Case 3: Sudden Loss of Vision in a 54 year old Man

A 54 year old man presented urgently to his local practice with sudden loss of vision in his R eye. He gave a history of loss of vision that occurred at 8am in the morning with no pain, photophobia or redness in his eye. He denies any previous trauma to the eye, gradual visual loss or any other problems with his vision until this morning.

He has a background of poorly controlled type II diabetes, mild angina and had previous episodes of recurrent transient ischaemic attacks. His HbA1C was elevated at 12 and he has a poor compliance with his hypoglycaemic medications. A carotid Doppler was arranged after his last TIA showing up to 50% stenosis of both carotid arteries. He is an ex-smoker, having quitted smoking 5 years ago before which he smoked 20 a day.

On examination, the gentleman has reduced visual acuity to counting fingers in his R eye, and normal vision in the L eye. His right pupil responded sluggishly to light and he has a relative afferent pupillary defect in his R eye. Fundoscopic examination revealed the following.



What is the likely diagnosis?



http://www.bnretina.com/CommonConditions/occlusion.jsp


The patient gives a history of sudden painless loss of vision suggesting a few possible diagnoses:

-proliferative diabetic retinopathy is possible in somebody who is a poorly controlled diabetic.
-central retinal vein occlusion
-central retinal artery occlusion

The fundoscopic examination points to the diagnosis of central retinal artery occlusion, with its characteristic appearance of a pale retina with cherry red spot.

Central retinal artery occlusion is a cause of sudden visual loss and should be suspected in those with vascular problems. The patient normally presents with a history of acute and painless visual loss with a relative afferent pupillary defect. The latter is demonstrated by the swinging flashlight test and the sign is also known as a Marcus Gunn pupil. It is important to distinguish this from other causes of sudden blindness such as central retinal vein occlusion because the management can be completely different.

On fundoscopic examination, the characteristic pattern is that of a pale retina with a cherry red spot in the middle due to relative ischaemia of the choroid, however this pattern only accounts for the initial 48 hours. Neovascularisation changes may occur, especially in the long term, possibly due to build up of angiogenic factors as a result of the ischaemia.

The cause of central retinal artery occlusion may include atheroembolic fragments, such as that arising from mural thrombus in the heart or carotid stenosis. Other causes include vasculitides such as giant cell arteritis and sudden increases in intraocular pressure. It should be noted that giant cell arteritis causes visual loss usually via anterior ischaemic optic neuropathy, rather than central retinal artery occlusion. Since this is a treatable cause, it is important to exclude the other signs such as jaw claudication, scalp tenderness and muscle pains and aches.

The majority of cases of central retinal artery occlusion is probably due to carotid artery embolism. This should be suspected in patients with cardiovascular risk factors, such as previous myocardial infarcts, strokes or transient ischaemic attacks. Amaurosis fugax is a transient form of visual loss that may predict the occurence of a cerebrovascular event.

Central retinal artery occlusion is a recognised emergency because it can cause irreversible sight loss if left untreated. Measures such as digital massage may help to dislodge the embolus from the eye. Lowering of the intraocular pressure may be attempted using acetazolamide or beta blockers. Use of other agents such as vasodilators of fibrinolytic agents are still being researched. Laser therapy may help to treat neovascularisation and its complications.

Case 2: Poor development in an Infant

A 7 month old infant has been brought to the attention of the doctor because of concerns of developmental delay. He was born prematurely at 34 weeks and was delivered by normal vaginal delivery. Apgar score performed at 1 and 5 minutes were 7 and 9 respectively. He was subsequently admitted to the Special Care Baby Unit for supportive care. His mother noted that he is not achieving the normal developmental milestones at 6months.

His charts showed his growth and height were approx 75th percentile and head circumference 50th percentile. On examination, the infant was irritable and was able to visually fixate on objects. Head control was poor and Moro's reflexes are present. Tendon reflexes were brisk and plantar responses were upgoing. Muscle tone was noted to be increased and spasticity in the lower limbs are apparent.


What are the likely diagnoses?




