Thrombotic thrombocytopenic purpura (TTP) is characterised by a thrombotic, haemolytic microangiopathy leading to microvascular occlusion, haemolysis and ischaemic dysfunction of various organs including the brain. TTP may present with a variety of neurological symptoms, including headache, focal deficits, seizures and coma. The authors describe a 55-year-old man presenting with abdominal pain and rapidly progressive deterioration into coma without focal neurological deficits or seizures. A concomitant, transient, rapid increase in blood pressure raised the suspicion of a hypertensive crisis. Yet, our patient did not improve after vigorous treatment with antihypertensives. Brain imaging excluded a hypertensive leucoencephalopathy. Despite the absence of a disintegrin and metalloproteinase with a thrombospondin type 1 motif member 13 (ADAMTS13) deficiency, the diagnosis idiopathic TTP was made after excluding secondary causes of TTP. Upon treatment with plasma exchange, corticosteroids and vincristin our patient gradually improved. On discharge to a rehabilitation centre he was awake and alert, had minor cognitive deficits and a mild proximal tetraparesis consistent with a critical illness poly(neuro)myopathy.

Thrombotic thrombocytopenic purpura (TTP) is a rare and potentially fatal microvascular occlusive disease. Prior to the use of plasma exchange and treatment with corticosteroids, it had a case fatality rate of over 90%. Nowadays, full recovery is possible when vigorous treatment is started early in the course of the disease. However, TTP remains a diagnostic challenge; in particular, if symptoms are atypical and laboratory results are inconclusive. In over 90% of cases TTP is complicated by neurological symptoms varying from headache, focal deficits to seizures and coma.^{1 2} Coma is in most cases preceded by focal deficits or seizures. Yet, in a descriptive study by Scully et al, 8% of all patients presented with coma as the predominant neurological feature of TTP.³ Therefore, it is important to increase the awareness that a coma even without premonitory focal neurological deficits and seizures may be a complication of untreated TTP; in particular, because treatment delay may negatively influence clinical outcome and could be fatal.

The authors present a 55-year-old Caucasian man, who had a history of hypertension, hypercholesterolaemia and diabetes mellitus—the latter being complicated by a diabetic retinopathy and peripheral neuropathy. His medication regimen included antihypertensives, a statin and oral antidiabetics, which had not changed in recent years. He was admitted to hospital by his general practitioner with a 2-day history of abdominal and lower back pain and light-headedness. Physical examination revealed several bruises, no petechiae or other abnormalities, a blood pressure of 160/80 mm Hg and no fever. Laboratory results showed a direct-antiglobulin-test negative haemolytical anaemia with red cell fragments, thrombocytopenia, decreased haptoglobin, elevated bilirubin, lactate dehydrogenase (LDH), urea and creatinin consistent with a diagnosis of TTP. Urea and creatinin levels remained high but stable during the next days. Plasma exchange and high-dose prednisone were started. Yet, a few days later his consciousness decreased during plasma exchange. Prior to plasma exchange, our patient did not receive analgesics or sedatives. Neurological examination revealed a Glasgow Coma Score (GCS) of E4M5V3 without focal neurological deficits except for an extensor response at both sides. Because of a blood pressure of 230/130 mm Hg prior to plasma exchange, hypertensive encephalopathy was considered initially. However, despite aggressive blood pressure lowering, our patient deteriorated to GCS 3, needed to be intubated and ventilated, and was transferred to the intensive care unit (ICU). Before this deterioration the patient did not receive analgesics or anaesthesia. He only received midazolam during the next 2 days at the ICU because a non-convulsive status epilepticus was suspected, and no analgesics, such as fentanyl or morphine, only acetaminophen. Repeated EEGs showed no evidence for a non-convulsive status epilepticus. Upon further treatment with plasma exchange and prednisone he improved and 2 days later his GCS was E4M6V4 Because a hypertensive crises was suspected to have caused the microangiopathic haemolysis, plasma exchange was stopped and his prednisone dose was lowered. Nevertheless, despite adequate control of his blood pressure, he became comatose again (GCS 3). Plasma exchange was restarted and the prednisone dosage increased upon which our patient gradually improved to E4M6V4. After a week, he was extubated and transferred to the haematology ward.

Reversible leucoencephalopathy, in particular due to a hypertensive crisis, toxic-metabolic causes of coma (in particular the use of sedatives/analgesics and uraemia) and (non-convulsive) status epilepticus.

Monitoring on ICU, plasma exchange, corticosteroids and vincristin.

Our patient gradually improved after plasma exchange and treatment with oral corticosteroids was started. He was transferred to the department of haematology awake and alert and with a GCS of 14 where vincristin was added to his treatment. At discharge to a rehabilitation centre he only had minor cognitive deficits and a minimal proximal tetraparesis without other focal neurological deficits—the latter being consistent with a critical illness poly(neuro)myopathy.