A 21-year-old male presents to the emergency department with a history of fevers to 100.4°F, headache, nausea, and vomiting for the last 48 hours. He has a history of tonic-clonic seizures for which he takes phenytoin. He has recently started taking ibuprofen for his headaches. He has no allergies. He has not had his flu shot this year, and no one else is unwell in his family. On examination, he is lying down in a dark room and requests for you to avoid turning on the light. He is somnolent but has no focal weakness. He is unable to flex his neck without discomfort.
The emergency room physician had empirically started ceftriaxone and vancomycin and performed a lumbar puncture with the following results:
CSF = cerebrospinal fluid
What is the MOST LIKELY cause of his symptoms?
Correct Answer: C
Aseptic meningitis refers to the patient population that have negative CSF gram stain and cultures but laboratory and clinical evidence of meningeal irritation. The most common causes are the enteroviruses such as coxsackie virus and echovirus. Additional etiologies form a fairly extensive list which includes other infections (mycobacteria, fungi, spirochetes), parameningeal infections (HIV, herpes simplex, varicella zoster, Epstein-Barr virus, cytomegalovirus, human herpes virus-6, and adenoviruses), medications (ibuprofen), and malignancies (lymphoma). CSF from bacterial meningitis would have positive gram stains, greatly elevated WBCs >150 cells/mm3 , high protein, and reduced glucose levels. Seizures may be associated with CSF pleocytosis and transiently elevated CSF protein levels, however, the clinical presentation does not fit this. Drug-induced aseptic meningitis is primarily a diagnosis of exclusion and unlikely to have elevated WBCs and RBCs. A fungal infection would be a very rare cause of aseptic meningitis in an immunocompetent individual; however, HIV testing would likely be warranted in this diagnostic workup.
A 41-year-old African American female presents with progressive left-sided upper and lower facial muscle weakness and headaches over the last 3 months. She reports polyuria and polydipsia with >10 L of urine output per day. Lumbar puncture reveals clear cerebrospinal fluid (CSF) with WBC count 22 cells/mm3 , protein 280 mg/dL, and glucose 25 mg/dL. The gram stain and culture were negative. A slice of her MRI brain imaging showing leptomeningeal enhancement (arrows) is shown in figure below:
Which test would be MOST LIKELY to assist with the diagnosis of her condition?
Correct Answer: B
Sarcoidosis is a rare multisystem noncaseating granulomatous disease, which affects 3 to 10 per 100 000 among Caucasians and 35 to 80 per 100 000 among African Americans. 5% to 10% of patients with systemic sarcoidosis will have neurological involvement whereas only 17% of patients will solely present with neurosarcoidosis. Any component of the central or peripheral nervous system can be affected. Cranial mononeuropathies are common, in particular, the peripheral facial nerve is affected in 25% to 50% of neurosarcoidosis cases. Neuroendocrine dysfunction may manifest as polyuria or disturbances in temperature, libido, or appetite due to hypothalamic inflammation. Diabetes insipidus may either be central from hypopituitarism or nephrogenic from activated macrophage calcitriol causing hypercalcemia. Lung parenchyma and mediastinal lymph nodes are the most common sites affected peripherally with reported involvement in 24% to 68% of individuals presenting with neurologic sarcoidosis. The diagnosis is based on clinical symptoms, CSF evidence of inflammation (pleocytosis, elevated CSF protein), and/or MRI imaging demonstrating leptomeningeal enhancement especially around the base of the brain (arrows); however, neurosarcoidosis can involve the bone, dura mater, nerve roots, and brain parenchyma. Confirmation of systemic sarcoidosis may occur either through positive histology or two indirect indicators (gallium scan imaging, chest imaging demonstrating enlarged lymphadenopathy, or elevated angiotensin-converting enzyme [ACE] levels). Corticosteroids remain the mainstay of initial treatment followed by immunomodulatory therapy.
Chest CT scan with evidence of hilar adenopathy or parenchymal changes is consistent with sarcoidosis and may also guide a tissue biopsy diagnosis, and thus is the correct answer. Tensilon test is useful in diagnosis of myasthenia gravis and is performed by administrating edrophonium which prevents acetylcholine breakdown causing improvement in symptoms. Synacthen test (or cosyntropin test) uses adrenocorticotropin hormone (ACTH) to evaluate adrenal gland function. 24-hour urinary electrolytes may help confirm suspicion of diabetes insipidus but would not assist with the diagnosis of neurosarcoidosis.
A homeless 35-year-old alcoholic male with a body mass index of 18 kg/m2 is admitted for seizures, encephalopathy, and dysarthria. On presentation, he had a serum sodium of 108 mmol/L, potassium 2.4 mmol/L, chloride 98 mmol/L, alanine aminotransferase 356 IU/L, aspartate aminotransferase 450 IU/L, and gamma-glutamyl transpeptidase 1200 IU/L. He was started on lactulose, thiamine replacement, and saline infusions. CT scan of brain was unremarkable. He recovered within 36 hours, coincident with a sodium correction to 130 mmol/L. The patient then deteriorated on day 6 to a catatonic state with flaccid paralysis of all extremities.
