Acute psychosis: A neuropsychiatric dilemma.

The acute onset of psychotic symptoms in elderly can be the presenting clinical feature for various Central Nervous System as well as other systemic illnesses. The diagnosis and treatment of such presentation require a cautious medical work up and high level of suspicion even if the patient is not showing any cardinal symptoms for organic pathology.

The acute onset of psychotic symptoms in elderly can be the presenting clinical feature for various central nervous system (CNS) as well as other systemic illnesses. The diagnosis and treatment of such presentation require a cautious medical workup and high level of suspicion to rule out organic cause even if the patient does not show any cardinal symptoms of organicity. We present here a 68-year-old person presenting with prominent psychotic symptoms in clear consciousness. The case is discussed in view of multiple etiological possibilities for acute psychosis in the elderly.

CASE REPORT

The case we present here is a 68-year-old male patient who was brought to the hospital with a history of acute onset of severe agitation, extreme fearfulness on seeing his reflection in the mirror or glass screens and refusal of food and water of 1 day duration preceded by low grade fever and head ache of 5 days (untreated). History revealed Class 1 dog bite (unprovoked stray dog bite) 6 months prior with no post exposure antirabies vaccination. Patient was on irregular treatment for hypertension. There was no significant past history of head injury, other medical or mental illnesses including substance use. There was no significant mental/medical illness in the family.

On physical examination, he was afebrile, conscious, and oriented. Systemic examination revealed a pulse of 110/min and blood pressure (BP) of 160/110 mmHg. Plantars were bilaterally extensor. Optic fundi were normal. Mental status examination showed increased psychomotor activity, ideas of reference and visual hallucinations. Primary cognitive functions were intact. Judgment and insight were impaired. Patient was evaluated for an organic cause for acute psychosis. Patient was admitted in an isolation room and all necessary precautions for rabies were taken. With parenteral haloperidol 5 mg patient was sedated. After 10 h of sleep he improved significantly and mini mental status examination (MMSE) showed a score of 26/30. BP came down to 120/80 mm of mercury. Neurologist's opinion suggested a possibility of herpes simplex viral (HSV) encephalitis.

Biochemical investigations and thoracic X-ray were normal. Electrocardiography and electroencephalography were also normal. Magnetic resonance imaging (MRI) brain revealed multiple vascular infarcts, demyelinating patches secondary to vascular/toxic/inflammatory etiology suggesting possible diagnosis of multiple vascular infarcts in different stages of evolution/rabies encephalitis [Figure 1]. A contrast MRI brain after 48 h too revealed the same. Lumbar puncture was refused by the patient and the relatives. Hence virological studies could not be carried out. Patient was treated with haloperidol 5 mg intramuscular injection once daily for 2 days and injection acyclovir 500 mg intravenously thrice daily for 5 days as per neurophysicians advice. Examination on day 3 of treatment showed normal mental status, a MMSE score of 28/30 and normal systemic examination. Patient was discharged on the 6th day on son's request. On review after 2 weeks, the patient was asymptomatic.

Figure 1

Magnetic resonance imaging brain shows multiple vascular infarcts

DISCUSSION

Acute psychotic episodes in elderly are not uncommon presentations. However, unlike in young, psychosis in elderly has different connotations. Psychosis in the elderly can be a presenting feature for various CNS as well as other systemic diseases. In acute psychosis, the organic of symptoms is indicated by a rapidly fluctuating course, the presence of visual hallucinations and absence of mood congruent delusions. Various differential diagnoses for psychotic behavior in elderly can be functional psychotic disorders and psychoses secondary to organic disease. After initial medical and radiological workup, we could narrow down the differential diagnoses of psychosis to rabies encephalitis (h/o dog bite without any post exposure prophylaxis, demyelinating patches on MRI), HSV encephalitis (h/o fever and headache and demyelinating patches on MRI) and cerebrovascular accident (CVA) (h/o headache, hypertension and multiple infarcts on MRI). With a history of Class 1 dog bite and no post exposure prophylaxis our first consideration for differential diagnosis was rabies. Rabies is acute, progressive encephalitis caused by a neurotropic ribonucleic acid virus of the rhabdoviridae family. Though rabies is uncommon in the developed world, it is a major public health problem in developing countries.[1] The psychiatric symptoms of agitation, hallucinations and alternating mood swings are often reported in rabies, especially in initial stages which finally progresses to other characteristic symptoms of disease that is, convulsions, coma and death.[2] The symptoms of rabies encephalitis are invariably progressive, patient becomes comatose and subsequently ends in death. However the patient's improvement so early in the intervention ruled out the diagnosis of rabies.

We also considered HSV encephalitis as patient presented with h/o fever and headache and altered behavior. Encephalitis due to HSV infection may have an atypical presentation with acute psychotic picture.[3] There are many case reports in literature of patients presenting with purely behavioral anomalies with or without psychosis that are eventually diagnosed with HSV encephalitis and treated successfully with antiviral therapy.[45] Generally, patients have a fever with at least one neurological deficit. The definitive diagnosis requires cerebrospinal fluid studies unfortunately because of patient's refusal and considering the possibility of rabies lumbar puncture was not done. The patient was thus started on empirical acyclovir injections. When brain MRI with contrast was done, the diagnosis of CVA looked more likely. Acute psychosis secondary to CVA without any physical deficit or impaired cognitive function is not often reported in the literature.[6] This may be due to nonrecognition of vascular events in many patients. When acute psychosis presents clinically with sudden onset of symptoms, neuro imaging reveals acute vascular events and symptoms are reversible within a certain period of time with or without treatment, then a diagnosis of organic psychosis secondary to cerebrovascular event should be considered.

CONCLUSION

The case is presented in view of various diagnostic possibilities in an elderly patient presenting with acute psychosis under a background history of Class 1 dog bite and faced with difficulty to carry out investigations.