Intern Report Case Discussion 1.14

intern-report

Presented by Alison Loynd, DO

HISTORY

A 35-year-old female is transferred from an urgent care center by EMS with chief complaint of altered mental status and fever. The patient is unable to answer questions. She is approximately 18 weeks pregnant and febrile. She has no nausea, vomiting, dyspnea or noted seizure activity. Her boyfriend reports that the patient was previously healthy. She had a dental extraction approximately one month prior. Since that time, she has had pain all over, headache, nausea and vomiting. She was seen in the ED one week ago and given antibiotics for dental infection. The patient has been taking antibiotics as prescribed for the last week.  She went to the dentist office today complaining of headache and facial swelling. At the clinic, she had a procedure done but the boyfriend does not know any more specifics. He reports that afterwards she was unable to ambulate and felt dizzy and weak.  Due to her changes in mental status, they called 911.

PMH: None per friend.
PSH: None per friend.
GYN: G1P0 currently 18 weeks pregnant with routine prenatal care.
Meds: Cephalexin and Amoxicillin x 1 week.
Allergies: None known
Social: She does not drink, smoke or use illicit drugs.

PHYSICAL EXAM

GENERAL: The patient is obtunded, at times somnolent but arousable to her name. She opens her eyes and moves extremities spontaneously. She is making no vocalizations.
VITALS: BP 145/85  HR 121  RR 20 Temp 39.2 R  94%RA
HEENT: Head is atraumatic, normocephalic. TM clear and intact bilaterally, no effusion or hemotympanum. PERRLA. 2mm bilaterally. Mucous membranes are dry. No tonsillar edema or exudates. There is some mild edema of the left mandible, it is not indurated or fluctuant. Left mandible and cheek are tender to palpation. Neck is supple. Trachea midline with no lymphadenopathy.
HEART: Tachycardic and regular No murmur, gallop or rub.
LUNGS: Clear to auscultation bilaterally with shallow breathing
ABD: Soft. Gravid. Fundus palpable below umbilicus. Bowel sounds are hyperactive.
EXT: No edema or cyanosis. She has full range of motion spontaneously. Pulses present and equal bilaterally.
SKIN: Hot and dry. No noted edema, cyanosis or rash.
NEURO: Patient has a GCS of 11 (3E, 2V, 6M). She is opening her eyes, initially following simple commands, moves spontaneously. She is not vocalizing. She has an intact gag. Face appears symmetrical. Her patellar and Achilles reflexes are normal with no clonus.

LABORATORY EVALUATION
CBC: WBC 23.8 (22.4 Neutrophils) / Hgb8.8/ Hct 26.7/ Platelets 352
LYTES: Na 133/K 3.2/HCO 19/BUN 6/Cr 0.6/Glucose 130   Mag 1.5 Ca 8.2
CSF: Hazy, 750 RBC, 700 nucleated cells, 93 N, 5 L, glucose < 20, protein 122
GS: No organisms on gram stain. Numerous PMNs, mod RBC
UDS Positive for cannibis

Bedside US: Active intrauterine fetus, heart rate 178. Gestational age 19 weeks by femur length and 20 weeks by fundal height.

QUESTIONS

1.    Considering your differential evaluation, what is most likely in this patient?
A.    Trauma
B.    Encephalitis/meningitis
C.    Brain Abscess
D.    Preeclampsia
E.    Saggital sinus thrombosis

2.    What is your diagnostic test of choice?
A.    CT with and without contrast.
B.    LP and serology.
C.    CT without contrast.
D.    Obtain 24 hour urinalysis, liver function and platelets.
E.    MRI.

3.    Treatment considerations include:
A.    Anticoagulation with heparin.
B.    Antiepileptic prophylaxis – IV phenytoin.
C.    Multiple antibiotics: IV Penicillin, Metronidazole, Ceftriaxone and glucocorticoid.
D.    Antihypertensive – IV hydralazine.
E.    Single antibiotic regimen – IV Clindamycin

Discussion

1. Considering your differential evaluation, what is most likely in this patient?

C. Brain Abscess. Our patient was found to have a brain abscess. Brain Abscess is a focal collection within the brain parenchyma that may arise as a complication of infections, trauma, or surgery. Up to 60 percent of cases come from direct spread via subacute or chronic otitis media, mastoiditis, sinusitis or dental infection. Foreign bodies can also cause abscess by acting as a nidus for infection. Finally, direct spread can complicate neurosurgical cases. Abscess occurring from bacteremia usually results in multiple abscesses mostly along the distribution of the middle cerebral artery. 20-40 percent of brain abscess will have no identified etiology.

Symptoms commonly include a headache, usually localized to the side of the abscess, with gradual or sudden onset. The pain tends to be severe and not relieved by typical over-the-counter pain medications. Changes in mental status range from lethargy progressing to coma and stupor and are indicative of severe cerebral edema. This is a poor prognostic sign. Patients with cerebral edema will frequently have associated nausea and vomiting.

Physical exam may include fever, however fever is unreliable as it is not always or even commonly associated with brain abscess. Focal neurologic deficits are observed in approximately fifity percent of patients. Deficits may include aphasia, anopsia, muscle weakness, hemiparesis, nystagmus or ataxia.

Your differential may have included trauma, encephalitis/meningitis, intoxication, preeclampsia, seizure and cerebral venous thrombosis. This patient had no known falls or accidents and was in a stable monogamous relationship making trauma and domestic violence unlikely. In any pregnant or postpartum patient, preeclampsia should be considered. She was observed at a medical clinic prior to EMS transfer and no seizure activity was noted. The patient’s urinalysis was negative for protein and she did not have edema, hypertension or hyperreflexia. Cerebral venous thrombosis is an uncommon entity but is a consideration in pregnant patients or women using hormonal birth control. Patients may present with headache, nausea, vomiting, focal neurological deficit and variations in mental status. The recent dental work followed by development of symptoms makes brain abscess more likely than cerebral venous thrombosis.