Which of the following MOST LIKELY caused his deterioration?
Correct Answer: D
Rapid correction of serum sodium with saline infusions (or hypertonic saline) in patients with chronic hyponatremia can cause central pontine myelinolysis (CPM) or osmotic demyelination syndrome. CPM was originally described in 1959 as a disease associated with malnourished alcoholics. Extrapontine myelinolysis was recognized in 1962, and the link with rapid correction of hyponatremic patients was found in 1982. It remains a rare disease with a biphasic presentation. Patients typically are encephalopathic or seizing upon presentation. Laboratory testing usually reveals profound hyponatremia (Na <120 mmol/L). The rapidity of sodium correction is thought to cause the damage to the myelin sheath. There is an initial period of symptom improvement before deterioration which may include corticobulbar fiber involvement (dysarthria and dysphagia), corticospinal tract involvement (flaccid quadriparesis followed by spasticity), and pupillary or oculomotor changes from tegmentum/pontine extension. The appearance of “locked-in syndrome” may also occur. Extrapontine involvement may be characterized by psychiatric, behavioral, parkinsonism, dystonia, catatonia, mutism, and movement disorders. There is no absolute “safe” limit for rate of sodium correction. A 10 mmol/L rise per 24 hours was previously recommended; however, now experts recommend a correction rate of <8 mmol/L per 24 hours. Clinical improvement or stability should not be considered evidence that sodium correction has not occurred too rapidly. Clinical symptoms of CPM, which are usually irreversible, most commonly occur 2 to 6 days following rapid sodium correction.
Hypophosphatemia rather than hyperphosphatemia is the hallmark and primary etiology of refeeding syndrome that can occur in severely malnourished patients following initiation of nutritional support. Refeeding syndrome most commonly involves multiorgan dysfunction and can result in neurologic symptoms due to electrolyte abnormalities and fluid shifts. Thiamine deficiency can result in a Wernicke encephalopathy and is associated with chronic alcoholics. Clinical manifestations include encephalopathy, ataxia, and oculomotor deficits.
A 22-year-old Scandinavian female presents with acute symptoms of vision loss, headaches, fatigue, and leg weakness. She reports that her mother has a history of multiple sclerosis (MS). MRI demonstrates inflammatory lesions of the same age found in multiple areas. Despite various treatment modalities, the patient progressed to death 6 months later.
Which of the following MS variant diseases is MOST likely?
MS is an autoimmune central nervous system (CNS) demyelinating disease with a prevalence of 15 to 250 per 100 000 people. It is more common in females, especially of Scandinavian descent, with increased prevalence associated with geographical latitude extremes. MS typically has a relapsing and remitting course separated in time and CNS location. A number of MS variant diseases has been described. The Marburg variant is a fulminant form of MS, typically characterized as monophasic with widespread involvement at onset with rapid progression to death usually within weeks to months. Balo concentric sclerosis is a demyelinating disease that affects the white matter of the brain involving alternating concentric rings of myelin loss and preservation. Initially the prognosis was considered similar to Marburg variant, but now there are reports of patients surviving and even having spontaneous remissions.
Neuromyelitis optica or Devic disease is a heterogenous inflammatory and demyelinating condition of the optic nerve and spinal cord. It has a relapsing and remitting course however with the discovery of a specific autoantibody NMO-IgG which targets astrocyte aquaporin-4, and it is now considered distinct from MS. Schilder disease or diffuse myelinoclastic sclerosis presents as pseudotumoral demyelinating lesions usually affecting children 5 to 14 years old. These intracranial lesions are often mistaken for tumors or abscess.
A 5-year-old male presents with irritability, ataxia, headaches, and progressive somnolence. His mother reports fevers after receiving his vaccinations for measles, mumps, and rubella, 3 weeks ago. The pediatrician is highly concerned for acute disseminated encephalomyelitis (ADEM). The mother believes that the recent vaccinations are the cause of the child’s symptoms.
Which of the following statements is LEAST true?
ADEM which affects 0.8 per 100 000 people can clinically appear similar to other demyelinating inflammatory conditions such as MS. It is however much more common in children ages 5 to 9 years old, is typically monophasic rather than having a relapsing and remitting course (although this has rarely been reported), and is usually temporally associated with a recent infection or up to 3 months following vaccination. Decreased level of consciousness with progression to coma and death is more a hallmark of ADEM than MS. MRI may demonstrate reversible ill-defined white matter lesions of the brain and spinal cord with frequent involvement of thalami and basal ganglia. CSF may have a mild pleocytosis and elevated protein but is usually negative for oligoclonal IgG bands. Measles vaccination has been linked to ADEM. However, the incidence of postimmunization ADEM for live measles vaccine is 1 to 2 cases per million vaccinations, which is much lower than the incidence of postinfectious ADEM caused by measles infection itself (1 in 1000). Since, there is no specific biomarker for ADEM, the diagnosis is usually one of exclusion. The treatment of choice is steroids. Plasmapheresis and cytotoxic medications are used as second-line therapy. Recovery has been reported in up to 75% of patients.
© 2010-2030 Your Doctor - Dr.Khalil Al-Yousifi - Kuwait - Contact Us