Expert Opinion :
This child has a bulging anterior fontanelle and is toxic. Thus he seems to have a CNS disease. The stiffness of the neck could be due to retropharyngeal disease or meningeal irritation. With a CNS disease, meningitis seems likely. With toxicity, mostly a bacterial infection seems a possibility. Thus at a glance bacterial meningitis seems likely. Now the decreased movement in the right lower limb could be hemiparesis, myositis or arthritis. With hemiparesis, the lower limb is usually in the extended position. A flexed position at the hip goes against the hemiparesis. A flexed position is seen whenever there is pain and the child tries to keep the limb in most comfortable position. Thus, arthritis of the hip seems likely and with bacterial meningitis, septic arthritis is a possibility. Electrolyte imbalance such as hypokalemia, pseudoparalysis such as scurvy is unlikely due to single limb affection.
Now the bulging anterior fontanelle. This could be a sign of raised intracranial tension {ICT} or it could be due to a space occupying lesion such as subdural collection, or hydrocephalus. However other features such as decerebration, squint do not seem to be apparent. Thus raised ICT alone does not seem to explain bulging anterior fontanelle and one must suspect subdural collection in this child. With a strong possibility of bacterial meningitis, and septic arthritis, there is a good possibility of subdural empyema in the child. Thus, likely diagnosis is bacterial meningitis with subdural empyema and septic arthritis.
This child on history was found to have fever for 7 days with decreased movement of right lower limb for 2 days. On examination, he had neck stiffness, pain on extending the hip, normal power in all limbs, bulging anterior fontanelle and signs of raised ICT such as bradycardia and hypertension. Investigations showed WBC count of 31,000, cumm with polymorphic predominance, elevated C-reactive proteins, thrombocytopenia. CT brain showed subdural empyema which was drained surgically. USG of right hip showed collection in the hip joint which was also drained. CSF analysis done later once condition stabilized showed meningitis.
Thus, by seeing the child lying on the bed can also reveal lot of information.