2. What is your diagnostic test of choice?

A. Diagnostic testing includes CT with and without contrast. CT scan must be done first. Only after a CT scan has ruled out cerebral edema can a lumbar puncture be preformed due to the risk of increased ICP leading to herniation.

Acutely, an abscess may be difficult to recognize on CT as it can be poorly demarcated and is associated with localized edema. There will be evidence of acute inflammation but no visible tissue necrosis. After two to three weeks, as the disease progresses, necrosis and liquefaction occur, and the lesion becomes more visible as surrounded by a fibrotic capsule.

A lumbar puncture is indicated and can be done only after a CT scan has been completed. Most initial CT scans do not identify the abscess. The LP is useful as your differential includes meningitis or encephalitis. The CSF pattern is variable and similar to meningitis showing elevated protein, decreased glucose and an elevated white cell count.

Definitive diagnosis of brain abscess may require direct examination of brain tissue obtained by open or stereotactic brain biopsy under the direction of an experienced neurosurgeon. A CT scan of the brain without contrast is done to evaluate the patient for acute intracranial hemorrhage but is insufficient evaluation alone.

This patient’s symptoms do not represent preeclampsia or eclampsia, thus HELLP evaluation of serology and urinalysis is not necessary though should be included in the evaluation of any obtunded pregnant patient. Preeclamspia may present at any time during pregnancy and into the postpartum period. An OBGYN consult should still be done in this pregnancy, but may be done on a routine basis when the patient is stabilized as the fetus is not viable at this gestational age. This patient does not appear to have any trauma and does not need general surgery.

An MRI is also a valid test for brain abscess, thought the patient’s stability and general medical condition must be weighted against the time delay required for proper imaging and availability of the MRI. CT with and without contrast is faster and more widely available on an emergent basis. The MRI can be obtained later if necessary.

3. Treatment considerations include:

C. Treatment requires a combination antimicrobial therapy and glucocorticoids. Definitive treatment usually requires eventual drainage.

Microbiology is variable and depends on the primary site of infection. In some cases, identification of the organism may provide a more information on the primary site or underlying condition yet undiagnosed. Commonly identified pathogens include Streptococcus species and anaerobes such as fusobacterium and enterobacterium commonly due to origination from oral flora.  As with any infection, immunocompromised hosts can present with a wide variety of infectious bacteria, parasites and fungi. Immigrants or foreign travelers may be infested with parasitic infection such as neurocystercercosis.

Current recommendations for an abscess from an oral, ear or sinus source calls for Metronidazole (15mg/kg IV load followed by 7.5mg/kg IV q 6-8hrs) PLUS Penicillin (24 million units daily divided into six doses) PLUS Ceftriaxone (2gm IV every 12 hours). Nafcillin (2gm IV every four hours) or Vancomycin (30mg/kg IV daily divided according to renal function) should be included in any patients for whom S. aureus bacteremia is considered or in patients with a history of penetrating trauma
Antibiotics that do not cross the blood brain barrier should not be used. This includes Aminoglycosides, Erythromycin, Tetracyclines, Clindamycin and the first generation cephalosporins.

Duration of therapy is prolonged, usually six to eight weeks. Further management is geared by follow-up assessment of the clinical course and repeat imaging. Indications for surgical excision include lack of clinical progress or deterioration, increased intracranial process (cerebral edema, intracerebral pressures), or progressive increase in the ring diameter.
Adjunctive use of glucocorticoids should be considered if the patient has signs of cerebral edema, depressed mentation or mass effect demonstrated on imaging.

Our patient’s course:

She was immediately admitted to Neurosurgical care for further management with presumed diagnosis of meningitis vs encephalitis based on her initial head CT. While in the Emergency Department, she did deteriorate from somewhat responsive and following commands to stupor and only minimal response to painful stimuli.

CT 1: Head without contrast: Loss of the gray-white matter interfaces in the left cerebral hemisphere, left frontotemporal parietal area. Effacement of the sulcal and gyral markings.  There is very mild compressive effect on the left frontal horn and body of the lateral ventricle. There is no uncal herniation. There is note of a phlegmonous appearing tissue in the left masticator space.

CT 2: CT Head with IV contrast: Noted difference from noncontrast scan is erosive changes in the left superior molar alveolar ridge appears related to the inferior aspect of the masticator space abscess.

On hospital day 3, follow-up CT #3: showed development of a large intraparenchymal abscess of the left temporal and parietal areas. Etiology was presumed to be from a dental infection eroding thru the bone and leading to masticator muscle abscess seeding to the brain.

The patient continued to deteriorate, undergoing surgical debridement complicated by intracranial hemorrhage. She remains alive today, minimally interactive with her environment requiring fulltime nursing care. She continues to be managed by an  Obstetrician for her developing and apparently healthy fetus and has reached 35 weeks gestation under their close observation.

References:
Southwick, Frederick (May 2009) Treatment and Prognosis of Brain Abscess UpToDate
Southwick, Frederick (May 2009) Pathogenesis, Clinical Manifestations, and Diagnosis
of Brain Abscess UpToDate
Thomas, Lisa (May 2009) Brain Abscess Emedicine

This case discussion presented by Alison Loynd, DO

One Response

  1. I continue to learn from the intern cases and find them fascinating. We have a huge number of patients with severe dental disease. This is exacerbated by lack of dental care coverage by many health insurances. This case points up the fact that prior dental care does not ensure the lack of dental disease.
    Thanks for an excellent discussion of a very interesting and ultimately tragic case.
    Gloria Kuhn

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