefly, a quick review of the most likely causes of this headache will be reviewed in the literature. Pre eclampsia indeed is on the differential despite the post partum status of this patient.  Unfortunately, pre eclampsia can present in a variety of ways.  Nevertheless, this patient's significant headache with slight elevation of liver enzymes, trace protein, and significantly elevated BP demands intervention.  Initial treatment should include efforts to lower blood pressure using something like hydralazine or labetalol.    A loading dose of MgSO4 + infusion is also important and probably should be done in consultatin with Ob/Gyn.  If the headache improves with the lowering of blood pressure and Mg therapy, it may lend one to accept the unual presentation of pre eclampsia in the post partum patient.

PDPH is possible.  PDPH is a result of intracranial hypotension and while can be dangerous (in some cases reports of SAH), this disease process is  benign and self limiting.  Therefore, any invasive treatment of this disorder is not recommended at this point.  Other self limiting and often less serious causes of headache in this woman could include simple migraine or tension headache. Less commonly, pseudotumor cerebri may be a cause.  A review of post partum headaches found the that migraine/tension type headache to be the cause 47% of the time, with pre eclampsia being the cause 24% of the time [5].  PDPH was the 3rd most common cause at 16%.
However, other serious conditions need to be considered. Venous sinus thrombosis can be a life threatening condition and is associated with headaches in the post partum patient. Venous sinus thrombosis occurs rarely (10 to 20 per 100,000), but often is misdiagnosed as PDPH and treated with EBP (epidural blood patch) [1].  It also occurs more frequently in pregnant patients compared to normal population (ratio of 1.5:1).  To complicate matters, some authors have proposed that dura puncture places women at increased risk for venous sinus thrombosis or intracranial venous thrombosis (ICVT).  In a review of women who were diagnosed with ICVT after regional anesthesia for labor, there was also a high incidence of a positional headache making it difficult to distinguish from PDPH.  Other common presentations include blurry vision, nausea or vomiting, dizziness, or lateralizing neurological symptoms.  Often patients experience lethargy, seizures and coma.  Unfortunately, all of these are non specific and do not really help the clinician narrow the diagnosis. Another difficulty is that to make the diagnosis, a CT scan may be needed.  Unfortunately, the diagnosis can be confirmed by CT in only 1/3 of patients [2].  A more sensitive radiological study is MRI with MRV (magnetic resonance venography) [2]. In any event, it is likely that ICVT is often misdiagnosed as PDPH causing estimates of incidence in the literature to be lower than actual occurrence.  Patients who present with headache after labor epidural or spinal may be treated conservatively with caffeine and hydration, improve slightly solidifying the diagnosis of PDPH in the mind of the clinician.  By two weeks post partum, the patient is no longer hypercoaguable and the ICVT resolves completely without therapy. Therefore, while some patients with ICVT are being misdiagnosed with PDPH and receiving an EBP as therapy, this in theory at least could be helpful.  Some authors [3,4]  feel that intracranial hypotension promotes venous stasis and thus the risk of developing ICVT in the hypercoaguable peripartum patient.  Therefore, placing an EBP can reduce the risk of forming or worsening of intracranial venous thrombosis (ICVT).
Another important characteristic to look for when consulted for an EBP in a headache patient is the coarse of the headache and whether it has changed over the previous 4 days or so.  This is an important characteristic of more severe intracranial pathology. In conjunction with a brief but careful neurologic exam, a more educated decision can be made regarding the need for MRI.
Another less common but serious entity that must be entertained in any patient presently with a headache is posterior reversible encephalopathy syndrome (PRES).  This syndrome presents with headache (which can be positional), altered mental function, seizure, and visual disturbances that results from vasogenic edema in the brain. This syndrome has been associated with renal insufficiency, abrupt increases of blood pressure or immunosuppression. While this syndrome is most often associated with significant neurological changes, it can also be complicated by PDPH making the diagnosis difficult and treatment choices challenging.  A case report in Anesthesia and Analgesia [6] of a 33 year old patient who developed both PRES and PDPH after C-section highlight this possibility. In this case the patient developed a typical PDPH 2 days after uncomplicated spinal anesthesia for cesarian section.  Five days post partum the patient developed another headache that included mental status changes and right sided facial and limb numbness. Non contrast head CT was normal, but the following day an MRI showed cyotoxic edema in the posterior parietal areas and MR angiography demonstrated diffuse cerebral artery vasospasm.  MgSO4 was given for treatment and the headache and neurological changes resolved over several days. Nimodipine has been used to treat cerebral artery vasospasm with good effect, but MgSO4 has been shown to equally efficacious with calcium channel blockers.  Shearer et al. reported on 8 post partum patients who developed PDPH that was associated with cortical blindness and seizures.  In three of these patients angiography was performed and demonstrated diffuse cerebral artery vasospasm [7]. This has resulted in some authors to speculate that intracranial hypotension can predispose patients to develop cerebral vasospasm reflexively. While PRES is often reversible, late diagnosis or inappropriate treatment can lead to permanent neurological damage.  As in IVCT, MRI with angiography is required to make a definitive diagnosis.
In summary, when called for EBP, first consider an expansive differential diagnosis to include the rare but serious entities of IVCT and PRES.  Perform a careful history and focused neurological exam prior to proceeding with EBP. If patients have any focal deficits or mental status changes, a more detailed neurologic exam should be performed and imaging considered prior to EBP.  Anesthesiologists should consider imaging in any patient who reports a changing or progressive nature of the headache, if EBP doesn't provide initial relief of headache or relief of very short duration, if the patient has risk factors for IVCT or examination results are suggestive of more severe intracranial pathology.
  Since the above recommendations require an H&P be performed it should be properly documented and billed. You should carefully document Subjective and Objective findings, your formal Assessment and Plan (SOAP note).  Use of the proper CPT code for an Evaluation and Management  (E&M): 99241 for outpatient setting or 99251 for the inpatient setting.  These codes are for a simple H&P taking about 15 minutes and of lowest complexity.  If you feel that your H&P required more complex management, then upcoding appropriately is indicated with appropriate documentation.

1. Lockhart and Baysinger C.  Anesthesiology. 2007; 107: 652.
2. Bousser MG et al.  J Neurol. 2000; 247: 252.
3. Wilder-Smith E. et al.  Nuerosurg psychiatry. 1997; 63:351.
4. Turnball DK et al. Br J Anesthesia.  2003; 91: 718.
5. Stella CL et al. Am J Obstet Gynecol. 2007;196:318.
6. Ho CM and Chan KH. Anesth Analg 2007; 105:770.
7. Shearer VE et al. Obstet Gynecol. 1995; 85:255.

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