This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
[{'content': 'A 10 month old child presents with two weeks history off fever, vomiting and alteration of sensorium Cranial CT scan reveals basal exudates and hydrocephalus, the most likely etiological agent is – \nSelect and explain. \nA. Mycobacterium tuberculosis, B. Cryptococcus neoformans, C. Listera monocytogenes, D. Streptococcus pneumoniae', 'role': 'user'}, {'content': "Answer: A \nExplanation: Insiduous /gradual onset of fever over a duration of two weeks, with features of raised intracranial tension in the form of vomiting and altered sensorium with characteristic basal exudates and hydrocephalus on cranial CT scan are almost characteristic of tuberculous meningitis.\nTUBERCULOUS MENINGITIS \n\nTuberculous meningitis usually arises from the formation of metastatic caseous lesions in the cerebral cortex or meningitis that develops during the lymphohaematogenous spread of primary infection. This initial lesion increases in size and discharges tubercle bacilli in the subarachnoid space.\nThis results in gelatinous basal exudate which interferes in the normal flow of CSF, in and out of the ventricular system at the level of basal cisterns leading to a communicating hydrocephalus.\n\nClinical manifestations of tuberculous meriins\n\nThe clinical course of TB meningitis has three stages -\n\n\nProdromal stage or stage of invasion\n\n\nInsidious onset\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0 o Headache and vomiting\nLow grade fever, loss of appetite\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0 o Photophobia\nDisturbed sleep\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0 o Constipation\n\n2. Stage of meningitis\nSigns of meningeal irritation develops - Neck rigidity, Kernig's sign\n3. Stage of coma\no Loss of consiousness\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0 o Bradycardia\n\nPupils are dilated & fixed\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0 ❑ Chyne-strokes or Biot type of respiration\nEpisodic decerebration\n\nCT findings in TBM\xa0:\n\nBasal cisterns are obliterated by isodense / hyperdense exudate\nPost contrast there is a avid enhancement of the basal meninges extending into the ambient, sylvian, pontine and chiasmatic cisterns.\n\nMeningeal enhancement may continue over the cerebral and cerebellar hemispheres.\n3. Hydrocephalus is present in 45-87% of patients at time of diagnosis.", 'role': 'assistant'}]