In considering infants with global developmental delay, it is important to classify the disorder into two main groups: static encephalopathy and progressive encephalopathy. It is important to note whether there is a trend of poor development - in a patient who is deteriorating rapidly then more investigations are likely to be needed. There is a wide variety of presenting symptoms including feeding problems, falling behind developmental milestones, muscle or sensory problems, speech and swallowing difficulties.

One of the best known reasons of static encephalopathy is cerebral palsy, which is caused by early damage to the brain at or around the time of birth. Causes can be variable and include hypoxic injuries, vascular strokes and certain infections such as Toxoplasma or Herpes simplex. MRI can be performed to assess the severity of this disease. Clinically, the infant may display a certain degree of spasticity and may exhibit speech and language disorders. There are some types of cerebral palsy where spasticity does not feature, eg ataxic or athetoid types.

Progressive encephalopathy is suspected when there is a persistent decline in development, vision, hearing or irritability in an infant. Sometimes, there is concomitant seizures and movement disorders, which can be confused with cerebral palsy. Causes of this can include rare metabolic or degenerative diseases, such as Friedriech's ataxia, ataxia telangiectasia or inherited leukodystrophies. Clinical correlation depends on the region of brain affected- damage to the gray matter can lead to cognitive defects and seizures; white matter lesions lead to spasticity and motor problems.

Several types of leukodystrophies exist in infants, and these are due to defects in the myelin production that ensure good conduction in the nerves. Examples include Tay Sachs disease, Alexander disease and metachromatic leukodystrophy. Although rare, it is important to recognize these as potential causes of developmental problems. In a lot of cases, child abuse or neglect is suspected and social services are often involved.

In conclusion, cerebral palsy is one of the commonest causes of poor development and static encephalopathy. It must be separated from progressive encephalopathy where the damage to the brain is onging. Prognosis is poor and often there are no available cures for these rare disorders.

Case 1: Young woman with dyspnoea

A 23 year old lady presented with progressive worsening of shortness of breath on exertion and fatigue. Initially, she was able to walk three blocks but now she is struggling to walk one block and is confined to her own house. At presentation, she has a dry cough and has no fevers, night sweats or weight loss or ankle swelling.

She has no recent travel history, does not take illicit drugs and is a non-smoker. She had not come into contact with anyone with infection, and does not have any family history of asthma, hayfever or cancer. She has no exposure to pets and has no allergies.

On examination, she appeared to be in slight respiratory distress. Normal blood pressure and pulse with reduced oxygen saturation that was corrected with 2L oxygen. Cardiovascular examination revealed L parasternal heave, and a loud second heart sound with a positive Kussmaul's sign. Lung fields were clear.

Blood tests were unremarkable. Chest radiograph (illustrated) showed a prominent R pulmonary artery segment with tapering of distal vessels on the left. ECG showed a right bundle branch block with right axis deviation and atrial enlargement. Spirometry tests were normal that excluded significant lung parenchymal disease.

What are the likely diagnoses?



















http://www.med.yale.edu/intmed/cardio/imaging/cases/hypertension/index.html


In this scenario, the young age of the patient and the clinical presentation suggested the following disorders:

• Pulmonary embolism - always need to exclude this as a cause of acute dyspnoea. A CTPA scan performed subsequently excluded emboli in the major vessels.
• Pulmonary hypertension - this is probably the most likely given the clinical findings. Pulmonary arterial pressure can be measured with R heart catheterisation. The normal pressure in the pulmonary artery is around 12-15 mmHg, and hypertension when the pressure exceeds 25mm Hg.

According to the WHO, pulmonary hypertension has been classified as follows:

• Pulmonary arterial hypertension
• Pulmonary venous hypertension (ie L heart failure)
• Hypertension secondary to hypoxaemia
• Thromboembolic hypertension (ie PE)
• Miscellaneous hypertensive disorders

The treatment of pulmonary arterial hypertension is usually with vasodilators, such as nitric oxide, calcium channel blockers, sildenafil (aka Viagra), prostanoids and the endothelin-receptor antagonist bosenta. One must note that there is a rare variant where these treatments can potentially worsen the condition (pulmonary veno-occlusive disease). Failing all these, the only other potential option is double lung transplant.