Contributor: Taylor Lynch, MD

Educational Pearls:

• Delusional parasitosis is a subtype of the psychiatric condition delusional disorder
  • Defined as a fixed, false belief of infestation by parasites or other organisms
  • A somatic type of delusional disorder
• Primary delusional parasitosis
  • Occurs in the absence of other psychiatric or medical conditions
• Secondary delusional parasitosis
  • Causes include methamphetamine use disorder, schizophrenia, neurologic diseases, or medical conditions such as thyroid disease
• Pathophysiology
  • Poorly understood
  • Upregulation of striatal dopamine system is implicated
• Management
  • Form a strong therapeutic alliance and do not discredit the patient immediately
  • Perform a full physical exam
    • This helps reassure the patient and strengthen the therapeutic alliance
    • Some day there may be a patient in whom this is not a delusion
• Treatment & Management
  • Discontinuation of substances if substance-induced
  • Antipsychotic medications like risperidone or olanzapine

References

1. Lepping P, Russell I, Freudenmann RW. Antipsychotic treatment of primary delusional parasitosis: systematic review. Br J Psychiatry. 2007;191:198-205. doi:10.1192/bjp.bp.106.029660
2. Moriarty N, Alam M, Kalus A, O'Connor K. Current Understanding and Approach to Delusional Infestation. Am J Med. 2019;132(12):1401-1409. doi:10.1016/j.amjmed.2019.06.017
3. Skelton M, Khokhar WA, Thacker SP. Treatments for delusional disorder. Cochrane Database Syst Rev. 2015;2015(5):CD009785. Published 2015 May 22. doi:10.1002/14651858.CD009785.pub2

Summarized and Edited by Jorge Chalit, OMS4

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Contributor: Aaron Lessen, MD
Educational Pearls:

The cause of Alzheimer’s disease is multifactorial, but the most widely suspected mechanism is the amyloid cascade hypothesis:

• Beta-amyloid proteins accumulate in the central nervous system, forming plaques that impair neuronal function.

In recent years, advances have led to the development of targeted therapies with monoclonal antibodies. These drugs:

• Work by degrading amyloid plaques
• Slow the rate of cognitive decline and disease progression
• Have major side effects, most notably the development of amyloid-related imaging abnormalities (ARIA)
  • ARIA may present as edema, effusion, or microhemorrhages, which are only detectable on MRI
  • Symptoms can include headache, vertigo, or focal neurologic deficits that mimic stroke

For patients presenting to the emergency department with stroke-like symptoms, it is important to consider whether they have a history of Alzheimer’s disease and whether they are taking these medications.

• This guides decisions about imaging and treatment:
  • The work-up may require MRI, which can delay thrombolytic or endovascular therapy in patients with true strokeConversely, treating a patient with ARIA using thrombolytics increases the risk of bleeding and other complications

References

1. Ebell MH, Barry HC, Baduni K, Grasso G. Clinically Important Benefits and Harms of Monoclonal Antibodies Targeting Amyloid for the Treatment of Alzheimer Disease: A Systematic Review and Meta-Analysis. Ann Fam Med. 2024 Jan-Feb;22(1):50-62. doi: 10.1370/afm.3050. PMID: 38253509; PMCID: PMC11233076.
2. Ma C, Hong F, Yang S. Amyloidosis in Alzheimer's Disease: Pathogeny, Etiology, and Related Therapeutic Directions. Molecules. 2022 Feb 11;27(4):1210. doi: 10.3390/molecules27041210. PMID: 35209007; PMCID: PMC8876037.
3. Perneczky R, Dom G, Chan A, Falkai P, Bassetti C. Anti-amyloid antibody treatments for Alzheimer's disease. Eur J Neurol. 2024 Feb;31(2):e16049. doi: 10.1111/ene.16049. Epub 2023 Sep 11. PMID: 37697714; PMCID: PMC11235913.

Summarized by Ashley Lyons, OMS3 | Edited by Ashley Lyons and Jorge Chalit, OMS4

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Contributor: Alec Coston, MD

Case Report Summary:

A 17-year-old female involved in a motor vehicle collision presented to a rural emergency facility via personally operated vehicle. During workup and initial CT scan, the patient began rapidly decompensating with CT revealing a 1.5cm epidural hematoma with 7mm of midline shift. The patient went from being able to walk and talk to being obtunded with a blown left pupil and unresponsive. Following intubation, the patient was being prepared for transport but potential delays required immediate emergency evacuation of the hematoma via a Burr Hole. A traditional Burr Drill was not immediately available at the facility, so an improvised Burr Drill using an Intraosseous (IO) drill was used. 35mL of blood was removed from the hematoma and the patient immediately improved from a GCS of 3 to GCS of 8. The patient was transferred to a higher level of care facility, extubated the following day, and made a full neurological recovery.

Educational Pearls:

What is an epidural hematoma?

• An epidural hematoma is a collection of blood between the dura mater (outermost layer of the meninges) and the skull, whereas a subdural hematoma is a collection of blood between the dura mater and arachnoid mater. Both can be life threatening depending on location and size.
• Epidural hematomas tend to be arterial, and are typically secondary to trauma and can rapidly expand, but with timely recognition and evacuation of the bleed, favorable outcomes are often possible.

What are typical intracranial pressures and at what levels do they become pathologic?

• Typical intracranial pressure (ICP) varies by age, but past infancy and early childhood, adolescents and adults have a value typically between 8-15mmHg. Values exceeding 20mmHg become pathologic and rise exponentially with increased volume.
• Initial symptoms may include headache, nausea, and vomiting, but with increased pressures may progress to more life threatening symptoms such as loss of consciousness, cranial nerve palsies, pupillary constriction or dilation (sign of herniation), and respiratory irregularities.

What is the takeaway in timing of epidural hematomas?

• Older studies show that evacuation of a hematoma with lateralizing features before the two hour mark of coma symptom onset is correlated with decreased mortality (ranging from 15-17%), but beyond 2 hours the mortality increases to well over 50%.
• Though mortality statistics have grown more variable, early targeted evacuation of epidural hematomas still remains critical for improved patient outcomes. In austere conditions with limited resources, improvisation with interosseous drills and needles can improve patient outcomes and achieve the target therapy for epidural hematomas.

References

1. Haselsberger K, Pucher R, Auer LM. Prognosis after acute subdural or epidural haemorrhage. Acta Neurochir (Wien). 1988;90(3-4):111-116. doi:10.1007/BF01560563
2. Hawryluk GWJ, Nielson JL, Huie JR, et al. Analysis of Normal High-Frequency Intracranial Pressure Values and Treatment Threshold in Neurocritical Care Patients: Insights into Normal Values and a Potential Treatment Threshold. JAMA Neurol. 2020;77(9):1150-1158. doi:10.1001/jamaneurol.2020.1310
3. Pisică D, Volovici V, Yue JK, et al. Clinical and Imaging Characteristics, Care Pathways, and Outcomes of Traumatic Epidural Hematomas: A Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury Study. Neurosurgery. 2024;95(5):986-999. doi:10.1227/neu.0000000000002982

Summarized by Dan Orbidan, OMS2 | Edited by Dan Orbidan and Jorge Chalit, OMS4

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