Lumbar puncture in subarachnoid haemorrhage: a necessary evil?
Authors: Steeds RP , Bulugahapitiya T , Muthusamy R 
Published: May 2014

A 70-year-old lady was admitted following the sudden onset of a severe, throbbing headache 7 days previously. The headache was occipital in location, with radiation to the back of the neck and both shoulders. The patient had vomited twice at the onset of the pain but, although initially severe, the headache had gradually resolved without further complication. The patient had a history of hypertension, controlled on bendrofluazide 2.5 mg once daily. A mastectomy had been performed in 1992 for carcinoma of the breast.

Clinical examination revealed a sinus tachycardia 120 beats per minute and systolic hypertension 170/80 mmHg. Examination was otherwise unremarkable. Investigations included a normal full blood count, liver function tests, bone profile, random glucose, and electrocardiogram. Computed tomography scan of the head was normal. The only abnormality was the finding of a low sodium 132 mmol/litre, attributed to the diuretic, and serum electrolytes were otherwise unremarkable. The patient was discharged as she was asymptomatic and the sinus tachycardia had settled.

Unfortunately, the patient was re-admitted the following day complaining of numbness on the right side of the face, together with low back pain. Clinical examination revealed mild cerebellar ataxia. A lumbar puncture was performed with the isolated finding of xanthochromia. A cell count was not performed on the cerebrospinal fluid (CSF). Subsequent cerebral angiography documented a right posterior communicating artery aneurysm, which was clipped 3 days later. The patient was discharged 10 days later with no neurological deficit.

A 37-year-old lady was admitted following the sudden onset of a severe occipital headache 5 days previously. The headache had failed to resolve on simple analgesics. She had vomited twice and had developed mild photophobia. There were no apparent precipitants for the pain and there was no other relevant history.

Clinical examination was unremarkable, except for the finding of mild neck stiffness and photophobia. The patient had an elevated white cell count (14.9 × 109/litre) but full blood count, serum electrolytes and glucose were otherwise normal. The initial report of the computed tomography scan of the head was normal, although a later review raised the possibility of hydrocephalus.

A lumbar puncture was performed with the finding of xanthochromia, CSF red blood cells 25 000 and CSF white cell count 200 (90% polymorphs). No organisms were seen. CSF opening pressure was 12 cm. The patient was transferred to the tertiary centre and she underwent cerebral angiography which documented a left posterior cerebral artery aneurysm. This was embolized at surgery 5 days later. Postoperative recovery was complicated by communicating hydrocephalus with a CSF pressure of 40 cm, which responded well to lumbar puncture. The patient was discharged 10 days later with no neurological deficit.

A 31-year-old lady was admitted following the sudden onset of headache 4 hours before admission. The headache was generalized, sharp in nature and associated with two episodes of vomiting. There was no neck stiffness and no photophobia. There were no other relevant features on the history.

Clinical examination revealed a stable pulse rate of 72 beats per minute, blood pressure 130/76 mmHg and mild neck stiffness but no other focal deficit. The patient had an elevated white cell count (16.4 x 109/litre) but full blood count, serum electrolytes, and glucose were otherwise normal. Computed tomography scan of the head was normal. Lumbar puncture was performed, with the finding of 101 000 red cells, 125 white cells (60% polymorphonuclear leucocytes; 40% lymphocytes) but no xanthochromia. The patient was transferred to the tertiary neurosurgical centre, where she underwent cerebral angiography. This documented an aneurysm arising from the left internal carotid artery, with a proximal daughter aneurysm. These were clipped at surgery and the patient was discharged 10 days later with no neurological deficit.