Tiago Aguiar

Association between type 1 diabetes mellitus and epilepsy: more than coincidence?

Background Type 1 diabetes mellitus (T1D) patients have an increased risk of seizures at extremes of glycemic control. There is growing evidence about the role of autoimmunity in the epileptogenesis and glutamic acid decarboxylase antibodies (GAD-ab), a well known antibody related to neurologic diseases, can be a link that justifies epilepsy in T1D population. GAD catalyzes the conversion of glutamic acid, the main excitatory central nervous system (CNS) amino acid, into gamma-aminobutyric acid (GABA), the main inhibitory CNS neurotransmitter. GABA-secreting neurons and pancreatic beta cells are the major cells expressing GAD. Seizures may be result of imbalance between excitation and inhibition determined by inhibition of GAD activity caused by autoantibodies. The potential pathogenic role of GAD-ab in neurological disorders is not fully understood, but inhibition of GABA synthesis or interfering with the exocytosis are plausible hypotheses. The spectrum of neurological disorders associated with GAD-ab includes cerebellar ataxia, myoclonus palatal, limbic encephalitis, encephalomyelitis, stiff person syndrome and others.

The Brissaud sign

A 65-year-old man has a three-month history of lumbar back pain and progressive lower extremity weakness due a T6 spinal cord compression secondary to hepatic metastatic carcinoma. Examination revealed, paraplegia, urinary incontinence, T10 sensory level, lower limbs hyperactive deep reflex, and hallux indifferent cutaneous plantar response but with an exuberant fascia lata reflex (Figure). The Brissaud sign, a succedaneum published only 22 days after Babinski’s famous lecture, is a twitch in the lateral portion of the quadriceps muscle on tickling the sole of the foot and represents a proximal component of the flexion reflex synergy owing to pyramidal tract disfunction.

The corneomandibular reflex: a light touch and wide conclusions

The corneomandibular reflex is present when the touching cornea induces an associated chin movement to the opposite side by contraction of the external pterygoid muscle (Figure). This reflex is seen most commonly in acutely ill patients with coma and elevated intracranial pressure, large cerebral hemispheric lesions with secondary brainstem pressure, intrinsic lesions of the upper brainstem or diencephalon, diffuse or metabolic processes, and involvement of corticobulbar pathways in amyotrophic lateral sclerosis or multiple sclerosis. According to Wartenberg, there is hardly a more valuable test than this to uncover a supranuclear lesion of the trigeminal nerve.

Hemichorea in tuberculous meningitis.

We report on a 14 y/o HIV-negative girl with diagnosis of miliary tuberculosis (meningitis and pulmonary disease) who presented with right hemichorea three weeks after initiation of prednisone, rifampin, isoniazide, pyrazinamide and ethambutol. Brain MRI showed ischemic lesions in left caudate and lenticulo-capsular area (Figure). Hemichorea is a rare neurological manifestation of tuberculosis. Basal ganglia infarcts caused by vasculitis probably decreased the GABAergic transmission in indirect basal ganglion pathway causing hemichorea. The major differential diagnoses in acquired hemichorea are Sydenham’s chorea, nonketotic hyperglycemia and cerebral toxoplasmosis. We emphasize the importance of brain MRI in the diagnostic evaluation of these patients.

Delayed hemichorea syndrome associated with nonketotic hyperglycemia

A 69-year-old woman was admitted for investigation of an acute-onset right hemichorea1. T1-weighted brain magnetic resonance imaging (MRI) showed hyperintensity in the left basal ganglia (Figs 1A and B). Although diabetic, she had no hyperglycemia. Interestingly, two weeks earlier, the patient was admitted due to nonketotic hyperglycemia. Brain computed tomography, previously reported as normal (Fig 1C), showed subtle Delayed hemichorea syndrome associated with nonketotic hyperglycemia Sindrome de hemicoreia tardia associada ao estado hiperglicemico nao cetotico Tiago Aguiar, Renata Nogueira, Rafael Vidon, Marcos Martins da Silva, Pericles Maranhao-Filho