Neurological diseases

My patient with low back pain was just diagnosed with a lumbar spinal epidural abscess. Should I order an MRI of the rest of the spine?

FA Manian MD, MPH, , , , , , Leave a comment

First, look closely for any signs or symptoms which may suggest cord involvement due to spinal epidural abscess (SEA) at other levels of the spine (in this case cervical or thoracic) which would necessitate an urgent MRI. Be particularly on the lookout for new pain (particularly radicular) or paresthesias involving the abdomen, chest or upper extremities (with or without weakness)1.

Otherwise, whether an MRI of the entire spine should be routinely obtained after a diagnosis of SEA in the absence of any suggestive signs or symptoms is less clear, in part related to lack of properly designed studies.1-4

Nevertheless, a retrospective study involving 233 patients with SEA may shed some light on the subject. Based on 22 cases of noncontiguous SEA (9.4% of total), the following independent risk factors were identified3:

  • Delay in presentation (≥1 week of symptoms)
  • Concomitant area of infection outside the spine and paraspinal region
  • ESR > 95 mm/h at presentation

Probability of non-contiguous SEA based on the number of risk factors was as follows:

  • 3 risk factors: 73%
  • 2 risk factors: 13%
  • 1 risk factor: 2%
  • Zero risk factor: 0%

Despite several shortcomings and the need to confirm its findings2,3, this study helps raise awareness of the potential for concurrent but asymptomatic SEA elsewhere in the spine whenever SEA is diagnosed.

 

References

  1. Bond A, Manian FA. Spinal epidural abscess: a review with special emphasis on earlier diagnosis. BioMed Res International 2016;Volume 2016, Article ID 1614328. https://www.hindawi.com/journals/bmri/2016/1614328/
  2. Schoenfeld AJ, Hayward RA. Predicting modeling for epidural abscess: what we can, can’t, and should do about it. Spine J 2015;15:102-104. http://www.sciencedirect.com/science/article/pii/S152994301401554X
  3. Ju KL, Kim SD, Melikian R, et al. Predicting patients with concurrent noncontiguous spinal epidural abscess lesions. Spine J 2015;15:95-101. https://www.ncbi.nlm.nih.gov/pubmed/24953159
  4. Pfister HW, vonRosen F, Yousry T. MRI detection of epidural spinal abscesses at noncontiguous sites. J Neurol 1996;243:315-7. https://www.ncbi.nlm.nih.gov/pubmed/8965103
My patient with low back pain was just diagnosed with a lumbar spinal epidural abscess. Should I order an MRI of the rest of the spine?

What pharmacological options should I consider when treating neurogenic orthostatic hypotension in my elderly patient with supine hypertension?

FA Manian MD, MPH, , , , , Leave a comment

Treating symptomatic neurogenic orthostatic hypotension (nOH) in patients with supine hypertension can be challenging.

Before adding new agents, consider discontinuation or dose reduction of medications that can potentially aggravate orthostatic symptoms (eg, diuretics, vasodilators, negative chronotropic agents, including beta blockers).

Midodrine (an α1-adrenoreceptor agonist) and droxidopa (a norepinephrine pro-drug) are the only 2 FDA-approved drugs for the treatment of OH.

  • Midodrine is typically dosed between 2.5 mg-15 mg 1-3x/d during waking hours (prior to getting out of bed, before lunch, mid-afternoon).
  • Droxidopa is dosed from 100-600 mg 3x/day during waking hours (eg, 8 AM, noon, 4PM).
  • To reduce the risk of supine hypertension, these agents are not recommended to be taken within 5 h of bedtime, and should be used with caution in patients with congestive heart failure and chronic renal failure.

Fludrocortisone and pyridostigmine are used off-label for treatment of nOH.

  • Fludrocortisone (typical dose 0.1-0.2 mg/day) expands intravascular blood volume by increasing renal sodium and water reabsorption, with an attendant risk of exacerbating supine hypertension, hypokalemia, and edema.
  • Pyridostigmine (typical dose 30-60 mg 1-3x/day) is an acetylcholinesterase inhibitor that potentiates neurotransmission in the sympathetic ganglia and has the advantage of not worsening supine hypertension. Side effects include abdominal cramps, diarrhea, excessive sweating and urinary incontinence.

In practice,  1 or more of these agents are often used along with non-pharmacological measures.

Also go to a related P4P pearl here. 

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Reference

Gibbons CH, Schmidt P, Biaggioni I, et al. The recommendations of a concensus panel for the screening, diagnosis, and treatment of neurogenic orthostatic hypotension and associated supine hypertension. J Neurol 2017;264:1567-82.https://www.ncbi.nlm.nih.gov/pubmed/28050656

 

What pharmacological options should I consider when treating neurogenic orthostatic hypotension in my elderly patient with supine hypertension?

