More than just a headache: idiopathic intracranial hypertension

Jan 18, 2018

Misdiagnosis leads to compensation claim

In one case*, a 23-year-old mother of one, presented to a general practitioner (GP) member with recent onset of headaches, on the background of obesity and recent childbirth. The examination was unremarkable and she was reassured.

However, her headaches persisted over the next month, and she also complained of blurred vision, neck pain, nausea and vomiting. She could not afford the suggested MRI privately and presented to a tertiary hospital. Investigations including CT, MRI and lumbar puncture were unremarkable, and she was diagnosed with a migraine and discharged. A few months later her headaches and other symptoms returned and progressed.

After receiving treatment for migraines during several consultations, she was readmitted to hospital, where her CT and MRI were again normal. A lumbar puncture, however, revealed an opening pressure of 44 cm H20. The patient was left with a visual deficit and commenced a civil claim against the GP and hospital.

Idiopathic intracranial hypertension (IIH)

Avant has been involved in 20 cases over the past eight years involving IIH in relation to delay or misdiagnosis, and requests for compensation regarding visual loss.

Previously known as benign intracranial hypertension or pseudotumour cerebri, IIH occurs at an incidence of about two diagnoses per 100,000 per year. However, the incidence in young obese women, the most at risk group, is as high as 12 diagnoses per 100,000 per year. Causes of secondary intracranial hypertension include hormonal contraceptives, tetracyclines, vitamin A derivatives, sleep apnoea, systemic lupus erythematosus, chronic kidney disease and others.

The cardinal feature of IIH is headache, usually throbbing in nature, which is worse in the morning combined with coughing and sneezing. However, the features of headaches are variable and nonspecific. Transient and then persistent visual obscurations are common, and usually provide the impetus to consider the diagnosis. There may be pain in the neck and shoulders, and associated nausea and vomiting. There may also be pulsatile tinnitus, peripheral paraesthesia and unsteadiness. All of these are common symptoms with other benign headaches and delay in diagnosis is common.

The most notable examination feature is papilloedema, but this finding may be difficult to assess by the occasional fundoscopist. Visual field loss is important both diagnostically and from a medico-legal standpoint. Other cranial nerve dysfunction may occur, most notably sixth nerve palsy.

The CT is usually normal, as are blood tests and CSF analysis. Some subtle findings on MRI can support the diagnosis, but are not of themselves diagnostic. Magnetic resonance venography is preferred to exclude central venous thrombosis. These investigations are necessary to exclude other causes. Diagnosis is established by measuring an opening pressure on lumbar puncture of greater than 25 cm H20. Drainage of CSF usually produces rapid symptomatic improvement of the headache.

Management involves cessation of any causative agents (although this may not be curative), acetazolamide, drainage of CSF by repeat lumbar puncture or diversion surgery (such as VP shunt). Venous sinus stenting and optic nerve sheath fenestration are other options, all aimed at preventing the complication of visual deficit and blindness. Despite treatment, some degree of permanent visual deficit will occur in up to 25% of patients and this may be disabling in 10%.

Comprehensive medical notes aid defence

In the case above, the patient was left with a visual deficit that significantly impacted her life. A comprehensive clinical examination including a neurological examination and cranial nerve assessment, and excellent medical notes allowed Avant to successfully defend the GP, particularly as she reasonably relied on the investigations and specialist assessments at the hospital.

In Avant’s experience, a constant feature associated with successful litigation is poor documentation. The absence of accurate, contemporaneous notes, including negative and positive features of history and examination, make a successful defence almost impossible to maintain.

Key messages

  • Be aware that there are many causes of headaches, most of them benign, but some are potentially disabling or life threatening.
  • Take note of ‘red flags’ such as morning headache, neurological symptoms, progressive symptoms or failure to respond to treatment. Investigate further or refer when it ‘doesn’t add up.’
  • Refer to an optometrist or ophthalmologist to assess visual fields and papilloedema if the patient complains of blurred vision in the context of a headache.
  • Be sure to document significant positive and negative features of history and examination.

*This case study has been based on a compilation of cases and any relation to actual people is purely coincidental.

More information

Complete our eLearning course, On the record: medical records and documentation and download our factsheet, Medical records – the essentials.

If you are subject to a complaint, visit our website or call our Medico-legal Advisory Service (MLAS) on 1800 128 268 for expert advice, 24/7 in emergencies.

You can also refer to our new handbook for information on how to deal with complaints and obtain CPD points.

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