Self-assessment corner 627 Sudden right-sided hemiparesis in a middle-aged woman J S Mehta, M M Sharr (figure). ~ ~ ~ ~ ~ ~. iE. . . . !.;: _ Departmnent of Neurosurgery, King's College Hospital, Denmark Hill, London SE5 9RS, UK J S Mehta ~~~~ ~ .... M M Sharr Correspondence to Mr MM Sharr Accepted 10 March 1998 Figure Cranial CT scan ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~...... .. Questions 1 What three features does the CT scan show ? 2 What is the phenomenon called whereby the intracranial lesion is on the same side as the focal neurological signs ? 3 How is it caused in this case ? Downloaded from https://academic.oup.com/pmj/article/74/876/627/7059911 by guest on 11 April 2024 A 58-year-old woman presented as an emergency having been found collapsed at home. She had a 2-hour history of difficulty moving her right limbs and problems with her speech. She had been active prior to the onset of symptoms. Clinical examination of the cardiovascular and respiratory systems was unremarkable. She was fully orientated with a Glasgow Coma Scale (GCS) score of 14/15 (E4 V4 M6), with normal sized and normal reacting pupils. There was right-sided weakness of the lower facial muscles and increased tone and reduced power (3/5) of the right limbs. Both plantar responses were extensor, but there were no reflex or sensory abnormalities. Full blood count, urea and electrolytes, clotting function, electrocardiogram and chest X-ray were all normal. Two days after admission she deteriorated to a GCS of 10/15 (E3 V2 M5). A computed tomography (CT) scan revealed a right-sided high-density collection with associated mass effect Self-assessment corner 628 Answers QUESTION 1 acute subdural haematoma; marked mass effect compressing the right lateral ventricle and displacing the midline structures; contralateral hydrocephalus. Right-sided Learning points * a Kernohan's notch phenomenon is a poor prognostic indicator ipsilateral hemiparesis to fully assess the patient * it is essential the patient begins rehabilitation soon after surgery * MRI should be done in cases presenting with QUESTION 2 Kernohan's notch. 1 Kernohan JW, Woltman HW. Incisura of the crus due to contralateral brain tumor. Arch. Neurol 1928;1:274-87. 2 Zafonte RD, Lee CY. Kernohan-Woltman notch phenomenon: an unusual cause of ipsilateral motor deficit. Arch Phys Med Rehabil 1997;78:543-5. 3 Jones KM, Seeger JF, Yoshino MT. Ipsilateral motor deficit resulting from a subdural hematoma and a Kernohan notch. Am J Neuroradiol 1991;12:1238-9. 4 Gentry LR, Godersky JC, Thompson BH. MR imaging of head trauma: review of the distribution and radiopathologic features of traumatic lesions. Am J Neuroradiol 1988;9:10110. 5 Jennett B, Teasdale G, Braakman R, Minderhoud J, Heiden J, Kurze T. Prognosis of patients with severe head injury. Neurosurgery 1979;4:283-9. 6 Zafonte RD, Hammond F, Mann N, Wood D, Black K, Millis S. Relationship between Glasgow Coma Scale and functional outcome. Am J Phys Med Rehabil 1996;75:364. Downloaded from https://academic.oup.com/pmj/article/74/876/627/7059911 by guest on 11 April 2024 QUESTION 3 of the brainstem. Large haematomas can Displacement of the midbrain away from the produce a direct compressive or diffuse ischaehaematoma leading to contralateral compres- mic necrosis if the intracranial pressure or cersion of the cerebral peduncle. Since this is ebral reaches a sufficient perfusion pressure above the medullary pyramidal decussation, it level.2 produces signs ipsilateral to the haematoma. Magnetic resonance imaging (MRI) has been shown to be superior to CT in the detecDiscussion tion of traumatic lesions, brainstem, or white matter injuries and, in view of the other possiThe phenomenon of compression of the crus ble diagnoses, its use has been advocated to cerebri against the free edge of the tentorium assess the full spectrum of lesions in unusual cerebelli by a contralateral supratentorial mass presentations.4 was first demonstrated by Kernohan and WoltThe phenomenon itself, in heralding a man in 1928 at the Mayo Clinic.' The transtentorial herniation with descending syndrome was first noted in a patient with a brainstem displacement and cisternal comprimary brain tumour, however, it is also seen, pression, may lead to a poor prognosis with a although rarely, after traumatic brain injuries.2 of than 50% in severe cases.5 The compression causes grooving with under- mortality CTgreater and the initial severity However, scanning lying tissue damage in the anterolateral aspect as indicated by GCS, may not be predictive of of the cerebral peduncle.' In trauma, the eventual function if rehabilitation is early condition is due to the effect of significant shift undertaken.6 secondary to oedema or haemorrhage.3 The Following craniotomy and evacuation of the resulting compressive forces cause the herniat- haematoma the patient's right-sided weakness ing midbrain to impinge on the contralateral gradually improved and 5 days later she was edge of the tentorium, hence damaging the transferred for further rehabilitation. descending corticospinal and corticobulbar tracts. Final diagnosis Other possible causes of an ipsilateral hemiparesis include a primary brainstem lesion, a Right-sided acute subdural haematoma causcontralateral contusion, pressure necrosis secondary to elevated intracranial pressure, or ing ipsilateral physical signs. arterial infarction.4 Primary brainstem lesions Keywords: hemiparesis; Kernohan's notch tend to produce severe and prolonged impairacknowledge the assistance of Miss Sarah Jane Smith, ment in the level of consciousness, associated We Department of Anatomy & Cell Biology, Guy's Hospital, in with typical damage in the dorsolateral region production of the illustration.