Which non-pharmacological approaches may help symptoms of orthostatic hypotension in my patient with autonomic insufficiency?

FA Manian MD, MPH, , , , , , 1 Comment

A number of simple measures to help reduce the symptoms of neurogenic orthostatic hypotension (nOH) in susceptible patients have been recommended.1

  • Blood volume repletion (a minimum of 64 oz or 2L of water intake daily), depending on cardiac status. In addition, rapid consumption (within 5 min) of 16 oz or 500 ml of water can raise blood pressure by 30 mmHg for about an hour. It’s worth noting that liquids other than water (eg, water plus salt) do not provide the same BP response, likely due to water-induced hypo-osmolar reflex in the portal circulation.2,3
  • Increase salt intake if possible (eg, add 1-2 teaspoons or 2.3-4.6 g of salt per day), as many patients with nOH have an inadequate salt intake.
  • Improve physical conditioning that is not gravitationally challenging (eg, stationary recumbent bicyle, rowing machine).
  • Avoid increased core body temperature (eg hot tubs, prolonged hot showers).
  • Head-up position while sleeping through use of a wedge under the mattress or blocks under the head of the bed so that the head is 6-9 inches (15-23 cm) higher than the feet. This is to minimize nocturnal supine hypertension which can cause pressure diuresis and volume depletion.
  • Compressive garments, preferably either an abdominal binder or thigh high stockings when erect; knee high stocking are not likely to be effective.
  • Smaller, more frequent,  meals not high in carbohydrates in patients with postprandial hypotension.
  • Dietary supplementation with B12 or iron, if deficient.

 

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References

  1. Gibbons CH, Schmidt P, Biaggioni I, et al. The recommendations of a consensus panel for the screening, diagnosis, and treatment of neurogenic orthostatic hypotension and associated supine hypertension. J Neurol 2017;264:1567-1582. https://www.ncbi.nlm.nih.gov/pubmed/28050656
  2. Jordan J, Shannon JR, Black BK, et al. The pressor response to water drinking in humans: a sympathetic reflex? Circulation 101:504-9. http://circ.ahajournals.org/content/101/5/504.long
  3. Raj SR, Biaggioni I, Black BK, et al. Sodium paradoxically reduces the gastropressor response in patients with orthostatic hypotension. Hypertension 2007;48:329-334. https://www.ncbi.nlm.nih.gov/pubmed/16785332

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, its affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

Which non-pharmacological approaches may help symptoms of orthostatic hypotension in my patient with autonomic insufficiency?

My elderly patient is scheduled to undergo elective surgery? Is there an objective “stress test for the brain” that may predict postoperative delirium?

FA Manian MD, MPH, , , , , Leave a comment

Possibly, in the near future! Although the pathophysiology of postoperative delirium (POD) is not fully understood, a recently proposed conceptual model of delirium may provide a basis for preoperative neurophysiologic testing1.

According to this model, delirium is a “consequence of the breakdown in brain network dynamics” precipitated by insults or stressors (eg, surgery) in persons with low brain resilience ie, low connectivity between brain regions and/or deficient neuroplasticity (the ability of brain to reorganize itself by forming new neural connections).  

As expected,  patients with strong baseline connectivity and optimal neuroplasticity would not be expected to have POD, whereas those with weakened connectivity (eg baseline cognitive dysfunction) and/or suboptimal neuroplasticity (eg due to aging) may be at higher risk. Transcranial magnetic stimulation (TMS)  is considered a powerful tool that measures the connectivity and plasticity of the brain through induced perturbation.  When applied in repetitive trains, TMS produces changes in cortical excitability that can be measured using electromyography and EEG,  and is thought to have the ability to assess neuroplasticity 2. If proven effective in predicting POD, it could revolutionize preoperative risk assessment in the elderly! Stay tuned!

 

Reference

  1. Shafi MM, Santarnecchi E, Fong TG, et al. Advancing the neurophysiological understanding of delirium. J Am Geriatr Soc 2017. DOI:10.1111/jgs.14748.
  2. Pascual-Leone A, Freitas C, Oberman L, et al. Characterizing brain cortical plasticity and network dynamics across the age-span in health and disease with TMS-EEG and TMS-fMRI. Brain Topogr 2011, 24:302-15.
My elderly patient is scheduled to undergo elective surgery? Is there an objective “stress test for the brain” that may predict postoperative delirium?

When should I suspect spinal epidural abscess in my 55 year old patient with severe back pain?

