In everyday clinical practice, neurologists frequently encounter complex clinical cases in which a full analysis of several variants are essential to reach the right diagnosis. The resolution of a doubtful case may rely on the recognition of a very specific diagnostic clue. The objective of this report was to describe a case in which the prompt recognition of a very subtle imaging feature in the emergency room could have precluded further extensive diagnostic investigations.
case rePorTA 34-year-old woman came into the Emergency department with a worsening headache. The symptoms had begun two weeks earlier, with a holocranial pulsatile headache that gradually worsened and became unbearable in the preceding three days. In association with the pain, she complained of nausea, vomiting and intolerance to movement, light and sound. As relevant medical history, she had dyslipidemia and was taking anphepramona for obesity. She had suffered occasional headaches in the past, but never of that intensity. She had already used several over the counter analgesics and nonsteroidal anti-inflammatory drugs with no relief.Neurologic examination disclosed left eye ptosis, which she claimed to be preexisting (Fig A), confirmed on an old photograph. Cerebrospinal fluid analysis was normal. A magnetic resonance angiogram (MRA) of the internal carotid artery (ICA) demonstrated no signal within left ICA (Fig B) absTracT At times in clinical neurology, the identification of a subtle clinical or radiological sign can lead to prompt diagnosis of a very rare or difficult case. We report on a patient who presented with untreatable headache and unilateral ptosis. Computed tomography (CT) scan of the head did not reveal any structural cause. Magnetic resonance angiogram showed absence of left internal carotid artery, which was eventually confirmed by a catheter angiography. Reviewing the case, it emerged that a feature on the initial CT scan "bone window" would have confirmed the diagnosis, had it been searched for: the underdeveloped carotid canal, which is a consequence and a marker of internal carotid artery agenesis.Key words: carotid artery agenesis, Horner syndrome, carotid canal underdevelopment, computed tomography. resumo Em algumas circunstâncias, o reconhecimento de um sinal clínico ou radiológico sutil pode tornar simples o diagnóstico de um caso raro ou muito difícil em neurologia clínica. Relatamos o caso de uma paciente que apresentava cefaleia intratável e ptose palpebral unilateral. A tomografia computadorizada (TC) de crânio não permitiu identificar nenhuma causa estrutural. A ressonância magnética evidenciou ausência da artéria carótida interna esquerda, posteriormente confirmada por arteriografia convencional. Retrospectivamente, descobriu-se que um dado da janela óssea da primeira TC de crânio teria confirmado o diagnóstico, tivesse ele sido pesquisado: o hipodesenvolvimento do canal carotídeo, que é uma consequência e um marcador de agenesia da artéria carótida interna.Palavras-Chave: agenesia da artéria carótida, sínd...