FA Manian MD, MPH, , , , , Leave a comment

 It cannot be overemphasized that up 50% of patients with spinal epidural abscess (SEA) have no known risk factors,  one-half may have no fever,  and 20-40% lack leukocytosis1. In fact, the “classic triad” of back pain, fever, and neurological deficits is found only in the minority of patients!  No wonder that up to 75% of patients SEA are misdiagnosed on their initial healthcare encounter1!

Potential “red flags” for infectious causes of low back pain include age >50 y, night pain, unremitting pain even when supine, duration > 6 weeks, fever, chills, night sweats, weight loss, conditions associated with Staphylococcus aureus bacteremia (eg intravenous drug use), incontinence, saddle anesthesia, and severe or rapidly progressive neurologic deficits1,2.  

ESR and C-reactive protein (CRP) are almost uniformly elevated in SEA1 and can serve as a good starting point in excluding this condition when in doubt.   In patients ≥50 y of age with low back pain, obtaining ESR routinely has been suggested for detection of systemic disease (eg cancer, infection)3.  Similarly, in a recent algorithm of severe back pain, routine measurements of ESR and CRP, even in the absence of any neurological findings, has been recommended1; elevation of either may necessitate consideration of MRI.

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References:

  1. Bond, A, Manian FA. Spinal epidural abscess: a review with special emphasis on earlier diagnosis. BioMed Res International 2016; https://www.hindawi.com/journals/bmri/2016/1614328/http://dx.doi.org/10.1155/2016/1614328  
  2. Della-Giustina. Acute low back pain: recognizing the “red flags” in the workup. Consultant 2013;53:436-440. http://www.consultant360.com/article/acute-low-back-pain-recognizing-%E2%80%9Cred-flags%E2%80%9D-workup
  3. Jarvik JG, Deyo RA. Diagnostic evaluation of low back pain with emphasis on imaging. Ann Intern Med 2002;137:586-597. http://annals.org/aim/article/715687/diagnostic-evaluation-low-back-pain-emphasis-imaging

Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Mercy Hospital-St. Louis or its affiliate healthcare centers, Mass General Hospital, Harvard Medical School or its affiliated institutions. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!

Additional disclosure: The author of this post (FAM) also coauthored reference 1.

When should I suspect spinal epidural abscess in my 55 year old patient with severe back pain?

How exactly do urinary tract infections (UTIs) cause delirium in my elderly patients?

FA Manian MD, MPH, , , , , , , , Leave a comment

 UTIs are often considered in the differential diagnosis of causes of delirium in the elderly. Though largely speculative, 2 possible pathophysiologic basis for this association are suggested:1-3

  •  Direct brain insult (eg, in the setting of sepsis/hypotension)
  • Indirect aberrant stress response, involving cytokines/inflammatory pathways,  hypothalamic-pituitary-adrenal [HPA] axis and sympathetic nervous system (SNS). One or both pathways can interact with the neurotransmitter and intracellular signal transduction systems underlying delirium in the brain, which may already be impaired in the elderly due to age-related or other pathologic changes.

The indirect aberrant stress pathway suggests that not only pain and discomfort (eg from dysuria) can contribute to delirium but UTI-associated circulating cytokines may also cause delirium.  Indeed, a large study of older adults undergoing elective surgery found a significant association between delirium postoperatively (postop day 2) and serum proinflammatory cytokine levels such as IL-6. 4  

The corollary is that bacteriuria is unlikely to be associated with delirium in the absence of significant systemic inflammatory response, pain or discomfort. We just need to do proper studies to prove it!

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References

1.Trzepacz P, van der Mast R. The neuropathophysiology of delirium. In Lindesay J,  Rockwood K, Macdonald A (Eds.). Delirium in old age, pp. 51–90. Oxford University Press, Oxford , 2002.

2.Flacker JM, Lipsitz LA. Neural mechanisms of delirium: current hypotheses and evolving concepts. J Gerontol A Biol Sci Med Sci. 1999; 54: B239–B246 https://www.ncbi.nlm.nih.gov/pubmed/10411009

3. Maclullich AM, Ferguson KJ, Miller T, de Rooij SE, Cunningham C. Unravelling the pathophysiology of delirium: a focus on the role of aberrant stress responses. J Psychosom Res. 2008;65:229–38. https://www.ncbi.nlm.nih.gov/pubmed/18707945

4. Vasunilashom SM, Ngo L, Inouye SK, et al. Cytokines and postoperative delirium in older patients undergoing major elective surgery. J Gerontol A Biol Sci Med Sci 2015;70:1289-95. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4817082/pdf/glv083.pdf

Contributed by Henrietta Afari MD, Mass General Hospital, Boston, MA

How exactly do urinary tract infections (UTIs) cause delirium in my elderly patients?

Should I routinely consider the possibility of pulmonary embolism (PE) in my patients hospitalized for syncope?

FA Manian MD, MPH, , , , , , Leave a comment

Syncope is a well-known initial manifestation of pulmonary embolism (PE)1.  However, given the varied causes of syncope, determining the prevalence of PE among patients hospitalized for syncope is important.   

A multicenter prospective study2 enrolled 560 patients not already on anticoagulation who were hospitalized for a first episode syncope.  Of patients who had either a high pretest probability for PE, positive D-dimer assay or both, PE was diagnosed in 17%, or nearly 1 of 6 of enrolled patients, based on CT or ventilation/perfusion scan. PE was found more frequently among patients with syncope of undetermined cause than those with an alternative explanation (25.4% vs 12.7%). 

Another multicenter prospective study (2019), however, found a much lower prevalence of PE (0.6%) among patients evaluated in the ED for syncope, including those who were not hospitalized.3 A related commentary on the article reported a prevalence of 4.1% in the total study population, assuming a “worst-case scenario calculation.” 4 

Given these divergent results, perhaps the best advice is to consider PE as cause of syncope in the proper context and minimize overtesting when suspicion remains low.

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References 

  1. Thames MD, Alpert JS, Dalen JE. Syncope in patients with pulmonary embolism. JAMA 1977;238:2509-2511. https://www.ncbi.nlm.nih.gov/pubmed/578884
  2. Prandoni P, Lensing AWA, Prins MH, et al. Prevalence of pulmonary embolism among patients hospitalized for syncope. N Engl J Med 2016;375:1524-31. http://www.nejm.org/doi/full/10.1056/NEJMoa1602172
  3. Thiruganasambandamoorthy V, Sivilotti MLA, Rowe BH, et al. Prevalence of pulmonary embolism among emergency department patients with syncope: a multicenter prospective cohort study [published online January 25, 2019]. Ann Emerg Med. doi:10.106/j.annemergmed.2018. https://www.annemergmed.com/article/S0196-0644(18)31535-X/fulltext
  4. Anonymous. Pulmonary embolism uncommon in syncope hospitalizations. Pulmonology Advisor. February 6, 2019.  https://www.pulmonologyadvisor.com/pulmonary-embolism-uncommon-in-syncope-hospitalizations/printarticle/832069/

 

Contributed in part by Rebecca Berger  MD, Department of Medicine, Mass General Hospital, Boston, MA

 

Should I routinely consider the possibility of pulmonary embolism (PE) in my patients hospitalized for syncope?

Does electroconvulsive therapy (ECT) pose a risk of embolic stroke in patients with atrial fibrillation (AF)?

FA Manian MD, MPH, , , , , , Leave a comment

Acute embolic stroke in the setting of AF without anticoagulation after ECT has been reported in a single case report in the absence of conversion to normal sinus rhythm (1). Several cases of episodic or persistent conversion to normal sinus rhythm (NSR) in patients with AF undergoing ECT have also been reported (in the absence of embolic stroke), leading some to recommend anticoagulation therapy in such patients (2), though no firm data exist.

The mechanism by which ECT promotes cardioversion from AF to NSR is unclear as direct electrical influence of ECT on the heart is thought to be negligible (1). Arrhythmias such as atrial flutter and AF have also been reported after ECT (1). Curiously, ECT is associated with increased 5- hydroxytryptamine (5- HT2)-receptor densities of platelets in patients with depression which may enhance platelet reactivity and increase the risk of embolic stroke (3) even in the absence of cardioversion.

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References

  1. Suzuki H, Takano T, Tominaga M, et al. Acute embolic stroke in a patient with atrial fibrillation after electroconvulsive therapy. J Cardiol Cases 2010; e12-e14. https://www.sciencedirect.com/science/article/pii/S1878540910000113
  2. Petrides G, Fink M. Atrial fibrillation, anticoagulation, electroconvulsive therapy. Convulsive Therapy 1996;12:91-98. https://journals.lww.com/ectjournal/Abstract/1996/06000/Atrial_Fibrillation,_Anticoagulation,_and.4.aspx
  3. Stain-Malmgren R, Tham A, Ǻberg-Wistedt A. Increased platelet 5-HT2 receptor binding after electroconvulsive therapy in depression. J ECT 1998;14:15-24. https://europepmc.org/abstract/med/9661089
Does electroconvulsive therapy (ECT) pose a risk of embolic stroke in patients with atrial fibrillation (AF)?